ZHCSKZ6A March   2020  – August 2020 LM25184

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  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  Integrated Power MOSFET
      2. 7.3.2  PSR Flyback Modes of Operation
      3. 7.3.3  Setting the Output Voltage
        1. 7.3.3.1 Diode Thermal Compensation
      4. 7.3.4  Control Loop Error Amplifier
      5. 7.3.5  Precision Enable
      6. 7.3.6  Configurable Soft Start
      7. 7.3.7  External Bias Supply
      8. 7.3.8  Minimum On-Time and Off-Time
      9. 7.3.9  Overcurrent Protection
      10. 7.3.10 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design 1: Wide VIN, Low IQ PSR Flyback Converter Rated at 12 V, 1 A
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2  Custom Design With Excel Quickstart Tool
          3. 8.2.1.2.3  Flyback Transformer – T1
          4. 8.2.1.2.4  Flyback Diode – DFLY
          5. 8.2.1.2.5  Leakgae Inductance Clamp Circuit – DF, DCLAMP
          6. 8.2.1.2.6  Output Capacitor – COUT
          7. 8.2.1.2.7  Input Capacitor – CIN
          8. 8.2.1.2.8  Feedback Resistor – RFB
          9. 8.2.1.2.9  Thermal Compensation Resistor – RTC
          10. 8.2.1.2.10 UVLO Resistors – RUV1, RUV2
          11. 8.2.1.2.11 Soft-Start Capacitor – CSS
      2. 8.2.2 Application Curves
      3. 8.2.3 Design 2: PSR Flyback Converter With Dual Outputs of 15 V and –8 V at 0.5 A
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
          1. 8.2.3.2.1 Flyback Transformer – T1
          2. 8.2.3.2.2 Flyback Diodes – DFLY1 and DFLY2
          3. 8.2.3.2.3 Input Capacitor – CIN
          4. 8.2.3.2.4 Output Capacitors – COUT1, COUT2
          5. 8.2.3.2.5 Feedback Resistor – RFB
          6. 8.2.3.2.6 Thermal Compensation Resistor – RTC
          7. 8.2.3.2.7 Output Voltage Clamp Zeners – DOUT1 and DOUT2
        3. 8.2.3.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 第三方产品免责声明
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 接收文档更新通知
    4. 11.4 支持资源
    5. 11.5 Trademarks
    6. 11.6 静电放电警告
    7. 11.7 术语表
  12. 12Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)

8.2.3.1 Design Requirements

The required input, output, and performance parameters for this application example are shown in Table 8-4.

Table 8-4 Design Parameters
DESIGN PARAMETER VALUE
Input voltage range (steady state) 4.5 V to 42 V
Output 1 voltage and current (at VIN ≥ 24 V) 15 V, 0.5 A
Output 2 voltage and current (at VIN ≥ 24 V) –8 V, 0.5 A
Input UVLO thresholds 4.5 V on, 4 V off
Output voltage regulation ±2%

The target full-load efficiency of this LM25184 design is 89% based on a nominal input voltage of 24 V and isolated output voltages of 15 V and –8 V sharing a common return. The selected flyback converter components are cited in Table 8-5, including the following:

  • A multi-winding flyback transformer
  • Input and output capacitors
  • Flyback rectifying diodes
  • A flyback converter IC
Table 8-5 List of Components for Design 2
REF DES QTY SPECIFICATION VENDOR PART NUMBER
CIN 1 10 µF, 50 V, X7R, 1210, ceramic TDK C3225X7R1H106M250AC
Taiyo Yuden UMK325AB7106KM-T
COUT1 2 22 µF, 25 V, X7R, 1210, ceramic TDK C3225X7R1E226M250AB
Taiyo Yuden TMK325B7226MM-PR
COUT2 2 47 μF, 16 V, X7S, 1210, Ceramic Murata GRM32EC81C476KE15L
Taiyo Yuden EMK325AC6476MM-P
47 μF, 16 V, X7R, 1210, Ceramic Murata GRM32ER71A476KE15L
Taiyo Yuden LMK325B7476MM-TR
Kemet C1210C476K8RAC7800
DCLAMP 1 Zener, 20 V, 3 W, SMA 3SMAJ5932B Micro Commercial
DF, DFLY2 1 Schottky diode, 60 V, 3 A, SOD-123FL FSV360FP OnSemi
DFLY1 2 Schottky diode, 100 V, 1 A, POWERDI123 DFLS1100-7 Diodes Inc.
DOUT1 1 Zener, 18 V, 5%, SOD-523 BZX585-C18 Nexperia
DOUT2 1 Zener, 9.1 V, 5%, SOD-523 BZX585-C9V1 Nexperia
RFB 1 102 kΩ, 1%, 0402 Std Std
RSET 1 12.1 kΩ, 1%, 0402 Std Std
RTC 1 221 kΩ, 1%, 0402 Std Std
T1 1 7 μH, 5 A, 1 : 1.5 : 0.8, 9.2 mm × 9.8 mm × 9.8 mm Würth Electronik 750318704
7 μH, 5 A, 1 : 1.5 : 0.8, 13 mm × 11 mm × 10 mm Coilcraft ZA9675-BE
U1 1 PSR flyback converter, VSON-8 Texas Instruments LM25184NGUR