Zero return photoelectric control system
AssigneeST Engineering Telematics Wireless Ltd.
InventorsNehemia Niv, Moshe Nissim
Life of this patent
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Abstract
A system controls high power devices according to ambient light levels. The system includes a latching relay, a latching relay driver, an ambient light sensor and a relay bulk power supply. The latching relay switches power on and off to the high power devices, and the latching relay driver energizes the latching relay, using power from on-periods when the latching relay is closed. The ambient light sensor controls when the latching relay driver energizes the latching relay, and the relay bulk power supply stores power from the on-periods to be used to energize the latching relay during off-periods when the latching relay is open.
Claims16
A system to control high power devices according to ambient light levels, the system comprising:
- a latching relay to switch power on and off to said high power devices;
- a latching relay driver to energize said latching relay, using power from on-periods when said latching relay is closed;
- an ambient light sensor to control when said latching relay driver energizes said latching relay;
- and
- a relay bulk power supply to store power from said on-periods to be used to energize said latching relay during off-periods when said latching relay is open,
- wherein said latching relay driver comprises:
- a first capacitor to store power during said on-periods;
- and
- a comparator to monitor a level of power stored in said relay bulk power supply, and to stop said latching relay driver from energizing said latching relay until said level of power is above a first predefined threshold value.
A method to control high power devices according to ambient light levels, the method comprising:
- switching power on and off to a load using a latching relay;
- energizing said latching relay, using only power from on-periods when said latching relay is closed;
- controlling when said energizing takes place;
- and
- storing power from said on-periods in a relay bulk power supply to be used for energizing said latching relay during off-periods when said latching relay is open,
- wherein said energizing comprises:
- second storing power in a first capacitor during said on-periods;
- monitoring a level of power stored in said relay bulk power supply;
- and
- stopping said energizing until said level of power is above a first predefined threshold value.
Dependencies are inferred from the claim text.