Half Bridge Gate Driver# Technical Documentation: FAN7382M High-Voltage Half-Bridge Gate Driver IC
Manufacturer : FAIRCHILD SEMICONDUCTOR (now part of ON Semiconductor)
## 1. Application Scenarios
### Typical Use Cases
The FAN7382M is a monolithic high-voltage, high-speed power MOSFET and IGBT gate driver designed for applications requiring high-side and low-side switching. Its primary function is to provide the necessary drive signals to control the upper and lower transistors in a half-bridge or full-bridge configuration.
* Motor Drive Circuits : It is extensively used to drive the three-phase inverter bridges in Brushless DC (BLDC) Motor controllers and Permanent Magnet Synchronous Motor (PMSM) drives. The driver interfaces directly with a microcontroller's PWM outputs to generate the high-current gate pulses needed for MOSFETs/IGBTs.
* Switch-Mode Power Supplies (SMPS) : Employed in high-power half-bridge and full-bridge topologies for AC-DC and DC-DC converters, particularly in server power supplies, telecom rectifiers, and welding power sources.
* Uninterruptible Power Supplies (UPS) : Used in the inverter stage to convert DC battery voltage to a stable AC output, ensuring clean and efficient switching.
* Solar Inverters : Drives the power switches in the DC-AC conversion stage, enabling efficient power harvesting from photovoltaic panels.
### Industry Applications
* Industrial Automation : Drives for conveyor systems, robotic arms, and CNC machinery.
* Consumer Appliances : High-end air conditioners (inverter-type compressors), washing machines (direct-drive motors), and refrigerator compressors.
* Automotive : Used in auxiliary systems, electric power steering (EPS), and electric vehicle traction inverters (in designs rated for appropriate voltage/current).
* Renewable Energy : Central and string solar inverters.
### Practical Advantages and Limitations
Advantages:
* High-Voltage Level-Shifting : Integrates a bootstrap diode and high-voltage level-shift circuitry, allowing the high-side driver to operate hundreds of volts above ground. This simplifies design by eliminating the need for an isolated power supply for the high-side gate.
* Robust Protection Features : Includes undervoltage lockout (UVLO) for both VCC (low-side supply) and VB-VS (floating high-side supply). This prevents the MOSFET/IGBT from operating in a partially-on state, which minimizes conduction losses and prevents shoot-through.
* High Noise Immunity : Features a negative VS swing handling capability (down to -9.8V typical), making it resilient against voltage spikes and ringing common in inductive switching environments.
* Matched Propagation Delays : The low-side and high-side channels have closely matched propagation delays (typ. 50ns), which is critical for maintaining precise PWM control and minimizing dead-time requirements.
Limitations:
* Bootstrap Circuit Constraint : The high-side driver's operation is dependent on the bootstrap capacitor (`C_BOOT`). This limits the maximum allowable continuous on-time for the high-side switch, as the capacitor can discharge. It is unsuitable for applications requiring a 100% duty cycle on the high side without additional circuitry.
* Limited Sink/Source Current : With a typical peak output current of 2.5A (source) and 2.5A (sink), it may not be sufficient for directly driving very large MOSFETs or IGBT modules with extremely high gate charge (`Qg`). External buffer stages may be required.
* Maximum Switching Frequency : While capable of high-speed operation, practical limits are imposed by bootstrap capacitor recharge time and power dissipation. Optimal performance is typically below several hundred kHz.
## 2. Design Considerations
### Common
