Power supply with reduced power consumption when a load is disconnected from the power supply
First Claim
Patent Images
1. A power supply comprising:
- a switch;
a transformer having a primary winding and a secondary winding, the primary winding being connected to the switch;
a rectifier connected to the secondary winding of the transformer;
a filter connected to the rectifier; and
a control circuit connected to the switch, the control circuit opening the switch only when the control circuit determines that no current is flowing out of the filter.
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Accused Products
Abstract
Detection and control circuitry are added to a conventional power supply to detect when a load, such as a portable electronic device, has been disconnected from the power supply and, when disconnected, interrupt a current path to the primary windings of a transformer within the power supply to substantially reduce the amount of reactive power that is consumed by the power supply.
16 Citations
20 Claims
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1. A power supply comprising:
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a switch; a transformer having a primary winding and a secondary winding, the primary winding being connected to the switch; a rectifier connected to the secondary winding of the transformer; a filter connected to the rectifier; and a control circuit connected to the switch, the control circuit opening the switch only when the control circuit determines that no current is flowing out of the filter. - View Dependent Claims (2, 3, 4, 5)
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6. A power supply comprising:
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a switch; a transformer having a primary winding and a secondary winding, the primary winding being connected to the switch; a rectifier connected to the secondary winding of the transformer; a filter connected to the rectifier; and a control circuit connected to the switch, the control circuit opening the switch only when the control circuit determines that a current flowing out of the filter has fallen below a minimum magnitude. - View Dependent Claims (7, 8, 9, 10)
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11. A power supply comprising:
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a switch; a transformer having a primary winding and a secondary winding, the primary winding being connected to the switch; a rectifier connected to the secondary winding of the transformer; a filter connected to the rectifier; and a control circuit connected to the switch, the control circuit determining a difference between an output voltage at an output of the filter and a reference voltage, the control circuit opening and closing the switch at a switching frequency in response to the difference, the control circuit opening the switch for a predetermined period of time only when the control circuit determines that no current is flowing out of the filter, the predetermined period of time being greater than any period of the switching frequency. - View Dependent Claims (12, 13, 14, 15)
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16. A power supply comprising:
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a switch; a transformer having a primary winding and a secondary winding, the primary winding being connected to the switch; a rectifier connected to the secondary winding of the transformer; a filter connected to the rectifier; and a control circuit connected to the switch, the control circuit determining a difference between an output voltage at an output of the filter and a reference voltage, the control circuit opening and closing the switch at a switching frequency in response to the difference, the control circuit opening the switch for a predetermined period of time only when the control circuit determines that a current flowing out of the filter has fallen below a minimum magnitude, the predetermined period of time being greater than any period of the switching frequency. - View Dependent Claims (17, 18, 19, 20)
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Specification