Circuit for driving dc motor

Abstract

Abstract PURPOSE:To decrease the loss caused by heating, by forming a bridge circuit by output transistors and control transistors, combining the bridge with the motor, and varying the magnitude of the power supply voltage depending on the input voltage. CONSTITUTION:The bridge circuit is formed by output transistors Q3 and Q4 and transistors Q5 and Q6 and Q7 and Q8. The DC servo motor M is connected between the intermediate points thereof. The connecting points of Q5, Q6 and that of Q7, Q8 are connected to power supplies 1 and 2 via diodes D1 and D2. The transistors Q5-Q8 are controlled by the output of a comparator COMP. In the case the input voltage ei is positive and smaller than the specified value, the motor M is operated by the system of the power supply E1. In the case ei is larger than the specified value, the motor is operated by the system of two power supplies E1 and E2. Since the power supplies are selected depending on the magnitude of the input voltage, heating can be decreased and efficiency can be enhanced.

Inventors

• 👤 Akira Kojima

Bibliographic Details