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TPS92561: DC/DC booster with battery input

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?

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

  • 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.