MSK4201 Datasheet, PDF (4/6 Pages) M.S. Kennedy Corporation – 28 VOLT 5 AMP MOSFET H-BRIDGE PWM MOTOR DRIVER/AMPLIFIER

TYPICAL SYSTEM OPERATION
This is a diagram of a typical application of the MSK4201. The design Vcc voltage is +12 volts and should have a good low ESR
bypass capacitor such as a tantalum. The PWM and DISABLE signals are typically provided by some type of microprocessor control.
The PWM signal will be a TTL signal with a pulse frequency required by the system, and pulse duty cycles according to the required
direction/speed. A 0% duty cycle (continuous TTL low) will mean full voltage to the motor in one direction. A 100% duty cycle
(continuous TTL high) will mean full voltage to the motor in the other direction. A 50% duty cycle will hold the motor at 0 RPM.
Current sensing is done in this case by a 0.1 ohm sense resistor to sense current from either leg of the bridge. It is important to
make the high current traces as wide as possible to keep inductance down. The storage capacitor connected to the V+ and the hybrid
should be large enough to provide the high energy pulse without the voltage sagging too far. The storage capacitor should be a low
ESR ceramic capacitor or large polypropylene capacitor. Mount capacitor as close to the MCM as possible. The connection between
GND and the V+ return should not be carrying any motor current. The sense resistor signal is common mode filtered as necessary to
feed the limiting circuitry for the microprocessor. This application will allow full four quadrant torque control for a closed loop servo
system.
A snubber network is usually required, due to the inductance in the power loop. It is important to design the snubber network to
suppress any positive spikes above 75V and negative spikes below -2V with respect to pin 5 (gnd) of the MCM.
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8548-116 Rev. F 3/14