Timer-based switching circuit synchronization in an electrical dimmer
First Claim
1. A dimmer for controlling electrical power of an AC wave to a load, the dimmer comprising:
- a line input terminal and a load output terminal, the line input terminal coupled to the AC wave, and the load output terminal coupled to the load;
a switching circuit electrically coupled between the line input terminal and the load output terminal, the switching circuit controlling a supply of electrical power to the load;
a controller to synchronize firing of the switching circuit with respect to the AC wave to provide electrical power to the load;
a timer having a predetermined timeout; and
a zero-crossing detector configured to output a zero-crossing signal indicative of a zero-crossing of the AC wave, wherein receipt of the zero-crossing signal starts the timer, and if a subsequent zero-crossing signal is received prior to reaching the timeout, the timer is restarted, and wherein responsive to reaching the timeout, the controller fires the switching circuit at a predetermined firing angle with respect to the zero-crossing signal to supply electrical power to the load.
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Accused Products
Abstract
Timer-based switching circuit synchronization in an electrical dimmer is provided. The energizing of a switching circuit in a dimmer is synchronized with an AC wave to facilitate providing by the dimmer electrical power to a load. The synchronizing includes starting a timer having a predetermined timeout, responsive to receipt of a zero-crossing signal. Responsive to receipt of a subsequent zero-crossing signal prior to reaching the timeout, the timer is restarted, and responsive to expiration of the timeout, a switching circuit is energized at a predetermined firing angle with respect to the zero-crossing signal to supply electrical power to the load.
120 Citations
17 Claims
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1. A dimmer for controlling electrical power of an AC wave to a load, the dimmer comprising:
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a line input terminal and a load output terminal, the line input terminal coupled to the AC wave, and the load output terminal coupled to the load; a switching circuit electrically coupled between the line input terminal and the load output terminal, the switching circuit controlling a supply of electrical power to the load; a controller to synchronize firing of the switching circuit with respect to the AC wave to provide electrical power to the load; a timer having a predetermined timeout; and a zero-crossing detector configured to output a zero-crossing signal indicative of a zero-crossing of the AC wave, wherein receipt of the zero-crossing signal starts the timer, and if a subsequent zero-crossing signal is received prior to reaching the timeout, the timer is restarted, and wherein responsive to reaching the timeout, the controller fires the switching circuit at a predetermined firing angle with respect to the zero-crossing signal to supply electrical power to the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of selectively providing electrical power to a load by controlling a switching circuit with respect to a zero-crossing of an AC wave, the method comprising:
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receiving a zero-crossing signal indicative of the occurrence of the zero-crossing of the AC wave; responsive to the zero crossing signal, starting a timer for a predetermined time interval; wherein if a subsequent zero-crossing signal is received prior to the predetermined time interval elapsing, the timer is restarted; and responsive to expiration of the predetermined time interval, energizing the switching circuit at a predetermined firing angle with respect to the zero-crossing signal and providing electrical power to the load. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification