| ??? 11/05/07 04:24 Read: times |
#146583 - I thought you said it was 220 VAC Responding to: ???'s previous message |
Hendryawan said:
Dear Richard,
Thank for your comment. In my illustration have approx. 300Vdc Vin, so I need the circuit to control switching the transistor to produce 12Vdc output, the transformer is not step-down type. It is smps power supply with named flyback converter. hendry It looks as though you're doing things the hard way. Is there a reason why you want to do things the more costly, noisy, and inherently less reliable way? 220 VAC => 12 VAC transformers are pretty common, and pretty inexpensive. I have one down in my basement somewhere that's about 2 cm x 2cm x 1.5cm. I'm pretty sure it will produce >>100 mA at its CT secondary (#22) winding. I doubt a rectifier pair would cost more than that 220-volt-capable switching transistor and a flyback transformer probably won't cost less than that little 220 => 12.6-volt transformer I mentioned. I bet a 7812 costs less than a switching regulator suitable for what you propose. If your boss says you have to do it the way you suggest, then you're stuck with that, I guess, but I'd give it a bit more thought, particularly the cost aspect. RE |
| Topic | Author | Date |
| small dimension power supply | 01/01/70 00:00 | |
| If you need to ask the question... | 01/01/70 00:00 | |
| And | 01/01/70 00:00 | |
| Mr.Wichit Sirichote | 01/01/70 00:00 | |
| input & output isolation | 01/01/70 00:00 | |
| No, that\'s not it | 01/01/70 00:00 | |
| it is smps | 01/01/70 00:00 | |
| I thought you said it was 220 VAC | 01/01/70 00:00 | |
| his boss probably right | 01/01/70 00:00 | |
| Toroidal x`mer | 01/01/70 00:00 | |
| cost | 01/01/70 00:00 | |
| Surges | 01/01/70 00:00 | |
| A capacitor main Supply. | 01/01/70 00:00 | |
| ARGH | 01/01/70 00:00 | |
They have their place - but not for Hendryawan | 01/01/70 00:00 |