US 4,061,930 AGranted

Base drive inhibit circuit

AssigneeRohr Industries, Inc.

InventorArne Nerem

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Abstract

A base drive inhibit circuit for positive and negative phase transistors of a switching amplifier. The circuit comprises a pair of comparators for comparing the voltage between the collector and emitter elements of the transistors with an appropriate reference voltage, and provides a signal to supply base drive voltage, when their associated output transistor is in a forward biased state and the level of reference voltage is less than the level of voltage between the collector and emitter. A logic control circuit supplies base drive voltage to one of the transistors when both a drive signal from an external source is in a proper polarity state and the output signal from the comparator indicates that the transistor is in a forward biased state. A timer is provided to delay base drive voltage to either transistor when the base drive signal is in a transition between polarity states.

Claims4

Dependent claims

A base drive inhibit circuit for positive and negative phase transistors of a switching amplifier comprising:

a source of base drive voltage having alternate positive and negative states;
a first means for producing a first signal responsive to the conduction state of said positive phase transistor and a positive phase reference voltage level;
a second means for producing a second signal responsive to the conduction state of said negative phase transistors and a negative phase reference voltage level;
and
a control means for selectively supplying said base drive voltage from said source to said positive phase transistor when said first signal indicates that said positive transistor is in a forward biased state with respect to said positive reference voltage level and said base drive voltage is in a positive state and to said negative phase transistor when said second signal indicates that said negative transistor is in a forward biased state with respect to said negative reference voltage level and said base drive voltage is in a negative state.

2 more elements

Dependencies are inferred from the claim text.