Probably an Issue with HG7881 Motor Driver

i newbie arduino world , been busy testing , playing of common cheap modules , sensors available direct interfacing arduino.

one of interesting modules dual channel motor driver based on hg7881 available on following link:
http://www.lctech-inc.com/hardware/detail.aspx?id=155c73e2-e972-473f-913d-ec443dbef0be

this module has 6 input header pins , 4 output driven power stepper or normal dc motors.

the issue have noticed (which can serious one) when drive motor external power supply has voltage less arduino vcc (say 2.5v), module start sink current arduino pwm pins, , can go high small 3v dc motor.

what have done connecting external 2.5v power supply vcc , gnd pins of module. gnd of arduino connected power supply gnd, , control pins (a-ia, a-ib) arduino pwm pins 10 , 9.

i wish more experience confirm might considered issue design of module.

while @ first glance looks cool motor driver, epecially because of 800 ma current capability, on closer inspection, absence of second ground pin motor power supply sets apart better l298 motor drivers have separate ground motor power supply. 1 poster had 1 , said there no continuity between 2 grounds confirming motor supply indeed isolated arduino interface side.
that being case , motor power supply should greater motor rating @ least 1.5 2v because driver has overhead , requires more voltage compensate voltage dropped across devices. 3v motors should set motor supply 5v , not 2.5v.

Arduino Forum > Using Arduino > Motors, Mechanics, and Power (Moderator: fabioc84) > Probably an Issue with HG7881 Motor Driver

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