DC-DC converter with improved dynamic response
First Claim
1. A method for minimizing the output voltage deviation of a DC-DC converter in response to a load current step;
- comprising;
(i) detecting a load current step to a new load current by estimating or detecting a change in stored charge of a parallel output capacitor of the DC-DC converter;
(ii) modulating a duty cycle of the DC-DC converter to change current through a series output inductor, such current being different than the new load current; and
(iii) modulating the duty cycle of the DC-DC converter to simultaneously cause (a) the inductor current to be equal the new load current and (b) the stored charge of the parallel output capacitor to be substantially returned to a state prior to the load current step;
wherein estimating or measuring includes using a double integrator.
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Accused Products
Abstract
The invention relates to a control method and a controller for a DC-DC converter, such as a synchronous Buck converter, which exploits the principle of capacitor charge balance to allow the converter to recover from a positive and/or negative load current step in the shortest achievable time, with the lowest possible voltage undershoot/overshoot. The control method may be implemented by either an analog or a digital circuit. The controller may be integrated with existing controller schemes (such as voltage-mode controllers) to provide superior dynamic performance during large-signal transient conditions while providing stable operation during steady state conditions. The invention also relates to a method and a modification of a DC-DC converter topology that comprises connecting a controlled current source between an input terminal and an output terminal of the DC-DC converter; detecting a load current step to a new load current; modifying a duty cycle of the DC-DC converter; and modifying current through a parallel output capacitor of the DC-DC converter by controlling current of the current source. The methods and circuits provided herein are applicable to Buck converters and Buck-derived converters such as forward, push-pull, half-bridge, and full-bridge converters.
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Citations
13 Claims
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1. A method for minimizing the output voltage deviation of a DC-DC converter in response to a load current step;
- comprising;
(i) detecting a load current step to a new load current by estimating or detecting a change in stored charge of a parallel output capacitor of the DC-DC converter; (ii) modulating a duty cycle of the DC-DC converter to change current through a series output inductor, such current being different than the new load current; and (iii) modulating the duty cycle of the DC-DC converter to simultaneously cause (a) the inductor current to be equal the new load current and (b) the stored charge of the parallel output capacitor to be substantially returned to a state prior to the load current step; wherein estimating or measuring includes using a double integrator. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- comprising;
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8. A controller for minimizing the output voltage deviation of a DC-DC converter in response to a load current step;
- comprising;
(i) a detector for detecting a load current step to a new load current by estimating or detecting a change in stored charge of a parallel output capacitor of the DC-DC converter; (ii) means for modulating a duty cycle of the DC-DC converter to change current through a series output inductor, such current being different than the new load current; and (iii) means for modulating the duty cycle of the DC-DC converter to simultaneously cause (a) the inductor current to be equal the new load current and (b) the stored charge of the parallel output capacitor to be substantially returned to a state prior to the load current step; wherein the detector comprises a double integrator. - View Dependent Claims (9, 10, 11, 12, 13)
- comprising;
Specification