In one embodiment, the present invention is directed to a contact hearing system including: an ear tip including a transmit circuit having a first Q value, wherein the ear tip includes a transmit coil wound on a ferrite core; a contact hearing device including a receive circuit having a second Q value, wherein the first Q value is greater than the second Q value; a receive coil positioned on the contact hearing device, wherein the receive coil includes a core of a non-ferromagnetic material.

A welding-type power supply including a balanced plate rectifier to rectify high frequency alternating current from one or more transformers. The balanced plate rectifier includes an output terminal symmetrically connected to the plates of the plate rectifiers. The impedance between the output terminal and each plate is substantially equal.

A welding-type power supply including a balanced plate rectifier to rectify high frequency alternating current from one or more transformers. The balanced plate rectifier includes an output terminal symmetrically connected to the plates of the plate rectifiers. The impedance between the output terminal and each plate is substantially equal.

A control chip applied in a switching power supply, where the switching power supply includes a rectifier circuit for receiving an AC input voltage and generating a rectified voltage, the control chip including: a high-voltage pin; a detection circuit coupled to the high-voltage pin to determine whether the high-voltage pin is coupled to the AC input voltage or the rectified voltage according to a sampling voltage representing a voltage received by the high-voltage pin; and a discharge circuit, where when the high-voltage pin is determined to be coupled to the AC input voltage, the control chip can enable the discharge circuit to discharge a safety capacitor coupled to an input port of the switching power supply after the switching power supply is powered off, and when the high-voltage pin is determined to be coupled to the rectified voltage, the control chip can disable the discharge circuit.

A control chip applied in a switching power supply, where the switching power supply includes a rectifier circuit for receiving an AC input voltage and generating a rectified voltage, the control chip including: a high-voltage pin; a detection circuit coupled to the high-voltage pin to determine whether the high-voltage pin is coupled to the AC input voltage or the rectified voltage according to a sampling voltage representing a voltage received by the high-voltage pin; and a discharge circuit, where when the high-voltage pin is determined to be coupled to the AC input voltage, the control chip can enable the discharge circuit to discharge a safety capacitor coupled to an input port of the switching power supply after the switching power supply is powered off, and when the high-voltage pin is determined to be coupled to the rectified voltage, the control chip can disable the discharge circuit.

Technologies for controlling AC-to-DC converters are disclosed. In one illustrative embodiment, a controller of an AC-to-DC converter measures two voltage levels of a split voltage bus of a power factor correction (PFC) circuit. The controller controls current drawn from the positive and negative terminals of the PFC circuit by a DC-to-DC converter. By controlling the current drawn from the two terminals, the controller can control the voltages on the terminals to be equal (but opposite).

Technologies for controlling AC-to-DC converters are disclosed. In one illustrative embodiment, a controller of an AC-to-DC converter measures two voltage levels of a split voltage bus of a power factor correction (PFC) circuit. The controller controls current drawn from the positive and negative terminals of the PFC circuit by a DC-to-DC converter. By controlling the current drawn from the two terminals, the controller can control the voltages on the terminals to be equal (but opposite).

A circuit breaker comprises a solid-state bidirectional switch, a switch control circuit, current and voltage sensors, and a processor. The solid-state bidirectional switch is connected between a line input terminal and a load output terminal of the circuit breaker, and configured to be placed in a switched-on state and a switched-off state. The switch control circuit control operation of the bidirectional switch. The current sensor is configured to sense a magnitude of current flowing in an electrical path between the line input and load output terminals and generate a current sense signal. The voltage sensor is configured to sense a magnitude of voltage on the electrical path and generate a voltage sense signal. The processor is configured to process the current and voltage sense signals to determine operational status information of the circuit breaker, a fault event, and power usage information of a load connected to the load output terminal.

The electronic apparatus including a power factor correction (PFC) circuit and a control circuit configured to control an operation of the PFC circuit is provided. The PFC circuit includes a first inductor part connected to one end of an AC voltage part and a first switch connected to a first inductor in series; a second inductor part connected to another end of the AC voltage part and a second switch connected to a second inductor in series; an output part connected to the first inductor part and the second inductor part; and a switching part, and the control circuit identically applies a switch on/off signal to the first switch and the second switch, and selectively applies a switch on/off signal to the third switch or the fourth switch based on a magnitude of an input voltage input through the AC voltage part.

The electronic apparatus including a power factor correction (PFC) circuit and a control circuit configured to control an operation of the PFC circuit is provided. The PFC circuit includes a first inductor part connected to one end of an AC voltage part and a first switch connected to a first inductor in series; a second inductor part connected to another end of the AC voltage part and a second switch connected to a second inductor in series; an output part connected to the first inductor part and the second inductor part; and a switching part, and the control circuit identically applies a switch on/off signal to the first switch and the second switch, and selectively applies a switch on/off signal to the third switch or the fourth switch based on a magnitude of an input voltage input through the AC voltage part.