AC power switching device with non-volatile memory unit
AssigneeCore Industries, Inc.
InventorMichael L. Beigel
Life of this patent
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Abstract
A solid state semiconductor power switch for controlling the application of AC power to a load wherein the power switch employs momentary ON/OFF switches for activating the power switch, and wherein additional circuit means is provided to preserve the ON/OFF condition or state of the power switch during a power-down situation such that upon restoration of the AC power the power switch can be caused to assume the same ON or OFF state it was in just prior to the power-down situation.
Claims21
An AC power switching device comprising means for conveying AC power to a load under control of switching means, and solid-state circuit means for maintaining the state of the switching means upon reduction or unavailability of the AC power.
A control circuit for providing a drive signal to operate a controllable switch for applying power to a load, comprising:
- a source of DC power to operate the control circuit, first means for sensing the voltage level outputted by the source, non-volatile memory means for storing the current ON-OFF condition of the controllable switch, a source of drive signals, and means connected to the sensing means and the means for storing and responsive to a falling voltage level outputted by the source to activate the means for storing to store the current condition of the controllable switch.
A method for controlling the application of AC power to a load, comprising the steps:
- (a) providing a controllable switch which when turned ON applies AC power to the load and when turned OFF interrupts application of the AC power applied to the load,
- (b) providing a control circuit for the controllable switch, said control circuit having an ON switch for turning the controllable switch ON and an OFF switch for turning the controllable switch OFF,
- (c) providing non-volatile memory means activated by the AC power for storing the state of the controllable switch while power is still available to activate same,
- (d) sensing the reduction or unavailability o power to store the state of the controllable switch such that when AC power is restored the controllable switch assumes the same state it possessed just prior to the reduction or unavailability of AC power.
A method for controlling the application of AC power to a load using an optoisolator including an LED which when driven with source current connects the load to an AC line, comprising:
- (a) providing a control circuit operated by a DC voltage derived from the AC line,
- (b) providing in the control circuit a bistable circuit to store a set or reset condition which controls the current source for the LED,
- (c) continually sensing the DC voltage,
- (d) when the sensed DC voltage falls below a determined value, shutting down the LED current source and storing the state of the bistable circuit in non-volatile memory,
- (e) when the DC voltage level is restored, using the state stored in the non-volatile memory to set or reset the bistable circuit to the same state it was in before the DC voltage fall.
Dependencies are inferred from the claim text.