Variable Frequency Charge Pump

• US 20150002195A1
• Filed: 07/01/2013
• Published: 01/01/2015
• Est. Priority Date: 01/18/2011
• Status: Active Grant

• Current Assignee: pSemi Corporation (Murata Manufacturing Co Limited)
• Original Assignee: Peregrine Semiconductor Corporation (Murata Manufacturing Co Limited)
• Inventors: Englekirk, Robert Mark
• Granted Patent: US 9,264,053 B2
• Time in Patent Office: Days
• US Class Current: 327/157
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/071 adapted to generate a negative voltage output from a positive voltage source
• CPC Class Codes: H02M 3/073 Charge pumps of the Schenkel-type
• CPC Class Codes: H03L 7/0891 the up-down pulses controlling source and sink current generators, e.g. a charge pump
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A charge pump circuit that utilizes a sensing circuit for determining the current loading or status of the output supply generated by the charge pump circuit to determine a corresponding frequency for a variable rate clock for the charge pump circuit. When a current load is present, the clock frequency automatically ramps up to a relatively high level to increase the output current of the charge pump circuit. When the current load is removed and the supply is settled out, the clock frequency is automatically reduced to a relatively quieter level and the charge pump circuitry operates at a lower power level. Accordingly, the charge pump circuit is only noisy when it has to be, thus providing optimal power when required and being electrically quiet and operating at lower power at all other times.

Claims

1. A variable frequency charge pump circuit including:

(a) a charge pump having an output;

(b) a clock source having a clock signal output coupled to the charge pump, for controlling the output of the charge pump as function of the frequency of the clock signal; and

(c) a feedback circuit coupled to the output of the charge pump and to the clock source, for controlling the frequency of the clock signal as a function of the output of the charge pump.

2. The variable frequency charge pump circuit of claim 1, wherein the clock source is controlled by an applied bias signal and the clock signal output is a function of the applied bias signal.

3. The variable frequency charge pump circuit of claim 2, wherein the feedback circuit monitors a voltage of the output of the charge pump, and controls the applied bias signal to the clock source as a function of the monitored voltage of the output of the charge pump.

4. The variable frequency charge pump circuit of claim 3, further including a noise source coupled to the clock source for varying the frequency of the output of the clock source in order to spread generated spur signals.

5. A variable frequency charge pump circuit including:

(a) a charge pump having a frequency controlled output current;

(b) a clock source having a clock signal output coupled to the charge pump, the clock source being coupled to an applied signal, wherein the frequency of the clock signal output is a function of the applied signal, for controlling the output current of the charge pump as function of the frequency of the clock signal; and

(c) a feedback circuit coupled to the output of the charge pump and to the clock source, wherein the feedback circuit monitors a current load of the output of the charge pump and controls the applied signal to the clock source as a function of the monitored voltage of the output of the charge pump, for controlling the frequency of the clock signal as a function of the current load of the output of the charge pump.

6. The variable frequency charge pump circuit of claim 5, further including a noise source coupled to the clock source for varying the frequency of the output of the clock source in order to spread generated spur signals.

7. A variable frequency charge pump including:

(a) means for generating a current output at a voltage that is a multiple of a voltage input;

(b) means for generating a variable clock signal coupled to the means for generating a current output, for controlling the current output as function of the frequency of the variable clock signal; and

(c) means for providing feedback control signals, coupled to the means for generating a current output and the means for generating a variable clock signal, for providing feedback control signals to the means for generating a variable clock signal as a function of the current output of the means for generating a current output.

8. A variable frequency charge pump including:

(a) voltage multiplying means having a current output at a voltage that is a multiple of an input voltage;

(b) clock means coupled to output a variable clock signal to the voltage multiplying means, for controlling the current output as function of the frequency of the variable clock signal; and

(c) feedback means, coupled to the voltage multiplying means and the variable clock signal means, for controlling the frequency of the variable clock signal as a function of the current output of the voltage multiplying means.

9. A method for controlling a charge pump circuit, including the steps of:

(a) providing a charge pump having a frequency controlled output current; and

(b) dynamically varying the frequency of a clock signal to the charge pump as function of the output current of the charge pump.

10. The method of claim 9, further including the step of randomly varying the frequency of the clock signal in order to spread generated spur signals.

11. A method for controlling a charge pump circuit, including the steps of:

(a) providing a charge pump having a frequency controlled output current;

(b) coupling a variable frequency clock signal to the charge pump;

(c) varying the frequency of the variable frequency clock signal to the charge pump as function of the output current of the charge pump.

12. The method of claim 11, further including the step of randomly varying the frequency of the variable frequency clock signal in order to spread generated spur signals.