Summary of Digital DC Power supply using PWM with PIC microcontroller
This project describes a digital DC power supply (5V-12V) controlled by push buttons to adjust voltage output using a PIC microcontroller. The output voltage regulation is achieved by varying the PWM signal width from the microcontroller, which is then filtered and amplified by an operational amplifier before controlling the LM317 voltage regulator's adjust pin. This setup allows easy and precise digital voltage adjustment instead of using traditional knobs.
Parts used in the Digital DC Power Supply using PWM with PIC microcontroller:
- PIC 16F73 microcontroller
- LCD 16x2 display
- 20 MHz Oscillator
- Variable resistors (5k Ω, 1k Ω, 50k Ω)
- 7805 Voltage Regulator
- 7818 Voltage Regulator
- LM317T Voltage Regulator
- LM741 Operational Amplifier
- Push Button Switch
- Resistors (1k Ω, 220 Ω)
- Capacitors (47 µF, 10 µF, 1 µF, 0.1 µF)
- Vero board
- Heat Sink
In our lab I saw many DC power supply which have a variable knob to regulate the output. I was dreaming to make such a project where I can regulate the voltage using push button.As I am not an industrial level expert so this project is just about a digital DC power supply of small range(5V-12V). You can press push buttons to increase or decrease output voltage.Here we use LM317 to regulate the output voltage. Output voltage is controlled by the PWM output of a pic microcontroller.An OP-AMP is required to amplify the PWM output level. The idea is simple and easy to implement in circuit.
Necessary Software:
1. Proteus 7.8 Professional
2. MicroC Pro
3. PICKIT 2.61 Boot Loader
Necessary Equipment:
1. PIC 16F73
2. LCD 16×2
3. 20 MHz Oscillator
4. Variable resistor (5k Ώ, 1k Ώ, 50k Ώ)
5. 7805 Voltage Regulator
6. 7818 Voltage Regulator
7. LM317T Voltage Regulator
8. LM741 Op Amp
9. Push Button Switch
10. Resistor (1k Ώ, 220Ώ)
11. Capacitor (47, 10, 1, 0.1 uF)
12. Vero board
13. Heat Sink
Description:
· LM317 can give output of 3-37V . It can change its output voltage according to the adjust pin voltage.
· PWM signal is generated from microcontroller. The signal is applied to RC low pass filter which makes a DC voltage level.
· This voltage is applied to Op Amp to get required gain.
· This amplified voltage is applied to LM317 adjust pin.
· From microcontroller we adjust the width of PWM signal. More width gives higher DC level.
· It also changes the adjust pin voltage which controls the output of LM317.
Source : Digital DC Power supply using PWM with PIC microcontroller
