Charge pump having level-shifting mechanism
AssigneeMediatek Inc.
InventorsYu-Li Hsueh, Chih-Hsien Shen, Chao-Ching Hung, Po-Chun Huang
Life of this patent
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Abstract
The present invention provides a charge pump including a pull-up circuit for selectively providing charges to an output terminal of the charge pump, and the pull-up circuit comprises a transistor, a capacitor and a switched-capacitor circuit, wherein the capacitor is coupled to an electrode of the transistor, and the switched-capacitor circuit is coupled between a supply voltage and another electrode of the transistor. The switched-capacitor circuit is configured to boost a voltage of the other electrode of the transistor to charge the capacitor via the transistor, then the capacitor and the output terminal of the charge pump are under a charge distribution operation.
Claims19
A charge pump, comprising:
- a pull-up circuit, for selectively providing charges to an output terminal of the charge pump, wherein the pull-up circuit comprises:
- a first transistor;
- a first capacitor, coupled to one electrode of the first transistor;
- and
- a switched-capacitor circuit, coupled between a supply voltage and another electrode of the transistor, for boosting a voltage of the other electrode of the first transistor to charge the first capacitor via the first transistor, then the first capacitor and the output terminal of the charge pump are under a charge distribution operation.
A phase-locked loop, comprising:
- a phase detector, for receiving an input signal and a feedback signal to generate a detection result;
- a charge pump, for generating a control signal according to the detection result, wherein the charge pump comprises:
- a pull-up circuit, for selectively providing charges to an output terminal of the charge pump, wherein the pull-up circuit comprises:
- a first transistor;
- a first capacitor, coupled to one electrode of the first transistor;
- and
- a switched-capacitor circuit, coupled between a supply voltage another electrode of the transistor, for boosting a voltage of the other electrode of the first transistor to charge the first capacitor via the first transistor, then the first capacitor and the output terminal of the charge pump are under a charge distribution operation;
- and
- a voltage-controlled oscillator, for generating an output clock signal according to the control signal;
- and
- a frequency divider, for frequency-dividing the output clock signal to generate the feedback signal.
A charge pump, comprising:
- a pull-up circuit, for selectively providing charges to an output terminal of the charge pump, wherein the pull-up circuit comprises:
- a first transistor;
- a first capacitor, coupled to a first electrode of the first transistor;
- and
- a switched-capacitor circuit, coupled between a supply voltage and a second electrode of the transistor,
- a switch, coupled between the first electrode of the first transistor and the output terminal of the charge pump;
- wherein when the pull-up circuit operates in a first phase, the switched-capacitor circuit is controlled to charge the first capacitor via the first transistor, and the switch is controlled to disconnect the first electrode of the first transistor from the output terminal of the charge pump;
- and when the pull-up circuit operates in a second phase, the switched-capacitor circuit is controlled to be disconnected from the second electrode of the first transistor, and the switch is controlled to connect the first electrode of the first transistor to the output terminal of the charge pump.
Dependencies are inferred from the claim text.