ZHCSLZ9C August 2020 – January 2024 UCC21732
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 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-Related Certifications
- 5.8 Safety Limiting Values
- 5.9 Electrical Characteristics
- 5.10 Switching Characteristics
- 5.11 Insulation Characteristics Curves
- 5.12 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 External Active Miller Clamp
- 7.3.7 Overcurrent and Short Circuit Protection
- 7.3.8 2-Level 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 External Active Miller Clamp
- 8.2.2.7 Overcurrent and Short Circuit Protection
- 8.2.2.8 Isolated Analog Signal Sensing
- 8.2.2.9 Higher Output Current Using an External Current Buffer
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Revision History
- 13Mechanical, Packaging, and Orderable Information
7.3.10 Isolated Analog to PWM Signal Function
The UCC21732 features an isolated analog to PWM signal function from AIN to APWM pin, which allows the isolated temperature sensing, high voltage dc bus voltage sensing, etc. An internal current source IAIN in AIN pin is implemented in the device to bias an external thermal diode or temperature sensing resistor. The UCC21732 encodes the voltage signal VAIN to a PWM signal, passing through the reinforced isolation barrier, and output to APWM pin on the input side. The PWM signal can either be transferred directly to DSP/MCU to calculate the duty cycle, or filtered by a simple RC filter as an analog signal. The AIN voltage input range is from 0.6 V to 4.5 V, and the corresponding duty cycle of the APWM output ranges from 88% to 10%. The duty cycle increases linearly from 10% to 88% while the AIN voltage decreases from 4.5 V to 0.6 V. This corresponds to the temperature coefficient of the negative temperature coefficient (NTC) resistor and thermal diode. When AIN is floating, the AIN voltage is 5 V and the APWM operates at 400 kHz with approximately 10% duty cycle. The accuracy of the duty cycle is ±5% across temperature without one time calibration. The accuracy can be improved to ±2% with calibration. The accuracy of the internal current source IAIN is 3% across temperature.
The isolated analog to PWM signal feature can also support other analog signal sensing, such as the high voltage dc bus voltage, ans so on. The internal current source IAIN should be taken into account when designing the potential divider if sensing a high voltage.
Figure 7-7 Isolated Analog to PWM Signal