| 摘要 |
A dual operating mode switching power driving circuit arrangement comprises an amplifying circuit (18) of conventional form which is operated substantially as a Class A feedback amplifier in a servosystem "following" mode and is switched to operate as a Class D amplifier in the "seeking" mode under program control calling for the latter mode and reswitched to the "following" mode only at the succeeding transition of the Glass D waveform whereby transients are avoided. For operating in Class D mode, the Class A feedback loop is opened and the amplifier circuit is arranged so that the input wave now overdrives the input circuit and drives the output circuit between +/- values of the energy potential, whereby the efficiency is very high. A single electronic switching circuit (16) and logical circuitry (40) connected thereto are arranged to deliver selectively a driving control signal from such input terminals to the input circuit of a conventional amplifier for operating it in the Class A linear second order negative feedback loop arrangement and to deliver an overdriving feedback signal from the output terminal of the amplifier, the duty cycle of which responds to load device current passing a sensing device for operating the amplifier in the Class D mode. Preferably, the application of control signals is under program control along with such control over the operation of the load device (20). |
