Problem with high capacitive load on TPS24720

Meysam Peykanu

Other Parts Discussed in Thread: TPS24720

Hi,

We want to use TPS24720 as a circuit breaker for 12 volt power rail but we have problem with high capacitive load. TPS24720 turns on a carrier board successfully so startup phase is finished. But when the carrier board enables the power rail of a demanding load e.g a big graphics card, the power drops to 4 volts for around 6 ms. The Ct is big enough not to let the timer to expire and the power is back on again. But this causes down-stream regulators to fail and the carrier board to RESET. A snapshot of the output rail and timer signals is attached.

The values for resistor are:

Rimon : 1k

Rprog: 4.99k

Rset : 100

Rsense: 0.001

So it seems that ILIM or PLIM are not limiting factors and the device actually detects a short circuit! Is this true? What can be done for such a case?

Best regards,

Meysam

over 10 years ago

0 Aleksandras_Kaknevicius over 10 years ago

TI__Genius 15780 points

Hi Meysam,

This part falls under the Power Interface forum. I will go ahead and move this post there.

Thanks,

Alek Kaknevicius

0 Eric Wright over 9 years ago in reply to Aleksandras_Kaknevicius

TI__Mastermind 42795 points

Can you quantify the downstream inrush current when the graphics card starts up? You might have to increase the current limit setpoint on the TPS24720 to allow the output to stay up as this current is drawn. But, it is critical to know the exact inrush profile of the load so that a safe and reliable hotswap circuit can be designed.

Please send a current waveform if possible.

Power management

Power management forum

Problem with high capacitive load on TPS24720