Infrared inductive light switch using triac trigger-control and early-charging-peak current limiter with adjustable power consumption

A switch comprising:

• terminals for receiving an alternating-current (A.C.) voltage, the A.C. voltage being a power source for the switch;
• rectifier means, receiving the A.C. voltage, for generating a direct current (D.C.) voltage, the D.C. voltage varying in cycle pulses synchronized to A.C. cycles of the A.C. voltage, the cycle pulses including an initial region when the D.C. voltage is less than a critical voltage, a middle region wherein the D.C. voltage is above the critical voltage, and a final region wherein the D.C. voltage is again below the critical voltage;
• current-switch means, coupled to the terminals, for switching the alternating-current voltage to selectively power an A.C. device in response to a trigger signal;
• limiter means, receiving the D.C. voltage from the rectifier means, for generating a high-current peak during the initial region, but for limiting current to below the high-current peak during the middle region;
• charge store means, coupled to receive the high-current peak from the limiter means, for storing charge and generating an internal D.C. supply voltage;
• and
• D.C. means, powered by the internal D.C. supply voltage from the charge store means, for generating the trigger signal to the current-switch means, the trigger signal causing the current-switch means to power the A.C. device,
• whereby the internal D.C. supply voltage is generated from the A.C. voltage by charging the charge store means during the initial region of the cycle pulses.

An alternating-current (A.C.) switch comprising:

• A.C. terminals for receiving an A.C. voltage having an A.C. cycle;
• a triac, coupled between the A.C. terminals, for connecting the A.C. terminals together to power an A.C. device in response to a trigger input;
• a rectifier bridge, coupled across the A.C. terminals, having a ground output and a rectified D.C. node with a rectified voltage;
• a special current limiter, coupled to the rectified D.C. node, having a first path that conducts a large peak current to an internal D.C. supply when the rectified voltage is below a critical voltage, and a second path that conducts a small current to the internal D.C. supply when the rectified voltage is above the critical voltage, the small current being less than the large peak current;
• a shunt capacitor, coupled across the internal D.C. supply and the ground, for storing charge from the large peak current;
• a shunt diode, coupled across the internal D.C. supply and the ground, for limiting a maximum voltage of the internal D.C. supply;
• a detector, coupled between the internal D.C. supply and the ground, for generating a detect signal indicating that the A.C. device be powered;
• a sync signal, having sync pulses generated in synchronization to the A.C. cycle;
• trigger control logic, coupled between the internal D.C. supply and the ground, receiving the detect signal and the sync signal, for generating a first pulse when the detect signal is activated and a sync pulse is received;
• and
• a coupler for coupling the first pulse to the trigger input of the triac,
• whereby the triac is triggered on by the first pulse generated by the trigger control logic powered by the shunt capacitor charged by the special current limiter.