Dimmer Switch With Adjustable High-End Trim
First Claim
1. A load control device with an adjustable high-end trim for controlling the amount of power delivered to an electrical load from an AC power source, the load control device comprising:
- a bidirectional semiconductor switch coupled in series electrical connection between the source and the load, and operable to control the amount of power delivered to the electrical load between a low-end trim and the adjustable high-end trim, the semiconductor switch having a control input for controlling the semiconductor switch in response to a firing voltage signal derived entirely from analog control circuitry; and
user-accessible means for reducing the adjustable high-end trim of the load control device from a first level to a second level lower than the first level, the user-accessible means for reducing having substantially no affect upon the low-end trim of the load control device.
4 Assignments
0 Petitions
Accused Products
Abstract
A dimmer switch has a user adjustable high-end trim. The dimmer switch includes a bidirectional semiconductor switch, such as a triac, for controlling the amount of power delivered from a source of alternating current power to a lighting load, such as an electric lamp. A user-adjustable timing circuit controls the conduction time of the triac from a minimum time to a maximum time. The maximum possible conduction time of the triac is the high-end trim. The minimum possible conduction time of the triac is the low-end trim. The timing circuit includes a user-accessible switch that allows a user to reduce the high-end trim from a first nominal level to a second reduced level, lower than the first level, without substantially affecting the low-end trim. The switch allows a user to switch a transient voltage suppressor into and out of parallel connection with a resistor that is part of an RC timing circuit for the triac. The dimmer switch advantageously uses less energy and the lifetime of the lamp is extended when the second reduced level of the high-end trim is selected.
15 Citations
44 Claims
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1. A load control device with an adjustable high-end trim for controlling the amount of power delivered to an electrical load from an AC power source, the load control device comprising:
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a bidirectional semiconductor switch coupled in series electrical connection between the source and the load, and operable to control the amount of power delivered to the electrical load between a low-end trim and the adjustable high-end trim, the semiconductor switch having a control input for controlling the semiconductor switch in response to a firing voltage signal derived entirely from analog control circuitry; and user-accessible means for reducing the adjustable high-end trim of the load control device from a first level to a second level lower than the first level, the user-accessible means for reducing having substantially no affect upon the low-end trim of the load control device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A load control device for controlling the amount of power delivered to an electrical load from an AC power source, the load control device comprising:
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a semiconductor switch operable to be coupled in series electrical connection between the source and the load, the semiconductor switch having a control input for controlling the semiconductor switch; a triggering circuit for rendering the semiconductor switch conductive each half-cycle of the AC voltage source; a timing circuit coupled in parallel electrical connection with the semiconductor switch, the timing circuit having an output for providing a firing voltage signal, the triggering circuit coupled to the output of the timing circuit and operable to control the semiconductor switch in response to the firing voltage signal, such that the amount of power delivered to the electrical load is controlled between a low-end trim and a high-end trim, the timing circuit further comprising a first circuit for causing the firing voltage signal to increase from substantially zero volts to a predetermined voltage during a first amount of time such that the semiconductor switch is rendered conductive at a first time each half-cycle of the AC voltage source at the low-end trim, and during a second amount of time such that the semiconductor switch is rendered conductive at a second time each half-cycle at the high-end trim, the second amount of time less than the first amount of time, the timing circuit further comprising a second circuit for causing the firing voltage signal to increase from substantially zero volts to the predetermined voltage during the first amount of time such that the semiconductor switch is rendered conductive at the first time each half-cycle at the low-end trim, and during a third amount of time such that the semiconductor switch is rendered conductive at a third time each half-cycle of the AC voltage source at the high-end trim, the third amount of time greater than the second amount of time, but less than the first amount of time; and a user-accessible adjustment actuator coupled to the timing circuit for selectively causing the semiconductor switch to be rendered conductive at either the second time or the third time each half-cycle of the AC voltage source when the amount of power delivered to the electrical load is at the high-end trim.
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26. A timing circuit for allowing the adjustment of a high-end trim of a load control device, the timing circuit operable to generate a firing voltage signal, the load control device operable to control the amount of power delivered to an electrical load from an AC power source in response to the firing voltage signal, the timing circuit comprising:
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a capacitor operable to conduct a charging current from the power source such that the firing voltage signal is produced across the capacitor; a potentiometer coupled to conduct the charging current of the capacitor, the potentiometer having a resistance variable between a minimum resistance and a maximum resistance for controlling the firing voltage signal; a first circuit for causing the firing voltage signal to increase from substantially zero volts to a predetermined voltage during a first amount of time when the potentiometer is set to the maximum resistance, and during a second amount of time when the potentiometer is set to the minimum resistance, the second amount of time less than the first amount of time; and a second circuit for causing the firing voltage signal to increase from substantially zero volts to the predetermined voltage during the first amount of time when the potentiometer is set to the maximum resistance, and during a third amount of time when the potentiometer is set to the minimum resistance, the third amount of time greater than the second amount of time, but less than the first amount of time; wherein the timing circuit is operable to selectively cause the firing voltage signal to increase from substantially zero volts to the predetermined voltage during either the second amount of time or the third amount of time each half-cycle of the AC voltage source when the potentiometer is set to the minimum resistance. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of adjusting a high-end trim of a load control device for controlling the amount of power delivered from an AC power source to an electrical load, the method comprising the steps of:
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generating a firing voltage signal entirely from analog control circuitry; controlling the amount of power delivered to the electrical load between a first low-end trim level and a first high-end trim level in response to the firing voltage signal; actuating a user-accessible high-end trim adjustment actuator; and subsequently controlling the amount of power delivered to the electrical load between a second low-end trim level and a second high-end trim level in response to the firing voltage signal, the second low-end trim level equal to the first low-end trim level, the second high-end trim level different than the first high-end trim level. - View Dependent Claims (44)
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Specification