An electronic fuse circuit includes an electronic switch with a load current path coupled between an output node and a supply node and that connects or disconnects the output node and the supply node in accordance with a drive signal. The circuit includes a control circuit to generate the drive signal based on an input signal. A monitoring circuit is included in the control circuit to receive a current sense signal representing the load current passing through the load current path and to determine a first protection signal based on the current sense signal and a wire parameter. The first protection signal is indicative of whether to disconnect the output node from supply node. The control circuit changes from normal mode to idle mode when the load current is below a given current threshold and another criterion is fulfilled.

In one example, an apparatus comprises: a voltage sensing circuit having a voltage sensing terminal and a voltage sensing output, the voltage sensing circuit configured to generate a first voltage at the voltage sensing output representing a second voltage at the voltage sensing terminal; a control circuit having a control circuit input and a control circuit output, the control circuit input coupled to the voltage sensing output, the control circuit configured to: determine a state of a transistor based on the first voltage; and generate a driver signal at the control circuit output based on the state; and a driver circuit having a driver input and a switch control output, the driver input coupled to the control circuit output, the driver circuit configured to provide a current at the switch control output responsive to the driver signal.

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.

According to one embodiment, a multichannel switch integrated circuit (IC) includes a multichannel switch circuit and a common test terminal. The multichannel switch circuit includes a plurality of switch circuitries. Each of the switch circuitries includes: an output transistor that outputs an output signal through an output terminal; an overcurrent detection circuit that detects a detection current according to a current flowing through the output transistor; and a diode having an anode that receives the detection current. The common test terminal is connected to each channel switch circuitry, connected to the overcurrent detection circuit through the diode, and connected to a cathode of the diode.

An apparatus includes a transistor coupled to a load through an output terminal of a load switch IC, a gate drive circuit connected to a gate of the transistor, wherein the gate drive circuit is configured such that in a short circuit event, a voltage on the gate of the transistor is gradually reduced, and wherein as a result of reducing the voltage on the gate of the transistor gradually, a negative voltage occurring at the output terminal of the load switch IC is minimized.

An apparatus, system and method of controlling the supply of DC current from a power source to an electrical load provides for a protective circuit that senses the characteristics of the connected load prior to permitting the enablement of a switch connecting the supply and the load. A voltage arising from applying a constant current to the load during a time period is compared with a predetermined threshold determined by the intended capacity of the switch so that, when closed, the current through the switch is compatible with the switch. The protective circuit may be used in conjunction with semiconductor switches, electromechanical contactors or relays. A plurality of such devices may be incorporated in an enclosure and controlled by logic so as to manage the supply of power from a power source to a plurality of electrical loads having differing power requirements.

A reverse current suppression circuit for a PMOS transistor, which includes: a gate drive unit, when the source potential of the first PMOS transistor is lower than the drain potential, the gate drive unit making the gate potential of the first PMOS transistor equal to the drain potential, so that the first PMOS transistor comes into a reverse current suppression state; and a substrate switching unit, when the source potential of the first PMOS transistor is lower than the drain potential, the substrate switching unit short-circuiting the substrate of the first PMOS transistor with the drain of the first PMOS transistor. According to the present invention, when the source potential of the PMOS transistor is lower than the drain potential, the PMOS transistor can be controlled to operate in the reverse current suppression state, so that the PMOS transistor can be effectively protected.

A control device for a vehicle includes a semiconductor switch, and opens and closes a connection between a capacitor connected to one end of the semiconductor switch and an on-board battery connected to another end of the semiconductor switch by turning ON/OFF the semiconductor switch. The control device includes: a wiring for applying a drive voltage for turning ON the semiconductor switch; a drive switch for short-circuiting the wiring to turn OFF the semiconductor switch; a Zener diode having an anode connected to the one end of the switching circuit, and a cathode connected to the wiring; a voltage detection unit detects a voltage at the one end of the switching circuit; and a control unit that controls the drive switch from OFF to ON, and determines whether or not the semiconductor switch is defective by comparing the voltage detected by the voltage detection unit with a threshold value.

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.

A gate drive circuit according to an embodiment includes: a voltage detector that detects a voltage between a first terminal and a second terminal of a switching device; a delay circuit that outputs, with a delay for a predetermined time, a detected value of the voltage obtained from the voltage detector; and a first off-mode drive circuit and a second off-mode drive circuit that apply a control signal to a control terminal of the switching device for turning off the switching device, wherein the first off-mode drive circuit turns off the switching device faster than the second off-mode drive circuit, and stops its operation to turns off the switching device when the delayed voltage value output from the delay circuit exceeds a predetermined threshold value.