SLUSC82B April   2017  – July 2026 UCC24630

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Start Up and UVLO
      2. 6.3.2 Volt-Sec SR Driver On-Time Control
      3. 6.3.3 CCM Dead Time
      4. 6.3.4 Standby Operation
      5. 6.3.5 Pin Fault Protection
        1. 6.3.5.1 VPC Pin Overvoltage
        2. 6.3.5.2 VPC Pin Open
        3. 6.3.5.3 VSC Pin Open
        4. 6.3.5.4 TBLK Pin Open
        5. 6.3.5.5 VPC and VSC Short to Ground
        6. 6.3.5.6 TBLK Pin Short to Ground
    4. 6.4 Device Functional Modes
      1. 6.4.1 Start-Up
      2. 6.4.2 Normal Operation
      3. 6.4.3 Standby Operation
      4. 6.4.4 Conditions to Stop Operation
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 AC-to-DC Adapter, 19.5V, 65W
      2. 7.2.2 Design Requirements
      3. 7.2.3 Calculation of Component Values
        1. 7.2.3.1 VPC Input
        2. 7.2.3.2 VSC Input
        3. 7.2.3.3 TBLK Input
      4. 7.2.4 Application Curves
    3. 7.3 Best Design Practices
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
        1. 7.5.1.1 VDD Pin
        2. 7.5.1.2 VPC Pin
        3. 7.5.1.3 VSC Pin
        4. 7.5.1.4 GND Pin
        5. 7.5.1.5 TBLK Pin
        6. 7.5.1.6 DRV Pin
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Device Nomenclature
        1. 8.1.1.1 Definition of Terms
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.1 Overview

The UCC24630 SR controller is targeted for flyback converters operating in DCM, TM, and CCM modes of operation. The control method to determine SR on time is based on the volt-second balance principle of primary and secondary conduction volt-second product. In converters operating in DCM and TM, the secondary current always returns to zero in each cycle. In CCM operation, volt-second balance occurs in steady state operation. The inductor charge voltage and time product is equal to the discharge voltage and time product. The device uses internal current ramp emulators to predict the proper SR on time based on voltage and time information on the VPC and VSC pins.

In CCM converters during the transition from DCM operation into CCM, volt-second balance does not occur for several cycles. In this case CCM operation compatibility is achieved by limiting the maximum SR MOSFET on time with a CCM dead-time function, based on the previous switching period. There is fault protection to disable the SR in the event the operating periods become unstable during extreme operating transients.

To achieve very low standby power in the converter, the UCC24630 has a standby mode of operation that disables the SR MOSFET drive and reduces the device bias current to ISTBY. The device monitors the average switching frequency of the converter to enter and exit the standby mode of operation. The device is compatible with converters operating in burst mode or constant frequency in light-load mode.