Reduction of power consumption and EMI of a switching amplifier
AssigneeRichtek Technology Corporation
InventorsJing-Meng Liu, Jwin-Yen Guo, Shao-Ming Sun
Life of this patent
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Abstract
A switching amplifier has a network including current sources and resistors connected to the two output terminals of the H-bridge of the switching amplifier, to provide a small current to the load connected between the two output terminals at zero input, whereby the common mode voltage bouncing is reduced and the switching amplifier has less power consumption and reduced electro-magnetic interference.
Claims29
An apparatus for reducing the power consumption and electro-magnetic interference of a switching amplifier having a first output terminal and a second output terminal for connecting with a load, and an H-bridge connected between a power input terminal and a ground terminal, being switched according to an input signal to generate an output voltage across the two output terminals, and a common mode voltage existing across the two output terminals at zero input, the apparatus comprising:
- a first current source and a first resistor connected in series between the power input terminal and the first output terminal;
- and
- a second resistor and a second current source connected in series between the second output terminal and the ground terminal;
- whereby a small current is supplied to the load at zero input to reduce the common mode voltage bouncing.
A method for reducing the power consumption and electro-magnetic interference of a switching amplifier having a first output terminal and a second output terminal for connecting with a load, and an H-bridge connected between a power input terminal and a ground terminal, being switched according to an input signal to generate an output voltage across the two output terminals, and a common mode voltage existing across the two output terminals at zero input, the method comprising the steps of:
- connecting a network including current sources and resistors to the two output terminals;
- and
- supplying a small current from the network to the load at zero input to reduce the common mode voltage bouncing.
A switching amplifier, comprising:
- an H-bridge connected between a power input terminal and a ground terminal;
- a first and a second output terminal extended from the H-bridge to be connected with a load therebetween;
- a controller connected to the H-bridge to switch the H-bridge according to an input signal so as to generate an output voltage across the two output terminals, wherein a common mode voltage exists across the two output terminals at zero input;
- and
- a network including current sources and resistors connected to the two output terminals to supply a small current to the load at zero input in order to reduce the common mode voltage bouncing.
A control method for a switching amplifier having a first output terminal and a second output terminal for connecting with a load, the control method comprising the steps of:
- according to an input signal, switching an H-bridge connected between a power input terminal and a ground terminal to generate an output voltage across the two output terminals in a first state;
- switching the H-bridge according to the input signal to generate a common mode voltage across the two output terminals in a second state;
- and
- supplying a small current to the load to reduce the common mode voltage bouncing in the second state.
Dependencies are inferred from the claim text.