SLUSBW3D March   2014  – December 2017 UCC28630 , UCC28631 , UCC28632 , UCC28633 , UCC28634


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Typical Application Measured Regulation
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     PIN Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information (UCC28630, UCC28631)
    5. 7.5 Thermal Information (UCC28632, UCC28633, (UCC28630, UCC28634)
    6. 7.6 Electrical Characteristics
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  High-Voltage Current Source Start-Up Operation
      2. 8.3.2  AC Input UVLO / Brownout Protection
      3. 8.3.3  Active X-Capacitor Discharge (UCC28630 and UCC28633 only)
        1. Improved Performance with UCC28630 and UCC28633
      4. 8.3.4  Magnetic Input and Output Voltage Sensing
      5. 8.3.5  Fixed-Point Magnetic Sense Sampling Error Sources
      6. 8.3.6  Magnetic Sense Resistor Network Calculations
        1. Step 1
        2. Step 2
        3. Step 3
        4. Step 4
      7. 8.3.7  Magnetic Sensing: Power Stage Design Constraints
      8. 8.3.8  Magnetic Sense Voltage Control Loop
      9. 8.3.9  Peak Current Mode Control
      10. 8.3.10 IPEAK Adjust vs. Line
      11. 8.3.11 Primary-Side Constant-Current Limit (CC Mode)
      12. 8.3.12 Primary-Side Overload Timer (UCC28630 only)
      13. 8.3.13 Overload Timer Adjustment (UCC28630 only)
      14. 8.3.14 CC-Mode IOUT(lim) Adjustment
      15. 8.3.15 Fault Protections
      16. 8.3.16 Pin-Fault Detection and Protection
      17. 8.3.17 Over-Temperature Protection
      18. 8.3.18 External Fault Input
      19. 8.3.19 External SD Pin Wake Input (except UCC28633)
      20. 8.3.20 External Wake Input at VSENSE Pin (UCC28633 Only)
      21. 8.3.21 Mode Control and Switching Frequency Modulation
      22. 8.3.22 Frequency Dither For EMI (except UCC28632)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Internal Key Parameters
  9. Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Notebook Adapter, 19.5 V, 65 W
      2. 9.2.2 UCC28630 Application Schematic
      3. 9.2.3 Design Requirements
      4. 9.2.4 Detailed Design Procedure
        1.  Custom Design With WEBENCH® Tools
        2.  Input Bulk Capacitance and Minimum Bulk Voltage
        3.  Transformer Turn Ratio
        4.  Transformer Magnetizing Inductance
        5.  Current Sense Resistor RCS
        6.  Transformer Constraint Verification
        7.  Transformer Selection and Design
        8.  Slope Compensation Verification
        9.  Power MOSFET and Output Rectifier Selection
        10. Output Capacitor Selection
        11. Calculation of CC Mode Limit Point
        12. VDD Capacitor Selection
        13. Magnetic Sense Resistor Network Selection
        14. Output LED Pre-Load Resistor Calculation
      5. 9.2.5 External Wake Pulse Calculation at VSENSE Pin (UCC28633 Only)
      6. 9.2.6 Energy Star Average Efficiency and Standby Power
      7. 9.2.7 Application Performance Plots
    3. 9.3 Dos and Don'ts
      1. 9.3.1 Test and Debug Recommendations
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 HV Pin
      2. 11.1.2 VDD Pin
      3. 11.1.3 VSENSE Pin
      4. 11.1.4 CS Pin
      5. 11.1.5 SD Pin
      6. 11.1.6 DRV Pin
      7. 11.1.7 GND Pin
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
        1. Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

AC Input UVLO / Brownout Protection

At start-up, once the VDD pin has reached the VDD(start) level, the internal start-up current source is turned off. The controller tests the voltage across the bulk capacitor to determine if the level is high enough to allow the power stage to start, if it has exceeded the rising ACON level. Because there is no load across the bulk capacitor at this stage, the bulk voltage can be used as a proxy for the peak of the AC line. In order to measure the bulk voltage in a low-loss fashion, the controller generates a sequence of three exploratory switching pulses at a frequency of fSW(uv), at minimum peak-current demand level VCS(min) to avoid audible noise, and to deliver minimum energy to the output of the power stage.

Based on the magnetic sampling information determined via the bias winding during these switching pulses, if the output voltage is greater than the output overvoltage threshold, the pulsing stops immediately, and the controller transitions into latched-fault mode. If, however, there is no overvoltage condition detected at the output, the pulse-set completes. If the sensed line voltage is above the line ACON start threshold, then the controller starts up normally, and begins to generate the PWM drive pulses that charge and regulate the output voltage. Alternatively, if the sensed bulk level is below the ACON threshold, then the controller enters low power mode for the reset period (tRESET(short)). It then depletes the VDD rail to the VDD(reset) level. At this point, the start-up sequence repeats, and the device generates another set of exploratory switching pulses. This sequence repeats indefinitely until the AC input is increased to a sufficient level that the bulk voltage exceeds the ACON level.

UCC28630 UCC28631 UCC28632 UCC28633 UCC28634 fig19_lusbw3.gifFigure 17. AC Input UVLO Detection and Start Up

Once started, the controller regularly monitors the bulk capacitor voltage. Because the ripple on the bulk capacitor depends on the load level, the device determines the maximum bulk level every 11 ms (approprite for minimum AC frequency of 47 Hz), so the AC peak can be determined. The controller provides input undervoltage protection based on the sensed AC peak level. Once the peak drops below the ACOFF level for the delay period (tUV(delay)), the PWM switching halts, and the controller enters low-power mode for the reset period (tRESET(short)). The device then discharges the bias voltage to the VDD(reset) level, followed by a restart sequence. The controller cycles through the ACON, monitoring (detailed above) indefinitely until the AC input again rises above the ACON level.