Block a load supplied by an LDO

What about using a supervisor chip (e.g., MCP130 or MCP100) as the trigger? Use the *Reset out line to gate a logic-level FET with a low Ron at the available Vcc.

Thanks .I never heard of them before.Pretty cheap to.

Sample the input voltage to the regulator and use a comparator to hold a P-channel MOSFET OFF until VIN has been stable long enough for you to know that the output of the regulator is where it's supposed to be.

View in Courier:

PCH VIN>--+-----+---+----+---[LDO]----S D---+ | | | | | G | [Rt] [R1] | [R] | | | | | | | | | | +-----|--|-\\ | | | [LOAD] | | | >--+-----|--------+ | | +--|+/ | | | | | | | [Ct] [R2] | | | | | | | | GND>--+-----+---+----------+--------------+

BTW, what are the LDO's input and output voltages?

JF

Hi John

It's a 9V battery so about 9.5-6.5V in; and 5.6Vdc out. I went with the 5.6vdc out so I could just use diodes as cheap reverse polairity protection on the loads.

I have everything I need to try your circuit tommorrow. I'll let you know how it goes.

Thanks

Thanks John worked like a charm!