SLUSEM9A September 2022 – June 2024 UCC21755-Q1
PRODUCTION DATA
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Pin Configuration and Functions
-
5 Specifications
- 5.1 Absolute Maximum Ratings
- 5.2 ESD Ratings
- 5.3 Recommended Operating Conditions
- 5.4 Thermal Information
- 5.5 Power Ratings
- 5.6 Insulation Specifications
- 5.7 Safety Limiting Values
- 5.8 Electrical Characteristics
- 5.9 Switching Characteristics
- 5.10 Insulation Characteristics Curves
- 5.11 Typical Characteristics
- 6 Parameter Measurement Information
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Power Supply
- 7.3.2 Driver Stage
- 7.3.3 VCC and VDD Undervoltage Lockout (UVLO)
- 7.3.4 Active Pulldown
- 7.3.5 Short Circuit Clamping
- 7.3.6 Internal Active Miller Clamp
- 7.3.7 Desaturation (DESAT) Protection
- 7.3.8 Soft Turn-Off
- 7.3.9 Fault (FLT), Reset and Enable (RST/EN)
- 7.3.10 Isolated Analog to PWM Signal Function
- 7.4 Device Functional Modes
-
8 Applications and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Input Filters for IN+, IN-, and RST/EN
- 8.2.2.2 PWM Interlock of IN+ and IN-
- 8.2.2.3 FLT, RDY, and RST/EN Pin Circuitry
- 8.2.2.4 RST/EN Pin Control
- 8.2.2.5 Turn-On and Turn-Off Gate Resistors
- 8.2.2.6 Overcurrent and Short Circuit Protection
- 8.2.2.7 Isolated Analog Signal Sensing
- 8.2.2.8 Higher Output Current Using an External Current Buffer
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Revision History
- 13Mechanical, Packaging, and Orderable Information
7.3.2 Driver Stage
The device has ±10-A peak drive strength and is suitable for high power applications. The high drive strength can drive a SiC MOSFET module, IGBT module or paralleled discrete devices directly without extra buffer stage. The device can also be used to drive higher power modules or parallel modules with extra buffer stage. Regardless of the values of VDD, the peak sink and source current can be kept at 10 A. The driver features an important safety function wherein, when the input pins are in floating condition, the OUTH/OUTL is held in LOW state. The split output of the driver stage is depicted in Figure 7-1. The driver has rail-to-rail output by implementing a hybrid pull-up structure with a P-Channel MOSFET in parallel with an N-Channel MOSFET, and an N-Channel MOSFET to pulldown. The pull-up NMOS is the same as the pull down NMOS, so the on resistance RNMOS is the same as ROL. The hybrid pull-up structure delivers the highest peak-source current when it is most needed, during the Miller plateau region of the power semiconductor turn-on transient. The ROH in Figure 7-1 represents the on-resistance of the pull-up P-Channel MOSFET. However, the effective pull-up resistance is much smaller than ROH. Because the pullup N-Channel MOSFET has much smaller on-resistance than the P-Channel MOSFET, the pullup N-Channel MOSFET dominates most of the turn-on transient, until the voltage on OUTH pin is about 3 V below VDD voltage. The effective resistance of the hybrid pullup structure during this period is about 2 x ROL. Then the P-Channel MOSFET pulls up the OUTH voltage to VDD rail. The low pullup impedance results in strong drive strength during the turn-on transient, which shortens the charging time of the input capacitance of the power semiconductor and reduces the turn on switching loss. The output pull-up and pull-down resistance can be found in the Electrical Characteristics table.
The pulldown structure of the driver stage is implemented solely by a pulldown N-Channel MOSFET. This MOSFET can ensure the OUTL voltage be pulled down to VEE rail. The low pulldown impedance not only results in high sink current to reduce the turn-off time, but also helps to increase the noise immunity considering the Miller effect.
Figure 7-1 Gate Driver Output Stage