TPS40200 Inverting buck-boost

Gadi Fishel1

Other Parts Discussed in Thread: TPS40200

Hi, I've made simulation for TPS40200 based on slvm023 for -5.2V and adjust it for my required output -15V @ 300mA. Simulation works good. I made 50uH inductror ( core C055050) but prototype didn't start. I suppose problem could be with feedback , it requires ~700V but positive. Some advise, please. Thank you!

over 12 years ago

0 Gadi Fishel1 over 12 years ago

Prodigy 70 points

>it requires ~700V but positive

means ~0.700V of feedback

0 Anthony F over 12 years ago in reply to Gadi Fishel1

TI__Mastermind 35165 points

Hi Gadi,

Can you share a schematic please?

Thanks,
Anthony

0 Gadi Fishel1 over 12 years ago in reply to Anthony F

Prodigy 70 points

Dear Anthony, please see attachment

2273.-15V 300mAmp TPS40200.docx

0 JohnTucker over 12 years ago in reply to Gadi Fishel1

TI__Guru**** 191445 points

Probably need some capacitance between VIN and the IC GND (-Vout).

0 Gadi Fishel1 over 12 years ago in reply to JohnTucker

Prodigy 70 points

Dear John, I've alredy put 10uF capacitors between Vin and Vout (-15V) per Na saggestion . But still nothing.

0 JohnTucker over 12 years ago in reply to Gadi Fishel1

TI__Guru**** 191445 points

I guess we will need to see some wave forms. Try triggering on teh rising edge of VIN, see what happens at the various pins, especially teh switching node.