Simple 12V To 24V DC-DC Converter Circuit Diagram

This is the Simple 12V To 24V DC-DC Converter Circuit Diagram. This simple DC-DC converter can provide up to 24V from a 12V source. It can be used to run radios, small lights, relays, horns and other 24V accessories from a 12V vehicle with a maximum draw of about 800mA. It can be used to charge one 12V battery from another, or step up the voltage just enough to provide necessary overhead for a 12V linear regulator. Using one op-amp as a squarewave oscillator to ring an inductor and another op-amp in a feedback loop, it won't drift around under varying loads, providing a stable 24V source for many applications. With a wide adjustment in output this circuit has many uses.

 Simple 12V To 24V DC-DC Converter Circuit Diagram

Parts
  
Part                          Total QTY    Description

R1, R2, R3, R4, R8, R7    6    100K 1/4W Resistor  
R5    1    470 Ohm 1/2W Resistor  
R6    1    10K Linear Pot  
C1    1    0.01uF Mylar Capacitor  
C2    1    0.1uF Ceramic Disc Capacitor  
C3    1    470uF 63V Electrolytic Capacitor  
D1    1    1N4004 Rectifier Diode  
D2    1    BY229-400 Fast Recovery Diode   
Q1    1    BC337 NPN Power Transistor  
U1    1    LM358 Dual Op Amp IC  
L1    1    See Notes  
MISC    1    Board, Wire, Socket For U1, Case, Knob For R6, Heatsink for Q1  
  

Notes

• R6 sets the output voltage. This can be calculated by Vout = 12 x (R8/(R8+R7)) x (R6B/R6A).
• L1 is made by winding 60 turns of 0.63MM magnet wire on a toroidial core measuring 15MM (OD) by 8MM (ID) by 6MM (H).
• D2 can be any fast recovery diode rated at greater then 100V at 5A. It is very important that the diode be fast recovery and not a standard rectifier.
• Q1 will need a heatsink.