Back to results
US 7,256,631 B2Granted
Charge pump with balanced and constant up and down currents
AssigneeSamsung Electronics Co., Ltd.
InventorJu-Hyung Kim
Life of this patent
Estimating the term…
Abstract
A charge pump generates a first sub up current and a second sub up current that vary complementarily with a change in a voltage at an output terminal. The charge pump also generates a first sub down current and a second sub down current that vary complementarily with the change in the voltage at the output terminal. With such complementary relationships, the total up/down currents remain substantially constant and balanced with the change in the voltage at the output terminal.
Claims20
A method of operating a charge pump comprising:
- generating a first sub up current and a second sub up current that vary complementarily with a change in voltage at an output terminal, wherein each of the first and second sub up currents flows into the output terminal for charging the output terminal;
- and
- generating a first sub down current and a second sub down current that vary complementarily with the change in the voltage at the output terminal, wherein each of the first and second sub down currents flows away from the output terminal for discharging the output terminal.
A charge pump comprising:
- sub up current sources for generating a first sub up current and a second sub up current that vary complementarily with a change in a voltage at an output terminal, wherein each of the first and second sub up current flows into the output terminal for charging the output terminal;
- and
- sub down current sources for generating a first sub down current and a second sub down current that vary complementarily with the change in the voltage at the output terminal, wherein each of the first and second sub down currents flows away from the output terminal for discharging the output terminal.
A phase-locked loop comprising:
- a phase frequency detector for activating an up signal or a down signal from comparing a reference signal with a feed-back signal;
- a charge pump including:
- sub up current sources for generating a first sub up current and a second sub up current that vary complementarily with a change in a voltage at an output terminal;
- sub down current sources for generating a first sub down current and a second sub down current that vary complementarily with the change in the voltage at the output terminal;
- wherein the first and second sub up currents flow to the output terminal when the up signal is activated, and wherein the first and second sub down current from the output terminal when the down signal is activated;
- a loop filter for filtering the voltage at the output terminal to generate a loop filter voltage;
- and
- a voltage controlled oscillator for generating the feedback signal in response to the loop filter voltage.
5 more elements
Dependencies are inferred from the claim text.