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TPS92515: We want to check whether the short LED and open LED test waveforms are ok.

Frank Xiao
Genius 12055 points
Part Number: TPS92515

Hi team,

My customer is using the TPS92515 now. When they do the LED open test and LED short test. The waveforms are below. Could you please help check whether the waveforms are right? And when my customer tests normal condition, the frequency is 240hz,

（open led test, frequency is 17.6hz)

 

（short led test, frequency is 4.2khz)

Thanks.

BR

Frank

  • 0
    TI__Mastermind 25500 points

    Hello Frank,

    Yes, those look correct. With an open LED string the output voltage will shoot up to the input voltage (switch stays on) until the boot cap discharges to its UVLO level and the switch turns off. When boot charges again the cycle repeats. During a shorted output (the device is designed for this) the switch off time will increase and the on time will become very short. The result is a low frequency.

    Regards,

    Clint