PMP10090: 12V to +/-24V loading issue with PMP10090 design

Hi Sanjay,

Can you help send the schematic and BOM for your design? At 24V, the PMP10090 output power stage components are not rated for a 24V output. Example is the 25V output caps. Was this adjusted on your board as well? 50V rated caps would be okay. With derated caps, the converter would have trouble supplying the output current at each cycle. Please let us know if this helps. Thanks!

Hi Darwin,

Yes, the output caps are rated at 50V. Pls find the Schematic attached below

Thanks for sending Sanjay, at higher output voltages there will be more stress on the diodes and 40V diodes are very marginal. Can you increase the voltage rating of the schottky diodes to 50-60V. And also can you try removing the snubber (C250) for now, this is probably dissipating some current. We need to narrow down where the extra current that's triggering the current limit is coming from. Thanks!

Hi Darwin,

I have changed D201, D202 to B280-13-F, 80V,2A Schottky diode as suggested and removed C250. Still the problem persists after connecting 100 ohms at 24V output. 

Thanks for checking Sanjay, I'll work with our team to see if we have missed anything else on this debug. Thanks!

Thanks Darwin, kindly suggest for further resolution asap

Hello Sanjay,

I recalculated and checked your design and it should be good up to 500mA load at each output at minimum input voltage 10V, current limit of internal switch is 4.5Apk;
remote troubleshooting is impossible, schematics seems similar to mine - so please check signals around controller via scope.

For 10Vin and 2x 500mAout duty is around 72%, current at switch is 3.0Arms and 3.9Apk, no current issue.
ON-time is 2.38us, OFF-time is 950ns, no timing or blanking issue.
Right half plane zero is at 13kHz, so loop bandwidth at 2.3kHz is acceptable, no loop issue.

So schematics looks good for me, please check layout and the signals at each controller pin.

That's all I could do remote, best regards, Bernd