Servo signal processor for CD# Technical Documentation: BU9312AKS High-Speed, High-Voltage Dual-Channel MOSFET Driver IC
Manufacturer : ROHM Semiconductor
Document Revision : 1.0
Date : 2023-10-27
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## 1. Application Scenarios
The BU9312AKS is a monolithic integrated circuit designed as a high-speed, high-voltage dual-channel MOSFET/IGBT gate driver . It is engineered to provide robust, efficient switching for power semiconductor devices in demanding applications.
### 1.1 Typical Use Cases
* Half-Bridge and Full-Bridge Topologies: The dual independent output channels (HO1, HO2, LO1, LO2) are ideally suited for driving the high-side and low-side switches in bridge configurations. This is its most common application.
* Synchronous Rectification: Driving the control and synchronous MOSFETs in DC-DC converters (e.g., buck, boost, half-bridge) to improve efficiency by replacing diode voltage drops with low Rds(on) MOSFET conduction.
* Motor Drive Phase Legs: Directly driving the MOSFETs or IGBTs in each phase leg of 3-phase Brushless DC (BLDC) or Permanent Magnet Synchronous Motor (PMSM) drives. Its high-speed capability is critical for PWM frequency control.
* Isolated Gate Driving: When paired with an isolated power supply and signal isolator (e.g., digital isolator, optocoupler), one channel can drive the high-side switch in offline flyback or forward converters.
### 1.2 Industry Applications
* Industrial Automation & Robotics: Servo drives, motor controllers, and programmable logic controller (PLC) output modules requiring precise and robust power switching.
* Consumer Electronics: High-efficiency power supplies for gaming consoles, high-end audio amplifiers (Class D), and large LED TV backlight inverters.
* Automotive Systems: Auxiliary motor controls (e.g., pumps, fans), onboard chargers (OBC), and DC-DC converters in electric and hybrid vehicles (xEV), where its ruggedness is beneficial.
* Renewable Energy: Inverters for solar micro-inverters and energy storage system (ESS) power conversion stages.
* Switched-Mode Power Supplies (SMPS): High-power AC-DC and DC-DC converters, particularly in telecom and server power supplies.
### 1.3 Practical Advantages and Limitations
Advantages:
* High Current Capability: Typical peak source/sink currents of 2.0A/2.0A allow for rapid switching of large MOSFETs, minimizing switching losses.
* High-Voltage Operation: Can withstand high-side floating supply voltages (Vs) up to 600V, making it suitable for off-line and bus-voltage applications.
* Integrated Bootstrap Function: Simplifies high-side drive by allowing the use of a bootstrap capacitor and diode, eliminating the need for a separate isolated power supply for each high-side channel.
* Cross-Conduction Prevention: Features built-in dead-time control or requires external dead-time insertion at the input stage to prevent shoot-through currents in half-bridge configurations.
* Wide VCC Range: Low-side logic supply (VCC) typically operates from 10V to 20V, offering design flexibility.
Limitations:
* Non-Isolated: The driver itself is not isolated. High-voltage isolation must be provided at the system level (e.g., via isolated sensors, controllers, or power supplies) if required for safety or functional reasons.
* Bootstrap Refresh Requirement: In applications with a 100% duty cycle requirement for the high-side switch, the bootstrap capacitor cannot recharge, leading to high-side gate drive failure. This necessitates special circuit techniques (e.g., a charge
