A DC to DC converter is an important circuit that can make voltage levels go up or down based on what is needed for different uses.
In this article, we will discuss about a Simple 12V to 24V DC Voltage Converter Circuit using IC LM324.
This special DC to DC converter circuit works by doubling the input voltage with a boost converter that uses an oscillator.
Remember the load current should not go over 800mA.
This circuit is really helpful for powering 24V devices from a 12V source making it great for cars, solar power and battery operated gadgets.
Circuit Working:
Parts List:
| Component Type | Value / Specification | Quantity |
|---|---|---|
| Resistors (1/4 watt unless specified) | ||
| Fixed Resistor | 100k | 6 |
| Fixed Resistor | 420Ω | 1 |
| Preset Resistor | 10k | 1 |
| Capacitors | ||
| Ceramic Capacitor | 0.01µF | 1 |
| Ceramic Capacitor | 0.1µF | 1 |
| Electrolytic Capacitor | 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 |
The circuit works like a boost converter using an operational amplifier (op-amp) oscillator, a transistor switch and an inductor to do its job.
The op-amp IC1 LM324 is arranged as an astable multivibrator, which makes a high frequency switching signal and works as a voltage comparator, making sure the output voltage stays stable and efficient.
The speed of the oscillation depends on the values of resistors R1, R2, R3, R4 and capacitors C1 and C2.
The signal from IC1 turns on the transistor Q1 BD139 which acts like a fast switch.
When Q1 is ON current flows through inductor L1 allowing it to gather energy in its magnetic field.
When Q1 turns OFF the inductor releases its stored energy creating a voltage spike.
Diode D1 1N4007 stops any reverse current letting only the higher voltage pass through.
This boosted voltage is then smoothed out by D2 and capacitor C3 giving a steady 24V DC output.
Formulas with Calculations:
The formulas with calculations are mentioned below Simple 12V to 24V DC Voltage Converter Circuit using IC LM324:
Oscillation Frequency:
frequency f is given by:
f = 1 / (1.38 × (R1 + 2R2) × C2)
assuming R1 = 100k, R2 = 100k, C2 = 0.1µF
f = 1 / (1.38 × (100k + 2 × 100k) × 0.1µF)
f = 1 / (1.38 × 300k × 0.1µF)
f = 1 / (1.38 × 30ms)
f = 24.2Hz
Inductor Voltage Boosting:
output voltage Vout is given by:
Vout = Vin / (1 – D)
assuming Vin = 12V and duty cycle D = 0.5
Vout = 12V / (1 – 0.5)
Vout = 12V / 0.5
Vout = 24V
Capacitor Selection:
capacitor value C3 is given by:
C = I / (f × Vripple)
assuming load current I = 1A, frequency f = 24.2Hz, ripple voltage Vripple = 1V
C = 1A / (24.2Hz × 1V)
C = 1 / 24.2
C = 41.3mF
since 41.3mF is not a standard capacitor value a 680µF capacitor is used with lower ripple.
How to Build:
To build a Simple 12V to 24V DC Voltage Converter Circuit using IC LM324 follow the below steps for connections:
- Gather all the components as mentioned in the above circuit diagram
- Connect pin 1 of IC1 LM324 to pin 3
- Connect resistor R2 one terminal from pin 2 of IC1 and other terminal to pin 1 of IC1
- Connect pin 3 of IC1 to one terminal of resistor R1 and other terminal of R1 connect to pin 1 of IC1
- Connect capacitor C1 and C2 in series between pin 2 and pin 4 of IC1
- Connect resistor R3 one terminal to pin 3 of IC1 and other terminal of R3 connect between the junction of capacitor C1 and C2 and GND.
- Connect pin 5 of IC1 to center pin of VR1 preset and upper pin of VR1 connect to +12V DC and lower pin of VR1 connect to GND.
- Connect resistor R5 one terminal to pin 6 of IC1 and other terminal connect to GND.
- Connect resistor R6 one terminal to the junction of resistor R5 and pin 6 and other terminal of R6 resistor connect to Vout output of 24V DC
- Connect resistor R4 one terminal to pin 3 of IC1 and other terminal connect to pin 7 of IC1
- Connect resistor R6 one terminal to pin 1 of IC1 and other terminal connect to base of transistor Q1
- Connect the collector of transistor Q1 to one terminal of L1 coil and other terminal of coil L1 connect to +12V DC
- Connect cathode of diode D1 to the junction of collector Q1 and L1 coil and anode of D1 connect to the junction of emitter of transistor Q1 and GND
- Connect capacitor C3 positive to Vout output of 24V DC and negative of C1 connect to GND.
- Connect anode of diode D2 between diode D1 and capacitor C3
Conclusion:
This Simple 12V to 24V DC Voltage Converter Circuit is power efficiently and at a low cost.
It uses an LM324 oscillator and a transistor to boost the voltage, ensuring a steady 24V output from a 12V source.
This design is especially handy for cars, battery operated gadgets and small industrial machines.