The present invention discloses a USB signal output circuit having reverse current prevention mechanism. A switch circuit turns on when a switch control terminal receives a first high level voltage to output a signal from a signal input terminal to a signal output terminal. A first voltage pull-low circuit includes a passive-component high-pass filter circuit and a discharging circuit. The passive-component high-pass filter circuit couples an output terminal voltage of the signal output terminal to a pull-low control terminal. The discharging circuit turns on when a voltage of the pull-low control terminal is larger than a predetermined voltage level to discharge the switch control terminal to pull the switch control terminal to a second high level voltage. A second voltage pull-low circuit pulls the switch control terminal to a low level voltage when the output terminal voltage is larger than a reference voltage and does not have a glitch.

The present invention discloses a USB signal output circuit having reverse current prevention mechanism. A switch circuit turns on when a switch control terminal receives a first high level voltage to output a signal from a signal input terminal to a signal output terminal. A first voltage pull-low circuit includes a passive-component high-pass filter circuit and a discharging circuit. The passive-component high-pass filter circuit couples an output terminal voltage of the signal output terminal to a pull-low control terminal. The discharging circuit turns on when a voltage of the pull-low control terminal is larger than a predetermined voltage level to discharge the switch control terminal to pull the switch control terminal to a second high level voltage. A second voltage pull-low circuit pulls the switch control terminal to a low level voltage when the output terminal voltage is larger than a reference voltage and does not have a glitch.

Circuitry and techniques for providing a bidirectional switch in devices for overcurrent protection and voltage protection are disclosed herein. In one embodiment, a circuit may include a first reverse-blocking insulating gate bipolar transistor (IGBT), having a first gate terminal, first collector terminal and a first emitter terminal. The circuit may include a second reverse-blocking IGBT, having a second gate terminal, a second collector terminal, electrically coupled to the first emitter terminal, and a second emitter terminal, electrically coupled to the first collector terminal. As such the first IGBT and the second IGBT may define a first current path, extending from the first collector to the second emitter; and a switch control circuit, coupled to send a control signal to at least one of: the first gate terminal and the second gate terminal, during an overcurrent event.

Circuitry and techniques for providing a bidirectional switch in devices for overcurrent protection and voltage protection are disclosed herein. In one embodiment, a circuit may include a first reverse-blocking insulating gate bipolar transistor (IGBT), having a first gate terminal, first collector terminal and a first emitter terminal. The circuit may include a second reverse-blocking IGBT, having a second gate terminal, a second collector terminal, electrically coupled to the first emitter terminal, and a second emitter terminal, electrically coupled to the first collector terminal. As such the first IGBT and the second IGBT may define a first current path, extending from the first collector to the second emitter; and a switch control circuit, coupled to send a control signal to at least one of: the first gate terminal and the second gate terminal, during an overcurrent event.

Circuitry for controlling current between a load and a power supply, the circuitry comprising: an output stage comprising: an input node configured to be coupled to the power supply; and an output node configured to be coupled to the load; and one or more control nodes for controlling a conduction path between the input node and the output node; and protection circuitry coupled to the one or more control nodes, the protection circuitry configured to break the conduction path between the input node and the output node when a load voltage at the output node exceeds a supply voltage at the input node, wherein the protection circuitry comprises: an active protection circuit configured to break the conduction path when the supply voltage exceeds an operational threshold of the active protection circuit; and a passive protection circuit configured to break the conduction path when the supply voltage is below an operation threshold of the active protection circuit.

Circuitry for controlling current between a load and a power supply, the circuitry comprising: an output stage comprising: an input node configured to be coupled to the power supply; and an output node configured to be coupled to the load; and one or more control nodes for controlling a conduction path between the input node and the output node; and protection circuitry coupled to the one or more control nodes, the protection circuitry configured to break the conduction path between the input node and the output node when a load voltage at the output node exceeds a supply voltage at the input node, wherein the protection circuitry comprises: an active protection circuit configured to break the conduction path when the supply voltage exceeds an operational threshold of the active protection circuit; and a passive protection circuit configured to break the conduction path when the supply voltage is below an operation threshold of the active protection circuit.

A protection circuit 100 of a power storage device 20 equipped with external terminals 58A, 58B, the protection circuit 100 being equipped with a return circuit 110 connected in parallel to a load 12 connected between the external terminals, and also equipped with a switching circuit 120, wherein: the return circuit 110 is equipped with a return element 111 which causes an induced current produced when the current to the load 12 is blocked to return to the load 12, and a current-blocking part 115 which is connected in series to the return element 111; and the switching circuit 120 switches the current-blocking part 115 from conducting to blocking after a delay of a prescribed interval from when a reverse voltage is applied to the external terminals 58A, 58B.

A protection circuit 100 of a power storage device 20 equipped with external terminals 58A, 58B, the protection circuit 100 being equipped with a return circuit 110 connected in parallel to a load 12 connected between the external terminals, and also equipped with a switching circuit 120, wherein: the return circuit 110 is equipped with a return element 111 which causes an induced current produced when the current to the load 12 is blocked to return to the load 12, and a current-blocking part 115 which is connected in series to the return element 111; and the switching circuit 120 switches the current-blocking part 115 from conducting to blocking after a delay of a prescribed interval from when a reverse voltage is applied to the external terminals 58A, 58B.

A reverse polarity protection device includes a protection unit, a detection unit, and a control unit electrically connected between a power supply device and a load device. The detection unit is electrically connected to the power supply device for detecting the polarity of an output signal of the power supply device, and the control unit is electrically connected to the detection unit and the protection unit. The detection unit outputs a detection signal to the control unit according to a detection result of the polarity of the output signal. If the detection signal shows that the polarity of the output signal is reverse, the control unit will control the protection unit to form an open circuit between the power supply device and load device to stop transmitting the output signal of the power supply device to the load device and achieve a reverse polarity protection effect of the load device.