The motor drive chip is a chip integrated with CMOS control circuits and DMOS power devices, which can form a complete motion control system with the main processor, motor, and incremental encoder. It can be used to drive inductive loads such as DC motors, stepper motors, and relays.

Principle of Motor Drive Chip

The motor driver chip integrates four DMOS transistors internally, forming a standardized H-type drive bridge. The charging pump circuit provides gate control voltage for the two switch tubes of the upper bridge arm, and the charging pump circuit operates at a frequency of around 300kHz.

The second charging pump circuit can be composed of external capacitors at pins 1 and 11. The larger the external capacitance, the faster the charging speed of the capacitor input to the switch gate, the shorter the time of voltage rise, and the higher the operating frequency. Pins 2 and 10 are connected to the DC motor armature, and the direction of current during forward rotation should be from pin step to pin 10; The direction of the current during rotation should be from pin 10 to pin 2, and the current detection output pin 8 can be connected to a ground resistance to output overcurrent conditions through the resistance.

The overcurrent threshold set by the internal maintenance circuit is 10A. When it exceeds this value, the output will be actively blocked and periodically recovered. If the overcurrent lasts for a long time, overheating maintenance will shut down the entire output. The overheat signal can also be output through pin 9, and when the junction temperature reaches 145 degrees, pin 9 has an output signal.

Motor drive chip function

1. Applied to robot control system

2. Applied to digital control system

3. Applied to computer printers and plotters.

The motor drive chip adopts standardized TTL logic level signal control, with two enable control terminals that allow or prevent device operation without being affected by the input signal. There is a logic power input terminal that allows the internal logic circuit to operate at low voltage; Able to externally detect resistance and provide feedback on changes to the control circuit. Drive the orientation and speed of the DC motor and stepper motor servo mechanism system.