Provided is a control unit of a power conversion device configured to select, in each first set cycle, a first target switching element and a second target switching element from a plurality of switching elements connected in parallel to each other. The control unit performs control so that, at a time of a turn-on operation of a switching circuit, a turn-on start time of the first target switching element is earlier by a first set time period than a turn-on start time of another switching element that is not the first target switching element. The control unit performs control so that, at a time of a turn-off operation of the switching circuit, a turn-off start time of the second target switching element is later by a second set time period than a turn-off start time of another switching element that is not the second target switching element.

In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

A power converter includes a semiconductor element disposed on a substrate, a thermistor element for detecting the temperature of the substrate, the thermistor element being disposed on the substrate, a current detection resistor having one end connected to a ground side node and another end that is grounded, a first voltage detection unit configured to detect a first potential at the other end of the current detection resistor and a second potential at the ground side node, and output a first detection signal, a control unit configured to control the semiconductor element based on the first detection signal, a temperature detection resistor having one end that is connected to a reference potential and another end that is connected to a detection node, and a temperature detection unit configured to detect a temperature based on a third potential at the detection node, and output a temperature information signal.

A semiconductor switch control device includes a first FET and a second FET arranged adjacent to each other, in which source terminals are connected in series. A drain terminal of the first FET is connected to a high voltage battery, and a drain terminal of the second FET is connected to a high voltage load. A controller determines a temperature state of a minus-side main relay including the second FET based on a forward voltage of a body diode of the first FET.

A protection and attenuation circuit for sensitive AC loads is described. The circuit provides AC power protection and attenuation utilizing high-efficiency switch-mode techniques to attenuate an AC power signal by incorporating a bidirectional, transistorized switch driven from a pulse width modulation signal, PWM. The circuit monitors characteristics of the AC power signal driving a known load and characteristics of the load or other elements and determines the duty cycle of the pulse width modulated signal, PWM, based upon the duration and amplitude of the over-voltage, over-current, over-limit or other event.

An ignition device capable of more reliably protecting a primary winding of an ignition coil from high temperature is provided. The ignition device includes an ignition coil, a switching element, a temperature sensor, and a thermal cutout circuit. A primary winding of the ignition coil is connected to a DC power supply and the switching element. The temperature sensor is provided to measure the temperature of the switching element. The thermal cutout circuit forcibly turns off the switching element when the temperature of the switching element becomes higher than a predetermined forcible turn-off temperature Toff. The thermal cutout circuit is configured to lower the forcible turn-off temperature Toff when the power supply voltage Vb of the DC power supply decreases.

A switch controller coupled to control a transistor. The switch controller comprising an interface coupled to receive a command signal in response to an event sensed in a control system. The command signal is representative of a first command to control the transistor with a first drive strength or a second command to control the transistor with a second drive strength. The switch controller is coupled to adjust a fall time or a rise time, or to adjust both the fall time and the rise time, of a voltage across the transistor in response to the command signal. The fall time or the rise time, or both the fall time and the rise time in response to the second command is shorter than the fall time or the rise time, or both the fall time and the rise time in response to the first command.

A control circuit of a power conversion apparatus is provided with a switch driving unit that drives the upper and lower arm switches; a short circuit control unit that causes the switch driving unit to execute a short circuit control when a failure occurs in the system, the short circuit control turning an ON side switch to an ON state and turning an OFF side switch to an OFF state; a checking unit that executes a checking process to check whether the short circuit control is able to perform correctly; and a protection control unit that causes the switch driving unit to execute a protection control when a failure occurs on either the upper arm switch or the lower arm switch, the protection control turning the switch where the failure occurs to an OFF state. The control circuit enables the protection control during execution of the checking process.

For example, an overcurrent protection circuit 71 includes a hiccup controller 71b which, when an output current To passing through a switching element 10 goes into an overcurrent state, hiccup-drives the switching element 10 such that predetermined on-period ton and off-period toff alternate. For example, the hiccup controller 71b may control at least one of the on- and off-period ton and toff according to a temperature sense signal S71c. For example, the temperature sense signal S71c may be generated by detecting at least one of temperature Tj of the switching element 10 and a difference in temperature ΔTj between the switching element 10 and another element. For example, when at least one of temperature Tj and the difference in temperature ΔTj is higher than a predetermined threshold value, the hiccup controller 71b may conduct at least one of reduction of the on-period ton and increase of the off-period toff.

Achieved is a load drive device capable of suppressing local concentration of temperature at the time of absorbing a counter electromotive force of an inductive load while suppressing a size of a power transistor. The load drive device includes a first transistor connected between a first control electrode and an inductive load. Further, the load drive device includes an active clamp circuit that becomes conductive when a terminal voltage of a second control electrode between the first transistor and the inductive load exceeds a threshold. Furthermore, the load drive device includes a second transistor connected to the second control electrode and connected in parallel to the first transistor.