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TPS61170-Q1: TPS61170 --Generating negative voltage with charge pump topology

Zhiyao Liu
Prodigy 120 points
Part Number: TPS61170-Q1

Tool/software:

Hi experts，

 I designed a negative voltage circuit  based on the charge pump topology. 

The load capacity of the circuit confuses me: We use a constant current source to extract the load. the -24V output can drive 160mA, while the -17V output can only drive 90mA. I’d like to ask what primarily determines the load capacity of this circuit.

Thanks 

Zhiyao

  • 0
    TI__Genius 16010 points

    Hi Zhiyao,

    What's the input voltage?

    In normal work conditions, higher Vout means lower max Iout. What's the behavior when Vout is configured as -17V and Iout > 90mA? Vout decreases, rings, or drops to zero?

    Regards

    Lei

  • 0
    Prodigy 120 points

    Hi Lei，

    The input voltage comes from a regulated power supply of 12V.

    I measured the waveforms under different loads and voltages.（CH1=Vout, CH2=IL, CH3=Vsw）.Vout drop when load increase.

    Thanks 

    Zhiyao

  • 0 in reply to Zhiyao Liu
    TI__Genius 16010 points

    Hi Zhiyao,

    From the schematic, I don't see where the problem is.

    Will it be available to ship one or two boards to me for debug?

    Or could you try the following solution?

    Just let me know if you have any new findings.

    Regards

    Lei