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UCC28782 High-Density Active-Clamp Flyback Controller with EMI Dithering, X-Cap Discharge, and Bias Power Management
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
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8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Detailed Pin Description
- 8.3.1 BUR Pin (Programmable Burst Mode)
- 8.3.2 FB Pin (Feedback Pin)
- 8.3.3 REF Pin (Internal 5-V Bias)
- 8.3.4 VDD Pin (Device Bias Supply)
- 8.3.5 P13 and SWS Pins
- 8.3.6 S13 Pin
- 8.3.7 IPC Pin (Intelligent Power Control Pin)
- 8.3.8 RUN Pin (Driver and Bias Source for Isolator)
- 8.3.9 PWMH and AGND Pins
- 8.3.10 PWML and PGND Pins
- 8.3.11 SET Pin
- 8.3.12 RTZ Pin (Sets Delay for Transition Time to Zero)
- 8.3.13 RDM Pin (Sets Synthesized Demagnetization Time for ZVS Tuning)
- 8.3.14 BIN, BSW, and BGND Pins
- 8.3.15 XCD Pin
- 8.3.16 CS, VS, and FLT Pins
- 8.4
Device Functional Modes
- 8.4.1 Adaptive ZVS Control with Auto-Tuning
- 8.4.2 Dead-Time Optimization
- 8.4.3 EMI Dither and Dither Fading Function
- 8.4.4 Control Law across Entire Load Range
- 8.4.5 Adaptive Amplitude Modulation (AAM)
- 8.4.6 Adaptive Burst Mode (ABM)
- 8.4.7 Low Power Mode (LPM)
- 8.4.8 First Standby Power Mode (SBP1)
- 8.4.9 Second Standby Power Mode (SBP2)
- 8.4.10 Startup Sequence
- 8.4.11 Survival Mode of VDD (INT_STOP)
- 8.4.12 Capacitor Voltage Balancing Function
- 8.4.13 Device Functional Modes for Bias Regulator Control
- 8.4.14
System Fault Protections
- 8.4.14.1 Brown-In and Brown-Out
- 8.4.14.2 Output Over-Voltage Protection (OVP)
- 8.4.14.3 Input Over Voltage Protection (IOVP)
- 8.4.14.4 Over-Temperature Protection (OTP) on FLT Pin
- 8.4.14.5 Over-Temperature Protection (OTP) on CS Pin
- 8.4.14.6 Programmable Over-Power Protection (OPP)
- 8.4.14.7 Peak Power Limit (PPL)
- 8.4.14.8 Output Short-Circuit Protection (SCP)
- 8.4.14.9 Over-Current Protection (OCP)
- 8.4.14.10 External Shutdown
- 8.4.14.11 Internal Thermal Shutdown
- 8.4.15 Pin Open/Short Protections
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9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application Circuit
- 9.2.1 Design Requirements for a 65-W USB-PD Adapter Application
- 9.2.2
Detailed Design Procedure
- 9.2.2.1 Input Bulk Capacitance and Minimum Bulk Voltage
- 9.2.2.2 Transformer Calculations
- 9.2.2.3 Clamp Capacitor Calculation
- 9.2.2.4 Bleed-Resistor Calculation
- 9.2.2.5 Output Filter Calculation
- 9.2.2.6 Calculation of ZVS Sensing Network
- 9.2.2.7 Calculation of BUR Pin Resistances
- 9.2.2.8 Calculation of Compensation Network
- 9.2.3 Application Curves
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
- IMPORTANT NOTICE
Data Sheet
UCC28782 High-Density Active-Clamp Flyback Controller with EMI Dithering, X-Cap Discharge, and Bias Power Management
1 Features
Active clamp recovers leakage inductance energy
Adaptive control for fast zero voltage switching (ZVS) tracking and dead time optimization
- Integrated switching bias regulator supports USB Type-C™ PD wide output voltage range with one auxiliary winding
- EMI frequency dithering without trade-offs on transient response or audible noise
- Dynamic bias power management for digital isolator and GaN driver
- Programmable Adaptive Burst Mode (ABM) with internal compensation
- Active X-capacitor (X-cap) discharge
- Over-temperature, over-voltage, output short-circuit, over-current, over-power, and pin-fault protections
Auto-recovery and group-latch fault options with fast latch-reset capability
4x4-mm 24-pin QFN package
