Hi MarkT
Happy New Year
I am attempting to use a POLOLU Baby Orangutan which has an on-board ATmega 328P + TOSHIBA TB6612FNG dual H-bridge.
It appears to draw woefully large amounts of power in sleep mode so I would like to use your above power isolation circuit to resolve this (in particular I like the functionality of the “sense button” circuit).
However I do have some questions which hopefully you’ll be able to advise on.
a) Do I need to de-bounce the momentary push button? The NXP Semiconductor datasheet for Quad 2 Input NOR gates 74AHC02; 74AHCT02 states that “All inputs have a Schmitt-trigger action”, would this negate the need for de-bounce circuitry?
b) When changing batteries, you advise “a cap to fix startup-state would work but you’d need another series-resistor then to limit current to controller pin”. Can you please advise values for these components and where they should be positioned?
c) I presume you recommend placing a 0.1u cap across the flip-flop Vcc / GND and tying the spare gates to GND?
d) I intend using a FAIRCHILD Semiconductor FQP27P06 P-Channel MOSFET to switch the power, any comments on my selection of that device?
Thanks in anticipation
RayK
PS I have attached datasheets for the 74AHC02; 74AHCT02 & FQP27P06
74AHC_AHCT02.pdf (86.8 KB)
FQP27P06.pdf (747 KB)