Ballast Control IC for Compact Fluorescent Lamp# Technical Documentation: FAN7387V High-Voltage Half-Bridge Gate Driver IC
Manufacturer : FAIRCHILD (ON Semiconductor)
Document Revision : 1.0
Date : October 26, 2023
## 1. Application Scenarios
### 1.1 Typical Use Cases
The FAN7387V is a monolithic high-voltage, high-speed gate driver IC designed to drive both high-side and low-side N-channel power MOSFETs or IGBTs in a half-bridge configuration. Its primary function is to provide the necessary voltage level shifting, isolation, and drive current to efficiently switch power devices in high-voltage circuits.
Primary Applications Include:
* Motor Drive Inverters : Controlling 3-phase AC induction motors, brushless DC (BLDC) motors, and permanent magnet synchronous motors (PMSM) in applications ranging from industrial pumps and fans to appliance compressors and e-bikes.
* Switch-Mode Power Supplies (SMPS) : Used in the primary-side switching stage of high-power AC-DC converters, particularly in half-bridge, full-bridge, and active-clamp forward topologies for server PSUs, telecom rectifiers, and welding equipment.
* Uninterruptible Power Supplies (UPS) : Driving the inverter stage that converts DC battery voltage to a stable AC output.
* Solar Inverters : Employed in the power conversion stage (DC-AC) of micro and string inverters.
* Electronic Ballasts : For driving high-voltage switches in high-intensity discharge (HID) and fluorescent lighting systems.
### 1.2 Industry Applications
* Industrial Automation : Variable frequency drives (VFDs) for conveyor systems, CNC machines, and robotics.
* Consumer Appliances : Inverter-driven compressors in air conditioners, refrigerators, and washing machines for improved efficiency and quieter operation.
* Automotive : Auxiliary systems in electric and hybrid vehicles (EV/HEV), such as battery management system (BMS) converters and electric power steering (EPS).
* Renewable Energy : Power conversion modules in solar and wind energy systems.
### 1.3 Practical Advantages and Limitations
Advantages:
* High-Voltage Operation : Features a high-side floating channel designed for bootstrap operation with a maximum voltage (`VBS`) of 625V, enabling direct use in off-line and high-voltage bus applications.
* Integrated Functions : Includes an under-voltage lockout (UVLO) for both channels, a shutdown feature, and matched propagation delays, which simplify design and enhance system reliability.
* Robustness : High `dV/dt` immunity and negative `VS` swing tolerance enhance noise immunity in harsh switching environments.
* Compact Solution : Replaces multiple discrete components (level shifters, isolators, drivers), reducing board space and component count.
Limitations:
* Bootstrap Limitation : The high-side driver requires a bootstrap capacitor for power. This limits the maximum duty cycle and on-time for the high-side switch, as the capacitor must be periodically recharged when the low-side switch is on.
* Peak Current Capability : While capable of sourcing/sinking typical peak currents (e.g., 350 mA source / 650 mA sink for FAN7387V), it may not be sufficient for very large MOSFET/IGBT modules with extremely high gate charge (`Qg`) without an additional booster stage.
* Lack of Isolation : Unlike optocoupler-based drivers, it does not provide galvanic isolation between the input logic and the high-voltage output. System-level isolation must be provided elsewhere if required.
## 2. Design Considerations
### 2.1 Common Design Pitfalls and Solutions
* Pitfall 1: Bootstrap Circuit Failure.
