JAJS124Q December   1999  – October 2019 UCC1895 , UCC2895 , UCC3895

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      アプリケーション概略図
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1  ADS (Adaptive Delay Set)
      2. 7.3.2  CS (Current Sense)
      3. 7.3.3  CT (Oscillator Timing Capacitor)
      4. 7.3.4  DELAB and DELCD (Delay Programming Between Complementary Outputs)
      5. 7.3.5  EAOUT, EAP, and EAN (Error Amplifier)
      6. 7.3.6  OUTA, OUTB, OUTC, and OUTD (Output MOSFET Drivers)
      7. 7.3.7  PGND (Power Ground)
      8. 7.3.8  RAMP (Inverting Input of the PWM Comparator)
      9. 7.3.9  REF (Voltage Reference)
      10. 7.3.10 RT (Oscillator Timing Resistor)
      11. 7.3.11 GND (Analog Ground)
      12. 7.3.12 SS/DISB (Soft Start/Disable)
      13. 7.3.13 SYNC (Oscillator Synchronization)
      14. 7.3.14 VDD (Chip Supply)
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Programming DELAB, DELCD and the Adaptive Delay Set
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Power Loss Budget
        2. 8.2.2.2  Preliminary Transformer Calculations (T1)
        3. 8.2.2.3  QA, QB, QC, QD FET Selection
        4. 8.2.2.4  Selecting LS
        5. 8.2.2.5  Selecting Diodes DB and DC
        6. 8.2.2.6  Output Inductor Selection (LOUT)
        7. 8.2.2.7  Output Capacitance (COUT)
        8. 8.2.2.8  Select Rectifier Diodes
        9. 8.2.2.9  Input Capacitance (CIN)
        10. 8.2.2.10 Current Sense Network (CT, RCS, RR, DA)
          1. 8.2.2.10.1 Output Voltage Setpoint
          2. 8.2.2.10.2 Voltage Loop Compensation
          3. 8.2.2.10.3 Setting the Switching Frequency
          4. 8.2.2.10.4 Soft Start
          5. 8.2.2.10.5 Setting the Switching Delays
          6. 8.2.2.10.6 Setting the Slope Compensation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 ドキュメントのサポート
      1. 11.1.1 関連資料
      2. 11.1.2 関連リンク
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 コミュニティ・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 Glossary
  12. 12メカニカル、パッケージ、および注文情報

8.2.2.3 QA, QB, QC, QD FET Selection

In this design to meet efficiency and voltage requirements 20 A, 650 V, CoolMOS FETs from Infineon are chosen for QA..QD.

FET drain to source on resistance:

Equation 37. UCC1895 UCC2895 UCC3895 qu31_lua560.gif

FET Specified COSS:

Equation 38. UCC1895 UCC2895 UCC3895 qu32_lua560.gif

Voltage across drain-to-source (VdsQA) where COSS was measured, data sheet parameter:

Equation 39. UCC1895 UCC2895 UCC3895 qu33_lua560.gif

Calculate average Coss [2]:

Equation 40. UCC1895 UCC2895 UCC3895 qu34_lua560.gif

QA FET gate charge:

Equation 41. UCC1895 UCC2895 UCC3895 qu35_lua560.gif

Voltage applied to FET gate to activate FET:

Equation 42. UCC1895 UCC2895 UCC3895 qu36_lua560.gif

Calculate QA losses (PQA) based on Rds(on)QA and gate charge (QAg):

Equation 43. UCC1895 UCC2895 UCC3895 qu59_lusa16.gif

Recalculate power budget:

Equation 44. UCC1895 UCC2895 UCC3895 eq_45_slus157.gif