Dual circuit wall switch occupancy sensor and method of operating same
First Claim
1. A method of supplying power to a load comprising the steps of:
- applying power to a current limiting circuit, the current limiting circuit being configured to limit one of leakage to ground current and leakage to neutral current to a selected average level;
accumulating charge in a capacitance circuit disposed at an output of the current limiting circuit;
selectively controlling discharge of the capacitance circuit into a power rail for powering a load connected to the power railshunt regulating an output voltage on the power rail and using the output voltage to set an input voltage on the power rail; and
receiving a pulse signal;
wherein said selectively controlling step comprises operating a switch to control current discharged from the capacitance circuit to the power rail and controlling a duty cycle of the switch by selectively controlling the opening and closing of the switch in accordance with the pulse signal to determine voltage on the capacitance circuit when average current out of the current limited circuit is less than the selected average level.
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Accused Products
Abstract
A method and apparatus are provided for detecting occupancy in an area using multiple detection technologies (e.g., ultrasound and infrared sensing) to intelligently control switching of plural load circuits whereby one of the circuits is affected by photocell control. A programmable controller implements auto-on, manual-on, reversion to auto-on and override operations with respect to the separately controlled load circuits based on sensor outputs and user inputs. An improved power supply for an occupancy sensor and load control device employs a DC voltage derived from leakage AC voltage between line and ground to drive the sensors and other circuits, and a switching regulator with a switching cycle controlled by a pulse width modulated (PWM) subsystem of the apparatus, allowing synchronous, delayed or exclusive operation relative to the sensing technology such as the US transmitter.
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Citations
15 Claims
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1. A method of supplying power to a load comprising the steps of:
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applying power to a current limiting circuit, the current limiting circuit being configured to limit one of leakage to ground current and leakage to neutral current to a selected average level; accumulating charge in a capacitance circuit disposed at an output of the current limiting circuit; selectively controlling discharge of the capacitance circuit into a power rail for powering a load connected to the power rail shunt regulating an output voltage on the power rail and using the output voltage to set an input voltage on the power rail; and receiving a pulse signal; wherein said selectively controlling step comprises operating a switch to control current discharged from the capacitance circuit to the power rail and controlling a duty cycle of the switch by selectively controlling the opening and closing of the switch in accordance with the pulse signal to determine voltage on the capacitance circuit when average current out of the current limited circuit is less than the selected average level. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A power supply for a load controller comprising:
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a rectifier circuit connected between an AC power source and a DC power rail; a regulator circuit connected to the DC power rail and operable to provide power to the load when the load is connected to the DC power rail, the regulator circuit comprising a storage device and a switch; and a capacitance circuit connected across the regulator circuit; wherein the regulator circuit is configured to selectively open and close the switch in accordance with a pulse signal, the switch allowing for current from the capacitance circuit to flow into the DC power rail and be stored in the storage device when the switch is closed and for current to flow into the DC power rail until the storage device is depleted with the switch is open; and wherein a duty cycle of the pulse signal is selected to control the operation of the switch synchronously with respect to operation of an occupancy sensor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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Specification