Power semiconductor devices are the core of modern power electronic systems

A grid driver is a power amplifier that accepts the low-power input of the controller IC and generates an appropriate high-current grid driver for the power device. With the increasing requirements of power electronic equipment, the design and performance of grid drive circuit are becoming more and more important.

Power semiconductor devices are the core of modern power electronic systems. These systems utilize many gated semiconductor devices such as common transistors, FETs, BJTS, MOSFETs, IGBTs, etc., as switching elements in switched mode power supplies (SMPS), general purpose power supplies (UPS), and motor drivers. Modern technological developments in power electronics usually follow the development of power semiconductor devices.

The power electronics industry is increasingly demanding power levels and switches. Transistor metal-oxide-semiconductor field effect (MOSFET) and insulated-gate bipolar transistor (IGBT) high-power switching supplies are two of the most popular and efficient semiconductor devices in most applications.

The gate of a MOSFET or IGBT is the electrical isolation control terminal for each device. The other terminals of the device are the source and drain or the emitter and collector. The MOSFET/IGBT voltage must be applied to the grid electrode, not the device source/emitter. The grid extremum must be set to positive with its source/emitter to drive the on-off of these switchgear.

The switching behavior of the power supply device is affected by the parasitic capacitors between the three terminals, that is, gate to source (CGS), gate to drain (CGD), and the leakage source is from the source. And the source of the leak. (CDS), which is usually nonlinear and is a function of the bias voltage. Charging of the gate capacitor results in a power device that allows current to flow between the drain and source. When discharging, the device is turned off, the drain on the source is blocked and the voltage is large.

Unless its gate input capacitor is charged, the gate voltage of the power device does not increase, and its gate voltage reaches the gate voltage (V thousand). A five-kilowatt device is defined as the minimum grid bias required to create a conductive path between the source and drain regions. For operations where the power device is switched, the voltage is sufficient to apply above V000 between the grid and the source/emitter terminals.

Power electronics use gate drivers

In high-power applications, the output of the logic IC (PWM controller) never drives the grid pole of the power switch. Due to the low current capability of these logic outputs, the grid capacitor charge time is too long and may be longer than the switching cycle. Therefore, special drivers must be used to apply voltage and provide driving current to the grid of the power supply device. It can be a drive circuit or a special IC. Separation of transistors or transformers. It can also be integrated into the PWM controller IC.

A grid driver is a power amplifier that accepts the low-power input of the controller IC and generates an appropriate high-current grid driver for the power device. It is used when the PWM controller does not provide the output current required to drive the grid capacitance of the relevant power device.

Grid drive circuit is a part of power electronic system. The grid drive is an important interface between high-power electronic devices and control circuits, and is used to drive power semiconductor devices. The output of a DC-DC converter or SMPS mainly depends on the behavior of the gate drive circuit, which means that if the gate drive circuit does not drive the gate of the power device correctly, the output of the DC-DC converter does not meet the design requirements. Therefore, the design of gate drive circuit is very important in the design of power electronic converter.

Grille drive isolator

To achieve functional and safety goals, the gate drive circuits of power inverters and converters often require electrical isolation. Supervise safety certification bodies to enforce isolation to prevent electric shock hazards. It also protects low-voltage electronics from any damage caused by circuit failures on the high power side and human error on the control side. Electrical isolation between functional circuits in the system prevents direct conduction paths between them and allows individual circuits to have different ground potentials. Inductive, capacitive, or optical methods can still transmit signal and power between isolated circuits.

Many applications of power devices (for example, requiring high power density and efficient converters) require isolated grid driver circuits. For example, in power converter topologies such as half-bridge, full-bridge, buck, two-switch forward, and active clamp forward. Since the low-side driver cannot be used directly to drive high-power devices, there is a high-low switch. High power devices need to isolate the grid driver because the source and emission of the upper device are not located at ground potential (float).