Digital PWM controller with efficiency optimization as a function of PWM duty cycle
First Claim
1. A method for optimizing the efficiency of a switching power supply having at least one switch for connecting an input voltage to an input node for driving an inductive storage element connected to an out put node to provide a regulated output voltage, and a second switch for shunting the intermediate node to a reference voltage in a complementary mode of operation, comprising the steps of:
- generating complementary switch control signals for controlling the operation of the first and second switches, wherein the ratio of the on time of the first switch to the period of a switching cycle determines the ratio of the output voltage to the input voltage;
controlling the duty cycle to provide a regulated voltage on the output node; and
providing a delay between the time one of the first and second switches is transitioned and the other of the first and second switches is transitioned;
for a given operating condition;
varying the delay, and determining the delay that provides the minimum duty cycle for the given operating condition.
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Accused Products
Abstract
A method for optimizing the efficiency of a digital power supply having at least one switch for connecting an input voltage to an input node for driving an inductive storage element connected to an out put node tp provide a regulated output voltage, and a second switch for shunting the intermediate node to ground in a complementary operation. Complementary switch control signals are generated for controlling the operation of the first and second switches, wherein the ratio of the on and off time of the first switch determines the ratio of the output voltage to the input voltage. The duty cycle is then controlled to provide a regulated voltage on the output node. A delay circuit provides a delay between the time the first switch is turned off and the second switch is turned on. For a given load, the delay is varied and then a minima for the delay is determined to provide the minimum duty cycle for the given load.
62 Citations
20 Claims
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1. A method for optimizing the efficiency of a switching power supply having at least one switch for connecting an input voltage to an input node for driving an inductive storage element connected to an out put node to provide a regulated output voltage, and a second switch for shunting the intermediate node to a reference voltage in a complementary mode of operation, comprising the steps of:
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generating complementary switch control signals for controlling the operation of the first and second switches, wherein the ratio of the on time of the first switch to the period of a switching cycle determines the ratio of the output voltage to the input voltage;
controlling the duty cycle to provide a regulated voltage on the output node; and
providing a delay between the time one of the first and second switches is transitioned and the other of the first and second switches is transitioned;
for a given operating condition;
varying the delay, and determining the delay that provides the minimum duty cycle for the given operating condition.
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2. A method for optimizing the efficiency of a switched power supply having a plurality of switches responsive to generated pulse control signals, one switch of which is turned on and off to drive an inductive element in the power supply from an input voltage, the duty cycle of the one switch defining the ratio of the output voltage to an input voltage, comprising the steps of:
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varying the initiation of conduction in at least another of the switches relative to the conduction in the one of the switches by controlling when an edge in an associated one of the pulse control signals is generated;
determining a minima in the duty cycle for a given operating condition of the power supply over the step of varying; and
after the step of determining, freezing the configuration of the respective pulse control signals at the minima. - View Dependent Claims (3, 4, 5, 6, 7)
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8. A method for optimizing the operation of a pulse width modulated power supply having a plurality of switches, of which at least two are complementary switches, one switch of which is turned on and off to drive an inductive element in the power supply from an input voltage, the duty cycle of the one switch defining the ratio of the output voltage to an input voltage, comprising the steps of:
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generating a plurality of pulse control signals, each operable to turn on and off respective ones of the switches;
controlling the pulse width of each of the pulse control signals with a controller to define the duty cycle thereof to define the ratio between the output and input voltages;
parameterizing the operation of the controller with a processor for applying predetermined parameters to the controller to define the operation thereof;
operating the processor in an optimization mode by;
determining the optimum dead time between the time that one of the two complementary switches changes to a non conductive state prior to the other of the complementary switches changing to the conductive state in order to minimize the duty cycle for a given operating condition; and
utilizing the determined optimized dead time as a parameter for normal operation of the processor. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A pulse width modulated power supply having a plurality of switches, of which at least two are complementary switches that require a dead time between the conduction of one to the conduction of the other, one switch of which is turned on and off to drive an inductive element in the power supply from an input voltage, the duty cycle of the one switch defining the ratio of the output voltage to an input voltage, comprising:
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a pulse width modulator (PWM) for generating a plurality of pulse control signals, each operable to turn on and off the one of the switches at the duty cycle;
a controller for controlling said PWM to define the pulse width of each of the pulse control signals and the duty cycle;
a processor for parameterizing the operation of the controller for applying predetermined parameters to the controller to define the operation thereof;
an optimizer for operating the processor in a dead time optimization mode by determining the optimum dead time between the time that one of the two complementary switches changes to a non conductive state prior to the other of the complementary switches changing to the conductive state in order to minimize the duty cycle for a given operating condition on the power supply; and
said processor utilizing the determined optimized dead time as a parameter for normal operation of the controller. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification