Reference voltage generator and analog-to-digital converter
AssigneeMediatek Inc.
InventorsChihhou TSAI, Ying-Zu LIN
Life of this patent
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Abstract
A reference voltage generator for an analog-to-digital converter (ADC) includes a current source coupled to a power supply, and a first transistor coupled between the current source and a first resistive circuit. The first resistive circuit is coupled to the first transistor. The reference voltage generator further includes a second transistor having a gate coupled to the current source and a gate of the first transistor, for providing a reference voltage to the ADC, an impedance circuit coupled to the second transistor, for selectively providing a variable impedance.
Claims21
A reference voltage generator for an analog-to-digital converter (ADC), comprising:
- a current source coupled to a power supply;
- a first transistor coupled between the current source and a first resistive circuit;
- the first resistive circuit coupled to the first transistor;
- a second transistor having a gate coupled to the current source and a gate of the first transistor, for providing a reference voltage to the ADC;
- and
- an impedance circuit coupled to the second transistor, for selectively providing a variable impedance.
An analog-to-digital converter (ADC) for converting an analog signal into a digital output signal, comprising:
- a reference voltage generator, providing a reference voltage;
- a sample-and-hold circuit, for sampling the analog signal in a first phase and storing the sampled analog signal in a second phase;
- a digital-to-analog converter, for providing an intermediate analog signal according to a plurality of control signals and the reference voltage in a comparison phase;
- a comparator, for providing a comparison result according to the intermediate analog signal and the stored analog signal;
- and
- a logic circuit, for providing the digital output signal and the control signals according to the comparison result,
- wherein the reference voltage generator comprises:
- a first current source coupled to a power supply;
- a first transistor coupled between the first current source and a first resistive circuit;
- the first resistive circuit coupled to the first transistor;
- a second transistor, having a gate coupled to the first current source and a gate of the first transistor, for providing the reference voltage;
- and
- a first impedance circuit coupled to the second transistor, for selectively providing a first variable impedance.
Dependencies are inferred from the claim text.