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JEast.1
JEast.1
Visitor II
October 19, 2020
Solved

Can Output Voltage be less than Supply voltage ona STP16DP05 Led Driver?

I am looking to drive 16 Infra Red Leds (1 per channel) at up to 100mA/25% duty Cycle. Doing the thermal calcs, I need to get the output much closer to the 1.35V led Vdrop to prevent excess heat at the STP16DP05 current sinks.

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    Peter BENSCH
    Peter BENSCHBest answer
    ST Technical Moderator
    October 26, 2020

    The min supply voltage of the STP16DP05 is 3.0V, so No chance of reducing it any further while adhering to the limits.

    It looks like the only options are either 2...3 of your IR LEDs in series, or using simple rectifier diodes in series with your IR LEDs. Depending on the switching frequency, zener diodes probably cannot be used due to their higher junction capacitance. However - that only moves the heat from the driver to the additional pn junctions.

    Good luck!

    /Peter

    In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
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    1 reply

    Peter BENSCH
    Peter BENSCHBest answer
    ST Technical Moderator
    October 26, 2020

    The min supply voltage of the STP16DP05 is 3.0V, so No chance of reducing it any further while adhering to the limits.

    It looks like the only options are either 2...3 of your IR LEDs in series, or using simple rectifier diodes in series with your IR LEDs. Depending on the switching frequency, zener diodes probably cannot be used due to their higher junction capacitance. However - that only moves the heat from the driver to the additional pn junctions.

    Good luck!

    /Peter

    In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
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