Power control circuits with enhanced nonlinear current sensing

Abstract

Analog and digital power control switching circuits and power strips for use with various electronic devices and electrically operated appliances all enable a first device to control the powering or start-up of other devices. A smart power strip variation enables a user to energize all computer peripherals simply by turning the computer on or off. All embodiments comprise a sensing subcircuit that monitors AC current passed through the device or appliance plugged into a sensing outlet, which, in turn, generates a conditioned DC monitoring signal. A related control subcircuit driven by the monitoring signal powers suitable relays or transistors for activating downstream devices or appliances. All sensing subcircuits comprise a transformer primary, a capacitor, and at least one pair of anti-parallel diodes all connected in parallel. The stepped-up transformer output is rectified and filtered, yielding a DC monitoring signal delivered to the control subcircuit. Each control subcircuit has a solid state switch responsive to the monitoring signal that controls relays or transistors that power the controlled appliance or device. Preferred digital control subcircuits comprise a microcontroller that executes suitable software for dynamically determining the precise points at which the relays controlling downstream components should be activated or deactivated. In one digital variation, the user inputs suitable set points with manual switches that program the microcontroller. In a preferred digital version, a self-learning program is implemented by the control subcircuit to automatically determine future operating parameters.