Methods and apparatus for maintaining an approximate constant current output characteristic in a switched mode power supply
First Claim
1. A method of regulating a level at a power supply output, comprising:
- receiving a control terminal current from a control terminal of a regulator circuit, the control terminal current including a feedback current and an internal supply current;
deriving a shunt regulator current from the control terminal current, wherein the shunt regulator current is the control terminal current in excess of the internal supply current; and
determining at least one of a first mode and a second mode of operation in response to a level of the control terminal current to maintain an approximate constant output current characteristic of the power supply.
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Accused Products
Abstract
A regulator circuit maintaining an approximate constant current output characteristic. In one aspect, a disclosed regulator controls a switch that has a current limit threshold. A supply terminal and feedback terminal of the regulator are connected together as a control terminal such that a shunt regulator current is the control terminal current in excess of the internal supply current consumed by the regulator. The current limit threshold of the switch is changed as a function of the shunt regulator current. In another aspect, a control input of the regulator circuit receives a current that is the sum of the internal supply current consumed by the regulator circuit and a feedback current. The feedback current is a fraction of the consumption current of the regulator circuit and the current limit threshold of the switch is changed as a function of the feedback current.
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Citations
11 Claims
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1. A method of regulating a level at a power supply output, comprising:
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receiving a control terminal current from a control terminal of a regulator circuit, the control terminal current including a feedback current and an internal supply current; deriving a shunt regulator current from the control terminal current, wherein the shunt regulator current is the control terminal current in excess of the internal supply current; and determining at least one of a first mode and a second mode of operation in response to a level of the control terminal current to maintain an approximate constant output current characteristic of the power supply. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification