ZHCSL42 April   2020 TPS92612

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     典型应用图
  4. 4 修订历史记录
  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 Timing Requirements
    7. 6.7 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 Device Bias
        1. 7.3.1.1 Power-On Reset (POR)
      2. 7.3.2 Constant-Current Driver
      3. 7.3.3 PWM Control
      4. 7.3.4 Protection
        1. 7.3.4.1 Short-to-GND Protection
        2. 7.3.4.2 Over Temperature Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Undervoltage Lockout, V(SUPPLY)< V(POR_rising)
      2. 7.4.2 Normal State, V(SUPPLY) ≥ 4.5 V
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Single LED Driver
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Single-Channel LED Driver With Heat Sharing
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11器件和文档支持
    1. 11.1 接收文档更新通知
    2. 11.2 支持资源
    3. 11.3 商标
    4. 11.4 静电放电警告
    5. 11.5 Glossary
  12. 12机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.1.2 Detailed Design Procedure

STEP 1: Determine the current setting resistor, R(SNS) value by using Equation 2.

Equation 2. TPS92612 tps92612-eq-2.gif

where

  • V(CS_REG) = 98 mV (typical)
  • I(LED) = 150 mA

STEP 2: Power consumption analysis for the worst application conditions.

Normally the thermal analysis is necessary for linear LED-driver applications to ensure that the operation junction temperature of TPS92612 is well managed. The total power consumption on the TPS92612 itself is one important factor determining operation junction temperature, and it can be calculated by using Equation 3. Based on the worst-case analysis for maximum power consumption on device, consider either optimizing PCB layout for better power dissipation as Layout describes or adding an extra heat-sharing resistor as described in Single-Channel LED Driver With Heat Sharing.

Equation 3. TPS92612 tps92612-eq-3.gif

where

  • V(CS_REG) = 98 mV (typical)
  • I(Quiescent) = 250 µA (maximum)

In this application, the calculated result for maximum power consumption on the TPS92612 is 0.489 W at V(SUPPLY) = 5.25 V and I(LED) = 150 mA conditions.

TI recommends to add capacitors C(SUPPLY) at SUPPLY and C(OUT) at OUT. TI recommends one 1-μF capacitor plus one 100-nF decoupling ceramic capacitor close to the SUPPLY pin for C(SUPPLY) and a 10-nF ceramic capacitor close to the OUT pin for C(OUT). The larger capacitor for C(SUPPLY) or C(OUT) is helpful for EMI and ESD immunity; however, large C(OUT) takes a longer time to charge up the capacitor and may affect PWM dimming performance.