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TPS92515-Q1: start up delay

Shinji Tsuji
Genius 14149 points
Part Number: TPS92515-Q1
Other Parts Discussed in Thread: TPS92515

Hi team,

I captured TPS92515 start up delay (CH2=VLED, CH1=VIN) and found about 500us of power up delay and about 150us of start up time.

Do you have a spec for this start up delay in the datasheet?

Does it change over temp/process/Vin/out condition?

regards, 

  • 0
    TI__Mastermind 28655 points

    Hello,

    There are a few things that cause start-up delay.  For example, iff the Vcc capacitor is 1 uF it will take, typical, 220 us to charge VCC to VCC uvlo level.  Output rise time can vary depending on the capacitor across the LEDs or output capacitor on the driver and the LED string voltage.  If boot voltage is low the TPS92515 needs to cycle the switch node to recharge the boot capacitor.  This topology can start up fast but it's still limited by capacitor charging times.

    Best Regards,