The invention relates to a method, a device and a system for monitoring the IGBT junction temperature, wherein the linear relationship between each turn-off DC bus ringing peak voltage and the corresponding turn-off IGBT junction temperature, the phase current directions, and the initial and secondary states of the half-bridge arms are used to accurately determine the monitoring time of the turn-off DC bus ringing peak voltage, thereby obtaining the IGBT junction temperature at a converter level with higher sensitivity. The IGBT junction temperature obtained using the junction temperature monitoring method provided by the invention is an appropriate converter-level parameter, which has a good application prospect in multi-IGBT junction temperature estimation.

A large-current MOS drive control method, comprising the following steps: 1) turning on a device, initializing the device, activating an MOS switching circuit, and completing a turn-on operation for the circuit; 2) monitoring the voltage connected to the switching circuit, connecting the switching circuit to a power supply after voltage detection, and activating the power supply; 3) connecting the power supply to a control circuit, processing, by the control circuit, information transmitted by the power supply, and driving, by the control circuit, a driving circuit; and 4) after the MOS switching circuit is connected, measuring the temperature of the switching circuit in real time by means of an infrared temperature measurement instrument, and if the temperature exceeds 80 Celsius degrees, giving an alarm by flashing a red alarm lamp.

A circuit device includes a control circuit configured to control a transistor current based on a detected temperature. The detected temperature is a temperature detected by a temperature sensor circuit that detects a temperature of a transistor. The transistor charges a load to which a power supply voltage is supplied. The transistor current is a current flowing through the transistor during charging. The control circuit reduces the transistor current when the detected temperature is higher than a first threshold value, and increases the transistor current when the detected temperature is lower than a second threshold value lower than the first threshold value.

A method for protecting a system including a driver integrated circuit includes receiving a driver input signal. The method includes driving an output signal externally to the driver integrated circuit. The output signal is driven based on the driver input signal and an indication of a delay between receipt of an edge of the driver input signal and arrival of a corresponding edge of the output signal at an output node coupled to a terminal of the driver integrated circuit.

A doorbell chime bypass circuit includes a first node, a second node, and a bi-directional FET switch in series with the first node and the second current node. The bi-directional FET switch includes a first FET and a second FET in series, and is configured to cease conducting current between the first and second nodes when gate voltages of the first and second FETs are below a cut-off threshold. The bypass circuit further includes a sensing circuit configured to determine a level of current flowing through the bi-directional FET switch, and a switch controller configured to set the gate voltages of the first and second FETs to a level below the cut-off threshold when the sensing circuit senses that the level of current meets a doorbell press current threshold, causing the bi-directional FET switch to cease conducting current between the first and second nodes.

A power supply control apparatus controls power supply from a DC power source to a load by switching on or off a power supply FET. The current adjustment circuit adjusts the current flowing through the resistor circuit to a value obtained by dividing the voltage between the drain and the source of the power supply FET by the resistance value of the resistor circuit. A drive circuit switches off the power supply FET when a voltage across the detection resistor exceeds a predetermined voltage. The on-resistance value of the power supply FET fluctuates according on the ambient temperature of the power supply FET. The resistance value of the resistor circuit fluctuates in the same direction as the on-resistance value according to the ambient temperature of the power supply FET.

Provided is a power semiconductor element gate driving circuit that performs ON/OFF control on main current of a power semiconductor element having a gate electrode by charging the gate electrode of the power semiconductor element with electric charges and discharging the electric charges on the basis of an inputted gate signal. When the gate signal is switched to an OFF signal, control is performed such that gate current for discharging the electric charges from the gate electrode increases in association with increase in a temperature of the power semiconductor element and decreases in association with increase in the main current.

A power module, including a power element, and a control unit that controls the power element. The control unit includes: a frequency divider circuit that receives a signal for driving the power element and has a frequency dividing function, by which the frequency divider circuit generates an output having a frequency lower than that of the received signal; an overcurrent detection comparator that detects an overcurrent of the power element; an overheat protection warning comparator that outputs a warning signal upon detection of the power element having a temperature higher than a predetermined temperature; and a logic circuit that outputs an enable signal to activate the frequency dividing function of the frequency divider circuit only while the overcurrent detection comparator does not detect the overcurrent and the overheat protection warning comparator outputs the warning signal. The power module further includes an overheat protection alarm comparator that outputs an alarm signal.

A semiconductor device includes: a first power semiconductor element; a second power semiconductor element that is connected in parallel with the first power semiconductor element; a voltage changing unit that changes a voltage applied to a control terminal of the first power semiconductor element when the second power semiconductor element is turned on; a detection unit that detects a current flowing in the first power semiconductor element when the voltage changing unit has changed the voltage applied to the control terminal of the first power semiconductor element; and a temperature estimation unit that estimates a temperature of the first power semiconductor element based on a characteristic of the change of the current of the first power semiconductor element with respect to a change of the voltage applied to the first power semiconductor element.

One embodiment relates to a system that includes a power electronic system and a cooling system. The power electronic system includes a semiconductor switch, which has a rated maximum temperature. The power electronic system itself has a rated maximum power. The system further includes a temperature sensor that is configured to sense a temperature of the (at least one) semiconductor switch. The cooling system is thermally coupled to the power electronic system and configured to carry heat away from the power electronic system using a cooling agent. A system controller is configured to receive information concerning the sensed temperature of the semiconductor switch and a temperature of the cooling agent (coolant). The system controller is further configured to adjust a power of the power electronic system by controlling the switching operation of the semiconductor switch. When the temperature of the coolant is below a threshold temperature, then the controller adjusts the power of the power electronic system to a target value greater than the rated maximum power based on the sensed temperature of the semiconductor switch and the temperature of the cooling agent.