An electrostatic discharge protection device includes a first well region, a second well region, a first doped region, and a first heavily doped region. The first well region and the second well region are disposed in a semiconductor substrate. The first doped region is disposed in the first well region and the second well region. The first heavily doped region is disposed in the first doped region in the first well region. The first well region and the first doped region have a first conductivity type, and the second well region and the first heavily doped region have a second conductivity type that is the opposite of the first conductivity type.

Embodiments of this application disclose a drive circuit of a power device and a drive system, to drive the power device by using a small quantity of components. The drive circuit of the power device includes: a drive signal generation circuit, configured to generate a drive signal; a resistor and a capacitor that are connected in series, coupled to the drive signal generation circuit and the power device, and configured to control turn-on and turn-off of the power device based on the drive signal; and a voltage clamp circuit, coupled to the power device, and configured to control a gate voltage of the power device to be not greater than a gate withstand voltage.

The present invention provides an ESD protection circuit including a control circuit, a first transistor, a filter and a second transistor. The control circuit is configured to detect a level of a supply voltage to generate a control signal. The first transistor is coupled between the supply voltage and a ground voltage, and is used to refer to the control signal to determine whether to be enabled as a discharging path for the supply voltage to discharge current to the ground voltage. The filter is configured to filter the control signal to generate a filtered control signal. The second transistor is coupled between the supply voltage and the ground voltage, and is used to refer to the filtered control signal to determine whether to be enabled as a discharging path for the supply voltage to discharge current to the ground voltage.

Snapback ESD protection circuits that include an Input/Output pad, a ground source, a first and a second NMOS transistor, and trigger circuit, pad bias circuit, and gate bias circuit. The first transistor drain connects to the pad. The second transistor drain connects to the first transistor source. The second transistor source connects to ground. The trigger circuit connects to the pad and a reference voltage to detect an ESD event at the pad. The pad bias circuit connects to the pad, the trigger circuit, ground, and the reference voltage to manage a voltage level for the reference voltage. The gate bias circuit connects to the reference voltage, a supply voltage, ground, and the gates of the first and second transistor to dynamically control the voltage of each gate of the first and a second NMOS transistor.

A current sense short protection circuit includes a switch unit, a current sensing unit, a detection circuit and a short detection module. The first terminal of the switch unit receives a first voltage. The control terminal of the switch unit receives a control signal. The first terminal of the current sensing unit is coupled to the second terminal of the switch unit. The second terminal of the current sensing unit receives a second voltage. The detection unit receives the second voltage and a third voltage provided by the first terminal of the current sensing unit, and generates a detection signal according to the second voltage and the third voltage. The short detection module receives the first voltage, the second voltage and the detection signal, and generates a short detection signal according to the first voltage, the second voltage and the detection signal.

An electrostatic discharge (ESD) device with fast response to high transient currents. The ESD device includes a short-pulse discharge (SPD) path and a long-pulse discharge (LPD) path. The SPD path provides robust response to ESD events, and it triggers a self-bias configuration of the LPD path. Advantageously, the SPD path reduces the risk of ESD voltage overshoot by promptly discharging short-pulse currents, such as a charge device model (CDM) current, whereas the LPD path provides efficient discharge of long-pulse currents, such as a human body model (HBM) current. In one implementation, for example, the SPD path includes a MOS transistor, and the LPD includes a bipolar transistor having a base coupled to the source of the MOS transistor.

Overvoltage protection circuits are provided. In some embodiments, an overvoltage protection circuit includes a first diode made of a first semiconductor material having a bandgap width greater than that of silicon. A second diode is included and is electrically cross-coupled with the first diode. The second diode is made of a second semiconductor material different from the first semiconductor material.

An Electrostatic Discharge protection circuit with low parasitic capacitance is provided, comprising a first bipolar junction transistor and a first ESD power clamp device. The first bipolar junction transistor is an NPN type of bipolar junction transistor, including a base and an emitter commonly connected to an I/O terminal and a collector connected with the first ESD power clamp device. The first ESD power clamp device is further connected to ground, and can be a Zener diode, PNP type, NPN type of bipolar junction transistor or the like. When a positive ESD pulse is injected, an ESD protection path is consisting of the first bipolar junction transistor and the first ESD power clamp device. When a negative ESD pulse is injected, the ESD protection path is consisting of a parasitic silicon controlled rectifier, thereby reducing parasitic capacitance effectively.

In some aspects, the techniques described herein relate to an electromagnetic interference (EMI) filter circuit including: an input terminal; an output terminal; an electrical ground terminal; a resistor electrically coupled between the input terminal and the output terminal; a first bipolar transistor including: a collector terminal electrically coupled with the input terminal; an emitter terminal electrically coupled with the electrical ground terminal; and a base terminal that is electrically floating; and a second bipolar transistor including: a collector terminal electrically coupled with the output terminal; an emitter terminal electrically coupled with the electrical ground terminal; and a base terminal that is electrically floating.

In a particular implementation, an apparatus to control clamping devices includes a detection circuitry, a clamping device, inverter circuitry, and first and second control circuitry. In response to a first voltage corresponding to a gate terminal of the clamping device, the first control circuitry is configured to generate a second voltage to set the first voltage below a first voltage threshold. Also, in response to the second voltage, the second control circuitry is configured to generate a third voltage to set a voltage of the detection circuitry below a second voltage threshold.