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TPS92390: use tps92390 LED blink, unstable.

Part Number: TPS92390

Dears:

   We use tps92390 as LED driver, input 5v, output 20V, 4 string LED, each string 80mA current. LED blink, unstable when power on. the schematic and test waveform as below, pls help to analysis, thanks!

    schematic:

LED+, normal is 20V, but max approach 40V. 

FB waveform:

SD waveform:

  • Hi,

    It seems the device is keeping shutdown and restart. We need to find where trigger the fault firstly. What the state for INT pin? Can you read the registers SUPPLY_FAULT_STATUS, BOOST_FAULT_STATUS and LED_STATUS?