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TPS92561: DC/DC booster with battery input

Egor Markov
Prodigy 180 points
Part Number: TPS92561
Other Parts Discussed in Thread: TPS92560

I have two kind of battery supply: 2 series Li-Ion battery for 48V 200mA LED and 2 series 12V Lead-Acid battery for 36V 600mA LED (customer request)

I need constant current output, but when battery voltage decreases, output current decreases so.

Tell me please, how to implement constant current?

  • 0
    Prodigy 180 points

    I know, that I need increase voltage at ADJ pin when input voltage decrease, but what is best way?

  • 0 in reply to Egor Markov
    TI__Mastermind 25500 points

    Hello Egor,

    As typically connected the TPS92561 is set up for high power factor for an AC input voltage, so you are modulating ADJ with the input. For a DC input that needs line regulation ADJ needs to be connected to a fixed voltage. That may be enough to get you where you need to be.

    However there may be better options for DC-DC. I would be happy to make a recommendation if you would like, but I would need full voltage/current ranges and whether or not you need dimming (analog or PWM). But the TPS92561 is a capable device and has no problem running from a DC input just like its companion the TPS92560.

    Regards,

    Clint