JAJS843E April   1998  – June 2019 LM2588

PRODUCTION DATA.  

  1. 1 特長
  2. 2 代表的なアプリケーション
  3. 3 概要
    1.     Device Images
      1.      フライバック・レギュレータ
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configurations
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Ratings
    4. 7.4 Electrical Characteristics: 3.3 V
    5. 7.5 Electrical Characteristics: 5 V
    6. 7.6 Electrical Characteristics: 12 V
    7. 7.7 Electrical Characteristics: Adjustable
    8. 7.8 Electrical Characteristics: All Output Voltage Versions
    9. 7.9 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Flyback Regulator Operation
      2. 8.3.2 Step-Up (Boost) Regulator Operation
      3. 8.3.3 Shutdown Control
      4. 8.3.4 Frequency Adjustment
      5. 8.3.5 Frequency Synchronization
      6. 8.3.6 Programming Output Voltage (Selecting R1 And R2)
      7. 8.3.7 Short-Circuit Condition
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Flyback Regulator Applications
        1. 9.2.1.1 Design Requirements
          1. 9.2.1.1.1 Transformer Selection (T)
          2. 9.2.1.1.2 Transformer Footprints
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.2.2 Flyback Regulator Input Capacitors
          3. 9.2.1.2.3 Switch Voltage Limits
          4. 9.2.1.2.4 Output Voltage Limitations
          5. 9.2.1.2.5 Noisy Input Line Condition
          6. 9.2.1.2.6 Stability
      2. 9.2.2 Typical Boost Regulator Applications
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
    3. 9.3 System Examples
      1. 9.3.1 Test Circuits
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Heat Sink/Thermal Considerations
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 デバイス・サポート
      1. 11.1.1 デベロッパー・ネットワークの製品に関する免責事項
      2. 11.1.2 開発サポート
        1. 11.1.2.1 WEBENCH®ツールによるカスタム設計
    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

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8.3.2 Step-Up (Boost) Regulator Operation

Figure 17 shows the LM2588 used as a step-up (boost) regulator. This is a switching regulator that produces an output voltage greater than the input supply voltage.

A brief explanation of how the LM2588 boost regulator works is as follows (refer to Figure 17). When the NPN switch turns on, the inductor current ramps up at the rate of VIN/L, storing energy in the inductor. When the switch turns off, the lower end of the inductor flies above VIN, discharging its current through diode (D) into the output capacitor (COUT) at a rate of (VOUT − VIN)/L. Thus, energy stored in the inductor during the switch on-time is transferred to the output during the switch off time. The output voltage is controlled by adjusting the peak switch current, as described in the section.

LM2588 01242049.pngFigure 17. 12-V Boost Regulator

By adding a small number of external components (as shown in Figure 17), the LM2588 can be used to produce a regulated output voltage that is greater than the applied input voltage. The switching waveforms observed during the operation of this circuit are shown in . Typical performance of this regulator is shown in .

LM2588 01242060.png
A: Switch Voltage, 10V/div

B: Switch Current, 5A/div

C: Output Rectifier Current, 5A/div

D: Output Ripple Voltage, 100 mV/div

AC-Coupled
Figure 18. Switching Waveforms
LM2588 01242061.png
Figure 19. VOUT Response To Load Current Step