DIGITAL CONTROLLER FOR SWITCH-MODE DC-DC CONVERTERS AND METHOD
First Claim
1. A digital controller for a switch-mode DC-DC converter, the DC-DC converter having at least two switching elements and an LC circuit for producing an output voltage on an output of the DC-DC converter that is maintained at a desired level regardless of load changes that can occur on the output, the digital controller comprising:
- an input stage configured to produce a difference signal between a reference voltage (Vref) and a feedback voltage (Vfbk) in a feedback loop of the DC-DC converter representative of the output voltage, wherein the input stage comprises one selected from the group consisting of (i) first and second delta-sigma-delta modulators and a subtractor, (ii) a delta-sigma-delta modulator and a subtractor, and (iii) a comparator;
a proportional-integral-derivative (PID) compensator configured to process the difference signal to stabilize the feedback loop by compensating for an undesired phase shift introduced in the DC-DC converter output voltage by the LC circuit for large variations on a load on the output of the DC-DC converter, the load variations ranging from no load to just more than zero ohms, the PID compensator having an output for outputting a processed difference signal; and
a digital sigma-delta modulator coupled to the PID compensator output configured to (i) generate at least one switching element control signal in response to the processed difference signal and (ii) output the at least one switching element control signal to a control input of at least one of the at least two switching elements for controlling a respective switching element of the DC-DC converter.
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Accused Products
Abstract
A fully digital synthesizable digital controller (152,152a) controls a switch-mode DC-DC converter (150,230,240,250,260) having switching elements (154) and an LC circuit (156,157) for producing an output voltage (160) that is maintained at a desired level regardless of load changes that can occur on the output. The digital controller (152,152a) comprises an input stage (164), proportional-integral-derivative (PID) compensator (170), and a digital sigma-delta modulator (172). The input stage (164) produces a difference signal between a reference voltage Vref and a feedback voltage Vfbk, and comprises (i) first and second delta-sigma-delta modulators (178,180) and a subtractor (182), (ii) a delta-sigma-delta modulator (180) and a subtractor (182); or (iii) a comparator (218). The PID compensator (170) processes the difference signal to compensate for an undesired phase shift and to stabilize the feedback loop. The digital sigma-delta modulator (172) generates a switching element control signal for controlling at least one of the switching elements.
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Citations
25 Claims
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1. A digital controller for a switch-mode DC-DC converter, the DC-DC converter having at least two switching elements and an LC circuit for producing an output voltage on an output of the DC-DC converter that is maintained at a desired level regardless of load changes that can occur on the output, the digital controller comprising:
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an input stage configured to produce a difference signal between a reference voltage (Vref) and a feedback voltage (Vfbk) in a feedback loop of the DC-DC converter representative of the output voltage, wherein the input stage comprises one selected from the group consisting of (i) first and second delta-sigma-delta modulators and a subtractor, (ii) a delta-sigma-delta modulator and a subtractor, and (iii) a comparator; a proportional-integral-derivative (PID) compensator configured to process the difference signal to stabilize the feedback loop by compensating for an undesired phase shift introduced in the DC-DC converter output voltage by the LC circuit for large variations on a load on the output of the DC-DC converter, the load variations ranging from no load to just more than zero ohms, the PID compensator having an output for outputting a processed difference signal; and a digital sigma-delta modulator coupled to the PID compensator output configured to (i) generate at least one switching element control signal in response to the processed difference signal and (ii) output the at least one switching element control signal to a control input of at least one of the at least two switching elements for controlling a respective switching element of the DC-DC converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of digitally controlling a switch-mode DC-DC converter, the DC-DC converter having at least two switching elements and an LC circuit for producing an output voltage on an output of the DC-DC converter that is maintained at a desired level regardless of load changes that can occur on the output, the method comprising:
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producing, via an input stage, a difference signal between a reference voltage (Vref) and a feedback voltage (Vfbk) in a feedback loop of the DC-DC converter representative of the output voltage, wherein producing the difference signal via the input stage comprises producing the difference signal via one selected from the group consisting of (i) first and second delta-sigma-delta modulators and a subtractor, (ii) a delta-sigma-delta modulator and a subtractor; and
(iii) a comparator;processing, via a proportional-integral-derivative (PID) compensator, the difference signal to stabilize the feedback loop by compensating for an undesired phase shift introduced in the DC-DC converter output voltage by the LC circuit circuit for large variations on a load on the output of the DC-DC converter, the load variations ranging from no load to just more than zero ohms, wherein processing further comprises outputting, via an output of the PID compensator, a processed difference signal; and generating, via a digital sigma-delta modulator coupled to the PID compensator output, at least one switching element control signal in response to the processed difference signal, wherein generating further comprises outputting, via an output of the digital sigma-delta modulator, the at least one switching element control signal to at least one of the at least two switching elements for controlling a respective switching element of the DC-DC converter. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A switch-mode DC-DC converter comprising:
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at least two switching elements, wherein at least one of the at least two switching elements is configured to switch in response to a switching element control signal; an LC circuit coupled to the at least two switching elements for producing an output voltage on an output of the DC-DC converter in response to switching of the at least two switching elements; and a digital controller, wherein the digital controller comprises; (a) an input stage for producing a difference signal between a reference voltage (Vref) and a feedback voltage (Vfbk) in a feedback loop of the DC-DC converter representative of the output voltage, wherein the input stage comprises one selected from the group consisting of (i) first and second delta-sigma-delta modulators and a subtractor, (ii) a delta-sigma-delta modulator and a subtractor, and (iii) a comparator; (b) a proportional-integral-derivative (PID) compensator for processing the difference signal to stabilize the feedback loop by compensating for an undesired phase shift introduced in the DC-DC converter output voltage by the LC circuit for large variations on a load on the output of the DC-DC converter, the load variations ranging from no load to just more than zero ohms, the PID compensator having an output for outputting a processed difference signal; and (c) a digital sigma-delta modulator coupled to the PID compensator output for (i) generating at least one switching element control signal in response to the processed difference signal and (ii) outputting the at least one switching element control signal to a control input of the at least one of the at least two switching elements for controlling a respective switching element of the DC-DC converter. - View Dependent Claims (24, 25)
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Specification