JAJSSS6B January   2024  – June 2024 TPS7H3014-SP

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Device Options
  6. 5 Pin Configuration and Functions
  7. 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 Quality Conformance Inspection
    8. 6.8 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input Voltage (IN), VLDO and REFCAP
        1. 8.3.1.1 Undervoltage Lockout (VPOR_IN < VIN < UVLO)
        2. 8.3.1.2 Power-On Reset (VIN < VPOR_IN )
      2. 8.3.2 SENSEx Inputs
        1. 8.3.2.1 VTH_SENSEX and VONx
        2. 8.3.2.2 IHYS_SENSEx and VOFFx
        3. 8.3.2.3 Top and Bottom Resistive Divider Design Equations
      3. 8.3.3 Output Stages (ENx,SEQ_DONE,PWRGD,PULL_UP1 and PULL_UP2)
      4. 8.3.4 User-Programmable TIMERS
        1. 8.3.4.1 DLY_TMR
        2. 8.3.4.2 REG_TMR
      5. 8.3.5 UP and DOWN
      6. 8.3.6 FAULT
      7. 8.3.7 State Machine
    4. 8.4 Daisy Chain
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Self Contained – Sequence UP and DOWN
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Input Power Supplies and Decoupling Capacitors
          2. 9.2.1.2.2 UP and DOWN Thresholds
          3. 9.2.1.2.3 SENSEx Thresholds
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Sequencing of Negative Voltage Rails
        1. 9.2.2.1 Negative Voltage Design Equations
    3. 9.3 Externally Induced System RESET
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

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

9.2.2 Sequencing of Negative Voltage Rails

It is possible to sequence negative voltage rails using the TPS7H3014 with the support of some external circuitry such as:

  1. Stable positive voltage reference.
  2. Comparator with hysteresis.

Figure 9-14, shows the typical connections to sense a negative voltage rail. When –VOUTx is at zero volts (initial state), the voltage at the inverting input of the external comparator is given by Equation 35. The resistive divider is selected such that the initial voltage at the non-inverting input of the comparator is greater than the reference voltage by a desired factor. This factor depends on the desired threshold at which the negative voltage must be considered to be in regulation.

When the negative voltage rail (–VOUTx) is turned-on the voltage at the non-inverting inputs starts decrementing until –VOUTx reaches steady-state. When the voltage at the non-inverting input is lower than the reference voltage the output of the comparators is forced high (the high value is determined by the positive bias of the comparator, V+).

As the TPS7H3014 implements the hysteresis via a current, when the output of the external comparator is high, a typical 24μA (IHYS_SESNSEx) are sunk into the output of the comparator. The selected comparator needs to be able to withstand this current sinking while maintaining a constant output.

Rx, Ry and Rh resistors attenuate the V+ voltage to provide the thresholds that ultimately determines when the –VOUTx is considered to in or out of regulation. For more details refer to TIDU020 and Section 9.2.2.1.

Equation 35. V I N V E R T I N G _ I N P U T   ( V ) = R T O P ( Ω ) R T O P   ( Ω ) + R B O T T O M ( Ω ) ×   V O F F S E T ( V )
TPS7H3014-SP Sensing Negative Rails Using External Circuitry Figure 9-14 Sensing Negative Rails Using External Circuitry
Note:
  • When using external components to sense negative voltage rail the rising and falling threshold accuracy are dependent upon the external circuitry selected.
  • The high voltage of the comparator most be below VTURN_OFF, otherwise the channel is internally disabled. An resistive divider can be used to attenuate the output of the comparator if needed.