Noise filter circuit with controllable transistor off-resistance and associated noise filtering method
AssigneeMediatek Inc.
InventorsChuan-Hung Hsiao, Sung-Han Wen
Life of this patent
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Abstract
A noise filter circuit includes a filter and a transistor off-resistance control circuit. The filter includes a first transistor and a charge storage component. The first transistor has off-resistance when turned off or operated under sub-threshold region. A control terminal of the first transistor is not directly tied to a reference voltage, and is used to receive a first control voltage. The charge storage component has one terminal coupled to a connection terminal of the first transistor. The transistor off-resistance control circuit is coupled to the first transistor, and arranged to set the first control voltage for controlling the off-resistance of the first transistor.
Claims20
A noise filter circuit comprising:
- a filter, comprising:
- a first transistor, arranged to have off-resistance when turned off or operated under sub-threshold region, wherein the first transistor comprises:
- a control terminal, arranged to receive a first control voltage, wherein the control terminal is not directly tied to a reference voltage;
- a first connection terminal;
- and
- a second connection terminal;
- and
- a charge storage component, having one terminal coupled to the second connection terminal of the first transistor;
- and
- a transistor off-resistance control circuit, coupled to the first transistor and arranged to set the first control voltage for controlling the off-resistance of the first transistor.
A noise filtering method comprising:
- setting a control voltage at a control terminal of a transistor for controlling off-resistance of the transistor, wherein the control terminal of the transistor is not directly tied to a reference voltage;
- and
- performing a filtering operation upon an input voltage to generate an output voltage, wherein the filtering operation is based on the transistor and a charge storage component.
Dependencies are inferred from the claim text.