| 摘要 |
PURPOSE:To reduce the motor speed by controlling an overcurrent with an overcurrent control means provided in a digital driver circuit, in which an overcurrent detected signal is generated, and a digital control signal is changed on the basis of the magnitude of the overcurrent when the revolution rate is sharply diminished. CONSTITUTION:A digital driver circuit comprises a comparator 3 for generating a PWM signal by comparing via an overcurrent control means 5 an output provided from a counter 2, which works on the basis of a clock signal 1, with a digital control signal 6 generated from a microcomputer, and a driving means 7 for driving a motor in response to the PWM signal. In this case, an overcurrent detected signal is not sent to the microcomputer, but the overcurrent control means 5 changes the digital control signal 6, and the comparator 3 generates the PWM signal so as to reduce the revolutions of the motor. Then, the overcurrent can be prevented. Consequently, the overcurrent control can be performed surely and instantaneously regardless of the state of the microcomputer. |
