Dynamically-controlled, intrinsically regulated charge pump power converter
First Claim
1. A power converter comprising:
- a power output stage including a load capacitor and a fly capacitor, the power output stage configured to receive an input voltage from an energy source and to provide an output voltage across output terminals, the load capacitor being electrically coupled across the output terminals, the power output stage further configured to switch between a charge state and discharge state, wherein the charge state includes the fly capacitor being electrically in parallel to the input voltage and wherein the discharge state includes the fly capacitor being electrically coupled across the load capacitor; and
, a dynamic controller operably coupled to the power output stage and adapted to respond to the output voltage across the load capacitor and to a predetermined reference voltage to command the switching from the charge state to the discharge state and providing a clockless, dynamically controlled charge pump cycle.
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Accused Products
Abstract
A charge pump power converter efficiently provides electrical power by dynamically controlling a switch matrix of the charge pump. Instead of open-loop oscillator-based control, a dynamic controller provides power upon demand by sensing the output voltage and changing the operating frequency of the charge pump in response. Moreover, this closed-loop dynamic control intrinsically voltage regulates the output voltage of the charge pump power converter without the inefficient addition of a step-down voltage regulator, downstream of the power converter. In addition, this closed-loop dynamic control allows for maintaining a desired output voltage even with variations in the input voltage. Also, the dynamic control accommodates the advantages of using ultra-capacitors in the charge pump. The power converter is capable of operating with a sub-one volt input voltage incorporating low-threshold, low on-resistance power MOSFET switches in the switch matrix of the charge pump. A progressive start-up circuit further allows the power converter to start from a discharged state even with a sub-one volt input voltage.
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Citations
43 Claims
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1. A power converter comprising:
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a power output stage including a load capacitor and a fly capacitor, the power output stage configured to receive an input voltage from an energy source and to provide an output voltage across output terminals, the load capacitor being electrically coupled across the output terminals, the power output stage further configured to switch between a charge state and discharge state, wherein the charge state includes the fly capacitor being electrically in parallel to the input voltage and wherein the discharge state includes the fly capacitor being electrically coupled across the load capacitor; and
,a dynamic controller operably coupled to the power output stage and adapted to respond to the output voltage across the load capacitor and to a predetermined reference voltage to command the switching from the charge state to the discharge state and providing a clockless, dynamically controlled charge pump cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
a first switch M1 closingly responsive to a first switch signal S1 from the dynamic controller for electrically coupling the first input voltage to a first terminal of the fly capacitor;
a second switch M2 closingly responsive to a second switch signal S2 from the dynamic controller for electrically coupling the first terminal of the fly capacitor to a first terminal of the load capacitor;
a third switch M3 closingly responsive to the first switch signal S1 from the dynamic controller for electrically coupling a ground of the energy source to a second terminal of the fly capacitor; and
a fourth switch M4 closingly responsive to the second switch signal S2 from the dynamic controller for electrically coupling the second terminal of the fly capacitor to the energy source.
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6. The power converter of claim 1, wherein the discharge state selectably comprises a step-up discharge state and a step-down discharge state, wherein the power output stage is further configured to switch between the step-up discharge state comprising the fly capacitor electrically coupled across the load capacitor and the step-down discharge state comprising a series combination of the energy source and the fly capacitor electrically coupled across the load capacitor, wherein the dynamic controller is further responsive to the input voltage being greater than the reference voltage for selecting the step-up discharge step and else selecting the step-down discharge state.
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7. The power converter of claim 6, wherein the power output stage includes:
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a first switch M1 closingly responsive to a first switch signal S1 from the dynamic controller for electrically coupling the first input voltage to a first terminal of the fly capacitor;
a second switch M2 closingly responsive to a second switch signal S2 from the dynamic controller for electrically coupling the first terminal of the fly capacitor to a first terminal of the load capacitor;
a third switch M3 electrically coupling a ground of the energy source to a second terminal of the fly capacitor in response to one of the step-down discharge state and a charge state; and
a fourth switch M4 electrically coupling the second terminal of the fly capacitor to the energy source in response to the step-up discharge state.
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8. The power converter of claim 1, wherein one of the fly capacitor and load capacitor includes an ultra-capacitor.
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9. The power converter of claim 1, further comprising a by-pass circuit adapted to respond to a high load demand to operatively couple the energy source to the output terminals.
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10. The power converter of claim 9, wherein the by-pass circuit is further adapted to respond to a high load demand by sensing an output voltage droop.
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11. The power converter of claim 9, wherein the by-pass circuit is further adapted to uncouple the energy source from the power output stage in response to an output voltage droop.
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12. The power converter of claim 1, further comprising a protection circuit responsive to sensed current from the energy source for electrically uncoupling the output terminals from the energy source by disabling the power output stage.
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13. The power converter of claim 1, wherein the power output stage includes low on-resistance FET switches.
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14. The power converter of claim 13, wherein the low on-resistance FET array switches comprise lightly doped MOSFET arrays for sub-one volt input voltage operation.
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15. The power converter of claim 1 for stepping down the output voltage with respect to the input voltage, wherein the power output stage includes:
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a first switch M1 closingly responsive to a first switch signal S1 from the dynamic controller for electrically coupling the first input voltage to a first terminal of the fly capacitor;
a second switch M2 closingly responsive to a second switch signal S2 from the dynamic controller for electrically coupling the first terminal of the fly capacitor to a first terminal of the load capacitor; and
a ground path electrically coupled to the energy source, the second terminal of the fly capacitor, and the second terminal of the load capacitor.
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16. The power converter of claim 1, further comprising a progressive start-up circuit adapted to electrically couple the energy source to the load capacitor in response to a discharged power output stage.
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17. The power converter of claim 16, wherein the progressive start-up circuit further comprises:
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a start-up capacitor;
a start-up switch closingly responsive to a discharged power converter to provide input voltage to charge the start-up capacitor;
a hysteretic start-up transfer switch responsive to a charged state of the start-up capacitor to couple the start-up capacitor for discharge to a storage capacitor.
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18. The power converter of claim 1, further comprising a progressive start-up circuit configured to activate a charge pump powered by a low input voltage and coupled to a load, the bootstrap circuit adapted to activate the charge pump by transferring charge from an energy source to a storage capacitor, the bootstrap circuit comprising:
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a start-up capacitor adapted to have a floating first terminal referenced to ground in response to the charge pump being deactivated, the start-up capacitor when charged operatively coupling the input voltage to the storage capacitor; and
a start-up switch adapted to couple the low input voltage to a second terminal of the startup capacitor, in response to a discharged storage capacitor, to charge the start-up capacitor.
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19. A method of providing a regulated output voltage at an output terminal, the method comprising:
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receiving an input voltage from an energy source;
sensing an output voltage at the output terminal;
comparing the output voltage to a reference voltage;
discharging a fly capacitor into a load capacitor coupled to the output terminal in response to the output voltage being less than the reference voltage;
comparing the reference voltage to the output voltage; and
,determining a discharge time from the comparison. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
(a) in response to said input voltage being provided to said charge pump, charging a start-up capacitor with the input voltage;
(b) discharging the start-up capacitor into a storage capacitor across the load; and
,(c) in response to the output voltage of said storage capacitor being insufficient to activate said charge pump, repeating step (a).
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28. An integrated power converter comprising a dynamic controller and a switching matrix adapted to couple to a fly capacitor, a load capacitor, and an energy source, the dynamic controller electrically responsive to and operably controlling the switching matrix, the integrated power converter adapted to provide an output voltage across the load capacitor, the dynamic controller comprising:
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a voltage reference circuit for providing a reference voltage;
a comparator responsive to the reference voltage and the output voltage to generate a switching command and providing a clockless, dynamically controlled charge pump cycle; and
,a timing circuit adapted to receive the switching command and to command the switching matrix. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A electronic device including an energy source, a load device, and a power converter interposed between the energy source and the load device, the power converter comprising:
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a power output stage including a load capacitor and a fly capacitor, the power output stage configured to receive an input voltage from an energy source and to provide an output voltage across the load capacitor, the power output stage further configured to switch between a charge state and discharge state, wherein the charge state includes the fly capacitor being electrically in parallel to the input voltage and wherein the discharge state includes the input voltage and the fly capacitor being additively electrically coupled series across the load capacitor; and
a dynamic controller operably coupled to the power output stage and adapted to respond to a voltage across the load capacitor and to a predetermined reference voltage to command the switching from the charge state to the discharge state matrix and providing a clockless, dynamically controlled charge pump cycle. - View Dependent Claims (39)
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40. A battery comprising an energy source, a power converter and output terminals, the output terminals adapted to electrically couple to a load device, the power converter interposed between the energy source and the output terminals, the power converter comprising:
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a power output stage including a load capacitor and a fly capacitor, the power output stage configured to receive an input voltage from said energy source and to provide an output voltage across the load capacitor, the load capacitor being electrically coupled across the output terminals, the power output stage further configured to switch between a charge state and discharge state, wherein the charge state includes the fly capacitor being electrically in parallel to the energy source and wherein the discharge state includes the fly capacitor being electrically coupled across the load capacitor; and
a dynamic controller operably coupled to the power output stage and adapted to respond to an output voltage across the load capacitor and to a predetermined reference voltage to command the switching from the charge state to the discharge state and providing a clockless, dynamically controlled charge pump cycle.
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41. A power converter for transferring charge from an energy source to a pair of output terminals adapted for coupling to a load device, the power converter comprising:
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a power output stage adapted for coupling to said energy source and said pair of output terminals, the power output stage configured to transfer charge from said energy source to a charge storage device across said pair of output terminals in response to a repetitive cycle of charge and discharge signals correlated to a demand for charge by said load device;
a dynamic controller responsive to the demand for charge by said load, as indicated by an output voltage across the charge storage device, for generating the repetitive cycle of charge and discharge signals correlated to a predetermined target output matrix and providing a clockless, dynamically controlled charge pump cycle; and
an environmental controller configured responsive to a control parameter, to alter the predetermined target output. - View Dependent Claims (42, 43)
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Specification