| 摘要 |
PURPOSE:To reduce the amount of heat caused by the collector loss of power amplifying transistor and the like for thereby lowering a power consumption and providing a compact radiator by a method wherein, an analog signal of amplifier is converted into PWM signal and thereby a switching amplifier is actuated. CONSTITUTION:Magnet drive circuits 307 and 308 are energized by positive and negative displacement signals respectively which are transmitted through a displacement detecting device 101 and a compensating circuit 102. The analog signals of amplifiers 107, 110 are compared by means of comparators 301, 304 with signals outputted from a reference signal generating circuit 300 which generates a saw tooth wave or a delta wave, and outputted from comparators 301, 304 in the form of PWM signal. The PWM signal which is amplified through switching amplifiers 302, 305 is again converted into an analog signal through smoothing circuits 303, 306 and energizes magnetic coils 104, 106. Said energizing current is detected by a coil electric current detecting circuit to load amplifiers 107, 110 with a negative feedback for actuating the magnetic driving circuit as a negative feedback. The electric current flows in the manner as above mentioned, and thus the amplifying transistor can generate less amount of heat. |
