Other Parts Discussed in Thread: TPS61170
I would like to generate a split supply from USB VBUS (4-5.25 V). Anything above ±4 V would be ok, but no more than ±6 V (and they don't need to be exactly symmetrical). It needs to supply no more than 20 mA from both outputs. It needs to be possible to shut it down completely, so a chip with synchronous switch inside that opens during shutdown would be good (or external diode with FET in series to shut it down).
I used the design tools to find the TPS61220, and am wondering if I can add a charge pump to it, for the negative supply, like this article:
However
Something like this, which shows similar currents at both outputs:
I tried simulating it in TINA:
but it takes a very long time to simulate, making me suspicious, and the transient simulation doesn't show the inductor current switching at all.
Any advice?