ZHCSLD2E may   2020  – july 2023 UCC28782

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 描述
  5. Revision History
  6. Device Comparison Table
  7. Pin Configuration and Functions
    1.     Pin Functions
  8. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Detailed Pin Description
      1. 8.3.1  BUR Pin (Programmable Burst Mode)
      2. 8.3.2  FB Pin (Feedback Pin)
      3. 8.3.3  REF Pin (Internal 5-V Bias)
      4. 8.3.4  VDD Pin (Device Bias Supply)
      5. 8.3.5  P13 and SWS Pins
      6. 8.3.6  S13 Pin
      7. 8.3.7  IPC Pin (Intelligent Power Control Pin)
      8. 8.3.8  RUN Pin (Driver and Bias Source for Isolator)
      9. 8.3.9  PWMH and AGND Pins
      10. 8.3.10 PWML and PGND Pins
      11. 8.3.11 SET Pin
      12. 8.3.12 RTZ Pin (Sets Delay for Transition Time to Zero)
      13. 8.3.13 RDM Pin (Sets Synthesized Demagnetization Time for ZVS Tuning)
      14. 8.3.14 BIN, BSW, and BGND Pins
      15. 8.3.15 XCD Pin
      16. 8.3.16 CS, VS, and FLT Pins
    4. 8.4 Device Functional Modes
      1. 8.4.1  Adaptive ZVS Control with Auto-Tuning
      2. 8.4.2  Dead-Time Optimization
      3. 8.4.3  EMI Dither and Dither Fading Function
      4. 8.4.4  Control Law across Entire Load Range
      5. 8.4.5  Adaptive Amplitude Modulation (AAM)
      6. 8.4.6  Adaptive Burst Mode (ABM)
      7. 8.4.7  Low Power Mode (LPM)
      8. 8.4.8  First Standby Power Mode (SBP1)
      9. 8.4.9  Second Standby Power Mode (SBP2)
      10. 8.4.10 Startup Sequence
      11. 8.4.11 Survival Mode of VDD (INT_STOP)
      12. 8.4.12 Capacitor Voltage Balancing Function
      13. 8.4.13 Device Functional Modes for Bias Regulator Control
        1. 8.4.13.1 Mitigation of Switching Interaction with ACF Converter
        2. 8.4.13.2 Protection Functions for the Bias Regulator
        3. 8.4.13.3 BIN-Pin Related Protections
        4. 8.4.13.4 BSW-Pin Related Protections
      14. 8.4.14 System Fault Protections
        1. 8.4.14.1  Brown-In and Brown-Out
        2. 8.4.14.2  Output Over-Voltage Protection (OVP)
        3. 8.4.14.3  Input Over Voltage Protection (IOVP)
        4. 8.4.14.4  Over-Temperature Protection (OTP) on FLT Pin
        5. 8.4.14.5  Over-Temperature Protection (OTP) on CS Pin
        6. 8.4.14.6  Programmable Over-Power Protection (OPP)
        7. 8.4.14.7  Peak Power Limit (PPL)
        8. 8.4.14.8  Output Short-Circuit Protection (SCP)
        9. 8.4.14.9  Over-Current Protection (OCP)
        10. 8.4.14.10 External Shutdown
        11. 8.4.14.11 Internal Thermal Shutdown
      15. 8.4.15 Pin Open/Short Protections
        1. 8.4.15.1 Protections on CS pin Fault
        2. 8.4.15.2 Protections on P13 pin Fault
        3. 8.4.15.3 Protections on RDM and RTZ pin Faults
  10. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application Circuit
      1. 9.2.1 Design Requirements for a 65-W USB-PD Adapter Application
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Input Bulk Capacitance and Minimum Bulk Voltage
        2. 9.2.2.2 Transformer Calculations
          1. 9.2.2.2.1 Primary-to-Secondary Turns Ratio (NPS)
          2. 9.2.2.2.2 Primary Magnetizing Inductance (LM)
          3. 9.2.2.2.3 Primary Winding Turns (NP)
          4. 9.2.2.2.4 Secondary Winding Turns (NS)
          5. 9.2.2.2.5 Auxiliary Winding Turns (NA)
          6. 9.2.2.2.6 Winding and Magnetic Core Materials
        3. 9.2.2.3 Clamp Capacitor Calculation
          1. 9.2.2.3.1 Primary-Resonance ACF
          2. 9.2.2.3.2 Secondary-Resonance ACF
        4. 9.2.2.4 Bleed-Resistor Calculation
        5. 9.2.2.5 Output Filter Calculation
        6. 9.2.2.6 Calculation of ZVS Sensing Network
        7. 9.2.2.7 Calculation of BUR Pin Resistances
        8. 9.2.2.8 Calculation of Compensation Network
      3. 9.2.3 Application Curves
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1  General Considerations
      2. 11.1.2  RDM and RTZ Pins
      3. 11.1.3  SWS Pin
      4. 11.1.4  VS Pin
      5. 11.1.5  BUR Pin
      6. 11.1.6  FB Pin
      7. 11.1.7  CS Pin
      8. 11.1.8  BIN Pin
      9. 11.1.9  BSW Pin
      10. 11.1.10 AGND Pin
      11. 11.1.11 BGND Pin
      12. 11.1.12 PGND Pin
      13. 11.1.13 EP Thermal Pad
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 支持资源
    4. 12.4 Trademarks
    5. 12.5 静电放电警告
    6. 12.6 术语表
  14. 13Mechanical, Packaging, and Orderable Information

Programmable Over-Power Protection (OPP)

The over-power protection (OPP) allows operation in an over-power condition for a limited amount of time, so the UCC28782 can support a power stage design with temporary peak power requirements. As shown in Figure 8-43, when VCST is higher than the threshold voltage of the OPP curve (VCST(OPP)), a 160-ms timer starts. For the auto-recovery mode, if VCST remains higher than VCST(OPP) continuously for 160 ms, the 1.5-s timer starts and the controller stays in fault state without switching. This long recovery time reduces the average current during a sustained over-power event. The system benefits includes the reduction of thermal stress in high density adapters and the protection of its output cable.

The OPP function uses IVSL as a line feed-forward signal to vary VCST(OPP) depending on VBULK, in order to make the OPP trigger point constant over a wide line voltage range. The UCC28782 allows programmability of the OPP curve by adding a line-compensation offset voltage on the CS pin through a resistor (ROPP) connected between the CS pin and current-sense resistor (RCS). An internal current source flowing out of CS pin creates the offset voltage on ROPP. This current level is equal to IVSL divided by a constant gain of KLC. As ROPP increases, the OPP trigger point becomes lower at high line, so lower peak magnetizing current is allowed to run continuously.

The OPP function uses VVS as an output voltage feed-forward signal to modify the line-dependent VCST(OPP) curve into the two different sets, such that the OPP trigger point can be more consistent across a wide output voltage range. The higher OPP threshold under VVS > 2.5 V contains two piece-wise linear regions, and the lower OPP threshold under VVS < 2.4 V contains one piece-wise linear region.

The highest threshold of OPP curve (VCST(OPP1)) of 0.6 V helps to determine RCS value at VBULK(MIN) .

Equation 19. GUID-B486D991-D1B2-4FF6-911A-CDB7D75DAF73-low.gif
  • where PO(OPP) is the output power that triggers OPP
  • tD(CST) is the sum of all delays in the peak current loop which contributes additional peak current overshoot

tD(CST) consists of propagation delay of the low-side driver, current sense filter delay (ROPP x CCS), internal CS comparator delay (tD(CS)), and nonlinear capacitance delay of QL. After RCS is determined, ROPP can be adjusted to keep a similar OPP point at highest line. Note that setting the OPP trigger point too far away from the full power may introduce more challenge on the thermal design, since the converter runs continuously with more power as long as the corresponding peak current is slightly less than OPP threshold.

GUID-49495E2B-E029-45B6-8E43-554EF7D4D50F-low.gifFigure 8-43 VCST OPP curve across IVSL
GUID-0E7A2B8D-62CD-4750-B756-9136B7641B02-low.gifFigure 8-44 Timing Diagram of OPP