IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0868306
(2004-06-15)
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발명자
/ 주소 |
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
6 인용 특허 :
10 |
초록
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A programmable soft-start control circuit having two memory registers for regulating the ramp-up time period of charging current in a charge pump of an integrated circuit. The two memory registers are programmed to provide two different soft-start settings for two distinct charge pump turn-on condit
A programmable soft-start control circuit having two memory registers for regulating the ramp-up time period of charging current in a charge pump of an integrated circuit. The two memory registers are programmed to provide two different soft-start settings for two distinct charge pump turn-on conditions, initial power-up and flash programming. Charge pump feedback logic is employed to detect the charge pump turn-on condition and activate the proper pre-programmed soft-start setting loaded in the memory registers.
대표청구항
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1. A programmable soft-start control for a charge pump comprising at least one programmable register for controlling charging duration of the charge pump, the charging duration being changeable with an n-bit word receivable by said at least one programmable register via a bus, the charge pump being
1. A programmable soft-start control for a charge pump comprising at least one programmable register for controlling charging duration of the charge pump, the charging duration being changeable with an n-bit word receivable by said at least one programmable register via a bus, the charge pump being charged in a series of discrete ramp steps which provide increasing charge current during each discrete ramp step.2. A programmable soft-start control as claimed in claim 1, wherein duration of said each discrete ramp step is set by writing a setting to said at least one programmable register.3. A programmable soft-start control as claimed in claim 1, wherein duration of said each discrete ramp step is programmed by writing a setting to said at least one programmable register, and wherein duration of said each discrete ramp step is uniform.4. A programmable soft-start control as claimed in claim 1, wherein duration of said each discrete ramp step is programmed by writing a setting to said at least one programmable register, and wherein said duration is in the range of about 0.03 μs to about 16 μs.5. A programmable soft-start control as claimed in claim 1, wherein said at least one programmable register is a pair of programmable registers.6. A programmable soft-start control as claimed in claim 1, wherein said at least one programmable register is a pair of programmable registers each assigned a distinct turn-on condition of the charge pump.7. A programmable soft-start control as claimed in claim 1, wherein said at least one programmable register is a pair of programmable registers each assigned a distinct turn-on condition of the charge pump selected from initial power up and flash programming.8. A programmable soft-start control as claimed in claim 1, further comprising feed back logic, wherein said at least one programmable register is a pair of programmable registers each assigned a distinct turn-on condition of the charge pump selected from initial power up and flash programming, each of said programmable registers being programmable with a setting controlling the charging duration of the charge pump, and wherein said feedback logic is adapted to detect the turn-on condition of the charge pump and select the assigned programmable register.9. A programmable soft-start control as claimed in claim 1, wherein duration of said each discrete ramp step is programmed by writing a setting to said at least one programmable register, and wherein said at least one programmable register is a pair of programmable registers each providing a different setting for the duration of said each discrete ramp step.10. A programmable soft-start control as claimed in claim 1, wherein duration of said each discrete ramp step is programmed by writing a setting to said at least one programmable register, wherein said at least one programmable register is a pair of programmable registers each providing a different setting for the duration of said each discrete ramp step, and wherein one of said pair of programmable registers has a setting providing a duration of said each discrete ramp step in the range of about 0.03 μs to about 4 μs, and the other has a setting providing a duration of said each discrete ramp step in the range of about 0.1 μs to 16 μs.11. A programmable soft-start control as claimed in claim 1, wherein for an initial power up condition, said soft-start control is programmed to charge the charge pump from about 3.3V to about 7.0V within about 100μs at about 2.2 μF load and no current load.12. A programmable soft-start control as claimed in claim 1, wherein for a flash programming condition, said soft-start control is programmed with instructions to turn on a current load of about 45 mA for about 10 μs and turn off said current load for about 0.5 μs, and repeat said instructions at least six times.13. A programmable soft-start control for a charge pump comprising:a first programmable register assigned to an initial power up condition of the charge pump, the charge pump being charged in a series of discrete ramp steps which provide increasing charge current during each discrete ramp step, said first programmable register is programmed with a first setting controlling duration of each discrete ramp step; a second programmable register assigned to a flash programming condition of the charge pump, and programmed with a second setting controlling duration of each discrete ramp step; and feed back logic adapted to detect said turn-on condition of the charge pump and select the assigned programmable register, each said programmable registers providing a different charging duration, wherein said charging duration for said programmable register assigned to said initial power up is longer than said charging duration for said programmable register assigned to said flash programming. 14. A programmable soft-start control as claimed in claim 13, wherein said first setting results in the soft-start control providing a ramp step duration in the range of about 0.03 μs to about 4 μs, and said second setting providing a ramp step duration in the range of about 0.1 μs to 16 μs.15. A programmable soft-start control as claimed in claim 13, wherein for said initial power up, said soft-start control is programmed with instructions to charge the charge pump from about 3.3V to about 7.0V within about 100 μs at about 2.2 μF load and no current load.16. A programmable soft-start control as claimed in claim 13, wherein for said flash programming, said soft-start control is programmed with instructions to turn on a current load of about 45 mA for about 10 μs and turn off said current load for about 0.5 μs, and repeat said instructions at least six times.17. A programmable soft-start control for a charge pump configured to provide a voltage output, a charge-off signal output when the voltage output is below a target voltage, a programmable clock input to provide PFM control of charge and discharge phases of the charge pump, and charge-strength selector inputs which set a voltage ramp-up rate of the voltage output.18. A programmable soft-start control as claimed in claim 17, further comprising a charging-series circuit coupled to the charge-off signal output and the charge-strength selector inputs of the charge pump, said charging-series circuit is configured to provide turn-on outputs to the charge-strength selector inputs.19. A programmable soft-start control as claimed in claim 17, further comprising at least one frequency selector circuit configured to provide a clock pulse output used by a charging-series circuit for a soft-start condition of the charge pump.20. A programmable soft-start control as claimed in claim 17, further comprising a detection and selection circuit coupled between a charging-series circuit and at least one frequency selector circuit, said detection and selection circuit is configured to detect a soft-start condition of the charge pump and select, for said soft-start condition, a clock pulse output of said at least one frequency selector circuit to clock said charging-series circuit when said detection and selection circuit and said charging-series circuit receive the charge-off signal output from the charge pump.21. A programmable soft-start control as claimed in claim 17, further comprising a charging-series circuit coupled to the charge-off signal output and the charge-strength selector inputs of the charge pump, said charging-series circuit is configured to provide turn-on outputs to the charge-strength selector inputs, wherein said charging-series circuit comprises a counter configured to provide a repeatable step series of turn-on outputs to the charge-strength selector inputs of the charge pump.22. A programmable soft-start control as claimed in claim 17, further comprising a charging-series circuit coupled to the charge-off signal output and the charge-strength selector inputs of the charge pump, said charging-series circuit is configured to provide turn-on outputs to the charge-strength selector inputs, wherein each of said turn-on outputs is coupled to a respective synchronous gate, and each said respective synchronous gate is coupled to a respective AND gate, and wherein said charging-series circuit is configured to provide each of said turn-on outputs to the charge pump when said respective AND gate receives the charge-off signal output from the charge pump and an output from said respective synchronous gate.23. A programmable soft-start control as claimed in claim 19, wherein said at least one frequency selector circuit comprises a programmable memory register configured to provide digital logic that selects said frequency of said clock pulse output.24. A programmable soft-start control as claimed in claim 19, wherein said at least one frequency selector circuit comprises a divide-by-n counter/prescaler having data inputs coupled to a programmable memory register which set a frequency division of said divide-by-n counter/prescaler, said divide-by-n counter/prescaler is configured to provide said clock pulse output.25. A programmable soft-start control as claimed in claim 19, wherein said at least one frequency selector circuit further comprises a T flip-flop and a multiplexer coupled to clock inputs of both a divide-by-n counter/prescaler and said T flip-flop, said T flip-flop is configured to receive a clock pulse output of said divide-by-n counter/prescaler and is configured to output said clock pulse output on a clock pulse from said multiplexer.26. A programmable soft-start control as claimed in claim 19, wherein said at least one frequency selector circuit comprises two frequency selector circuits, each of said two frequency selector circuits is configured to provide a clock pulse output for a specific soft-start condition of the charge pump.27. A programmable soft-start control as claimed in claim 20, wherein said detection and selection circuit comprises a two-to-one multiplexer, and a D flip-flop configured to receive the charge-off signal output of the charge pump and an external pump turn-on signal in order to correctly switch said two-to-one multiplexer to said clock pulse output of said frequency selection circuit for a specific soft-start condition.28. A method for controlling a voltage ramp-up rate of a charge pump configured to provide an output voltage under specific soft-start conditions, the charge pump having charge-strength selector inputs that set a voltage ramp-up rate of the output voltage, the method comprising programming at least one memory register to set both a divisor for a divide-by-n counter/prescaler and a clock signal input for a specific soft-start condition of the charge pump.29. A method as claimed in claim 28 further comprises producing a clock signal pulse of a specific frequency based on digital logic stored in said at least one memory register.30. A method as claimed in claim 28 further comprises producing a clock signal pulse of a specific frequency based on digital logic stored in said at least one memory register, and driving a charging-series output with said clock signal pulse at said specific frequency.31. A method as claimed in claim 28 further comprises driving a charging-series output with a clock signal pulse at a specific frequency, and providing a charging-series output to the charge-strength selector inputs of the charge pump to vary the voltage ramp-up rate of the output voltage of the charge pump for each of the specific soft-start condition.32. A method as claimed in claim 28, wherein said at least one memory register comprises two memory registers and said method further comprises detecting said specific soft-start condition of the charge pump and providing a clock signal pulse produced according to digital logic of one of said two memory registers for the specific soft-start condition.
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