Hi
Just a comment on this Dual 30A Hbridge available from lots of suppliers
eg
I used it to run 2 dc motors and run with arduino.
When I send an analogwrite value of 255 (motor full on) the supply volts of 13.7v drops to 10.5v on forward and 7.5v on reverse on the motor connections.
This is also true if I just feed the PWM pin 5v.
I found that I had to use a value of 254 as my full on PWM value and the the motor ran with virtually no voltage drop.
Not sure why but seems to be a quirk of this hbridge.
The driver can operate at 0% -99% of the duty cycle of the PWM modulation, the motor driving voltage can be obtained sufficiently.
So setting the output level above 252 is probably going to cause problems.
With most MOSFET half-bridge drivers the output cannot be held high continuously as the top
MOSFET loses its bootstrapped gate driver supply. So avoid setting to the highest values of PWM
where the Arduino outputs continuous HIGH.
The bootstrap circuit raises the MOSFET gate voltage higher than the MOSFET supply voltage so the MOSFET will fully turn on. Attached pix is a bootstrap circuit that requires a pulsed driver supply to raise the gate voltage.
