ZHCSHC3B january   2018  – june 2023 TPS61280D , TPS61280E , TPS61281D

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 说明（续）
  7. 6 Device Comparison Table
  8. 7 Pin Configuration and Functions
  9. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 I2C Interface Timing Characteristics #GUID-BD85FD7C-B9AF-4F5D-9DFF-CD61365A592A/SLVS5401494
    7. 8.7 I2C Timing Diagrams
    8. 8.8 Typical Characteristics
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Voltage Scaling Management (VSEL)
      2. 9.3.2 Spread Spectrum, PWM Frequency Dithering
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Save Mode
      2. 9.4.2 Pass-Through Mode
      3. 9.4.3 Mode Selection
      4. 9.4.4 Current Limit Operation
      5. 9.4.5 Start-Up and Shutdown Mode
      6. 9.4.6 Undervoltage Lockout
      7. 9.4.7 Thermal Shutdown
      8. 9.4.8 Fault State and Power-Good
    5. 9.5 Programming
      1. 9.5.1 Serial Interface Description (TPS61280D/E)
      2. 9.5.2 Standard-, Fast-, Fast-Mode Plus Protocol
      3. 9.5.3 HS-Mode Protocol
      4. 9.5.4 TPS6128xD/E I2C Update Sequence
    6. 9.6 Register Maps
      1. 9.6.1  Slave Address Byte
      2. 9.6.2  Register Address Byte
      3. 9.6.3  I2C Registers, E2PROM, Write Protect
      4. 9.6.4  E2PROM Configuration Parameters
      5. 9.6.5  CONFIG Register [reset = 0x01]
      6. 9.6.6  VOUTFLOORSET Register [reset = 0x02]
      7. 9.6.7  VOUTROOFSET Register [reset = 0x03]
      8. 9.6.8  ILIMSET Register [reset = 0x04]
      9. 9.6.9  Status Register [reset = 0x05]
      10. 9.6.10 E2PROMCTRL Register [reset = 0xFF]
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 TPS61281D with 2.5V-4.35 VIN, 1500 mA Output Current (TPS61280D with default I2C Configuration)
        1. 10.2.1.1 Design Requirement
        2. 10.2.1.2 Detailed Design Parameters
          1. 10.2.1.2.1 Inductor Selection
          2. 10.2.1.2.2 Output Capacitor
          3. 10.2.1.2.3 Input Capacitor
          4. 10.2.1.2.4 Checking Loop Stability
        3. 10.2.1.3 Application Performance Curves
      2. 10.2.2 TPS61282D with 2.5V-4.35 VIN, 2000 mA Output Current (TPS61280D with I2C Programmable)
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedures
        3. 10.2.2.3 Application Performance Curves
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Information
  14. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 第三方产品免责声明
    2. 13.2 接收文档更新通知
    3. 13.3 支持资源
    4. 13.4 Trademarks
    5. 13.5 静电放电警告
    6. 13.6 术语表
  15. 14Mechanical, Packaging, and Orderable Information
    1. 14.1 Package Summary

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9.4.5 Start-Up and Shutdown Mode

The TPS6128xD/E automatically powers-up as soon as the input voltage is applied. The device has an internal soft-start circuit that limits the inrush current during start-up. The first phase in the start-up procedure is to bias the output node close to the input level (so called pre-charge phase).

In this operating mode, the device limits its output current to ca. 500mA. Should the output voltage not have reached the input level within a maximum duration of 750µs, the device automatically increases its pre-charge current to ca. 2000mA. If the output voltage still fails to reach its target after 1.5ms, a fault condition is declared. After waiting 1ms, a restart is attempted.

When output voltage being close to Vout, the device enters into boost startup mode (for Auto Mode only). The device provides a reduced current limit of ~1.25A (I2C programable for TPS61280D to set it back to normal current limit) when the output voltage is below pre-set voltage to avoid the high inrush current from battery.

During start-up, it is recommended to keep DC load current draw below 250mA.

The TPS6128xD/E device contains a thermal regulation loop that monitors the die temperature during the pre-charge phase. If the die temperature rises to high values of about 110°C, the device automatically reduces the current to prevent the die temperature from increasing further. Once the die temperature drops about 10°C below the threshold, the device will automatically increase the current to the target value. This function also reduces the current during a short-circuit condition.

When the EN and nBYP pins are set high, the device enters normal operation (that is, automatic dc/dc boost, pass-through mode) and ensures that the output voltage remains above a pre-defined threshold (that is, 3.3 V).

Setting the EN pin low (nBYP = 1) forces the TPS6128xD/E device in shutdown mode with a current consumption of <8.5 µA typical. In this mode, the output of the converter is regulated to a minimum level so as to limit the input-to-output voltage difference to less than 3.6 V (typical). The device is capable of sinking up to 10 mA output current and prohibits reverse current flow from the output to the input. For proper operation, the EN pin must be terminated and must not be left floating.

Changing operating mode from auto mode (EN = nBYP = 1) to low IQ Pass-through mode (EN = nBYP = 0) with device pins EN and nBYP can either be done controlling EN and nBYP pins from same control signal (delay between signal < 60ns) or first switching in forced pass-through mode (EN = 1, nBYP = 0) followed by switching to low IQ Pass-through mode (EN = nBYP = 0).

The TPS6128xD/E device also features the possibility of shutting the converter output for a short period of time, either via the nRST/nFAULT (GPIO). Pulling this input low initiates a reset of the converter's output. The sequence is falling edge-triggered and consists of a discharge phase (down to ca. 600 mV or lower) of the capacitance located at the converter's output followed by a start-up phase.

Table 9-2 Mode of Operation
EN InputnBYP InputDevice State
00The device is shut down in pass-through mode featuring a shutdown current down to ca. 3µA typ.
The load current capability is limited (up to ca. 250mA).
01The device is shut down and the output voltage is reduced to a minimum value (VIN - VOUT ≤ 3.6V).
The device shutdown current is approximately 8.5µA typ.
10The device is active in forced pass-through mode.
The device supply current is approximately 15µA typ. from the battery. The device is short circuit protected by a current limit of ca.7300mA.
11The device is active in auto mode (dc/dc boost, pass-through).
The device supply current is approximately 50µA typ. from the battery.