Method and apparatus to limit maximum switch current in a switch of a switching power supply
First Claim
1. A switching regulator circuit, comprising:
- a switch to be coupled to an energy transfer element;
a controller coupled to the switch to control switching of the switch;
a current sensor included in the controller and including first and second comparators coupled to compare a current in the switch with first and second current limits, respectively, the controller to open the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch in response to the first or second comparators; and
a frequency adjuster included in the controller and coupled to the second comparator, the frequency adjuster to adjust an oscillating frequency of an oscillator included in the controller in response to the second comparator.
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Abstract
Techniques are disclosed to limit the current in a switch of a switching power supply. An example switching regulator circuit includes a switch to be coupled to an energy transfer element. A controller is coupled to the switch to control switching of the switch. A current sensor is included in the controller. The current sensor includes first and second comparators coupled to compare a current in the switch with first and second current limits, respectively. The controller is to open the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch in response to the first or second comparators. A frequency adjuster is also included in the controller and coupled to the second comparator. The frequency adjuster is to adjust an oscillating frequency of an oscillator included in the controller in response to the second comparator.
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Citations
20 Claims
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1. A switching regulator circuit, comprising:
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a switch to be coupled to an energy transfer element;
a controller coupled to the switch to control switching of the switch;
a current sensor included in the controller and including first and second comparators coupled to compare a current in the switch with first and second current limits, respectively, the controller to open the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch in response to the first or second comparators; and
a frequency adjuster included in the controller and coupled to the second comparator, the frequency adjuster to adjust an oscillating frequency of an oscillator included in the controller in response to the second comparator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for regulating a transfer of energy, comprising:
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switching a switch coupled to an energy transfer element to regulate a transfer of energy through the energy transfer element;
opening the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch if a current in the switch is greater than a first or second current limit; and
delaying the next switching cycle of the switch if the current in the switch is greater than the second current limit. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A power supply, comprising:
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an energy transfer element coupled between an input and an output of the power supply;
a switch coupled to the input of the energy transfer element to regulate a transfer of energy from the input of the power supply to the output of the power supply;
a controller coupled to the switch to control switching of the switch;
a current sensor included in the controller and including first and second comparators coupled to compare a current in the switch with first and second current limits, respectively, the controller to open the switch for a remainder of a current switching cycle of the switch until a next switching cycle of the switch in response to the first or second comparators; and
a frequency adjuster included in the controller and coupled to the second comparator, the frequency adjuster to adjust an oscillating frequency of an oscillator included in the controller in response to the second comparator. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification