LOAD CONTROL DEVICE HAVING A GATE CURRENT SENSING CIRCUIT
First Claim
1. A load control circuit for controlling the amount of power delivered to an electrical load from an AC power source for generating an AC line voltage, the load control circuit comprising:
- a controllably conductive device adapted to be coupled in series electrical connection between the power source and the electrical load, the controllably conductive device having a conductive state and a non-conductive state, the controllably conductive device having a control input and operable to enter the conductive state in response to a gate current conducted through the control input; and
a controller operable to drive the controllably conductive device to change the controllably conductive device from the non-conductive state to the conductive state each half-cycle of the AC line voltage, the controller operable to determine, in response to the magnitude of the gate current through the control input of the controllably conductive device, whether the controllably conductive device is presently conducting current to the load.
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Accused Products
Abstract
A gate drive circuit for a controllably conductive device, such as a triac, includes a trigger circuit for conducting a gate current through a control input of the controllably conductive device, and a sense circuit operable to generate a control signal representative of the magnitude of the gate current. The controllably conductive device is adapted to be coupled in series between an AC power source and an electrical load for controlling the amount of power delivered to the electrical load. The controllably conductive device is operable to change from a non-conductive state to a conductive state in response to the gate current being conducted through the control input. A controller is operable to control the controllably conductive device via the gate drive circuit and to determine, in response to the magnitude of the gate current through the control input of the controllably conductive device, whether the controllably conductive device is presently conducting current to the load.
76 Citations
33 Claims
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1. A load control circuit for controlling the amount of power delivered to an electrical load from an AC power source for generating an AC line voltage, the load control circuit comprising:
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a controllably conductive device adapted to be coupled in series electrical connection between the power source and the electrical load, the controllably conductive device having a conductive state and a non-conductive state, the controllably conductive device having a control input and operable to enter the conductive state in response to a gate current conducted through the control input; and a controller operable to drive the controllably conductive device to change the controllably conductive device from the non-conductive state to the conductive state each half-cycle of the AC line voltage, the controller operable to determine, in response to the magnitude of the gate current through the control input of the controllably conductive device, whether the controllably conductive device is presently conducting current to the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A gate drive circuit adapted to be coupled to the control input of a bidirectional semiconductor switch operable to change from a non-conductive state to a conductive state in response to a gate current conducted through the control input, the gate drive circuit comprising:
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a trigger circuit adapted to be coupled in series electrical connection with the control input of the bidirectional semiconductor switch to conduct the gate current; and a sense circuit having an input adapted to be in series with the control input of the bidirectional semiconductor switch, the sense circuit operable to generate a control signal representative of the magnitude of the gate current. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method of controlling the amount of power delivered to an electrical load from a power source, the method comprising the steps of:
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coupling a controllably conductive device in series electrical connection between the power source and the electrical load, the controllably conductive device having a conductive state and a non-conductive state; conducting a gate current through the control input to cause the controllably conductive device to enter the conductive state; monitoring the gate current; and determining, in response to the step of monitoring the gate current, whether the controllably conductive device is presently conducting current to the load. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification