A controller for a secondary side of a switched mode power supply. A thermistor and an LED of an optocoupler are connected in parallel with each other between a voltage-supply-pin and a STOP pin of the controller. A reference-source provides a reference-signal between the STOP pin and the voltage-supply-pin. The STOP pin receives a temperature-measurement-signal from the thermistor, wherein the temperature-measurement-signal is representative of the resistance of the thermistor. The controller also includes an OTP-comparator that compares: (i) the temperature-measurement-signal; with (ii) a threshold-level, and provides an OTP-signal that is representative of whether or not the temperature-measurement-signal at the STOP pin crosses the threshold-level; and a switchable-current-source that selectively provides a bias-current to the STOP pin based on the OTP-signal, wherein the bias-current causes the LED to emit a light-signal that is representative of a fault to an associated photo-detector.

A boost converter includes a voltage output terminal, a power transistor, and short circuit protection circuitry. The voltage output terminal is configured to provide a boosted output voltage generated by the boost converter. The power transistor is configured to draw current through an inductor. The short circuit protection circuitry is configured to control current flow through the inductor responsive to detection of a short circuit at the voltage output terminal. The short circuit protection circuitry includes an output switch coupled to an input terminal of the power transistor and connected to the voltage output terminal. The output switch is configured to switch current flow from the inductor to the voltage output terminal. The output switch is a negative (N) channel metal oxide semiconductor field effect transistor (MOSFET).

A switching power supply protection circuit includes a protection circuit, a switching circuit, a voltage feedback circuit, and a control circuit. The protection circuit is connected to the switching circuit, the voltage feedback circuit, and the control circuit, and controls output switch-on or output switch-off, controls switch-on or switch-off of the switching circuit, and controls the supply voltage. The switching circuit is connected to the control circuit and controls a working state of the control circuit. The voltage feedback circuit is connected to the control circuit and adjusts a control voltage and transmits the feedback voltage to the protection circuit. The control circuit is connected to a power supply and receives a voltage of the power supply for charging, provides a starting voltage for the protection circuit and controls the supply voltage according to the control voltage.

According to an embodiment, provided is a direct current/direct current converter comprising: a first switch unit located between a direct current link capacitor and a bridge circuit unit; a second switch unit connected in parallel with the first switch unit; a sensing unit for sensing a voltage across both ends of an inverter and a voltage across both ends of a second switch; and a control unit which controls an on-off operation of the first switch unit and the second switch unit, and determines whether a short circuit or a disconnection occurs by using the voltage across both ends of the inverter and the voltage across both ends of the second switch unit, wherein the control unit determines whether a short circuit or a disconnection occurs by using a voltage across both ends of the inverter and a voltage across both ends of the second switch unit, which are measured when the first switch unit is in an on state and the second switch unit is in an off state, and determines whether a disconnection occurs by using a voltage across both ends of the inverter, which is measured when the second switch unit is in an on state and the first switch unit is in an off state.

A first converter station is part of a high voltage direct current transmission system that includes a DC transmission link connected to the first converter station a second converter station. A DC current and a DC voltage of the DC transmission link are sensed by the first converter station. It is determined that the sensed DC current is equal to or larger than a threshold current value, that the sensed DC current is equal to or larger than the threshold current value, and that at least a partial recovery of the sensed DC voltage has occurred. On the basis that it is determined that the at least a partial recovery of the sensed DC voltage has occurred, it is determined that a phase-to-ground fault has occurred. In response to determining that a phase-to-ground fault has occurred, a power delivered by the first converter station can be reduced.

A power conversion device according to one or more embodiments may include: a microcomputer; and an output circuit controlled by the microcomputer, including an output unit that converts an input power into a predetermined power and outputs the predetermined power, an internal power source that supplies a power source to the microcomputer, a driver that drives the output unit by a signal from the microcomputer, and a microcomputer stop transition unit that, when an operation of the power conversion device is stopped, outputs a microcomputer stop signal to the microcomputer and causes an operation of the microcomputer to transition to a stop state. In one or more embodiments, after the microcomputer stop transition unit causes the operation of the microcomputer to transition to a stop state, the microcomputer or the output circuit may stop an output of the internal power source.

A switching power supply device has a switching output stage generating an output voltage from an input voltage by switching operation and a controller controlling the switching output stage based on a feedback voltage commensurate with the output voltage. The switching power supply device can perform switching suspension control whereby it stops switching operation on detecting a light-load condition based on the feedback voltage, though it restarts switching operation on detection of an overvoltage condition during suspension of switching operation.

System controller and method for a power converter. For example, a system controller for a power converter includes a logic controller configured to generate a modulation signal, and a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to switch to affect a current flowing through an inductive winding for a power converter. Additionally, the system controller includes a voltage-to-voltage converter configured to receive a first voltage signal, the modulation signal, and a demagnetization signal, and to generate a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal.

A power system and related methods provide sense resistor fault detection and safe operation of switching power converters and connected devices such as portable electronic devices powered by the switching power converter. The power system detects an open circuit or short circuit condition of the sense resistor and controls output current of the switching power converter to ensure safe operating conditions of the power system and connected equipment. The power system can also detect initial inrush current of the connected equipment and detect a duty cycle of the switching power converter to positively detect a short circuit condition of the sense resistor.

A power supply system includes: a first power circuit having a first battery, a second power circuit having a second battery, a voltage converter which converter voltage between the first power circuit and second power circuit, a current sensor which acquires a passing current value Iact of the voltage converter, a passing power control unit which operates the voltage converter, and a failure determination unit which determines failure of the voltage converter. The failure determination unit determines that the voltage converter has failed in a case of the passing current value Iact becoming negative in a state in which the passing power control unit is not operating the high-arm element of the voltage converter to ON, and makes a time from when the passing current value Iact first became negative until determining that the voltage converter failed shorter as the passing current value Iact increases to the negative side.