TPS61194: Design Review and NTC question

Michael Gilge

Part Number: TPS61194

Hello,

I need to design a backlight solution for a 4P11S display. The total current is typ. 240mA., i.e. 60mA per channel. Forward voltage is specified to be above 30.8 and below 36.3V.

Could you review the attached schematic for correctness?

Also, the LCD features an NTC for current reduction.Is there a way to couple the NTC with the Riset-resistor for current reduction for higher temperatures?

Best regards,

Michael

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Michael,

The switching frequency seems a little high, it may affect the efficiency, and for the thermal consideration, it is ok, but I think it should be a PTC, not NTC, since for PTC, temperature increase, resistor increase, so the current drop.

Regrads

Sean

0 Michael Gilge over 5 years ago in reply to Sean Zhou

Expert 1720 points

Hi Sean,

thanks for your quick response. What switching frequency do you recommend for highest efficiency? The 1.3MHz were motivated by the smaller and flat 10uH inductor.

Best regards,

MIchael

0 Sean Zhou over 5 years ago in reply to Michael Gilge

TI__Mastermind 22745 points

Hi Michael,

I can't give you a target switching frequency, you can get the 1.3Mhz as the start point, and you need to test the board and get the efficiency results and adjust the switching frequency, then you can get the best results.

Regards

Sean

Power management

Power management forum

TPS61194: Design Review and NTC question