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Original question:

TPS922055: High Power LED Flash Driver for Machine Vision

TPS92641: Ultra Fast and High-Current LED Driver

Lorenz Max
Prodigy 20 points
Part Number: TPS92641

Hi Steven,

thank you for your feedback, I created a new thread. 

Challenge:
We want to generate very short LED pulses (1µs or better 0.5µs) with high current (minimum 2A, better 3A) that can be controlled (dimmed).

The pulses should be adjustable with a frequency between 30 and 200Hz. Input voltage is probably around 24V but could be changed if needed. We want to drive 1 to 4 LEDs with each 3V to 3.6V drop.

Can we do this with the TPS92641 and how do we need to configure it? Is there a dev board for testing?

Thank you very much!

  • 0
    Prodigy 20 points

    ok, this seems to be the suiting dev board: https://www.ti.com/tool/TPS92641EVM 

  • 0
    TI__Mastermind 23150 points

    Hi Lorenz,

    It is possible to achieve this with the shunt FET PWM dimming feature of TPS92641. You can use TPS92641EVM for evaluation.

    Best Regards,

    Steven

  • 0
    Prodigy 20 points

    Hi Steven, 


    thanks for your answer. Unfortunately, the TPS92641EVM seems to limit testing opportunities. The input voltage has to be above 43V and LED current is limited to 1A. Is it possible to run two TPS92641EVM  synchronously to achieve 2A?

    Using 24V doesn't provide sufficient supply?

    The     TPS92641 works with a maximum of 20000:1 Shunt FET PWM Dimming. Hence, we can apply a 50Hz PWM with duty cycle 1:20000 to achieve a 1µs current pulse. Can we generate a 0.5µs current pulse with 100Hz PWM?

    Best

    Lorenz

  • 0 in reply to Lorenz Max
    TI__Mastermind 23150 points

    Hi Lorenz,

    Lorenz Max said:

    thanks for your answer. Unfortunately, the TPS92641EVM seems to limit testing opportunities. The input voltage has to be above 43V and LED current is limited to 1A. Is it possible to run two TPS92641EVM  synchronously to achieve 2A?

    Using 24V doesn't provide sufficient supply?

    You can modify the components on the EVM based on your application condition. Section 8.2 Typical Applications from the datasheet should give you some idea on how to choose those components.

    Lorenz Max said:
    The TPS92641 works with a maximum of 20000:1 Shunt FET PWM Dimming. Hence, we can apply a 50Hz PWM with duty cycle 1:20000 to achieve a 1µs current pulse. Can we generate a 0.5µs current pulse with 100Hz PWM?

    The minimum pulse width that TPS92641 can output with shunt FET depends on your application condition and your acceptable range of current rising / falling time. Changing the shunt FET PWM dimming frequency will not change the minimum pulse width that TPS92641 can output.

    Best Regards,

    Steven