Control unit for occupancy sensor switching of high efficiency lighting

Claim 1

A control unit adapted trot switching an AC powered high efficiency lighting load in response to an occupancy sensor comprising: an on/off control circuit for controlling a relay control circuit and a noise-insensitive semiconductor switch control circuit, the on/off control circuit being adapted to receive signals from an occupancy sensor, the control circuit providing an on/off control signal having an on state indicating the load should be turned on when occupancy is sensed and an off state indicating the load should be turned off thereafter; the relay control circuit being directly responsive to the on/off control signal and not responsive to the semiconductor switch control circuit and including a delay means for delaying the on state and the off state of the on/off control signal for a delay time; a relay having an actuator connected to the relay control circuit which actuates relay switch contacts upon receipt of the delayed on/off control signal, the relay switch contacts being adapted to carry AC load current of the load and being movable from an open to a closed position during a relay closing time and movable from a closed to an open position during a relay opening time; the delay time plus the shorter of the relay closing time or the relay opening time being greater than the time between successive zero crossings of the AC power; the noise-insensitive semiconductor switch control circuit having an output for controlling a semiconductor switch and a zero voltage crossing detector that switches the output of thee semiconductor switch control circuit only at the zero crossings of the AC power responsive to the on/off control signal; a semiconductor switch which switches in response to the noise insensitive semiconductor control circuit immediately, the semiconductor switch being adapted to carry the AC load current and having switch leads connected in parallel across the relay switch contacts; and the control unit switching the relay based on the time of the on/off control signal as delayed by the relay control circuit and not based on the time of the zero crossings of the AC power detected by the zero voltage crossing detector in the noise insensitive semiconductor control circuit.

Claim 18

A method for saving energy by automatically turning on an electronically ballasted AC powered high efficiency fluorescent lighting load installed in a room whenever the room is occupied and automatically turning off the lighting load whenever the room is unoccupied, comprising: sensing the presence of a person in a room containing electronically ballasted AC powered high efficiency fluorescent lights with an occupancy sensor producing an occupancy signal whenever occupancy is sensed in the room; generating an on/off control signal in an on/off control circuit responsive to the occupancy signal from the occupancy sensor, the on/off control signal being generated in an on state indicating the load should be turned on when occupancy is sensed; timing in a timer for a preset interval after the on/off control signal is turned to the on state and turning the on/off control signal to the off state indicating the load should be turned off; resetting the timer to the beginning of the preset interval each time the occupancy sensor senses the presence of a person in the room switching the electronically ballasted AC powered high efficiency fluorescent lights on and off with a hybrid switch specially adapted to be noise insensitive, the lights being switched on by the hybrid switch whenever the on/off control signal is in the on state and switching the lights off whenever the on/off control signal is in the off state, the hybrid switch including: a relay control circuit responsive to the on/off control signal and including a delay means for delaying the on state and the off state of the on/off control signal for a delay time; a relay having an actuator connected to the relay control circuit which actuates relay switch contacts upon receipt of the delayed on/off control signal, the relay switch contacts being adapted to carry AC lead current of the electronically ballasted high efficiency fluorescent lighting lead; a noise-insensitive semiconductor switch control circuit specially adapted for controlling a semiconductor switch in a noisy electrical environment generated by the electronically ballasted AC powered high efficiency fluorescent lighting lead, the semiconductor switch control circuit including a noise-insensitive zero voltage crossing detector that switches the output of the semiconductor switch control circuit only at the zero crossings of the AC power responsive to the on/off control signal; a semiconductor switch which switches in response to the noise-insensitive semiconductor control circuit, the semiconductor switch being adapted to carry the AC lead current of the electronically ballasted high efficiency fluorescent lighting lead and having switch leads connected in parallel across the relay switch contacts; and the hybrid switch switching the relay based on the time of the on/off control signal as delayed by the relay control circuit and not based on the time of the zero crossings of the AC power detected by the zero voltage crossing detector in the noise insensitive semiconductor switch control circuit.

Claim 19

A method for saving energy by automatically turning on an electronically ballasted AC powered high efficiency fluorescent lighting load installed in a room whenever the room is occupied and automatically turning off the lighting load whenever the room is unoccupied, comprising: sensing the presence of a person in a room containing electronically ballasted AC powered high efficiency fluorescent lights with an occupancy sensor producing an occupancy signal whenever occupancy is sensed in the room; generating an on/off control signal in an on/off control circuit responsive to the occupancy signal from the occupancy sensor, the on/off control signal being generated in an on state indicating the load should be turned on when occupancy is sensed; timing in a timer for a preset interval after the on/off control signal is turned to the on state and turning the on/off control signal to the off state indicating the load should be turned off; resetting the timer to the beginning of the preset interval each time the occupancy sensor senses the presence of a person in the room switching the electronically ballasted AC powered high efficiency fluorescent lights on and off with a hybrid switch specially adapted to be noise insensitive, the lights being switched on by the hybrid switch whenever the on/off control signal is in the on state and switching the lights off whenever the on/off control signal is in the off state, the hybrid switch including: a relay control circuit responsive to the on/off control signal and including a delay means for delaying the on state and the off state of the on/off control signal for a delay time; a relay having an actuator connected to the relay control circuit which actuates relay switch contacts upon receipt of the delayed on/off control signal, the relay switch contacts being adapted to carry AC lead current of the electronically ballasted high efficiency fluorescent lighting lead; a noise-insensitive semiconductor switch control circuit specially adapted for controlling a semiconductor switch in a noisy electrical environment generated by the electronically ballasted AC powered high efficiency fluorescent lighting lead, the semiconductor switch control circuit including a noise-insensitive zero voltage crossing detector that switches the output of the semiconductor switch control circuit only at the zero crossings of the AC power responsive to the on/off control signal; a semiconductor switch which switches in response to the noise-insensitive semiconductor control circuit, the semiconductor switch being adapted to carry the AC lead current of the electronically ballasted high efficiency fluorescent lighting lead and having switch leads connected in parallel across the relay switch contacts; and the hybrid switch switching the relay based on the time of the on/off control signal as delayed by the relay control circuit and not based on the time of the zero crossings of the AC power detected by the zero voltage crossing detector in the noise insensitive semiconductor switch control circuit.