DC to DC converter is good circuit.
It can make voltage up or down for many use.
In this article we will talk about 12V to 24V DC Voltage Converter Circuit using IC LM324
This circuit is a double input voltage using boost converter and oscillator.
Load current must not be more than 800mA.
The circuit help power 24V devices from 12V source which is good for cars, solar and battery devices.
Circuit Working:
Parts List:
| Component Type | Value / Specification | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | ||
| 100k | 6 | |
| 420Ω | 1 | |
| Preset 10k | 1 | |
| Capacitors | ||
| Ceramic 0.01µF | 1 | |
| Ceramic 0.1µF | 1 | |
| Electrolytic 680µF 50V | 1 | |
| Semiconductors | ||
| IC LM324 | 1 | |
| Transistor BD139 | 1 | |
| Diode 1N4007 | 1 | |
| Diode FR502 | 1 | |
| Inductor 60 turns of 22SWG enamelled copper wire. Core Dimensions: Outer diameter: 0.6 inch, Inner diameter: 0.3 inch, Height: 0.25 inch | 1 |
Circuit work like boost converter with op-amp oscillator, transistor switch, and inductor.
Op-amp IC1 LM324 is astable multivibrator which make high frequency signal and compare voltage to keep output stable.
Oscillation speed change by resistors R1, R2, R3, R4 and capacitors C1, C2.
Signal from IC1 turns ON the transistor Q1 BD139 and act like fast switch.
When Q1 is ON current flow in inductor L1 and store energy in magnetic field.
When Q1 is OFF inductor release energy and make voltage spike.
Diode D1 1N4007 block reverse current and only higher voltage goes through.
Boosted voltage is smooth by D2 and capacitor C3 and give steady 24V DC output.
Formulas with Calculations:
Formulas and calculation for simple 12V to 24V converter with IC LM324:
Oscillation frequency f = 1 / (1.38 × (R1 + 2R2) × C2)
where,
- R1 is 100k
- R2 is 100k
- C2 is 0.1µF
- f is 24.2Hz
Inductor voltage boost:
Vout = Vin / (1 – D)
where,
- Vin is 12V
- D is 0.5
- Vout is 24V
Capacitor C3 value:
C = I / (f × Vripple)
where,
- I is 1A
- f is 24.2Hz
- Vripple is 1V
- C is 41.3mF
Since 41.3mF is not a standard capacitor so we can use 680µF capacitor for less ripple.
How to Build:
To build a 12V to 24V DC Voltage Converter Circuit using IC LM324 follow the below steps for connections:
- Gather all parts from the above circuit diagram
- Connect pin 1 of IC1 LM324 to pin 3.
- Connect resistor R2 between pin 2 and pin 1 of IC1.
- Connect resistor R1 between pin 3 and pin 1 of IC1.
- Connect capacitors C1 and C2 in series from pin 2 to pin 4 of IC1.
- Connect resistor R3 from pin 3 to junction of C1 and C2 and then to GND.
- Connect pin 5 of IC1 to center pin of VR1 preset.
- Upper pin of VR1 to +12V and lower pin of VR1 goes to GND.
- Connect resistor R5 from pin 6 of IC1 to GND.
- Connect resistor R6 between junction of R5 and pin 6 to 24V output (Vout).
- Connect resistor R4 between pin 3 and pin 7 of IC1.
- Connect resistor R6 from pin 1 of IC1 to base of transistor Q1.
- Collector of Q1 to one end of coil L1 and other end of L1 connect to +12V.
- Cathode of diode D1 to junction of Q1 collector and L1 and anode of D1connect to junction of Q1 emitter and GND.
- Connect capacitor C3 positive to 24V output (Vout) and negative to GND.
- Connect anode of diode D2 between diode D1 and capacitor C3.
Conclusion:
This 12V to 24V DC Voltage Converter Circuit using IC LM324 is low cost and power efficient.
It uses LM324 oscillator and transistor to boost voltage.
It gives steady 24V from 12V source.
The circuit is good for cars, battery devices and for small machines.