| 摘要 |
In a power supply apparatus (100) for driving a DC motor (5) of a car cassette player, there are provided a switching regulator circuit (20) for regulating a DC (direct current) input voltage (VIN) to produce a desired DC output voltage (VOUT3); a motor driving circuit (4) for driving a motor (5) by receiving the DC output voltage (VOUT3) of the switching regulator circuit (20); a sensor element (6) for sensing a speed of the motor (5) to output a sensor signal (SMT); a motor speed judging circuit (7) for comprising said sensor signal (SMT) from the sensor element (6) with a reference signal to produce a judgement signal (SCOMP); and, a control voltage generating circuit (8) for producing a control voltage (VREG) based upon the judgement signal (SCOMP) of the motor speed judgement circuit (7), whereby the DC output voltage (VOUT3) of the switching regulator circuit (20) is controlled in response to the control voltage (VREG). |
