ncl30486 - dimmable power factor corrected led driver• cc / cv accurate control vin up to 320 v...
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© Semiconductor Components Industries, LLC, 2020
August, 2020 − Rev. 01 Publication Order Number:
NCL30486/D
Dimmable Power Factor
Corrected LED Driver
NCL30486
The NCL30486 is a power factor corrected flyback controllertargeting isolated constant current LED drivers. The controlleroperates in a quasi−resonant mode to provide high efficiency. Thanksto a novel control method, the device is able to tightly regulate aconstant LED current from the primary side. This removes the needfor secondary side feedback circuitry, its biasing and for anoptocoupler.
The device is highly integrated with a minimum number of externalcomponents. A robust suite of safety protection is built in to simplifythe design. This device is specifically intended for very compact spaceefficient designs and supports analog and digital dimming with twodedicated dimming inputs control ideal for Smart LED Lightingapplications.
Features• High Voltage Startup
• Quasi−resonant Peak Current−mode Control Operation
• Primary Side Feedback
• CC / CV Accurate Control Vin up to 320 V rms
• Tight LED Constant Current Regulation of ±2% Typical
• Digital Power Factor Correction
• Analog and Digital Dimming
• Cycle by Cycle Peak Current Limit
• Wide Operating VCC Range
• −40 to + 125°C
• Robust Protection Features♦ Brown−Out♦ OVP on VCC♦ Constant Voltage / LED Open Circuit Protection♦ Winding Short Circuit Protection♦ Secondary Diode Short Protection♦ Output Short Circuit Protection♦ Thermal Shutdown♦ Line over Voltage Protection
• This is a Pb−Free Device
Typical Applications• Integral LED Bulbs
• LED Power Driver Supplies
• LED Light Engines
SOIC−9CASE 751BP
See detailed ordering and shipping information on page 27 ofthis data sheet.
ORDERING INFORMATION
MARKINGDIAGRAM
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1
9
L30486 = Specific Device CodeXX = VersionA = Assembly LocationL = Wafer LotYW = Assembly Start Week� = Pb−Free Package
L30486XXALYWX
�
1
9
1
2
3
4
5
8
6
7
10
ZCD
COMP
CS
GND DRV
VCC
HV
PDIM
ADIM
PIN CONNECTIONS
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.
.
Aux.
NCL30386
1
2
3
4
5
8
6
7
10
ADIMV
PWM signal
Figure 1. Typical Application Schematic for NCL30486
9
PIN FUNCTION DESCRIPTION NCL30486
Pin N� Pin Name Function Pin Description
1 ADIM Analog dimming This pin is used for analog control of the output current. Applying a voltage varyingbetween VDIM(EN) and VDIM100 will dim the output current from 0% to 100%.
2 COMP OTA output for CV loop This pin receives a compensation network to stabilize the constant voltage loop
3 ZCD Zero crossing DetectionVaux sensing
This pin connects to the auxiliary winding and is used to detect the core reset event.This pin also senses the auxiliary winding voltage for accurate output voltage control
4 CS Current sense This pin monitors the primary peak current.
5 GND − The controller ground
6 DRV Driver output The driver’s output to an external MOSFET
7 VCC Supplies the controller This pin is connected to an external auxiliary voltage.
8 PDIM PWM dimming This pin is used for PWM dimming control. An optocoupler can be connected directlyto the pin if the PWM control signal is from the secondary side
9 NC creepage
10 HV High Voltage sensing This pin connects after the diode bridge to provide the startup current and internalhigh voltage sensing function.
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INTERNAL CIRCUIT ARCHITECTURE
Figure 2. Internal Circuit Architecture NCL30486
LeadingEdge
Blanking
Power factor andConstant −current control
Zero crossing detection Logic(ZCD blanking, Time−Out, …)
Aux . Winding Short Circuit Prot .
Constant VoltageControl
Valley Selection
Frequency foldback
VCV
VREFX VHVdiv
Max. PeakCurrent Limit
COMP
CS
CS ShortProtection
Winding /Output diode
SCP
Maximumon−time
Driverand
Clamp
DRVLine
feed−forwardQ_drv
VHVdiv
Aux_SCP
Slow_OVP
Fast_OVP
Slow_OVP
Ipk_maxSTOP
WOD_SCP
CS_short
HVBrown −OutLine OVP
VHVdiv
BO_NOK
VHVdiv
STOP
VCC ManagementFault
Management
ThermalShutdown
VCC
VCCOVP
UVLO
OFF
VCC_OVP
Fast_OVP
Aux_SCP
STOP
CS_short
GND
Q_drvS
R
Q
Q
VDIMA dc_DIM
HVStartup
ADIMAnalog
Dimming
PDIMPWM
Dimmingdc_DIM
VDIMA
Standby
Enable
Enable
ZCD
Standby
CS_reset
VREFX
Enable
L_OVP
L_OVP
dimCV_mode
dimCV_mode
dimCV_mode
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MAXIMUM RATINGS TABLE
Symbol Rating Value Unit
VCC(MAX)ICC(MAX)
Maximum Power Supply voltage, VCC pin, continuous voltageMaximum current for VCC pin
−0.3 to 30Internally limited
VmA
VDRV(MAX)IDRV(MAX)
Maximum driver pin voltage, DRV pin, continuous voltageMaximum current for DRV pin
−0.3, VDRV (Note 1)−300, +500
VmA
VHV(MAX)IHV(MAX)
Maximum voltage on HV pinMaximum current for HV pin (dc current self−limited if operated within the allowed range)
−0.3, +700±20
VmA
VMAXIMAX
Maximum voltage on low power pins (except pins DRV and VCC)Current range for low power pins (except pins DRV and VCC)
−0.3, 5.5 (Note 2)−2, +5
VmA
RθJ−A Thermal Resistance Junction−to−Air 210 °C/W
TJ(MAX) Maximum Junction Temperature 150 °C
Operating Temperature Range −40 to +125 °C
Storage Temperature Range −60 to +150 °C
ESD Capability, HBM model except HV pin (Note 3) 4 kV
ESD Capability, HBM model HV pin 1.5 kV
ESD Capability, CDM model (Note 3) 1 kV
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionalityshould not be assumed, damage may occur and reliability may be affected.1. VDRV is the DRV clamp voltage VDRV(high) when VCC is higher than VDRV(high). VDRV is VCC otherwise.2. This level is low enough to guarantee not to exceed the internal ESD diode and 5.5 V ZENER diode. More positive and negative voltages
can be applied if the pin current stays within the −2 mA / 5 mA range.3. This device series contains ESD protection and exceeds the following tests: Human Body Model 4000 V per Mil−Std−883, Method 3015.
Charged Device Model 1000 V per JEDEC Standard JESD22−C101D.4. This device contains latch−up protection and exceeds 100 mA per JEDEC Standard JESD78.
ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V)For min/max values TJ = −40°C to +125°C, Max TJ = 150°C, VCC = 12 V)
Parameter Test Condition Symbol Min Typ Max Unit
HIGH VOLTAGE SECTION
High voltage current source VCC = VCC(on) – 200 mV IHV(start2) 3.9 5.1 6.2 mA
High voltage current source VCC = 0 V IHV(start1) − 300 − �A
VCC level for IHV(start1) to IHV(start2) transition VCC(TH) − 0.8 − V
Minimum startup voltage VCC = 0 V VHV(MIN) − 17 − V
HV source leakage current VHV = 450 V IHV(leak) − 4.5 10 �A
Maximum input voltage (rms) for correct operation ofthe PFC loop
VHV(OL) 320 − − V rms
SUPPLY SECTION
Supply VoltageStartup ThresholdMinimum Operating VoltageHysteresis VCC(on) – VCC(off)Internal logic reset
VCC increasingVCC decreasingVCC decreasing
VCC(on)VCC(off)
VCC(HYS)VCC(reset)
169.37.64
1810.2−5
2010.7−6
V
Over Voltage ProtectionVCC OVP threshold
VCC(OVP) 25 26.5 28 V
VCC(off) noise filter (Note 5)VCC(reset) noise filter (Note 5)
tVCC(off)tVCC(reset)
−−
520
−−
�s
Supply CurrentDevice Disabled/Fault Device Enabled/No output load on pin 5Device Switching (Fsw = 65 kHz) Device switching (Fsw = 700 Hz)
VCC > VCC(off)Fsw = 65 kHzCDRV = 470 pF, Fsw = 65 kHzVCOMP � 0.9 V
ICC1ICC2ICC3ICC4
1.2–−−
1.353.03.51.7
1.63.54.01.88
mA
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ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V)For min/max values TJ = −40°C to +125°C, Max TJ = 150°C, VCC = 12 V) (continued)
Parameter UnitMaxTypMinSymbolTest Condition
CURRENT SENSE
Maximum Internal current limit VILIM 1.33 1.40 1.47 V
Leading Edge Blanking Duration for VILIM tLEB 283 345 407 ns
Propagation delay from current detection to gateoff−state
tILIM − 100 150 ns
Maximum on−time (option 1) ton(MAX) 29 39 49 �s
Maximum on−time (option 2) ton(MAX) 16 20 24 �s
Threshold for immediate fault protection activation(140% of VILIM)
VCS(stop) 1.9 2.0 2.1 V
Leading Edge Blanking Duration for VCS(stop) tBCS − 170 − ns
Current source for CS to GND short detection ICS(short) 400 500 600 �A
Current sense threshold for CS to GND short detection
VCS rising VCS(low) 20 60 90 mV
GATE DRIVE
Drive ResistanceDRV SinkDRV Source
RSNKRSRC
−−
1330
−−
�
Drive current capabilityDRV Sink (Note GBD)DRV Source (Note GBD)
ISNKISRC
−−
500300
−−
mA
Rise Time (10% to 90%) CDRV = 470 pF tr – 30 − ns
Fall Time (90 %to 10%) CDRV = 470 pF tf – 20 − ns
DRV Low Voltage VCC = VCC(off)+0.2 VCDRV = 470 pF, RDRV = 33 k�
VDRV(low) 8 – − V
DRV High Voltage VCC = VCC(MAX)CDRV = 470 pF, RDRV = 33 k�
VDRV(high) 10 12 14 V
ZERO VOLTAGE DETECTION CIRCUIT
Upper ZCD threshold voltage VZCD rising VZCD(rising) − 90 150 mV
Lower ZCD threshold voltage VZCD falling VZCD(falling) 35 55 − mV
Threshold to force VREFX maximum during startup VZCD(start) − 0.7 − V
ZCD hysteresis VZCD(HYS) 15 − − mV
Propagation Delay from valley detection to DRV high(no tLEB4)
VZCD decreasing tZCD(DEM) − − 150 ns
Additional delay from valley lockout output to DRVlatch set (prog option)
tLEB4 125 250 375 ns
Equivalent time constant for ZCD input (GBD) tPAR − 20 − ns
Blanking delay after on−time (option 1) VREFX > 0.35 V tZCD(blank1) 1.1 1.5 1.9 �s
Blanking delay after on−time (option 2) VREFX > 0.35 V tZCD(blank1) 0.75 1.0 1.25 �s
Blanking Delay at light load (option 1) VREFX < 0.25 V tZCD(blank2) 0.6 0.8 1.0 �s
Blanking Delay at light load (option 2) VREFX < 0.25 V tZCD(blank2) 0.45 0.6 0.75 �s
Timeout after last DEMAG transition tTIMO 5 6.5 8 �s
Pulling−down resistor VZCD = VZCD(falling) RZCD(pd) − 200 − k�
ZCD pin current source for forcing CV mode whenminimum dimming
VADIM = 0.5 V IZCDdim 145 170 195 �A
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ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V)For min/max values TJ = −40°C to +125°C, Max TJ = 150°C, VCC = 12 V) (continued)
Parameter UnitMaxTypMinSymbolTest Condition
CONSTANT CURRENT CONTROL
Reference Voltage Tj = 25°C − 85°C VREF/3 327.9 334.2 341.2 mV
Reference Voltage Tj = −40°C to 125°C VREF/3 324 334.2 346 mV
10% Reference Voltage Tj = 25°C − 85°C VREF10/3 30 33.33 36.66 mV
10% Reference Voltage Tj = −40°C to 125°C VREF10/3 27.33 33.33 39.33 mV
5% Reference Voltage Tj = 25°C − 85°C VREF05/3 14.17 17 19.17 mV
5% Reference Voltage Tj = −40°C to 125°C VREF05/3 13.34 17 20 mV
Current sense lower threshold for detection of theleakage inductance reset time
VCS falling VCS(low) 20 50 100 mV
Blanking time for leakage inductance reset detection tCS(low) − 120 − ns
POWER FACTOR CORRECTION
Clamping value for VREF(PFC) TJ = 0°C to 125°C VREF(PFC)CLP 2.06 2.2 2.34 V
Line range detector for PFC loop VHV increases VHL(PFC) − 240 − Vdc
Line range detector for PFC loop VHV decreases VLL(PFC) − 230 − Vdc
CONSTANT VOLTAGE SECTION
Internal voltage reference for constant voltage regulation
VREF(CV) 3.41 3.52 3.63 V
CV Error amplifier Gain GEA 40 50 60 �S
Error amplifier current capability VREFX = VREF (no dimming) IEA − ±60 − �A
COMP pin lower clamp voltage VCV(clampL) − 0.6 − V
COMP pin higher clamp voltage TJ = 0°C to 125°C VCV(clampH) 4.05 4.12 4.25 V
COMP pin higher clamp voltage TJ = −40°C to 125°C VCV(clampH) 4.01 4.12 4.25 V
Internal ZCD voltage below which the CV OTA isboosted
VREF(CV) * 85% Vboost(CV) 2.796 2.975 3.154 V
Threshold for releasing the CV boost VREF(CV) * 90% Vboost(CV)RST 2.96 3.15 3.34 V
Internal ZCD voltage below which the CV OTA isboosted (opt.2)
VREF(CV) * 80% Vboost(CV)2 2.632 2.8 2.968 V
Error amplifier current capability during boost phase IEAboost − ±140 − �A
ZCD OVP 1st level (slow OVP) option 1 VREF(CV) * 115% VOVP1 3.783 4.025 4.267 V
ZCD OVP 1st level (slow OVP) option 2 VREF(CV) * 120% VOVP1 3.948 4.2 4.452 V
ZCD voltage at which slow OVP is exit (option 1) VREF(CV) * 105% VOVP1rst − 3.675 − V
ZCD voltage at which slow OVP is exit (option 2) VREF(CV) * 110% VOVP1rst − 3.85 − V
Switching period during slow OVP Tsw(OVP1) − 1.5 − ms
ZCD fast OVP option 2 Vref(CV) * 130% + 150 mV VOVP2 − 4.7 − V
ZCD fast OVP option 1 Vref(CV) * 125% + 150 mV VOVP2 4.253 4.525 4.797 V
Number of switching cycles before fast OVP confirmation
TOVP2_CNT − 4 −
Duration for disabling DRV pulses during ZCD fastOVP
Trecovery − 4 − s
COMP pin internal pullup resistor (prog option) Rpullup − 15 − k�
LINE FEED FORWARD
VHV to ICS(offset) conversion ratio KLFF 0.189 0.21 0.231 �A/V
Offset current maximum value VHV > (450 V or 500 V) Ioffset(MAX) 76 95 114 �A
Line feed−forward current DRV high, VHV = 200 V IFF 35 40 45 �A
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ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V)For min/max values TJ = −40°C to +125°C, Max TJ = 150°C, VCC = 12 V) (continued)
Parameter UnitMaxTypMinSymbolTest Condition
VALLEY LOCKOUT SECTION
Threshold for line range detection VHV increasing (1st to 2nd valley transition for VREFX > 80% VREF)(prog. option: 1st to 3rd valley transition)
VHV increases VHL 228 240 252 V
Threshold for line range detection VHV decreasing (2nd to 1st valley transition for VREFX > 80% VREF)(prog. option: 3rd to 1st valley transition)
VHV decreases VLL 218 230 242 V
Blanking time for line range detection tHL(blank) 15 25 35 ms
Valley thresholds1st to 2nd valley transition at LL and 2nd to 3rd valleyHL, VREF decr. (prog. option: 3rd to 4th valley HL) 2nd to 1st valley transition at LL and 3rd to 2nd valleyHL, VREF incr. (prog. option: 4th to 3rd valley HL) 2nd to 3rd valley transition at LL and 3rd to 4th valleyHL, VREF decr. (prog. option: 4th to 5th valley HL) 3rd to 2nd valley transition at LL and 4th to 3rd valleyHL, VREF incr. (prog. option: 5th to 4th valley HL) 3rd to 4th valley transition at LL and 4th to 5th valleyHL, VREF decr. (prog. option: 5th to 6th valley HL)4th to 3th valley transition at LL and 5th to 4th valleyHL, VREF incr. (prog. option: 6th to 5th valley HL)4th to 5th valley transition at LL and 5th to 6th valleyHL, VREF decr. (prog. option: 6th to 7th valley HL)5th to 4th valley transition at LL and 6th to 5th valleyHL, VREF incr. (prog. option: 7th to 6th valley HL)
VREF decreases
VREF increases
VREF decreases
VREF increases
VREF decreases
VREF increases
VREF decreases
VREF increases
VVLY1−2/2−3
VVLY2−1/3−2
VVLY2−3/3−4
VVLY3−2/4−3
VVLY3−4/4−5
VVLY4−3/5−4
VVLY4−5/5−6
VVLY5−4/6−5
−
−
−
−
−
−
−
−
0.80
0.90
0.65
0.75
0.50
0.60
0.35
0.45
−
−
−
−
−
−
−
−
V
VREF value at which the FF mode is activated VREF decreases VFFstart − 0.25 − V
VREF value at which the FF mode is removed VREF increases VFFstop − 0.35 − V
FREQUENCY FOLDBACK
Added dead time VREFX = 0.25 V tFF1LL 0.8 1.0 1.2 �s
Added dead time VREFX = 0.08 V tFFchg − 40 − �s
Dead−time clamp ( option 1) VREFX < 3 mV tFFend1 − 675 − �s
Dead−time clamp ( option 2) VREFX < 11.2 mV tFFend2 − 250 − �s
DIMMING SECTION
DIM pin voltage for zero output current (OFF voltage) VADIM(EN) 0.475 0.5 0.525 V
ADIM pin voltage for 1% reference voltage VADIM(MIN) 0.668 0.7 0.732 V
Minimum dimming level (option 1) KDIM(MIN)1 − 0 − %
Minimum dimming level (option 2) KDIM(MIN)2 − 1 − %
Minimum dimming level (option 3) KDIM(MIN)3 − 5 − %
Minimum dimming level (option 4) KDIM(MIN)4 − 8 − %
ADIM pin voltage for maximum output current (VREFX = 1 V)
VADIM100 − 3.0 3.1 V
Dimming range VADIM(range) − 2.3 − V
Clamping voltage for DIM pin VADIM(CLP) − 6.8 − V
Dimming pin pull−up current source IADIM(pullup)1 8 10 12 �A
Current Comparator threshold for PDIM IPDIM rising IPDIM(THR) 60 70 80 �A
Current Comparator threshold for PDIM IPDIM falling IPDIM(THD) 131 153 175 �A
Cascode current limit for PDIM IPDIM(LIM) − 1080 − �A
PDIM pin voltage VPDIM − 3 − V
Maximum period of the PWM dimming signal − 6 − ms
Minimum on−time for PWM signal applied on PDIM − 8 − �s
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ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V)For min/max values TJ = −40°C to +125°C, Max TJ = 150°C, VCC = 12 V) (continued)
Parameter UnitMaxTypMinSymbolTest Condition
FAULT PROTECTION
Thermal Shutdown (Note 5) Device switching (FSWaround 65 kHz)
TSHDN 130 150 170 °C
Thermal Shutdown Hysteresis TSHDN(HYS) − 20 – °C
Threshold voltage for output short circuit or aux.winding short circuit detection
VZCD(short) 0.6 0.65 0.7 V
Short circuit detection Timer VZCD < VZCD(short) tOVLD 70 90 110 ms
Auto−recovery Timer trecovery 3 4 5 s
Line OVP threshold VHV increasing VHV(OVP) 457 469 485 Vdc
HV pin voltage at which Line OVP is reset VHV decreasing VHV(OVP)RST 430 443 465 Vdc
Blanking time for line OVP reset TLOVP(blank) 15 25 35 ms
BROWN−OUT AND LINE SENSING
Brown−Out ON level (IC start pulsing) VHV increasing VHVBO(on) 101.5 108 114.5 Vdc
Brown−Out ON level (IC start pulsing) option 2 VHV increasing VHVBO(on)2 129.7 138 146.3 Vdc
Brown−Out OFF level (IC stops pulsing) VHV decreasing VHVBO(off) 92 98 104 Vdc
Brown−Out OFF level (IC stops pulsing) option 2 VHV decreasing VHVBO(off)2 121 129 137 Vdc
HV pin voltage above which the sampling of ZCD isenabled low line
VHV decreasing, low line VsampENLL − 55 − V
HV pin voltage above which the sampling of ZCD isenabled highline
VHV decreasing, highline VsampENHL − 105 − V
ZCD sampling enable comparator hysteresis VHV increasing VsampHYS − 5 − V
BO comparators delay tBO(delay) − 30 − �s
Brown−Out blanking time tBO(blank) 15 25 35 ms
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Productperformance may not be indicated by the Electrical Characteristics if operated under different conditions.5. Guaranteed by design.
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TYPICAL CHARACTERISTICS
Figure 3. IHV(start2) vs. Temperature Figure 4. IHV(start1) vs. Temperature
Figure 5. VHV(OL) vs. Temperature Figure 6. VCC(on) vs. Temperature
Figure 7. VCC(off) vs. Temperature Figure 8. VCC(OVP) vs. Temperature
4,5
4,6
4,7
4,8
4,9
5
5,1
5,2
5,3
5,4
−50 −25 0 25 50 75 100 125
I HV
(sta
rt2)
(m
A)
TEMPERATURE (°C)
349
351
353
355
357
359
361
−50 −25 0 25 50 75 100 125
VH
V(O
L) (
V r
ms)
284
289
294
299
304
309
−50 −25 0 25 50 75 100 125
I HV
(sta
rt1)
(�A
)
TEMPERATURE (°C)
18,14
18,19
18,24
18,29
18,34
−50 −25 0 25 50 75 100 125
VC
C(o
n) (
V)
10,11
10,13
10,15
10,17
10,19
10,21
10,23
10,25
−50 −25 0 25 50 75 100 125
VC
C(o
ff) (
V)
26,66
26,71
26,76
26,81
26,86
26,91
26,96
−50 −25 0 25 50 75 100 125
VC
C(O
VP
) (V
)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
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TYPICAL CHARACTERISTICS (continued)
Figure 9. ICC1 vs. Temperature Figure 10. ICC4 vs. Temperature
Figure 11. VILIM vs. Temperature Figure 12. VCS(low)F vs. Temperature
Figure 13. VCS(stop) vs. Temperature Figure 14. ton(MAX)2 vs. Temperature
1,29
1,31
1,33
1,35
1,37
1,39
1,41
−50 −25 0 25 50 75 100 125
I CC
1 (m
A)
1,62
1,63
1,64
1,65
1,66
1,67
1,68
1,69
1,7
−50 −25 0 25 50 75 100 125
I CC
4 (m
A)
0,7
0,75
0,8
0,85
0,9
0,95
1
1,05
1,1
1,15
1,2
−50 −25 0 25 50 75 100 125
VIL
IM (
V)
50
50,5
51
51,5
52
52,5
53
53,5
54
−50 −25 0 25 50 75 100 125
VC
S(lo
w)F
(m
V)
1,94
1,96
1,98
2
2,02
2,04
2,06
−50 −25 0 25 50 75 100 125
VC
S(s
top)
(V
)
19,84
19,89
19,94
19,99
20,04
20,09
20,14
20,19
20,24
−50 −25 0 25 50 75 100 125
t on(
MA
X)2
(m
s)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
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TYPICAL CHARACTERISTICS (continued)
Figure 15. tLEB vs. Temperature Figure 16. tBCS vs. Temperature
Figure 17. tILIM vs. Temperature Figure 18. RSNK vs. Temperature
Figure 19. RSRC vs. Temperature Figure 20. tr vs. Temperature
334
339
344
349
354
359
−50 −25 0 25 50 75 100 125172
173
174
175
176
177
178
179
180
−50 −25 0 25 50 75 100 125
t BC
S (
ns)
50
60
70
80
90
100
110
120
−50 −25 0 25 50 75 100 125
t ILIM
(ns
)
3,5
4,5
5,5
6,5
7,5
8,5
9,5
10,5
−50 −25 0 25 50 75 100 125
RS
NK (�
)
5,5
7,5
9,5
11,5
13,5
15,5
−50 −25 0 25 50 75 100 125
RS
RC
(�
)
20
22
24
26
28
30
32
34
−50 −25 0 25 50 75 100 125
t r (n
s)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
t LE
B (
ns)
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TYPICAL CHARACTERISTICS (continued)
Figure 21. tf vs. Temperature Figure 22. VZCD(rising) vs. Temperature
Figure 23. VZCD(falling) vs. Temperature Figure 24. VZCD(short) vs. Temperature
Figure 25. tZCD(dem) vs. Temperature Figure 26. tZCD(blank1)OPN1 vs. Temperature
12,5
13,5
14,5
15,5
16,5
17,5
18,5
19,5
20,5
21,5
−50 −25 0 25 50 75 100 125
t F (
ns)
79
79,5
80
80,5
81
81,5
82
82,5
83
−50 −25 0 25 50 75 100 125
VZ
CD
(ris
ing)
(m
V)
49,5
50,5
51,5
52,5
53,5
54,5
−50 −25 0 25 50 75 100 125
VZ
CD
(fal
ling)
(m
V)
0,658
0,66
0,662
0,664
0,666
0,668
0,67
0,672
−50 −25 0 25 50 75 100 125
VZ
CD
(sho
rt) (
V)
76
81
86
91
96
101
106
111
116
−50 −25 0 25 50 75 100 125
t ZC
D(D
EM
) (ns
)
1,555
1,565
1,575
1,585
1,595
1,605
−50 −25 0 25 50 75 100 125
t ZC
D(b
lank
1)O
PN
1 (�
s)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
NCL30486
www.onsemi.com13
TYPICAL CHARACTERISTICS (continued)
Figure 27. tZCD(blank1)OPN2 vs. Temperature Figure 28. tZCD(blank2)OPN1 vs. Temperature
Figure 29. tZCD(blank2)OPN2 vs. Temperature Figure 30. tTIMO vs. Temperature
Figure 31. VREF/3 vs. Temperature Figure 32. VREF10/3 vs. Temperature
1,042
1,047
1,052
1,057
1,062
1,067
1,072
−50 −25 0 25 50 75 100 125
t ZC
D(b
lank
1)O
PN
2 (�
s)
0,836
0,841
0,846
0,851
0,856
0,861
−50 −25 0 25 50 75 100 125
t ZC
D(b
lank
2)O
PN
1 (�
s)
0,564
0,569
0,574
0,579
0,584
−50 −25 0 25 50 75 100 125
t ZC
D(b
lank
2)O
PN
2 (�
s)
6,72
6,77
6,82
6,87
6,92
−50 −25 0 25 50 75 100 125
t TIM
O (�s)
331,8
332,3
332,8
333,3
333,8
334,3
334,8
335,3
335,8
336,3
336,8
−50 −25 0 25 50 75 100 125
VR
EF
/3 (
mV
)
32,6
33,1
33,6
34,1
34,6
−50 −25 0 25 50 75 100 125
VR
EF
10/3
(m
V)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
NCL30486
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TYPICAL CHARACTERISTICS (continued)
Figure 33. VREF5/3 vs. Temperature Figure 34. VREF(CV) vs. Temperature
Figure 35. VCV(clampH) vs. Temperature Figure 36. VOVP1 vs. Temperature
Figure 37. VOVP2 vs. Temperature Figure 38. KLFF vs. Temperature
16,3
16,5
16,7
16,9
17,1
17,3
17,5
17,7
−50 −25 0 25 50 75 100 125
VR
EF
5/3
(mV
)
3,475
3,485
3,495
3,505
3,515
3,525
3,535
3,545
−50 −25 0 25 50 75 100 125
VR
EF
(CV
) (V
)
4,08
4,09
4,1
4,11
4,12
4,13
4,14
4,15
−50 −25 0 25 50 75 100 125
VC
V(c
lam
pH) (
V)
3,995
4,005
4,015
4,025
4,035
4,045
4,055
4,065
4,075
−50 −25 0 25 50 75 100 125
VO
VP
1 (V
)
4,49
4,5
4,51
4,52
4,53
4,54
−50 −25 0 25 50 75 100 125
VO
VP
2 (V
)
0,2005
0,2015
0,2025
0,2035
0,2045
0,2055
0,2065
0,2075
0,2085
0,2095
−50 −25 0 25 50 75 100 125
KLF
F (�A
/V)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
NCL30486
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TYPICAL CHARACTERISTICS (continued)
Figure 39. Ioffset(MAX) vs. Temperature Figure 40. IFF vs. Temperature
Figure 41. tFF1LL vs. Temperature Figure 42. VREF(PFC)CLP vs. Temperature
Figure 43. VADIM(EN) vs. Temperature Figure 44. VADIM(MIN) vs. Temperature
96
97
98
99
100
101
102
103
104
−50 −25 0 25 50 75 100 125
I offs
et(M
AX
) (�A
)
40,1
40,3
40,5
40,7
40,9
41,1
41,3
41,5
41,7
−50 −25 0 25 50 75 100 125
I FF (�A
)
1,0305
1,0315
1,0325
1,0335
1,0345
1,0355
1,0365
1,0375
1,0385
1,0395
−50 −25 0 25 50 75 100 125
t FF
1LL
(�s)
2,168
2,173
2,178
2,183
2,188
2,193
2,198
2,203
2,208
−50 −25 0 25 50 75 100 125
VR
EF
(PF
C)C
LP (
V)
0,4975
0,4985
0,4995
0,5005
0,5015
0,5025
0,5035
0,5045
0,5055
−50 −25 0 25 50 75 100 125
VA
DIM
(EN
) (V
)
0,694
0,696
0,698
0,7
0,702
0,704
0,706
0,708
−50 −25 0 25 50 75 100 125
VA
DIM
(MIN
) (V
)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
NCL30486
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TYPICAL CHARACTERISTICS (continued)
Figure 45. IPDIM(THR) vs. Temperature Figure 46. IPDIM(THD) vs. Temperature
Figure 47. IPDIM(LIM) vs. Temperature Figure 48. VPDIM vs. Temperature
Figure 49. VADIM100 vs. Temperature Figure 50. VHVBO(on)ONP1 vs. Temperature
69,6
70,1
70,6
71,1
71,6
−50 −25 0 25 50 75 100 125
I PD
IM(T
HR
) (�A
)
149,2
149,7
150,2
150,7
151,2
151,7
152,2
152,7
153,2
−50 −25 0 25 50 75 100 125
I PD
IM(T
HD
) (�A
)
1,056
1,061
1,066
1,071
1,076
1,081
1,086
−50 −25 0 25 50 75 100 125
I PD
IM(L
IM) (
mA
)
2,978
2,983
2,988
2,993
2,998
3,003
3,008
3,013
−50 −25 0 25 50 75 100 125
VP
DIM
(V
)
2,976
2,981
2,986
2,991
2,996
3,001
3,006
3,011
−50 −25 0 25 50 75 100 125
VA
DIM
100
(V)
106,9
107,1
107,3
107,5
107,7
107,9
108,1
108,3
108,5
108,7
108,9
−50 −25 0 25 50 75 100 125
VH
VB
O(o
n)O
PN
1 (V
)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C) TEMPERATURE (°C)
NCL30486
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TYPICAL CHARACTERISTICS (continued)
Figure 51. VHVBO(off)ONP1 vs. Temperature Figure 52. VHV(OVP) vs. Temperature
Figure 53. VHV(OVP)RST vs. Temperature
97,8
98
98,2
98,4
98,6
98,8
99
99,2
99,4
99,6
−50 −25 0 25 50 75 100 125
VH
VB
O(o
ff)O
PN
1 (V
)
464
465
466
467
468
469
470
471
472
−50 −25 0 25 50 75 100 125
VH
V(O
VP
) (V
dc)
439
440
441
442
443
444
445
446
−50 −25 0 25 50 75 100 125
VH
V(O
VP
)RS
T (
V d
c)
TEMPERATURE (°C) TEMPERATURE (°C)
TEMPERATURE (°C)
NCL30486
www.onsemi.com18
Application InformationThe NCL30486 implements a current−mode architecture
operating in quasi−resonant mode. Thanks to proprietarycircuitry, the controller is able to accurately regulate thesecondary side current and voltage of the fly−back converterwithout using any opto−coupler or measuring directly thesecondary side current or voltage. The controller providesnear unity power factor correction• Quasi−Resonance Current−Mode Operation:
implementing quasi−resonance operation in peakcurrent−mode control, the NCL30486 optimizes theefficiency by switching in the valley of the MOSFETdrain−source voltage. Thanks to an internal algorithmcontrol, the controller locks−out in a selected valley andremains locked until the input voltage or the outputcurrent set point significantly changes.
• Primary Side Constant Current Control: thanks to aproprietary circuit, the controller is able to take intoaccount the effect of the leakage inductance of thetransformer and allows an accurate control of thesecondary side current regardless of the input voltage andoutput load variation.
• Primary Side Constant Voltage Regulation: Bymonitoring the auxiliary winding voltage, it is possible toregulate accurately the output voltage. The output voltageregulation is typically within ±2%.
• Load Transient Compensation: Since PFC has low loopbandwidth, abrupt changes in the load may causeexcessive over or under−shoot. The slow Over VoltageProtection contains the output voltage when it tends tobecome excessive. In addition, the NCL30486 speeds upthe constant voltage regulation loop when the outputvoltage goes below 80% or 85% of its regulation level.
• Power Factor Correction: A proprietary concept allowsachieving high power factor correction and low THDwhile keeping accurate constant current and constantvoltage control.
• Line Feed−forward: allows compensating the variation ofthe output current caused by the propagation delay.
• VCC Over Voltage Protection: if the VCC pin voltageexceeds an internal limit, the controller shuts down andwaits 4 seconds before restarting pulsing.
• Fast Over Voltage Protection: If the voltage of ZCD pinexceeds 130% of its regulation level, the controller shutsdown and waits 4 s before trying to restart.
• Brown−Out: the controller includes a brown−out circuitwhich safely stops the controller in case the input voltageis too low. The device will automatically restart if the linerecovers.
• Cycle−by−cycle peak current limit: when the currentsense voltage exceeds the internal threshold VILIM, theMOSFET is turned off for the rest of the switching cycle.
• Winding Short−Circuit Protection: an additionalcomparator senses the CS signal and stops the controller
if VCS reaches 1.5 x VILIM (after a reduced LEB of tBCS).This additional comparator is enabled only during themain LEB duration tLEB, for noise immunity reason.
• Output Under Voltage Protection: If a too low voltage isapplied on ZCD pin for 90 ms time interval, thecontrollers assume that the output or the ZCD pin isshorted to ground and shutdown. After waiting 4 seconds,the IC restarts switching.
• Analog Dimming: the ADIM pin is dedicated to analogdimming. There are several options for the minimumdimming level. Pulling the pin voltage lower thanVADIM(EN) disables the controller.
• PWM dimming: the PDIM pin is dedicated to PWMdimming. The controller measures the duty ratio of asignal applied to the pin and reduces the output currentaccordingly. If this pin is left open, the controller deliversthe maximum output current. If the pin is pulled down, thecontroller is disabled.
• Thermal Shutdown: an internal circuitry disables the gatedrive when the junction temperature exceeds 150°C(typically). The circuit resumes operation once thetemperature drops below approximately 100°C.
POWER FACTOR AND CONSTANT CURRENTCONTROL
The NCL30486 embeds an analog/digital block to controlthe power factor and regulate the output current bymonitoring the ZCD, CS and HV pin voltages (signalsVZCD, VHV_DIV, VCS). This circuit generates the currentsetpoint signal and compares it to the current sense signal toturn the MOSFET off. The HV pin provides the sinusoidalreference necessary for shaping the input current. Theobtained current reference is further modulated so that whenaveraged over a half line period, it is equal to the outputcurrent reference (VREFX). The modulation and averagingprocess is made internally by a digital circuit. If the HV pinproperly conveys the sinusoidal shape, power factor will beclose to 1. Also, the Total Harmonic Distortion (THD) willbe low especially if the output voltage ripple is small.
IOUT �
VREF
2NspRsense(eq. 1)
Where:• Nsp is the secondary to primary transformer turns ratio:
Nsp = NS / NP
• Rsense is the current sense resistor
• VREFX is the output current reference: VREFX = VREF ifno dimmingThe output current reference (VREFX) is VREF unless the
constant voltage mode is activated or ADIM pin voltage isbelow VADIM(100) or a PWM signal with a duty−cycle below95% is applied on PDIM.
NCL30486
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PRIMARY SIDE CONSTANT VOLTAGE CONTROLThe auxiliary winding voltage is sampled internally
through the ZCD pin.A precise internal voltage reference VREF(CV) sets the
voltage target for the CV loop.The sampled voltage is applied to the negative input of the
constant voltage (CV) operational transconductanceamplifier (OTA) and compared to VREFCV.
A type 2 compensator is needed at the CV OTA output tostabilize the loop. The COMP pin voltage modify the theoutput current internal reference in order to regulate theoutput voltage.
When VCOMP ≥ 4 V, VREFX = VREF.When VCOMP < 0.9 V, VREFX = 0 V.
.
ZCD & signalsampling
RZCDU
RZCDL
ZCDCOMP
VREF(CV)
R1
C 1
C 2
VZCDsamp
OTA
Gm
Aux.
Figure 54. Constant Voltage Feedback Circuit
Secondary Side Regulation CompatibleThe NCL30486 is able to support secondary−side
regulation as well. The controller features an option toprovide a pullup resistor Rpullup on COMP pin instead of theCV OTA output. This allows connecting directly anoptocoupler collector and properly biases it. The internalvoltage biasing Rpullup is around 5 V.
In secondary side regulation, the slow and fast OVP onZCD pin are still active thus providing an additional overvoltage protection. In this case, the ZCD pin resistors shouldbe calculated to trigger VOVP2 at the output voltage ofinterest.
Figure 55. COMP Pin Configuration for SecondarySide Regulation
COMP−
+
VDD
VREF(CV)
CV OTA Boost
Rpullup
STARTUP PHASE (HV STARTUP)It is generally requested that the LED driver starts to emit
light in less than 1 s and possibly within 300 ms. It ischallenging since the start−up consists of the time to chargethe VCC capacitor and that necessary to charge the outputcapacitor until sufficient current flows into the LED string.This second phase can be particularly long in dimming caseswhere the secondary current is a portion of the nominal one.
The NCL30486 features a high voltage startup circuit thatallows charging VCC capacitor very fast.
When the power supply is first connected to the mainsoutlet, the internal current source is biased and charges upthe VCC capacitor. When the voltage on this VCC capacitorreaches the VCC(on) level, the current source turns off. At thistime, the controller is only supplied by the VCC capacitor,and the auxiliary supply should take over before VCCcollapses below VCC(off).
The HV startup circuitry is made of two startup currentlevels, IHV(start1) and IHV(start1). This helps to protect thecontroller against short−circuit between VCC and GND. Atpower−up, as long as VCC is below VCC(TH), the sourcedelivers IHV(start1) (around 300 �A typical). Then, whenVCC reaches VCC(TH), the source smoothly transitions toIHV(start2) and delivers its nominal value. As a result, in caseof short−circuit between VCC and GND occurring at highline (Vin = 305 V rms), the maximum power dissipation willbe 431 x 300 � = 130 mW instead of 1.5 W if there was onlyone startup current level.
To speed−up the output voltage rise, the following isimplemented:• The digital OTA output is increased until VREF(PFC)
signal reaches VREFX. Again, this is to speed−up thecontrol signal rise to their steady state value.
• At the beginning of each operating phase of a VCC cycle,the digital OTA output is set to 0. Actually, the digitalOTA output is set to 0 in the case of a cold start−up or inthe case of a start−up sequence following an operationinterruption due to a fault. On the other hand, if the VCChiccups just because the system fails to start−up in oneVCC cycle, the digital OTA output is not reset to ease thesecond (or more) attempt.
NCL30486
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• If the load is shorted, the circuit will operate in hiccupmode with VCC oscillating between VCC(off) and VCC(on)until the output under voltage protection (UVP) trips.UVP is triggered if the ZCD pin voltage does not exceedVZCD(short) within a 90 ms operation of time. Thisindicates that the ZCD pin is shorted to ground or that anexcessive load prevents the output voltage from rising.
HV Startup Power DissipationAt high line (305 V rms and above) the power dissipated
by the HV startup in case of fault or when the controller isdisabled with PDIM becomes high. Indeed, in case of fault,the NCL30486 is directly supplied by the HV rail. When thecontroller is disabled with PDIM, the optocoupler collectorcurrent is also supplied by the controller, since theNCL30486 allows directly connecting the optocouplertransistor to PDIM pin. Thus, the HV startup circuit alsosupplies the optocoupler transistor in case of faults. Thecurrent flowing through the HV startup will heat thecontroller. It is highly recommended adding enough copperaround the controller to decrease the R�JA of the controller.
Adding a minimum pad area of 215 mm2 of 35 �m copper(1 oz) drops the R�JA to around 120°C/W (no air flow, R�JAmeasured at ADIM pin)
The PCB layout shown in Figure 56 is a layout exampleto achieve low R�JA.
Figure 56. PCD Layout Example
The application note ANDXXXX gives more details aboutstrategies to decrease the power dissipation of the HVstartup circuit.
Cycle−by−Cycle Current LimitWhen the current sense voltage exceeds the internal
threshold VILIM, the MOSFET is turned off for the rest of theswitching cycle.
Winding and Output Diode Short−Circuit ProtectionIn parallel to the cycle−by−cycle sensing of the CS pin,
another comparator with a reduced LEB (tBCS) and athreshold of (VCS(stop) = 140% x VILIM) monitors the CS pinto detect a winding or an output diode short circuit. Thecontroller shuts down if it detects 4 consecutives pulsesduring which the CS pin voltage exceeds VCS(stop) .
The controller goes into auto−recovery mode.
PWM DimmingThe NCL30486 has a dedicated pin for PWM dimming.The controller directly measures the duty ratio of a PWM
signal applied to PDIM.Two counters with a high frequency clock are used for this
purpose. A first counter measure the high state duration ofthe PWM signal (ton_PDIM) and the second counter measuresits period (Tsw_PDIM). A divider computes (ton_PDIM /Tsw_PDIM) and the result is directly the output currentsetpoint (VREFX set point). A filter is added after the digitaldivider to remove the ripple of the signal. A cascodeconfiguration on PDIM pin allows decreasing the fall timeof the signal.
Thanks to this circuit, the LED current is controlled in ananalog way, even if a PWM signal is used for dimming. Thisallows having a good PF during dimming.
NCL30486
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Figure 57. PDIM Internal Waveforms
VDIM_sec
IPDIM
IPDIM(THR)
IPDIM(THD)
VPDIM_int
Ton
Tsw
Practically, the controller extracts the duty−cycle bymeasuring the current inside PDIM pin which is directly theopto coupler collector current.
If PDIM pin is left open, the controller delivers 100% ofIout. If the pin is pulled down for longer than 25 ms, thecontroller is disabled.
If the PWM dimming signal is removed during dimming,the controller delivers 100% of Iout.
The NCL30486 set 100% of output current when theduty−cycle of the signal applied on PDIM is above 93%.
Analog DimmingThe pin ADIM pin allows implementing analog dimming
of the LED light.If the power supply designer applies an analog signal
varying from VDIM(EN) to VDIM100 to the DIM pin, theoutput current will increase or decrease proportionally to thevoltage applied. For VDIM = VDIM100, the power supplydelivers the maximum output current (VREFX = 1 V).
If a voltage lower than VADIM(MIN) is applied to ADIMpin, the output current is clamped to the selected dimmingclamp value (see Dimming clamp section below)
NCL30486
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If a voltage lower than VADIM(EN) is applied to the DIMpin, the DRV pulses are disabled for controllers without thedimming CV mode option.
The DIM pin is pulled up internally by a small currentsource or resistor. Thus, if the pin is left open, the controlleris able to start.
NOTE:• Interaction between ADIM and PDIM: if ADIM and
PDIM are both used at the same time, the resultingdimming set point if a multiplication of VADIM and theduty−ratio of PDIM signal.
• During dimming, when the “Enable” signal is OK, thecontroller starts pulsing after 1 time−out pulse, even if ahigher valley number is selected by VREFX. This is toavoid too long startup time while dimming at low outputcurrent value.
Figure 58. ADIM Pin Dimming Curves
VADIM(EN) VADIM(MIN) VADIM100
100% VREF
1% VREF
VREF
VADIM
5% VREF
8% VREF
Dimming ClampFor smart dimming applications, need to bias the
secondary−side MCU. This can be achieved by clampingVREFX when the dimming setpoint is small.
There are 4 options for the dimming clamp:• No dimming clamp
• 1%
• 5%
• 8%
Figure 59. Dimming Clamp Options
1%5%8%
Scaled dimming voltage ordimming duty−ratio
VREFX (%)
100%
0.01 0.05 0.08 1.0
NCL30486
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Dimming CurvesBy default, there is a linear relationship between the
voltage applied on ADIM pin and VREFX setpoint. In thesame way, there is a linear relationship between theduty−ratio of the signal applied on PDIM and VREFXsetpoint.
An internal memory allows selecting a root squarerelationship between dimming and VREFX.
The square like curve is based on CIE 1931 lightnessformula.
Figure 60. Dimming Curves
0
10
20
30
40
50
60
70
80
90
100
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Out
put C
urre
nt (
%)
Scaled Dimming Voltage or Dimming Duty Ratio
Output Current vs. Dimming
linear
CIE 1931
Valley LockoutQuasi−Square wave resonant systems have a wide
switching frequency excursion. The switching frequencyincreases when the output load decreases or when the inputvoltage increases. The switching frequency of such systemsmust be limited.
The NCL30486 changes valley as VREFX decreases and asthe input voltage increases and as the output current setpoint
is varied during dimming. This limits the frequencyexcursion.
By default, when the output current is not dimmed, thecontroller operates in the first valley at low line and in thesecond valley at high line.
There is an option to have the valley thresholdsincremented by 1 at high line for better Iout control at305 V rms.
Table 1. VALLEY SELECTION
VHV_DIV Voltage for Valley Change
VREFX value at which the ControllerChanges Valley (Iout Decreasing)
VREFX Value at Which the ControllerChanges Valley(Iout Increasing)0 −−LL−− 2.3 V −−HL−− 5 V
I out
dec
reas
es
100%80%
65%
50%
35%
25%0%
1st 2nd (3rd) 100%80%
65%
50%
35%
25%0%
I out
dec
reas
es
2nd 3rd (4th)
3rd 4th (5th)
4th 5th (6th)
5th 6th (7th)
FF mode FF mode
0 −−LL−− 2.3 V −−HL−− 5 V
Internal VHV_DIV Voltage for Valley Change
NCL30486
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Zero Crossing Detection BlockThe ZCD pin allows detecting when the drain−source
voltage of the power MOSFET reaches a valley.A valley is detected when the ZCD pin voltage crosses
below the 55 mV internal threshold.At startup or in case of extremely damped free
oscillations, the ZCD comparator may not be able to detectthe valleys. To avoid such a situation, Optimus Primefeatures a Time−Out circuit that generates pulses if thevoltage on ZCD pin stays below the 55 mV threshold for6.5 �s.
The Time−out also acts as a substitute clock for the valleydetection and simulates a missing valley in case of toodamped free oscillations.
At startup, the output voltage reflected on the auxiliarywinding is low. Because of the ZCD resistor bridge settingthe constant voltage regulation target, the voltage on theZCD pin is very low and the ZCD comparator might beunable to detect the valleys. In this condition, setting theDRV latch with the 6.5 �s time−out leads to a continuousconduction mode operation (CCM) at the beginning of thesoft−start. This CCM operation only last a few cycles untilthe voltage on ZCD pin becomes high enough and trips theZCD comparator.
VVIN
increases
low
high
Clock
TimeOut
low
high
low
high
low
43
14
12
15
16
17
high
ZCD comp
2nd , 3 rd
VZCD
VZCD(th)
Iout decreases or Vinincreases
Figure 61. Valley Detection and Time−out Chronograms
If the ZCD pin or the auxiliary winding happen to beshorted the time−out function would normally make thecontroller keep switching and hence lead to improperregulation of the LED current.
The Under Voltage Protection (UVP) is implemented toavoid these scenarios: a secondary timer starts countingwhen the ZCD voltage is below the VZCD(short) threshold. Ifthis timer reaches 90 ms, the controller detects a fault andenters the auto−recovery fault mode.
ZCD Over Voltage ProtectionBecause of the power factor correction, it is necessary to
set the crossover frequency of the CV loop very low (target10 Hz, depending on power stage phase shift). Because theloop is slow, the output voltage can reach high value duringstartup or during an output load step. It is necessary to limitthe output voltage excursion. For this, the NCL30486features a slow OVP and a fast OVP on ZCD pin.
Slow OVPIf ZCD voltage exceeds VOVP1 for 4 consecutive
switching cycles, the controller stops switching during1.4 ms. The PFC loop is not reset. After 1.4 ms, thecontroller initiates a new DRV pulse to refresh ZCDsampling voltage. If VZCD is still too high (VZCD > 110%VREF(CV)), the controller continues to switch with a 1.4 msperiod. The controller resumes its normal operation whenVZCD < 110% VREF(CV).
During slow OVP, the peak current setpoint is COMP pinvoltage scaled down by a fixed ratio.
Fast OVPIf ZCD voltage exceeds VZCD(OVP2) (130% of VREF(CV))
for 4 consecutive switching cycles (slow OVP not triggered)or for 2 switching cycles if the slow OVP has already beentriggered, the controller detects a fault and starts theauto−recovery fault mode (cf: Fault Management Section)
NCL30486
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Line Feedforward
Figure 62. Line Feed−Forward and Brown−out Schematic
HV
CS
v DD
R sense
R LFFI CS(offset)
Q_drv
K LFF
v VS
+
−
BO_NOK25 msBlanking
1 V / 0.9 V
The line voltage is sensed by the HV pin and convertedinto a current. By adding an external resistor in seriesbetween the sense resistor and the CS pin, a voltage offsetproportional to the line voltage is added to the CS signal. Theoffset is applied only during the MOSFET on−time in orderto not influence the detection of the leakage inductancereset.
The offset is always applied even at light load in order toimprove the current regulation at low output load.
Brown−outIn order to protect the supply against a very low input
voltage, the controller features a brown−out circuit with afixed ON/OFF threshold. The controller is allowed to startif a voltage higher than VHVBO(on) is applied to the HV pinand shuts−down if the HV pin voltage decreases and stays
below VHVBO(off) for 25 ms typical. Exiting a brown−outcondition overrides the hiccup on VCC (VCC does not waitto reach VCC(off)) and the IC immediately goes into startupmode.
An option with higher brown−out levels is also available(see ordering table and electricals parameters)
Line OVPIn order to protect the power supply in case of too high
input voltage, the NCL30486 features a line over voltageprotection. When the voltage on HV pin exceeds VHV(OVP)the controller stops switching; VCC hiccups.
When VHV becomes lower than VHV(OVP)RST for morethan 25 ms, the controller initiates a clean startup sequenceand re−starts switching.
NCL30486
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Figure 63. Line OVP Chronograms
VHV(OVP)
VHV(OVP)RST
VCC(on)
VCC(off)
VDRV
Iout
VCC
VHV
t LOVP(blank)
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ProtectionsThe circuit incorporates a large variety of protections to
make the LED driver very rugged.Among them, we can list:
• Fault of the GND connectionIf the GND pin is properly connected, the supply currentdrawn from the positive terminal of the VCC capacitor,flows out of the GND pin to return to the negative terminalof the VCC capacitor. If the GND pin is not connected, thecircuit ESD diodes offer another return path. Theaccidental non connection of the GND pin can hence bedetected by detecting that one of this ESD diode isconducting. Practically, the ESD diode of CS pin ismonitored. If such a fault is detected for 200 �s, the circuitstops generating DRV pin.
• Output short circuit situation (Output Under VoltageProtection)Overload is detected by monitoring the ZCD pin voltage:if it remains below VZCD(short) for 90 ms, an output shortcircuit is detected and the circuit stops generating pulsesfor 4 s. When this 4 s delay has elapsed, the circuitattempts to restart.
• ZCD pin incorrect connection:♦ If the ZCD pin grounded, the circuit will detect an
output short circuit situation when 90 ms delay haselapsed.
♦ A 200 k� resistor pulls down the ZCD pin so thatthe output short circuit detection trips if the ZCD pinis not connected (floating).
• Winding or Output Diode Short Circuit protectionThe circuit detects this failure when 4 consecutive DRVpulses occur within which the CS pin voltage exceeds(VCS(stop) = 140% x VILIM). In this case, the controllerenters auto−recovery mode (4−s operation interruptionbetween active bursts).
• VCC Over Voltage ProtectionThe circuit stops generating pulses if the VCC exceedsVCC(OVP) and enters auto−recovery mode. This featureprotects the circuit if output LEDs happen to bedisconnected.
• ZCD fast OVPIf ZCD voltage exceeds VZCD(OVP2) for 4 consecutiveswitching cycles (slow OVP not triggered) or for 2switching cycles if the slow OVP has already beentriggered, the controller detects a fault and entersauto−recovery mode (4 s operation interruption betweenactive bursts).
• Die Over Temperature (TSD)The circuit stops operating if the junction temperature(TJ) exceeds 150°C typically. The controller remains offuntil TJ goes below nearly 130°C.
• Brown−Out Protection (BO)The circuit prevents operation when the line voltage is toolow to avoid an excessive stress of the LED driver.Operation resumes as soon as the line voltage is highenough and VCC is higher than VCC(on).
NCL30486
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• CS pin short to groundThe CS pin is checked at start−up (cold start−up or aftera brown−out event). A current source (Ics(short)) is appliedto the pin and no DRV pulse is generated until the CS pinexceeds Vcs(low). Ics(short) and Vcs(low) are 500 �A and60 mV typically (VCS rising). The typical minimumimpedance to be placed on the CS pin for operation is then120 �. In practice, it is recommended to place more than
250 � to take into account possible parametric deviations.Also, along the circuit operation, the CS pin could happento be grounded. If it is grounded, the MOSFETconduction time is limited by the 20 �s maximumon−time. If such an event occurs, a new pin impedancetest is made.
• Line overvoltage protection(see Line OVP section)
ORDERING TABLE OPTION
OPN #NCL30486_ _
Maximum Dead−time VREF Max. On−time ZCD Blanking
ValleyTransition
from LL to HL Standby ModeLine Range
Detector
250 �s 687 �s 1.4 ms 200 mV 333 mV 20 �s 33 �s 1 �s 1.5 �s 1st to2nd
1st to3rd
On Off On Off
NCL30486A2 x x x x x x x
OPN #NCL30486_ _
Line OVP
Frozen Peak CurrentDuring Standby Mode
VCS(SBY) Brown−out Levels Dimming ClampDimming
Curve
On Off 380 mV 330 mV 280 mV On: 108 VOff: 98 V
On: 138 VOff: 129 V
0% 1% 5% 8% Linear Square
NCL30486A2 x NA x x x
ORDERING INFORMATION
Device Marking Package type Shipping†
NCL30486A2 L30486A2 SOIC9 – P7 COMP VHV PBFH(Pb−Free)
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel PackagingSpecifications Brochure, BRD8011/D.
NCL30486
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PACKAGE DIMENSIONS
SOIC−9 NBCASE 751BP
ISSUE A
SEATINGPLANE
15
610
hX 45�
NOTES:1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.2. CONTROLLING DIMENSION: MILLIMETERS.3. DIMENSION b DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE PROTRUSIONSHALL BE 0.10mm TOTAL IN EXCESS OF ’b’AT MAXIMUM MATERIAL CONDITION.
4. DIMENSIONS D AND E DO NOT INCLUDEMOLD FLASH, PROTRUSIONS, OR GATEBURRS. MOLD FLASH, PROTRUSIONS, ORGATE BURRS SHALL NOT EXCEED 0.15mmPER SIDE. DIMENSIONS D AND E ARE DE-TERMINED AT DATUM F.
5. DIMENSIONS A AND B ARE TO BE DETERM-INED AT DATUM F.
6. A1 IS DEFINED AS THE VERTICAL DISTANCEFROM THE SEATING PLANE TO THE LOWESTPOINT ON THE PACKAGE BODY.
D
EH
A1A
DIM
D
MIN MAX
4.80 5.00
MILLIMETERS
E 3.80 4.00
A 1.25 1.75
b 0.31 0.51
e 1.00 BSC
A1 0.10 0.25A3 0.17 0.25
L 0.40 1.27
M 0 8
H 5.80 6.20
CM0.25
M
� �
DIMENSION: MILLIMETERS
*For additional information on our Pb−Free strategy and solderingdetails, please download the ON Semiconductor Soldering andMounting Techniques Reference Manual, SOLDERRM/D.
SOLDERING FOOTPRINT*
h 0.37 REF
L2 0.25 BSC
AC0.20
4 TIPS
TOP VIEW
C0.205 TIPS A-B D
C0.10 A-B
2X
C0.10 A-B
2X
e
C0.10
b9XB
C
C0.10
9X
SIDE VIEW END VIEW
DETAIL A
6.50
9X 1.18
9X 0.58 1.00PITCH
RECOMMENDED
1
L
F
SEATINGPLANEC
L2 A3
DETAIL A
D
NCL30486
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