Load control device for a light-emitting diode light source having different operating modes
First Claim
1. A load control device for controlling an amount of power delivered to an electrical load, the load control device comprising:
- a load regulation circuit configured to control a magnitude of a load current conducted through the electrical load to control the amount of power delivered to the electrical load, the load regulation circuit comprising an inverter circuit characterized by a burst duty cycle; and
a control circuit coupled to the load regulation circuit and configured to control an average magnitude of the load current, the control circuit configured to control the inverter circuit to operate in active state periods during which the inverter circuit is active and inactive state periods during which the inverter circuit is inactive, the control circuit further configured to operate in at least a low-end mode, an intermediate mode, and a normal mode, wherein;
during the low-end mode, the control circuit is configured to keep a length of the active state periods constant and adjust a length of the inactive state periods in order to adjust the burst duty cycle and the average magnitude of the load current,during the intermediate mode, the control circuit is configured to keep the length of the inactive state periods constant and adjust the length of the active state periods in order to adjust the burst duty cycle and the average magnitude of the load current, andduring the normal mode, the control circuit is configured to regulate the average magnitude of the load current by holding the burst duty cycle constant and adjusting a target load current conducted through the electrical load.
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Accused Products
Abstract
A load control device for regulating an average magnitude of a load current conducted through an electrical load may operate in different modes. The load control device may comprise a control circuit configured to activate an inverter circuit during an active state period and deactivate the inverter circuit during an inactive state period. In one mode, the control circuit may adjust the average magnitude of the load current by adjusting the inactive state period while keeping the active state period constant. In another mode, the control circuit may adjust the average magnitude of the load current by adjusting the active state period while keeping the inactive state period constant. In yet another mode, the control circuit may keep a duty cycle of the inverter circuit constant and regulate the average magnitude of the load current by adjusting a target load current conducted through the electrical load.
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Citations
20 Claims
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1. A load control device for controlling an amount of power delivered to an electrical load, the load control device comprising:
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a load regulation circuit configured to control a magnitude of a load current conducted through the electrical load to control the amount of power delivered to the electrical load, the load regulation circuit comprising an inverter circuit characterized by a burst duty cycle; and a control circuit coupled to the load regulation circuit and configured to control an average magnitude of the load current, the control circuit configured to control the inverter circuit to operate in active state periods during which the inverter circuit is active and inactive state periods during which the inverter circuit is inactive, the control circuit further configured to operate in at least a low-end mode, an intermediate mode, and a normal mode, wherein; during the low-end mode, the control circuit is configured to keep a length of the active state periods constant and adjust a length of the inactive state periods in order to adjust the burst duty cycle and the average magnitude of the load current, during the intermediate mode, the control circuit is configured to keep the length of the inactive state periods constant and adjust the length of the active state periods in order to adjust the burst duty cycle and the average magnitude of the load current, and during the normal mode, the control circuit is configured to regulate the average magnitude of the load current by holding the burst duty cycle constant and adjusting a target load current conducted through the electrical load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An LED driver for controlling an intensity of an LED light source, the LED driver comprising:
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an LED drive circuit configured to control a magnitude of a load current conducted through the LED light source to control an amount of power delivered to the LED light source, the LED drive circuit comprising an inverter circuit characterized by a burst duty cycle; and a control circuit coupled to the LED drive circuit and configured to control an average magnitude of the load current, the control circuit configured to control the inverter circuit to operate in active state periods during which the inverter circuit is active and inactive state periods during which the inverter circuit is inactive, the control circuit further configured to operate in at least a low-end mode, an intermediate mode, and a normal mode, wherein; during the low-end mode, the control circuit is configured to keep a length of the active state periods constant and adjust a length of the inactive state periods in order to adjust the burst duty cycle and the average magnitude of the load current, during the intermediate mode, the control circuit is configured to keep the length of the inactive state periods constant and adjust the length of the active state periods in order to adjust the burst duty cycle and the average magnitude of the load current, and during the normal mode, the control circuit is configured to regulate the average magnitude of the load current by holding the burst duty cycle constant and adjusting a target load current conducted through the LED light source. - View Dependent Claims (14, 15, 16)
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17. An LED driver for controlling an intensity of an LED light source, the LED driver comprising:
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an LED drive circuit configured to control a magnitude of a load current conducted through the LED light source in order to achieve a target intensity of the LED light source, the LED drive circuit comprising an inverter circuit characterized by a burst duty cycle; and a control circuit coupled to the LED drive circuit and configured to control an average magnitude of the load current, the control circuit configured to control the inverter circuit to operate in active state periods during which the inverter circuit is active and inactive state periods during which the inverter circuit is inactive, the control circuit further configured to operate in a burst mode and a normal mode, wherein, during the normal mode, the control circuit is configured to regulate the average magnitude of the load current by holding the burst duty cycle constant and adjusting a target load current conducted through the LED light source, and wherein, during the burst mode, the control circuit is configured to adjust the burst duty cycle and the average magnitude of the load current by keeping a length of the active state periods constant and adjusting a length of the inactive state periods if the target intensity of the LED light source is within a first intensity range, and by keeping the length of the inactive state periods constant and adjusting the length of the active state periods if the target intensity of the LED light source is within a second intensity range. - View Dependent Claims (18, 19, 20)
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Specification