High-Side Gate Driver# Technical Documentation: FAN7361MX Gate Driver IC
Manufacturer : FAIRCHILD (ON Semiconductor)
Component : FAN7361MX - High-Voltage, High-Speed Gate Driver IC
Document Version : 1.0
Date : October 2023
---
## 1. Application Scenarios
### 1.1 Typical Use Cases
The FAN7361MX is a monolithic high-side and low-side gate driver IC designed to drive power MOSFETs and IGBTs in high-voltage, high-frequency switching applications. Its primary function is to provide the necessary current and voltage translation to efficiently switch power devices while maintaining isolation between control logic and power stages.
Primary Applications Include:
- Half-Bridge and Full-Bridge Configurations : The device contains independent high-side and low-side driver channels with a floating high-side driver capable of operating up to +600V. This makes it ideal for bridge topologies in motor drives, inverters, and switched-mode power supplies (SMPS).
- Synchronous Rectification : In high-efficiency DC-DC converters, the FAN7361MX can drive synchronous MOSFETs to replace diode rectifiers, significantly reducing conduction losses.
- Resonant Converters : Such as LLC and phase-shifted full-bridge converters, where precise timing and high-side drive capability are critical for zero-voltage switching (ZVS) operation.
### 1.2 Industry Applications
- Industrial Motor Drives : Used in variable frequency drives (VFDs) for AC induction and BLDC motors, providing robust and reliable gate driving in harsh industrial environments.
- Uninterruptible Power Supplies (UPS) : Drives the inverter stage in online and line-interactive UPS systems, ensuring clean and efficient AC output.
- Solar Inverters : Employed in the DC-AC conversion stage of photovoltaic inverters, where high-voltage isolation and efficiency are paramount.
- Switched-Mode Power Supplies (SMPS) : Particularly in high-power AC-DC front-end PFC (Power Factor Correction) stages and high-voltage DC-DC converters (e.g., for server power supplies).
- Electric Vehicle (EV) Chargers : Used in both onboard chargers (OBC) and off-board charging stations for the power conversion stages.
### 1.3 Practical Advantages and Limitations
Advantages:
- High Voltage Capability : The high-side driver can withstand bootstrap or isolated bias supply voltages up to 600V, suitable for many offline and three-phase applications.
- Integrated Bootstrap Functionality : Simplifies design by allowing the use of a bootstrap capacitor to generate the high-side supply, eliminating the need for an isolated DC-DC converter in many cases.
- Fast Switching Speeds : Typical propagation delays of 120ns (max) and rise/fall times of 80ns/40ns (into 1 nF load) enable high-frequency operation, reducing switching losses and magnetic component size.
- Robustness : Features like under-voltage lockout (UVLO) for both channels prevent malfunction during power-up/down, and a shutdown pin provides system-level protection.
- Compact Solution : The 8-pin SOIC package offers a space-efficient solution for high-power gate driving.
Limitations:
- Bootstrap Limitation : In applications with very high duty cycles (e.g., >99%) or requiring long continuous high-side on-times, the bootstrap capacitor may discharge, causing high-side UVLO fault. This necessitates careful capacitor selection or an alternative bias supply.
- Peak Current Capability : While capable of sourcing/sinking 2.5A/3.5A peak currents, it may not be sufficient for directly driving very large IGBT modules or paralleled MOSFETs with extremely high gate charge (`Qg`). An external booster stage may be required.
- Limited Configuration Flexibility : As
