Digitally selectable 1.5A voltage regulator

Here a simple digitally selectable voltage voltage regulator using LM317It can provide maximum 1500mA. Diode D1 and D2 is for protection from short circuit. Vs2,Vs3,Vs4,Vs5 is jest for simulation purpose. You can connect the 4 input to an TTL logic. Even you can change the resistor value and get 16 combination of voltages.

Design Equation

Vout= 1.25*(1+R2/R1)+Iadj*R2

where Vout= Output voltage from voltage regulatorR2= Equivalent resistance of R6,R7,R8 and R9 (parallel combination)R1= 120OhmIadj=50uA

Drawing 1: Digitally selectable voltage regulator

outputInput