JAJSH61A April   2019  – September 2019 UC1843B-SP

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略回路図
  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 Diagram
    3. 7.3 Feature Description
      1. 7.3.1 UVLO
      2. 7.3.2 Reference
      3. 7.3.3 Totem-Pole Output
    4. 7.4 Device Functional Modes
  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 Switching Frequency
        2. 8.2.2.2 Transformer
        3. 8.2.2.3 RCD Diode Clamp
        4. 8.2.2.4 Output Diode
        5. 8.2.2.5 Output Filter and Capacitor
        6. 8.2.2.6 Compensation
        7. 8.2.2.7 Sense Resistor and Slope Compensation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Feedback Traces
      2. 10.1.2 Input/Output Capacitors
      3. 10.1.3 Compensation Components
      4. 10.1.4 Traces and Ground Planes
    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 ドキュメントの更新通知を受け取る方法
    2. 11.2 コミュニティ・リソース
    3. 11.3 商標
    4. 11.4 静電気放電に関する注意事項
    5. 11.5 Glossary
  12. 12メカニカル、パッケージ、および注文情報

8.2.2.6 Compensation

The poles and zeros of a flyback converter can be found with the following equations:

Equation 36. f Z E S R = 1 + D 2 π × C o u t × R E S R
Equation 37. f Z E S R = 1 +0 .5 2 π ×1146   μ F ×0 .009   Ω =23 .15   k H z
Equation 38. f P = 1 2 π × C o u t × R o
Equation 39. f P = 1 2 π ×1146   μ F ×0 .5 =278   H z
Equation 40. f R H P Z = R o u t × (1 - D M A X )2 2 π × L P R I N p s 2 × D M A X
Equation 41. f R H P Z = 0 .5 × (1 -0 .5 )2 2 π × 21   μ H 3 .332 ×0 .5 =21   k H z
Equation 42. f C o m p e n s a t i o n   Z e r o = 1 2 π × R C O M P × C C O M P = 1 2 π ×5 .11   k Ω ×0 .22   μ F =142   H z
Equation 43. f C o m p e n s a t i o n   P o l e = 1 2 π × R C O M P × C H F = 1 2 π ×5 .11   k Ω ×1500   p F =20 .76   k H z

Type IIB compensation was selected to compensate the poles and zeros of the flyback converter for the design. Since the right half plane zero (RHPZ) of the flyback converter is unable to be compensated, the crossover frequency of the converter should be between one fourth to a whole decade below the RHPZ of the converter. Type IIB compensation has 1 pole and 1 zero to help compensate the converter. The pole from the compensation is suggested to be placed by the RHPZ of the converter and the zero from compensation is suggested to be placed a decade before the expected crossover frequency. Using these guidelines the compensation values for the converter were picked for the converter. For the non-isolated portion of the board this means choosing the value of the compensation resistors and capacitors along these guidelines. Increasing or decreasing the gain of the design can be compensated for by dividing the resistor from compensation down and increasing the values of the capacitors by the same amount. This allows for the gain to be controlled in the system without changing the poles and zeros of the system. Optimization is needed for compensation values, and those values can be validated through testing.