A new method for the construction of adjustable AC and DC power supplies is proposed based on adjusting the RMS value of the utility voltage by providing the non-conducting periods centered at the time where the sinusoidal voltage is maximum. This technique minimizes the peaks of the voltage that are normally applied to the loads by the prior arts. Among others, the benefits are smoother control and torque of motor loads, and simpler construction of transformerless power supplies.

A power supply, includes: a hot node coupled to a hot wire of an AC source, and a ground node coupled to an earth ground, where a neutral wire of the source is not present; a storage component, coupled to a return node and in series with a current limiter, where the current limiter enables the storage component to charge to a voltage while limiting leakage current to a prescribed value; a low voltage power supply including a buck-boost regulator, coupled to the storage component and to a return node that provides a reference voltage, where the low voltage power supply receives the voltage and generates an output voltage on an output node that is referenced to the reference voltage; and a wireless transceiver that employs the output voltage to transmit and receive messages from one or more corresponding wireless devices.

A converter circuit includes first and second input terminals, control circuitry, and a storage capacitor. The first and second input terminals are configured for connection to an AC power supply to receive an AC signal. The control circuitry is coupled to the first and second input terminals. A terminal of the storage capacitor is coupled to an output node of the control circuitry. The storage capacitor is charged by the control circuitry and configured for use as a DC power source. The control circuitry is configured to couple the first input terminal to the storage capacitor during a portion of a positive half-cycle of the input AC signal to charge the storage capacitor and to decouple the first input terminal from the storage capacitor during an entirety of each negative half-cycle of the input AC signal, to thereby prevent discharging of the storage capacitor by the input AC signal.

Systems and techniques are provided for a power receiver circuit. A power generating mechanism may include power generating elements that may generate alternating current signals. Rectifier circuit may include rectifiers that may generate a direct current signal from an alternating current signal, and diodes. Group circuits that may connect groups of rectifier circuits in electrical circuits to combine the direct current signals from the rectifier circuits in a group into a single direct current signal. A step down converter may be connected to the group circuits. The step down converter may convert a direct current signal to a direct current signal of a target voltage level. An output switch may be connected to the step down converter. A linear regulator may be connected to the step down converter. A microcontroller may be connected to the linear regulator and the output switch and may control the output switch.

In an example, a rectifier circuit includes first and second capacitors, first and second current control devices, and a switch. The first current control device is configured to provide an input current to the first capacitor during a positive cycle of an alternating current (AC) input voltage. The second capacitor is configured to store a charge and the switch is configured to couple the second capacitor to a ground terminal so the second capacitor discharges a capacitor current during the positive cycle of the input voltage responsive to the stored charge in the second capacitor. The second current control device is configured to provide the capacitor current to the first capacitor during the positive cycle of the input voltage. The first capacitor is configured to store a charge responsive to the input current and the capacitor current.

An apparatus for conversion between AC and DC voltages includes a rectifier and first and second stages coupled to each other and having a regulator and a switched-capacitor circuit respectively. The first stage receives a first voltage from the rectifier and the second stage provides a second voltage. A controller controls the first and second stages.

A power supply, includes: a hot node coupled to a hot wire of an AC source, and a ground node coupled to an earth ground, where a neutral wire of the source is not present; a storage component, coupled to a return node and in series with a current limiter, where the current limiter enables the storage component to charge to a voltage while limiting leakage current to a prescribed value; a low voltage power supply including a buck-boost regulator, coupled to the storage component and to a return node that provides a reference voltage, where the low voltage power supply receives the voltage and generates an output voltage on an output node that is referenced to the reference voltage; and a wireless transceiver that employs the output voltage to transmit and receive messages from one or more corresponding wireless devices.

An extremely-sparse parallel AC-link universal power conversion device is provided that is capable of converting between various power schemas using a reduced number of switches. The number of heat-dissipating elements and the overall size of the power converter are reduced, while the power density is increased. The expected failure rate is lowered, increasing the reliability of the power conversion device and reducing maintenance frequency and operating cost.

A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boost converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.

A zero-crossing detection circuit includes a zero-crossing detection unit arranged to compare a first monitoring target signal and a second monitoring target signal respectively input through diodes from a first node and a second node between which an AC signal is applied, so as to generate a first comparison signal, and a logic unit arranged to estimate a zero cross of the AC signal from the first comparison signal so as to generate a zero-crossing detection signal. The zero-crossing detection circuit preferably includes a monitoring unit arranged to adjust the first monitoring target signal and the second monitoring target signal to be suitable for input to the zero-crossing detection unit. The logic unit preferably counts a period of the first comparison signal and estimates a zero cross of the AC signal using a count value thereof.