This is a circuit of Bi-Directional Motor Drive with Speed Control. This circuit is designed to replace the conventional drivers. The component cost can be reduced and efficiency will increase if we use this circuit. Here is the schematic diagram of the circuit:

Bi Directional Motor Drive with Speed Control circuit schematic

This circuit include all required circuitry to modulate two bi-directional pulse train outputs in proportion to the error signal polarity and magnitude and generate an analog error signal. The UC1637 consist of error amplifier, two PWM comparators with  100mA output stages as standard features and sawtooth oscillator.

Pulse-by-pulse current limiting, a shutdown port with a 2.5V temperature compensated threshold and under-voltage lockout are the protection that included in the device. The operation temperature range of the UC1637 is -55°C to +125°C. [Source: Texas Instruments Application Note]