TC4427 Driver problems .... possible solution
Hope I'm in the right forum here.
Also, hope nobody's had a day like mine today, chasing TC4427 "failures" ........ but I might have a solution.
I'm using multiple TC4427 drivers to control many external linear actuators FORWARD/REVERSE.
The linear motors each need 12VDC power (6A fused on my PCB) and a signal ON=EXTEND, OFF=RETRACT.
They have internal relays, to drive the motor in each direction and stop automatically at each end.
The TC4427 can take 2 inputs from the PIC and drive 2x12V power outputs .... all in an 8 pin package....... lovely.
Simple ! ....... until the TC4427 start "failing".
During long "OUTPUTS-OFF" periods, individual TC4427's can suddenly latch-up and cannot be switched off by the PIC.
This is obviously due to transients, grounding problems, etc.
So, I've done loads of google-ing about latch-ups, etc .... and I think I've found a work-around.
The TC4427's have not failed, they work fine when tried again in circuit.
The secret seems to be to "Flash" their inputs, from the PIC, about every 1 second.
Flashing them ON for about 50uS, then OFF again seems to keep them healthy throughout.
Clearly, the outputs being ON for only 50uS, is far too fast for the linear motor relays to react, so happy days.
Working well so far !
Hope this helps someone else.