IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
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출원번호 |
UP-0784560
(2007-04-06)
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등록번호 |
US-7646184
(2010-02-22)
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발명자
/ 주소 |
- Balakrishnan, Balu
- Djenguerian, Alex B.
- Wong, Kent
- Matthews, David Michael Hugh
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출원인 / 주소 |
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대리인 / 주소 |
Blakely Sokoloff Taylor & Zafman, LLP
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인용정보 |
피인용 횟수 :
3 인용 특허 :
43 |
초록
▼
A power supply including a regulation circuit that maintains an approximately constant load current with line voltage. In one embodiment, a regulation circuit includes a semiconductor switch and current sense circuitry to sense the current in the semiconductor switch. The current sense circuitry has
A power supply including a regulation circuit that maintains an approximately constant load current with line voltage. In one embodiment, a regulation circuit includes a semiconductor switch and current sense circuitry to sense the current in the semiconductor switch. The current sense circuitry has a current limit threshold. The regulation circuit current limit threshold is varied from a first level to a second level during the time when the semiconductor switch is on. One embodiment of the regulation circuit is used in a power supply having an output characteristic having an approximately constant output voltage below an output current threshold and an approximately constant output current below an output voltage threshold.
대표청구항
▼
What is claimed is: 1. A power supply regulator, comprising: a comparator having first and second inputs and an output, the first input adapted to sense a current flow between first and second terminals of a switch during an on time of the switch, the second input of the comparator coupled to recei
What is claimed is: 1. A power supply regulator, comprising: a comparator having first and second inputs and an output, the first input adapted to sense a current flow between first and second terminals of a switch during an on time of the switch, the second input of the comparator coupled to receive a variable current limit threshold signal, wherein the variable current limit threshold signal increases between a first level and a second level during the on time of the switch; an oscillator adapted to generate a variable waveform, wherein the variable current limit threshold signal is generated in response to the variable waveform; and a control circuit adapted to generate a control signal in response to the output of the comparator, the control signal to be coupled to a control terminal of the switch to control switching of the switch to regulate the output of a power supply. 2. The power supply regulator of claim 1 wherein the control circuit further comprises a latch adapted to provide the control signal, wherein the latch includes a first input coupled to the oscillator and a second input coupled to output of the comparator. 3. The power supply regulator of claim 2, wherein the first input is the set input of the latch and the second input is the reset input of the latch. 4. The power supply regulator of claim 1 wherein the comparator, the oscillator and the control circuit are incorporated in a single monolithic integrated circuit. 5. The power supply regulator of claim 4 wherein the switch is incorporated in the single monolithic integrated circuit. 6. The power supply regulator of claim 1, further comprising a current mirror coupled to a supply voltage and the variable waveform to generate the variable current limit threshold signal. 7. The power supply regulator of claim 1 wherein the oscillator is further adapted to generate a maximum duty cycle signal. 8. The power supply regulator of claim 1, wherein the variable waveform generated by the oscillator is a sawtooth waveform. 9. A power supply regulator, comprising: a comparator having first and second inputs and an output, the first input adapted to sense a current flow between first and second terminals of a switch during an on time of the switch, the second input of the comparator coupled to receive a variable current limit threshold signal, wherein the variable current limit threshold signal increases between a first level and a second level during the on time of the switch; an oscillator adapted to generate a variable waveform and a maximum duty cycle signal, wherein the variable current limit threshold signal is generated in response to the variable waveform; and a control circuit adapted to generate a control signal in response to the output of the comparator, wherein the control signal is to be coupled to a control terminal of the switch to control switching of the switch to regulate the output of a power supply. 10. The power supply regulator of claim 9 wherein the control circuit further comprises a latch adapted to provide the control signal, wherein the latch includes a first input coupled to the oscillator and a second input coupled to output of the comparator. 11. The power supply regulator of claim 10, wherein the first input is the set input of the latch and the second input is the reset input of the latch. 12. The power supply regulator of claim 9 wherein the comparator, oscillator and control circuit are incorporated in a single monolithic integrated circuit. 13. The power supply regulator of claim 12 wherein the switch is incorporated in the single monolithic integrated circuit. 14. The power supply regulator of claim 9, further comprising a current mirror coupled to a supply voltage and the variable waveform to generate the variable current limit threshold signal. 15. The power supply regulator of claim 9, wherein the variable waveform generated by the oscillator is a sawtooth waveform 16. A power supply regulator, comprising: a comparator having first and second inputs and an output, the first input adapted to sense a current flow between first and second terminals of a switch during an on time of the switch, the second input of the comparator coupled to receive a variable current limit threshold signal, wherein the variable current limit threshold signal increases between a first level and a second level during the on time of the switch; an oscillator adapted to generate a sawtooth waveform and a maximum duty cycle signal, wherein the variable current limit threshold signal is generated in response to the sawtooth waveform; and a control circuit adapted to generate a control signal in response to the output of the comparator, the control circuit comprising a latch including a set input coupled to the oscillator and a reset input coupled to the output of the comparator, wherein the control signal is to be coupled to a control terminal of the switch to control switching of the switch to regulate the output of a power supply. 17. The power supply regulator of claim 16 wherein the comparator, oscillator and control circuit are incorporated in a single monolithic integrated circuit. 18. The power supply regulator of claim 16, further comprising a current mirror coupled to a supply voltage and the variable waveform to generate the variable current limit threshold signal. 19. A power supply regulator, comprising: a comparator having first and second inputs and an output, the first input adapted to sense a current flow between first and second terminals of a switch during an on time of the switch, the second input of the comparator coupled to receive a variable current limit threshold signal; wherein the variable current limit threshold signal increases between a first level and a second level during the on time of the switch; an oscillator adapted to generate a sawtooth waveform and a maximum duty cycle signal; a current mirror coupled to a supply voltage and the sawtooth waveform to generate the variable current limit threshold signal in response to the sawtooth waveform; and a control circuit adapted to generate a control signal in response to the output of the comparator, the control circuit comprising a latch including a set input coupled to the oscillator and a reset input coupled to the output of the comparator, wherein the control signal is to be coupled to a control terminal of the switch to control switching of the switch to regulate the output of a power supply. 20. The power supply regulator of claim 19 wherein the comparator, oscillator, current mirror and control circuit are all included in a single monolithic integrated circuit.
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