Charge pump system and clock generator
AssigneeMacronix International Co., Ltd.
InventorsNai-Pin Kuo, Su-Chueh Lo, Wen-Yi Hsieh, Yufe Lin
Life of this patent
Estimating the term…
Abstract
A current produced by a current mirror in a clock generator circuit for a charge pump is controlled by a temperature dependent, current-adjusting MOSFET which has a threshold voltage (Vt) that varies with temperature. As the temperature varies, the current through the a temperature dependent, current-adjusting MOSFET varies, to thereby control a frequency of the clock generator circuit. The MOSFET can be provided with a temperature-independent power supply, so that the current of the temperature dependent, current-adjusting MOSFET can be more closely controlled.
Claims15
A clock generator comprising:
- a resistor;
- a MOSFET having a gate, a drain and a source connected to said resistor for generating a reference current;
- a first reference voltage independent on VDD and temperature for controlling said MOSFET;
- a current mirror circuit for generating a first and a second mirror current by mirroring said reference current;
- a first capacitor receiving said first mirror current and generating a first charged voltage;
- a second capacitor receiving said second mirror current and generating a second charged voltage;
- a second reference voltage generated from an input supply voltage for controlling said first and second charged voltage;
- and
- a logic circuit receiving said first and second charged voltage and generating a clock signal.
A clock generator comprising:
- a current mirror circuit for generating a first and a second mirror current by mirroring a reference current, which increases with temperature;
- and
- a first capacitor receiving the first mirror current and generating a first charged voltage;
- a second capacitor receiving the second mirror current and generating a second charged voltage;
- and
- a logic circuit receiving the first and second charged voltages and generating a clock signal.
A method of generating a clock signal in a charge pump, comprising:
- mirroring a reference current, which increases with temperature, to generate a first and a second mirror current;
- receiving the first mirror current and generating a first charged voltage with a first capacitor;
- receiving the second mirror current and generating a second charged voltage with a second capacitor;
- and
- receiving the first and second charged voltages into a logic circuit and generating a clock signal.
Dependencies are inferred from the claim text.