230V 12V, 1A SMPS Circuit Diagram and Connection

Hey, in this article we are going to see the circuit diagram of a 230V/12V, 1A SMPS. It basically, converts 230V AC supply into 12V DC supply. SMPS means Switched Mode Power Supply. SMPS power supplies are very power efficient, compact in design, and lightweight. The other way to convert 230V AC into 12V DC is by connecting a rectifier circuit with a step-down transformer. But this arrangement is very less power efficient and heavy in weight due to the big transformer size. Nowadays, the use of switched-mode power supply is everywhere from our mobile chargers to industrial electronic systems.

Components Required

• 5A Glass Fuse - 1 PCs
• 275V MOV - 1 PCs
• 1N4007 Diodes - 4 PCs
• Electrolytic Capacitor 10uF - 1 PCs, 470uF - 1 PCs
• Polyester Capacitor 0.1uF, 400V - 1 PCs
• Flyback Transformer EE20 - 1 PCs
• IC TNY267 - 1 PCs
• Optocoupler IC EL817 - 1 PCs
• Resistor 100 ohm - 1 PCs, 470 ohm - 1 PCs
• Schottkey Diode SB160 - 1 PCs
• TVS Diode P6KE200A - 1 PCs
• General Diode FR106 - 1 PCs
• Zener Diode 12V - 1 PCs

Circuit Diagram

Here, you can see the SMPS Circuit Diagram and the Connection between each component.

Connection Procedure

1. Connect the 5A glass in series with the phase terminal of the power source.
2. After the fuse connect the 275V MOV in parallel across the power source.
3. After the MOV connect the bridge rectifier circuit is built with 1N4007 PN Junction Diodes.
4. Connect a 10uF, 400V electrolytic capacitor across the output of the bridge rectifier circuit.
5. Connect the positive terminal of the rectifier output to the flyback transformer input side.
6. Connect pin no 2(source), pin no 3(source), pin no 7(high voltage return), and pin no 8(high voltage return) of the IC TNY267 to the negative terminal of the rectifier output.
7. Connect pin no 1(Bypass) of the IC TNY267 to the negative terminal of the rectifier output in series with a 0.1uF polyester capacitor.
8. Connect pin no 5(Drain) of the IC TNY267 to the rest input terminal of the flyback transformer.
9. Connect the P6KE200A TVS diode and FR106 Diode in series but in the opposite direction and connect this series combination across the flyback transformer input terminals.
10. Connect pin no 4(Enable) of the IC TNY267 to the Collector terminal(pin 4) of the EL817 IC.
11. Connect emitter pin(3) of the IC EL817 to the negative terminal of the rectifier output.
12. Connect an SB160 Schottky diode in series with the output of the flyback transformer.
13. Connect a 470uF, 25V electrolytic capacitor across the output terminal of the transformer after the Schottky diode.
14. Now the terminal of the transformer comes through the Schottky diode is to be used as the positive terminal and another terminal as the negative terminal.
15. Connect the negative terminal of the transformer to the cathode terminal(pin2) of the IC EL817.
16. Connect a series combination of a 100ohm resistor, a Zener diode, and a 470ohm resistor across the output positive and negative terminals.
17. Connect the anode side of the Zener diode to the anode terminal(pin 1) of the IC 817.

Operation and Working Principle

The 5A fuse is used for overcurrent or short-circuit protection purposes. The MOV is used for the input filter that can absorb the input power surge. The bridge rectifier circuit converts the 230V AC into 300V DC. Now this 300V DC is applied as an alternating AC supply to the flyback transformer with the help of the IC TNY267. The IC 817 is used to give feedback from the output to the IC TNY267. Also, it provides isolation between input and output. The SB160 Schottky diode helps to convert the AC supply from the output of the Flyback Transformer into the output DC supply. The 12V Zener diode is used to keep stable the 12V output DC voltage.

Read Also: 

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• Adjustable or Variable Power Supply Circuit Diagram (0-30V)
• A Simple Battery Charger Circuit Diagram for 12V Battery
• Battery Status Level Indicator Circuit Diagram (For 3V-12V Battery)

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