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TPS92515: Startup time by using PWM pin

tateo yamashiro
Guru 10890 points
Part Number: TPS92515

Hi,

We got a question from the customer about TPS92515.
Could you help us?

[Question]
- How much is the startup time by using PWM pin. They want 30usec startup time. Can this device meet their requirement? I would appreciate it, if you could provide the waveform.

- Condition -
Vin=24V
LED=6 series
If=800mA

- Does the start-up time depend on some kind of factor? If there is possibiity to vary due to some factors, please let me know these factors.

Best Regards,
tateo

  • 0
    TI__Mastermind 28655 points
    Hello Tateo,

    If the part is powered up and PWM is held low, when PWM is pulled high it can meet their start up time requirement dependent on their design. Vin is 24V, Vled (assuming 3V LED) is 18V, V applied to the inductor is Vin - Vled = 6V. V = L*(di/dt), di is 800 mA, dt is 30 uS or less, that means L has to be 220 uH or smaller.

    Regards,