LM5027A: LM5027A asynchronous rectifier control

Kai Nomiyama

Part Number: LM5027A

Hi Team,

I have a following question about LM5027A so could you help below?

Question

Is it OK to float #4 pin(TIME2), #12 pin(OUTSR) and #18pin(SSSR) while LM5027A secondary side is working as asynchronous rectifier?

Please also let me know if there are anything to take care during working as asynchronous rectifier at secondary side instead of synchronous rectifier?

thanks,

Regards,

Kai

over 7 years ago

0 Brian Johnson96 over 7 years ago

TI__Expert 3200 points

Kai - an AE will respond to your question soon.

0 Wangxin Huang over 7 years ago

TI__Intellectual 1550 points

Hi Kai,

If you don't need the SR control signal, just ground SSSR, TIME2 and OUTSR.

Regards,

Wangxin

0 Kai Nomiyama over 7 years ago in reply to Wangxin Huang

TI__Expert 5295 points

Hi Wangxin,

Please let me double check about connecting GND.

I dont need the SR control signal but when SSSR is connected to GND, current souce of 25uA is also connected to GND.

in addition, when OUTSR starts to work, OUTSR becomes short to GND.

Are these stil no impact for normal opearation?

thanks,

Regards,

Kai

0 Wangxin Huang over 7 years ago in reply to Kai Nomiyama

TI__Intellectual 1550 points

Kai,

The current source flows to GND while SSSR pin is clamped to 0V. This will turn off OUTSR.

Regards,

Wangxin

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LM5027A: LM5027A asynchronous rectifier control