A power transistor generates an output current and a sense transistor generates a proportional sense current. A differential amplifier generates a gate voltage applied to the power and sense transistors in response to first and second input signals. A comparator circuit compares the gate voltage to a switching reference to detect whether the power and sense transistors are operating in a triode mode of operation or in a saturation mode of operation. At least one of the first and second input signals is modified in response to the detection made by the comparator circuit. In one instance, different reference voltages are applied to an input of the amplifier depending on the detected mode of operation. In another instance, different resistances are used to convert the sense current to a voltage for application to an input of the amplifier in response to the detected mode of operation.

An overcurrent protection circuit limits a monitoring target current to or below a limit current value IOCP. For example, it can operate so as to give the limit current value IOCP, when temperature Tj is lower than a threshold value Tx, a flat temperature response and, when temperature Tj is higher than the threshold value Tx, a negative temperature response. For another example, it can operate so as to set the limit current value IOCP, when temperature Tj is lower than a threshold value Tx, at a first limit current value IOCP having a flat temperature response and, when temperature Tj is higher than the threshold value Tx, at a second limit current value IOCP having a flat temperature response and lower than the first limit current value IOCP.

The electronic circuit protector of the invention comprises a first semiconductor, a second semiconductor, a third semiconductor, a first diode, a second diode, a first resistor, a second resistor and a third resistor, constituting an application circuit with load overload or short circuit protection function, which avoids the damage caused by overload or short circuit at both terminals of the load.

The present invention provides topologies of phase-controlled IGBT bridge type and GTO bridge type Fault Current Limiter (FCL), which allow the precise limitation of fault currents to the desired values and can keep these values constant despite variations (dynamic behavior) of the fault currents. According to an embodiment of the invention, the topologies enable to use a phase control approach for optimal firing angles calculation. This control approach can be used in the proposed FCL topologies and other controlled bridge topologies such as SCRs bridge, GTO bridge, and IGBT/IGCT/Mosfet bridge topologies.

A voltage regulation apparatus and an overcurrent protection method are disclosed. The voltage regulation apparatus includes a current detection control circuit, a power stage circuit, a voltage input terminal, and a voltage output terminal. The power stage circuit includes at least one transistor. Because a current parameter indicates a load current of the at least one transistor, and a plurality of preset overcurrent protection thresholds are dynamic overcurrent protection thresholds obtained after being preset based on temperature information and the like, after obtaining the current parameter, the current detection control circuit compares the current parameter with the plurality of preset overcurrent protection thresholds, to output a control signal, to implement a limiting operation on the current parameter.

There is provided a current limiting diode comprising a gate, a source, and a drain electrically connected to the source by an n-channel or p-channel; wherein the source and the gate are electrically connected by a fill structure comprising a phase-change fill material, and wherein the phase-change fill material is configured to absorb heat from the n-channel or p-channel by changing phase.

A surge protection circuit includes a DC trigger circuit that generates a trigger signal when a surge pulse occurs, and a current conducting unit, coupled to the DC trigger circuit, that generates a first clamp voltage as an output voltage of the surge protection circuit and conducts surge currents to ground in response to the trigger signal. The DC trigger circuit includes a surge detection circuit and a first amplification circuit. The surge detection circuit detects if a surge pulse occurs, and triggers the first amplification circuit to generate the trigger signal when the surge detection circuit detects a surge pulse.

Systems and methods are provided for overcurrent protection in a battery charger. In certain embodiments, a method includes turning on an adapter switch to receive electrical power from an adapter connected to the battery charger; controlling a switching regulator to direct electrical current between the switching regulator and a battery port. Further, the method includes sensing a voltage drop that is related to the electrical current passing between the switching regulator and the battery port; comparing the sensed voltage drop against at least one reference voltage; and, when the sensed voltage exceeds the reference voltage, changing operation of the adapter switch to protect the battery charger from an overcurrent state.

The present disclosure relates to a power supply device for a protective relay. The power supply device comprises a power circuit for supplying a power to the control circuit, wherein the power circuit includes: a semiconductor switch element having an input terminal connected to a first node for receiving a direct current, and an output terminal connected to a reference node, wherein the reference node has a voltage lower than a voltage of the first node; and a first voltage drop element disposed between the first node and a second node, wherein the second node is connected to a switching terminal of the semiconductor switch element.

A device for protecting a direct current source and method are provided. Electric energy outputted from the direct current source is stored and an enable signal is received by the hiccup drive circuit. In a case that the enable signal is an OFF-ENABLE signal, the driving signal is generated based on the electric energy stored internally. By periodically switching on the switching device based on the driving signal, the output voltage of the direct current source is periodically short-circuited. Therefore, the issue of a large conduction loss in the conventional art is avoided, which is caused by the fact that a minimum required voltage for driving the electronic switch is required to be continuously provided by the output voltage of the direct current source.