ZHCSDX1B June   2015  – September 2018 TPL5111

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化应用电路原理图
  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 Ratings
    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 DRVn
      2. 7.3.2 DONE
    4. 7.4 Device Functional Modes
      1. 7.4.1 Start-Up
      2. 7.4.2 Timer Mode
      3. 7.4.3 One-Shot Mode
    5. 7.5 Programming
      1. 7.5.1 Configuring the Time Interval With the DELAY/M_DRV Pin
      2. 7.5.2 Manual Power ON Applied to the DELAY/M_DRV Pin
        1. 7.5.2.1 DELAY/M_DRV
        2. 7.5.2.2 Circuitry
      3. 7.5.3 Selection of the External Resistance
      4. 7.5.4 Quantization Error
      5. 7.5.5 Error Due to Real External Resistance
  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
      3. 8.2.3 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 社区资源
    3. 11.3 商标
    4. 11.4 静电放电警告
    5. 11.5 术语表
  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

7.5.5 Error Due to Real External Resistance

REXT is a theoretical value and may not be available in standard commercial resistor values. It is possible to closely approach the theoretical REXT using two or more standard values in parallel. However, standard values are characterized by a certain tolerance. This tolerance will affect the accuracy of the time interval.

The accuracy can be evaluated using the following procedure:

  1. Evaluate the min and max values of REXT (REXT_MIN, REXT_MAX with Equation 1 using the selected commercial resistance values and their tolerances.
  2. Evaluate the time intervals (TADC_MIN[REXT_MIN], TADC_MAX[REXT_MAX]) with the TADC equation mentioned in Equation 3.
  3. Find the errors using Equation 3 with TADC_MIN, TADC_MAX.
The results of the formula indicate the accuracy of the time interval.

The example below illustrates the procedure.

  • Desired time interval, T_desired = 600 s,
  • Required REXT from Equation 1, REXT= 57.44 kΩ.

From Table 3 REXT can be built with a parallel combination of two commercial values with 1% tolerance: R1 = 107 kΩ, R2 = 124 kΩ. The uncertainty of the equivalent parallel resistance can be found using Equation 4:

Equation 4. TPL5111 uRp.gif

where

  • uRn (n=1,2) represent the uncertainty of a resistance (see Equation 5)

SPACER

Equation 5. TPL5111 uR.gif

The uncertainty of the parallel resistance is 0.82%, which means the value of REXT may range between REXT_MIN = 56.96 kΩ and REXT_MAX = 57.90 kΩ.

Using these value of REXT, the digitized timer intervals calculated by TADC equation mentioned in Equation 3 are respectively TADC_MIN = 586.85 s and TADC_MAX = 611.3 s, giving an error range of –1.88% / +2.19%. The asymmetry of the error range is due to the quadratic transfer function of the resistance digitizer.