Load control circuit with timed interruption

• US 4,338,562 A
• Filed: 07/10/1980
• Issued: 07/06/1982
• Est. Priority Date: 07/10/1980
• Status: Expired due to Term

• Current Assignee: Robert D. Terwilliger
• Original Assignee: Robert D. Terwilliger
• Inventors: Terwilliger, Robert D.
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US06/168,426
• Time in Patent Office: 726 Days
• Field of Search: 307/141, 307/141.4, 315/209 R, 315/209 SC, 315/360, 323/320, 323/322, 323/323, 323/326
• US Class Current: 323/323
• CPC Class Codes: H05B 47/16 by timing means
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

The control circuit is preferably provided in an integral unit with a momentary on-off switch, preferably inside a switch housing box and adapted to replace a common wall switch to provide for the automatic turn-off of the light or other load operated by the switch after a presetable period of time. The circuit is constructed so as not to require a third wire (usually a power lead) at the unit. The use of low power logic circuit controls, employing preferably CMOS chips enables use of a capacitor storage element of manageable size, with very low power consumption of the circuit in its "off" state. The "on" duration of the light is adjustable over a suitable time range and the circuit is further characterized by a "flashing" period preceding total turn-off.

Claims

1. A lower power consumption control circuit for controlling a load to provide for automatic interruption of power to the load a preselected period of time after load power is initiated, comprising;

a semiconductor switch adapted for selectively coupling power to the load,

a manually operated switch for initiation of load power,

means responsive to said manual switch moved to its operating position for, in turn, operating said semiconductor switch to its power coupling state,

memory means responsive to said manual switch moved to its operating position for establishing an operating voltage,

said memory means comprising a capacitor,

a timer operated by said operating voltage and defining an "on" time period,

means responsive to said timer and termination of said time period for operating said semiconductor switch to uncouple power to the load,

a gated semiconductor electronic switch coupled in series with said memory capacitor,

one side of said load being connected in series with said semiconductor switch and also in series with the capacitor,

said gated semiconductor electronic switch including means responsive to the voltage across said capacitor for controlling the delivery of power to said capacitor when needed but only for a minor portion of the voltage swing delivered to the load to thereby cyclically recharge the capacitor, the remainder of the power of the voltage swing being delivered directly to the load.

2. A control circuit as set forth in claim 1 wherein said semiconductor switch comprises a TRIAC.

3. A control circuit as set forth in claim 2 wherein said manually operated switch comprises a momentary switch.

4. A control circuit as set forth in claim 1 wherein said timer comprises an oscillator set into operation when the manual switch is operated, and a counter counted from the oscillator.

5. A control circuit as set forth in claim 4 wherein said counter has at least two outputs, one output for operating the semiconductor switch in a flashing mode and another output for interrupting power to the load via the semiconductor switch.

6. A control circuit as set forth in claim 5 wherein the one output is a lower count output than the other output to provide a flashing load condition prior to load interruption.

7. A control circuit as set forth in claim 1 including means for adjusting the "on" time period.

8. A control circuit as set forth in claim 1 including means coupling AC power to the memory means to periodically refresh it.

9. A control circuit as set forth in claim 1 including means responsive to a timer signal prior to the end of the "on" period for providing a sensory signal distinguishable from the load on signal to indicate approach of the end of the "on" period.

10. A control circuit as set forth in claim 9 wherein the sensory signal is visual.

11. A control circuit as set forth in claim 9 wherein the signal is the flashing of the load.

12. A control circuit as set forth in claim 10 wherein the signal is the flashing of the load.