Gate control circuit with soft start/stop function

摘要

A control terminal driver circuit for a switching amplifier including a driver for each of a pair of output power transistors responsive to a PWM information signal. The circuit operates in response to an operating state signal indicating a start up condition for the amplifier to vary the amplitude of the drive pulses for the output transistors between a zero value and a maximum value for normal operation of the amplifier over a start up interval, and to reverse the process during a shut down interval. A DC offset detector is provided to detect a DC offset at amplifier output, and an error circuit responsive to an output of the DC offset detector controls the relative amplitude of the driver outputs during at least a portion of the start up interval to substantially eliminate the DC offset. Also disclosed is a switching amplifier including a control terminal driver circuit as described above.