Switching amplifier for driving a load through an alternating-current path.

摘要

Anamplifier includes first (42) and second (44) switches coupied at a juncture (46) to form a series circuit. The series circuit is serially coupled with an inductor (48) across a source of energizing potential (BL). A capacitor (54) couples the juncture (46) between the switches to a switch arrangement (62). The switches conduct alternately under the control of a duty cvcle modulator. The duty cycle modulation tends to vary the amplitude of the two opposite-polarity portions of the signal appearing at the control electrode of the switch arrangement (62)A clamp (50) is coupled to the junction of the series switch cucit and the inductor (48). The clamp (50) operates during a first of the two alternate switch conduction intervals to clamp the voltage across the inductor (48) at a fixed value. Since a direct voltage cannot be established ross an inductor, the voltage across the inductor during the second switch conduction interval is established by the clamp voltage and the duty cycle, and varies with duty cycle. The amplitude of the sgnal; atthe juncture of the two switches (42 and44) varies with duty cycle variations in such a manner as to maintain the signai of one poiarnty at the control electrode of the switch arrangement (62) at a constant amplitude. This also reduces errors arising from unwanted variations in the turn-off time of the duty-cycling switches (42.44).