IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0804364
(2001-03-12)
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발명자
/ 주소 |
- Groom, Terry J.
- Pullen, Stuart
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출원인 / 주소 |
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대리인 / 주소 |
Coats & Bennett, P.L.L.C.
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인용정보 |
피인용 횟수 :
156 인용 특허 :
4 |
초록
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A system and method provides virtual ripple signal generation for use in voltage regulation applications. Some switch-mode power converters or voltage regulators use output signal ripple to effect voltage regulation. A virtual ripple generator provides this type of voltage regulator with a virtual r
A system and method provides virtual ripple signal generation for use in voltage regulation applications. Some switch-mode power converters or voltage regulators use output signal ripple to effect voltage regulation. A virtual ripple generator provides this type of voltage regulator with a virtual ripple signal comprising an offset component responsive to actual load voltage, but with a generated AC ripple component of arbitrary magnitude that is independent of actual output signal ripple. Unlike the actual output ripple signal, the generated AC ripple component is not dependent on implementation specifics, such as circuit board layout or output capacitor ESR, and may have its gain set independent of the offset component. The generated AC ripple component is synchronized to the inductor switching actions of the voltage regulator and thus reflects actual inductor phase switching in single and multi-phase regulation applications. Virtual ripple signal generation can include output (load) voltage droop compensation.
대표청구항
▼
A system and method provides virtual ripple signal generation for use in voltage regulation applications. Some switch-mode power converters or voltage regulators use output signal ripple to effect voltage regulation. A virtual ripple generator provides this type of voltage regulator with a virtual r
A system and method provides virtual ripple signal generation for use in voltage regulation applications. Some switch-mode power converters or voltage regulators use output signal ripple to effect voltage regulation. A virtual ripple generator provides this type of voltage regulator with a virtual ripple signal comprising an offset component responsive to actual load voltage, but with a generated AC ripple component of arbitrary magnitude that is independent of actual output signal ripple. Unlike the actual output ripple signal, the generated AC ripple component is not dependent on implementation specifics, such as circuit board layout or output capacitor ESR, and may have its gain set independent of the offset component. The generated AC ripple component is synchronized to the inductor switching actions of the voltage regulator and thus reflects actual inductor phase switching in single and multi-phase regulation applications. Virtual ripple signal generation can include output (load) voltage droop compensation. generate a resistance control signal; and where the variable characteristic element further comprises a variable resistance element having a variable resistance, the variable resistance being controlled by the resistance control signal. 4. The control circuit of claim 2, where the measuring circuit further includes a radio signal strength indicator (RSSI) circuit for generating the amplitude signal. 5. The control circuit of claim 1, where the transfer function control circuit further comprises: a first analog-to-digital (A/D) converter configured to convert the phase difference signal to a digital phase difference signal; a capacitance encoder circuit configured to receive the digital phase difference signal and generate a first capacitance control signal; and where the variable characteristic element further comprises a first variable capacitance element having a first variable capacitance, the first variable capacitance being controlled by the first capacitance control signal. 6. The control circuit of claim 5, where: the measuring circuit is further configured to generate an amplitude signal responsive to the output voltage level at the output terminal of the switching voltage regulator circuit; the transfer function control circuit further includes: a second analog-to-digital converter configured to convert the amplitude signal to a digital amplitude signal, a second capacitance encoder circuit configured to receive the digital amplitude signal and the digital phase difference signal and generate a second capacitance control signal, a resistance encoder circuit configured to receive the digital amplitude signal and the digital phase difference signal and generate a resistance control signal; and where the variable characteristic element further includes a variable resistance element having a variable resistance, the variable resistance being controlled by the resistance control signal and a second variable capacitance element controlled by the second variable capacitance control signal. 7. The control circuit of claim 6, where at least one of the first variable capacitance element, the second variable capacitance element, and the variable resistance element further comprises an analog look-up array that implements a predetermined function. 8. The control circuit of claim 6, where the first and second A/D converters are each further configured to receive a reset signal and a switching frequency signal and, responsive thereto, latch the digital amplitude and phase difference signal values, respectively, after a predetermined number of cycles of the switching frequency signal. 9. The control circuit of claim 6, where the variable resistance element is further configured to control a gain of an error amplifier within the current control feedback loop of the switching voltage regulator circuit. 10. The control circuit of claim 1, where the measuring circuit further comprises: a first strip section having an input terminal coupled to the first input terminal of the measuring circuit, where the first strip section is configured to generate a measured phase signal in response to the output voltage signal; a second strip section having an input terminal coupled to the second input terminal of the measuring circuit, where the second strip section is configured to generate a reference signal responsive to a signal at the output of the switch drive circuit; a multiplier configured to receive and multiply the measured phase signal and the reference signal to generate the phase difference signal; and a low pass filter configured to filter the phase difference signal. 11. A method for automatically adjusting a switching voltage regulator circuit to account for an external component, the method comprising the steps of: measuring a phase of a ripple signal caused by the external component; generating a reference signal; comparing the measured phase of the ripple signal to the reference signal to obtain a phase difference signal; and adjusting a transfer function of a feedback path of the switching voltage regulator responsive to the phase difference signal to obtain stable operation of the switching voltage regulator circuit. 12. The method of claim 11, where the step of adjusting a transfer function of a feedback path further includes the steps of: converting the phase difference signal to a variable characteristic control signal; and adjusting a variable characteristic in the feedback path of the switching voltage regulator responsive to the variable characteristic control signal. 13. The method of claim 12, where the step of adjusting a variable characteristic in the feedback path of the switching voltage regulator responsive to the variable characteristic control signal further comprises adjusting a variable capacitance in the feedback path responsive to the variable characteristic control signal. 14. The method of claim 11, where the step of adjusting a transfer function of a feedback path of the switching voltage regulator responsive to the phase difference signal further comprises introducing at least one of a pole or zero to the transfer function responsive to the phase difference signal. 15. The method of claim 11, the method further including the steps of: measuring an amplitude of the ripple signal; converting the phase difference signal and the measured amplitude of the ripple signal into a second variable characteristic control signal; and adjusting the transfer function of the feedback path of the switching voltage regulator responsive to the second variable characteristic control signal to improve a transient response of the switching voltage regulator circuit. 16. The method of claim 15, where the step of adjusting the transfer function of the feedback path of the switching voltage regulator responsive to the second variable characteristic control signal to improve a transient response of the switching voltage regulator circuit further comprises adjusting a gain in the feedback loop responsive to the second variable control signal and introducing at least one of a second pole or zero to the transfer function responsive to the second variable control signal. 17. An apparatus for automatically adjusting a switching voltage regulator circuit to account for an external component, the apparatus comprising: means for measuring a phase of a ripple signal caused by the external component; means for generating a reference signal; means for comparing the measured phase of the ripple signal to the reference signal to obtain a phase difference signal; and means for adjusting a transfer function of a feedback path of the switching voltage regulator responsive to the phase difference signal to obtain stable operation of the switching voltage regulator circuit. 18. The apparatus of claim 17, where the means for adjusting a transfer function of a feedback path further includes: means for converting the phase difference signal to a variable characteristic control signal; and means for adjusting a variable characteristic in the feedback path of the switching voltage regulator responsive to the variable characteristic control signal. 19. The apparatus of claim 18, where the means for adjusting a variable characteristic in the feedback path of the switching voltage regulator responsive to the variable characteristic control signal further comprises means for adjusting a variable capacitance in the feedback path responsive to the variable characteristic control signal. 20. The apparatus of claim 17, where the means for adjusting a transfer function of a feedback path of the switching voltage regulator responsive to the phase difference signal further comprises means for introducing at least one of a pole or zero to the transfer function responsive to the phase difference signal. 21. The apparatus of claim 17, the method further including: means for measuring an amplitude of the ripple signal; means for converting the phase difference signal and the measured amplitude of the ripple signal into a second variable characteristic control signal; and means for adjusting the transfer function of the feedback path of the switching voltage regulator responsive to the second variable characteristic control signal to improve a transient response of the switching voltage regulator circuit. 22. The method of claim 21, where the means for adjusting the transfer function of the feedback path of the switching voltage regulator responsive to the second variable characteristic control signal to improve a transient response of the switching voltage regulator circuit further comprises means for adjusting a gain in the feedback loop responsive to the second variable control signal and means for introducing at least one of a second pole or zero to the transfer function responsive to the second variable control signal. comprising a synchronization logic circuit adapted to receive ramp start signals for initiating the plurality of ramp generators synchronously with respective ones of the plurality of output phases. 13. The circuit of claim 12 wherein the synchronization logic circuit is further adapted to prevent more than one of the plurality of ramp generators from being initiated simultaneously. 14. The circuit of claim 1 further comprising a shut-down circuit responsive to a disable signal and adapted to disable operation of the ramp generator. 15. The circuit of claim 14 wherein the shut-down circuit further comprises a bypass switch adapted to provide the regulated output signal of the voltage regulator as the feedback signal when the disable signal is asserted. 16. The circuit of claim 1 wherein the ramp generator comprises: a ramp circuit adapted to generate an arbitrary ramping voltage responsive to a ramp start signal synchronized to the switching cycle of the voltage regulator; and an output circuit adapted to sink a ramp current proportional to the ramping voltage to impress the ripple signal in the feedback signal. 17. The circuit of claim 16 wherein the ramp circuit is further adapted to disable the ramp generator responsive to a disable signal. 18. The circuit of claim 16 wherein the ramp circuit includes a ramp adjustment input to control at least one characteristic of the ripple signal imparted to the feedback signal. 19. The circuit of claim 18 wherein the ramp adjustment input is adapted to connect with an external capacitor, such that a capacitance value of the external capacitor controls a magnitude of the ripple signal. 20. The circuit of claim 18 wherein the ramp adjustment input is adapted to connect with an external resistor, such that a resistance value of the external resistor controls a magnitude of the ripple signal. 21. The circuit of claim 16 wherein the ramp circuit generates the ripple signal as a single-slope waveform in a first configuration and generates the ripple signal as a dual-slope waveform in a second configuration, said first configuration corresponding to use of the circuit with a constant on-time controller as the voltage regulator and said second configuration corresponding to use of the circuit with a hysteretic controller as the voltage regulator. 22. The circuit of claim 1 wherein the buffer comprises a voltage follower circuit. 23. The circuit of claim 1 further comprising a droop compensator adapted to impart a voltage offset in the feedback signal that is proportional to a current of the regulated output signal, thereby imparting output voltage droop compensation to the voltage regulator. 24. The circuit of claim 23 wherein an input of the buffer is coupled to the regulated output signal through a series impedance, and further wherein the droop compensator comprises an amplifier adapted to inject a droop current proportional to the current of the regulated output signal into a node connecting the series impedance with the buffer. 25. The circuit of claim 1 wherein the ripple generating circuit comprises an integrated portion of the voltage regulator. 26. The circuit of claim 1 further comprising a coupling capacitor to couple said ramp generator to an output of said buffer. 27. The circuit of claim 26 wherein said ramp generator comprises: a ramp circuit to generate a ramping voltage signal; and a follower amplifier to generate said ripple signal as a voltage ripple signal, wherein said voltage ripple signal is coupled through said coupling capacitor to said feedback signal. 28. The circuit of claim 27 wherein said ramp circuit comprises: a current source to generate a charging current; and a ramp capacitor to develop said ramping voltage signal based on said charging current. 29. The circuit of claim 26 wherein said buffer comprises: a buffer amplifier configured as a voltage follower to generate said feedback signal based on buffering said regulated output signal; an
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