JP2008154289A5 - - Google Patents

Claims (1)

In a class D amplifying apparatus comprising a plurality of full-bridge amplifiers and a synthesizer that serially synthesizes outputs from the plurality of amplifiers,
The amplifier is
A first transistor that turns on and off in accordance with a carrier signal from an oscillator;
A second transistor that is turned on / off according to a signal having a phase opposite to that of the carrier signal;
A pulse transformer that performs a push-pull operation around the primary side midpoint by turning on and off the first and second transistors, and outputs an in-phase or anti-phase rectangular wave to the carrier signal from the secondary side;
A third transistor and a fourth transistor that are turned on / off with a rectangular wave in phase with the carrier wave signal output from the secondary side of the pulse transformer to form a full bridge;
A fifth transistor and a sixth transistor which are turned on / off with a rectangular wave having a reverse phase to the carrier wave signal output from the secondary side of the pulse transformer, and constitute a full bridge type;
A power supply for applying a voltage to the third to sixth transistors constituting a full-bridge type;
A seventh transistor that is turned on / off depending on the presence or absence of an audio signal, and sets the bases of the third transistor and the fifth transistor to the ground level when turned on;
The other terminal with respect to the terminal connected to the base of the fourth transistor and the terminal connected to the base of the fifth transistor on the secondary side of the pulse transformer is turned on / off by the inverted output of the presence or absence of the audio signal And an eighth transistor that is set to the ground level when turned on ,
A class D amplifying apparatus characterized in that a plurality of the carrier signals output from the secondary side of the pulse transformer are serially added and combined by the combiner and output .