Low-noise current-in class D amplifier with slew rate control mechanism
AssigneeMediatek Inc.
InventorsChuan-Hung Hsiao, Kuan-Ta Chen
Life of this patent
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Abstract
A circuit applied to speaker includes a tri-level current DAC and a class D amplifier. The current DAC is arranged to receive a digital signal to generate a current signal, and the class D amplifier is arranged to directly receive the current from the current DAC and to amplify the current signal to generate an output signal. SNR performance is well improved class D amplifier due to small signal noise reduced by preceding tri-level DAC. In addition, the circuit further includes a driving stage, and a gate-drain voltage of a power transistor within the driving stage can be controlled to set the appropriate slew rate.
Claims17
A circuit, comprising:
- a current digital-to-analog converter (DAC), for receiving a digital signal to generate a current signal;
- a class D amplifier, coupled to the current DAC, for receiving the current signal from the current DAC and amplifying the current signal to generate an output signal;
- and
- a driving stage, coupled to the class D amplifier, for generating a driving signal according to the output signal of the class D amplifier, wherein a gate-drain capacitance of a transistor within the driving stage is programmable.
A circuit, comprising:
- a digital-to-analog converter (DAC), for receiving a digital signal to generate an analog signal;
- and
- an amplifier, coupled to the DAC, for generating an output signal according to the analog signal;
- and
- a driving stage, coupled to the amplifier, for generating a driving signal according to the output signal of the amplifier, wherein a gate-drain capacitance of a transistor within the driving stage is programmable.
A circuit, comprising:
- a digital-to-analog converter (DAC), for receiving a digital signal to generate an analog signal;
- and
- an amplifier, coupled to the DAC, for generating an output signal according to the analog signal;
- a common voltage generator, coupled to the DAC and the class D amplifier, for generating a common voltage to the DAC and the amplifier;
- and
- a driving stage, coupled to the amplifier, for generating a driving signal according to the output signal of the amplifier, wherein a gate-drain capacitance of a transistor within the driving stage is programmable.
Dependencies are inferred from the claim text.