Voltage boosting system with slew rate control and method thereof
AssigneeFreescale Semiconductor, Inc.
InventorPerry H. Pelley
Life of this patent
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Abstract
A system includes a voltage controlled oscillator, a charge pump, and a current regulator circuit. The voltage controlled oscillator has a control input and a clock output that provides a clock signal at a clock frequency that is variable. The charge pump is coupled to the clock output and has an output that provides a boosted output voltage. The current regulator circuit is coupled to the control input of the voltage controlled oscillator to adjust the clock frequency based on a simulation of a rate of change of the boosted output voltage. This allows for a controlled slew rate for the output of the charge pump.
Claims20
A system, comprising:
- a voltage controlled oscillator having a control input and a clock output that provides a clock signal at a clock frequency that is variable;
- a charge pump coupled to the clock output having an output that provides a boosted output voltage;
- and
- a current regulator circuit coupled to the control input of the voltage controlled oscillator to adjust the clock frequency based on a simulation of a rate of change of the boosted output voltage.
A method of obtaining a boosted voltage, comprising:
- generating the boosted voltage from a power supply voltage in response to a clock signal having a clock frequency that is variable;
- simulating a rate of change of the boosted voltage to provide a simulated rate of change value;
- comparing the simulated rate of change value to a reference value;
- and
- changing the clock frequency of the clock signal in response to the comparing.
A system, comprising:
- a voltage controlled oscillator having a control input and a clock output that provides a clock signal at a clock frequency that is variable;
- a clock generator that provides a first clock and a second clock at the clock frequency in response to the clock signal, wherein the first clock and the second clock are complementary;
- a charge pump that provides a boosted output voltage relative to a power supply voltage in response to the first and second clocks;
- and
- a current regulator circuit coupled to the control input of the voltage controlled oscillator to adjust the clock frequency based on a simulation of a rate of change of the boosted output voltage using the first and second clocks.
Dependencies are inferred from the claim text.