Class D amplifier with passive RC network
AssigneeMicrosemi Corporation
InventorBengt-Olov Andersson
Life of this patent
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Abstract
A Class D amplifier device with reduced power consumption uses a passive RC network. The output of the RC network directly feeds a comparator resulting in increased efficiency. The RC network is configured to perform several functions, including the low pass filtering of the feedback signal to remove high frequency/high amplitude clock components and provides a DC path from its output to reduce duty cycle errors. Additionally, the input signal receives low pass filtering, creating a generally flat frequency response. Finally,the clock signal is filtered to generate a triangle wave of good linearity and appropriate amplitude.
Claims36
A Class D amplifier, comprising:
- a passive RC network being adapted to accept an inverted and non-inverted input signal, an inverted and non-inverted clock signal and an inverted and non-inverted feedback signal;
- the passive RC network being further adapted to provide a summed output of the inverted and non-inverted input signal, the inverted and non-inverted clock signal and the inverted and non-inverted feedback signal input
- a comparator being adapted to receive the summed output and provide a pulse width modulated signal;
- a pulse conditioner being adapted to receive the pulse width modulated signal and further condition the signal;
- and
- an output stage being adapted to receive the conditioned signal and drive a load at the inverted and non-inverted output terminals of the output stage.
A method of amplifying signals, comprising:
- inputting an inverted and non-inverted input signal, an inverted and non-inverted clock signal and an inverted and non-inverted feedback signal into a passive RC network;
- summing the inverted and non-inverted input signal, inverted and non-inverted clock signal and inverted and non-inverted feedback signal in the passive RC network and outputting the combined waveform to the input of a comparator;
- outputting the inverted and non-inverted conditioned pulse width modulated waveform from the comparator to the data input of a pulse conditioner;
- outputting the signal of the pulse conditioner to the input of an output stage;
- and
- amplifying the signal in the output stage to drive a load at the inverted and non-inverted output terminals of the output stage.
Dependencies are inferred from the claim text.