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

7.4 Power Supply Recommendations

The UCC24630 is recommended as a synchronous rectifier controller in a wide variety of flyback power supplies. It is compatible with Discontinuous Conduction Mode (DCM) and Transition Mode (TM) controllers in fixed frequency or variable frequency applications. It is compatible with Continuous Conduction Mode (CCM) controllers in fixed frequency applications.

It is an excellent choice as a synchronous rectifier for flyback power supplies with an input from 85VAC to 265VAC and an output from 5V to 24V. It can also be used in other flyback applications with different input and/or output voltages. But be sure all voltages and currents are within the recommended operating conditions and absolute ratings of the device.

It is compatible with flyback converters operating at the transition mode limit, at low line, with switching frequencies as low as 40kHz. It can also be used in switching speeds up to 200kHz.

The VDD operating range allows direct connection to converter outputs from 5V to 24V. Since the driver and control share the same VDD and ground, place a good quality ceramic capacitor as close as possible to VDD and GND pins. To reduce VDD noise and eliminate high-frequency ripple current injected from the converter output, it is recommended to place a small resistance from 2.2Ω to 10Ω between the converter output and VDD. The device can tolerate VDD rise times from 100µs to very long rise times typical of constant current chargers. The start-up sequence always is as shown in Figure 6-1. VDD can connect to an external bias to extend the device's operating range below 3.5V or above 24V converter outputs.