Boost Converter 12V to 120V DC Step-Up Circuit is made to raise 12V to 120V DC.
It helps to change voltage level when needed.
It takes 12V input and makes strong 120V output.
Circuit is good for using high voltage from low voltage like battery.
Output powers to about 100 watts.
Circuit has two parts first is simple inverter and second is rectifier and filter.
IC 555 timer runs at 100Hz as astable multivibrator and it connects to clock input of CD 4013 flip-flop IC.
Circuit works by switching with IC 555, CD 4013 flip-flop, power transistors and step-up transformer to raise the voltage.
Circuit Working:
Parts List:
| Component | Value | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | ||
| 18k | 1 | |
| 3.3k | 1 | |
| 1k | 1 | |
| 1.5k | 2 | |
| Preset 100k | 1 | |
| Capacitors | ||
| Ceramic 330nF | 1 | |
| PPC 220nF 250V | 1 | |
| Electrolytic 1000µF 25V | 1 | |
| Electrolytic 2200µF 250V | 1 | |
| Semiconductors | ||
| Transistor MJ3001 | 2 | |
| 9-0-9V /120V / 3A Mains Transformer | 1 | |
| 1N5408 Bridge Rectifier Diodes | 4 |
Boost Converter 12V to 120V DC work like this:
Oscillator Stage IC1 555 Timer:
IC1 555 timer is made as astable multivibrator.
It makes clock pulse to control flip-flop IC2 CD 4013 IC
Speed depend on resistors VR1, R1 and capacitor C1.
Flip-Flop CD 4013 IC2:
CD 4013 flip-flop cuts frequency from IC1 555 timer in half.
Make pulses to turn power transistors Q1 and Q2 ON and OFF.
Power Transistors MJ3001:
Q1 and Q2 act as switches.
Control current in transformer primary side.
Make magnetic field to raise voltage in transformer secondary.
Step-Up Transformer:
Transformer 9-0-9V raise voltage from 12V AC to about 120V AC.
Rectification and Filtering:
Bridge rectifier D1 changes AC to DC.
Capacitors C3 and C4 smooth output to steady 120V DC.
Formulas with Calculations:
IC1 555 Timer Frequency:
f = 1.44 / ((VR1 + 2R1) * C1)
Put values:
f = 1.44 / ((100k + 218k) * 330nF) = 24.5 Hz
Flip-Flop Output Frequency:
CD 4013 divides frequency by 2:
f_out = 24.5 / 2 = 12.25 Hz
Transformer Voltage Gain:
V_secondary = V_primary * (N_secondary / N_primary)
With 12V primary and 1:10 turns ratio:
V_secondary = 12V * 10 = 120V AC
Output DC Voltage after Rectification:
V_DC = V_AC_peak – V_drop
where,
- V_drop is diode voltage loss
Peak AC Voltage Calculation:
V_AC_peak = V_AC_rms * 1.414 (sqrt(2)
Converts RMS voltage to peak voltage.
How to Build:
To build a Boost Converter 12V to 120V DC Step-Up Circuit follow the below mentioned steps for connections:
- Get all parts from circuit diagram
IC1 555 timer:
- Pin 1 connects to GND
- Pin 2 connects to pin 6
- Pin 3 connects to pin 3 of IC2 through resistor R4
- Pin 4 & 8 go to +12V supply
- VR1 resistor connect between pin 7 and +12V
- R1 resistor connect between pin 7 and pin 6
- C1 capacitor connect between pin 2 & 6 and GND
- R2 resistor from Pin 3 goes to GND
- C2 capacitor positive go to +12V and negative go to GND
IC2 CD 4013 flip-flop:
- Pin 1go to base of Q1 through resistor R4
- Pins 4, 6, 7 go to GND
- Pins 2 & 5 go to base of Q2 through resistor R5
- Pin 14 connects to +12V supply
Transistors Q1 and Q2:
- Collector of Q1 goes to primary transformer wire
- Emitter of Q1 connects to emitter of Q2
- Primary center wire of transformer goes to +12V
- Collector of Q2 connects to other primary transformer wire
- Transformer secondary wires goes to bridge rectifier D1 to D4 ends
- Other two bridge rectifier ends connect to 120V DC output
- Capacitors C3 & C4 connect across bridge rectifier output
Conclusion:
This Boost Converter 12V to 120V DC Step-Up Circuit raises 12V DC to steady 120V DC using 555 timer, CD4013 flip-flop, power transistors and transformer.
It is good for small power, emergency lights and portable high voltage devices.