JAJSH44C April   2011  – March  2019 UCD90120A

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    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 I2C/SMBus/PMBus 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 TI Fusion GUI
      2. 7.3.2 PMBus Interface
      3. 7.3.3 Rail Configuration
    4. 7.4 Device Functional Modes
      1. 7.4.1  Power-Supply Sequencing
        1. 7.4.1.1 Turn-On Sequencing
        2. 7.4.1.2 Turn-Off Sequencing
        3. 7.4.1.3 Sequencing Configuration Options
      2. 7.4.2  Pin-Selected Rail States
      3. 7.4.3  Monitoring
        1. 7.4.3.1 Voltage Monitoring
        2. 7.4.3.2 Current Monitoring
        3. 7.4.3.3 Remote Temperature Monitoring and Internal Temperature Sensor
        4. 7.4.3.4 Temperature by Host Input
      4. 7.4.4  Fault Responses and Alert Processing
      5. 7.4.5  Shut Down All Rails and Sequence On (Resequence)
      6. 7.4.6  GPIOs
      7. 7.4.7  GPO Control
      8. 7.4.8  GPO Dependencies
      9. 7.4.9  GPO Delays
      10. 7.4.10 State Machine Mode Enable
      11. 7.4.11 GPI Special Functions
      12. 7.4.12 Power-Supply Enables
      13. 7.4.13 Cascading Multiple Devices
      14. 7.4.14 PWM Outputs
        1. 7.4.14.1 FPWM1-8
        2. 7.4.14.2 PWM1-4
      15. 7.4.15 Programmable Multiphase PWMs
      16. 7.4.16 Margining
        1. 7.4.16.1 Open-Loop Margining
        2. 7.4.16.2 Closed-Loop Margining
      17. 7.4.17 System Reset Signal
      18. 7.4.18 Watch Dog Timer
      19. 7.4.19 Run Time Clock
      20. 7.4.20 Data and Error Logging to Flash Memory
      21. 7.4.21 Brownout Function
      22. 7.4.22 PMBus Address Selection
    5. 7.5 Programming
      1. 7.5.1 Device Configuration and Programming
        1. 7.5.1.1 Full Configuration Update While in Normal Mode
      2. 7.5.2 JTAG Interface
      3. 7.5.3 Internal Fault Management and Memory Error Correction (ECC)
  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 Estimating ADC Reporting Accuracy
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    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 ドキュメントのサポート
      1. 11.1.1 関連資料
    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

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

7.4.18 Watch Dog Timer

A GPI and GPO can be configured as a watchdog timer (WDT). The WDT can be independent of power-supply sequencing or tied to a GPIO functioning as a watchdog output (WDO) that is configured to provide a system-reset signal. The WDT can be reset by toggling a watchdog input (WDI) pin or by writing to SYSTEM_WATCHDOG_RESET over I2C. The WDI and WDO pins are optional when using the watchdog timer. The WDI can be replaced by SYSTEM_WATCHDOG_RESET command and the WDO can be manifested through the Boolean Logic defined GPOs or through the System Reset function.

The WDT can be active immediately at power up or set to wait while the system initializes. Table 7 lists the programmable wait times before the initial timeout sequence begins.

Table 7. WDT Initial Wait Time

WDT INITIAL WAIT TIME
0 ms
100 ms
200 ms
400 ms
800 ms
1.6 s
3.2 s
6.4 s
12.8 s
25.6 s
51.2 s
102 s
205 s
410 s
819 s
1638 s

The watchdog timeout is programmable from 0.001s to 32.256s. See the UCD90xxx Sequencer and System Health Controller PMBus Command Reference for details on configuring the watchdog timeout. If the WDT times out, the UCD90120A can assert a GPIO pin configured as WDO that is separate from a GPIO defined as system-reset pin, or it can generate a system-reset pulse. After a timeout, the WDT is restarted by toggling the WDI pin or by writing to SYSTEM_WATCHDOG_RESET over I2C.

UCD90120A watchdog_t_lvs966.gifFigure 27. Timing of GPIOs Configured for Watchdog Timer Operation