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TPS922052: TPS922052 requires a 10uS pulse for optical applications.

zhichao chen
Prodigy 60 points
Part Number: TPS922052
Other Parts Discussed in Thread: LM3409

Tool/software:

Hello, we are using tps922052 for optical pulse output. It takes more than 2ms to light up the LED with this chip for the first time, but we would like the rise time to be in microseconds, similar to the LM3409. We want the LED to stay lit for 10us before turning off, but the LED's hysteresis effect is too pronounced. Do you have any other chips that can do pulse output? How can Mr. Hu design with this chip to meet my requirements?

  • 0
    TI__Mastermind 30551 points

    Dear Sir,

    Thanks for reaching out! May I know the reason to choose other LED drivers but not LM3409? Is it because customer prefer integrated FET solutions. LM3409 is hysteresis control and TPS922052 is constant off time peak current control. So that the response time performance is different. Besides, the internal ADIM and PDIM operation is different. 

    Thank you!

    BRs

    Lucia

  • 0 in reply to Lucia Gao
    Prodigy 60 points

    Hello, the optical power stability of TPS922052 is very good right now, but the startup time is too long for us to accept. We also tested the LM3409, which has a very short startup time, but when using analog control, the minimum current is still 20-40mA. Such a small current is not acceptable for optical dimming using PWM, so we are currently unable to solve the shortcomings of both chips.