Pogo pins power clarification - reading schematics
04-07-2021, 05:25 PM
(03-14-2021, 07:42 AM)megous Wrote: - USB-5V seems like it should always be 5V if PS-5V is enabled and if it has some other voltage when PS-5V is disabled, it's only because there's some remaining charge on the capacitors, or some current going in the reverse direction via U1302 via internal N-MOSFET body diode (see https://megous.com/dl/tmp/06d11858b841c503.png - there's a parasitic diode between S-D in that direction) You're not supposed to rely on USB-5V in this case, when PS-5V is off (another diode on the PS-5V output prevents backfeeding of power through PS-5V)
Actually, the LPW5206 has no parasitic body diode, as specified on page 1 of the datasheet. Here's a quotation:
Quote:A built-in charge pump is used to drive the N-Channel MOSFET that is free of parasitic body diode to eliminate any reversed current flow across the switch when it is powered off.
