Kingpin094
New Member
Does this circuit (see attachment) look like a good way to drive a 12V gear motor with stall current of roughly 700mA? (Vcc is 12V)
I built the circuit and it seams to work..... sorta. The motor spins quit nicely when the PWM is 100%.
There is little drop accross the H-bridge. When the PWM is set to below 100% ie. 90% the voltage
on the bridge drops from 11.5 to less then 6 and the transitors begin to get hot. The input logic
seams to function correctly and the bridge works if a'b = Vcc and ab' = GND (counterclockwise
rotation) and if a'b = GND and ab' = Vcc (clockwise rotation).
Anyone have any ideas on what could be wrong? Is this a good circuit or should I start over with
a different one?
Thanks ahead of time.
I built the circuit and it seams to work..... sorta. The motor spins quit nicely when the PWM is 100%.
There is little drop accross the H-bridge. When the PWM is set to below 100% ie. 90% the voltage
on the bridge drops from 11.5 to less then 6 and the transitors begin to get hot. The input logic
seams to function correctly and the bridge works if a'b = Vcc and ab' = GND (counterclockwise
rotation) and if a'b = GND and ab' = Vcc (clockwise rotation).
Anyone have any ideas on what could be wrong? Is this a good circuit or should I start over with
a different one?
Thanks ahead of time.