JAJSM11 may   2021 BQ25720

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Description (continued)
  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 Timing Requirements
    7. 8.7 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  Power-Up Sequence
      2. 9.3.2  Vmin Active Protection (VAP) with Battery only
      3. 9.3.3  Two-Level Battery Discharge Current Limit
      4. 9.3.4  Fast Role Swap Feature
      5. 9.3.5  CHRG_OK Indicator
      6. 9.3.6  Input and Charge Current Sensing
      7. 9.3.7  Input Voltage and Current Limit Setup
      8. 9.3.8  Battery Cell Configuration
      9. 9.3.9  Device HIZ State
      10. 9.3.10 USB On-The-Go (OTG)
      11. 9.3.11 Converter Operation
      12. 9.3.12 Inductance Detection Through IADPT Pin
      13. 9.3.13 Converter Compensation
      14. 9.3.14 Continuous Conduction Mode (CCM)
      15. 9.3.15 Pulse Frequency Modulation (PFM)
      16. 9.3.16 Switching Frequency and Dithering Feature
      17. 9.3.17 Current and Power Monitor
        1. 9.3.17.1 High-Accuracy Current Sense Amplifier (IADPT and IBAT)
        2. 9.3.17.2 High-Accuracy Power Sense Amplifier (PSYS)
      18. 9.3.18 Input Source Dynamic Power Management
      19. 9.3.19 Input Current Optimizer (ICO)
      20. 9.3.20 Two-Level Adapter Current Limit (Peak Power Mode)
      21. 9.3.21 Processor Hot Indication
        1. 9.3.21.1 PROCHOT During Low Power Mode
        2. 9.3.21.2 PROCHOT Status
      22. 9.3.22 Device Protection
        1. 9.3.22.1 Watchdog Timer
        2. 9.3.22.2 Input Overvoltage Protection (ACOV)
        3. 9.3.22.3 Input Overcurrent Protection (ACOC)
        4. 9.3.22.4 System Overvoltage Protection (SYSOVP)
        5. 9.3.22.5 Battery Overvoltage Protection (BATOVP)
        6. 9.3.22.6 Battery Discharge Overcurrent Protection (BATOC)
        7. 9.3.22.7 Battery Short Protection (BATSP)
        8. 9.3.22.8 System Undervoltage Lockout (VSYS_UVP) and Hiccup Mode
        9. 9.3.22.9 Thermal Shutdown (TSHUT)
    4. 9.4 Device Functional Modes
      1. 9.4.1 Forward Mode
        1. 9.4.1.1 System Voltage Regulation with Narrow VDC Architecture
        2. 9.4.1.2 Battery Charging
      2. 9.4.2 USB On-The-Go
      3. 9.4.3 Pass Through Mode (PTM)-Patented Technology
    5. 9.5 Programming
      1. 9.5.1 SMBus Interface
        1. 9.5.1.1 SMBus Write-Word and Read-Word Protocols
        2. 9.5.1.2 Timing Diagrams
    6. 9.6 Register Map
      1. 9.6.1  ChargeOption0 Register (SMBus address = 12h) [reset = E70Eh]
      2. 9.6.2  ChargeCurrent Register (SMBus address = 14h) [reset = 0000h]
        1. 9.6.2.1 Battery Pre-Charge Current Clamp
      3. 9.6.3  ChargeVoltage Register (SMBus address = 15h) [reset value based on CELL_BATPRESZ pin setting]
      4. 9.6.4  ChargerStatus Register (SMBus address = 20h) [reset = 0000h]
      5. 9.6.5  ProchotStatus Register (SMBus address = 21h) [reset = B800h]
      6. 9.6.6  IIN_DPM Register With 10-mΩ Sense Resistor (SMBus address = 22h) [reset = 4100h]
      7. 9.6.7  ADCVBUS/PSYS Register (SMBus address = 23h)
      8. 9.6.8  ADCIBAT Register (SMBus address = 24h)
      9. 9.6.9  ADCIINCMPIN Register (SMBus address = 25h)
      10. 9.6.10 ADCVSYSVBAT Register (SMBus address = 26h)
      11. 9.6.11 ChargeOption1 Register (SMBus address = 30h) [reset = 3300h]
      12. 9.6.12 ChargeOption2 Register (SMBus address = 31h) [reset = 00B7]
      13. 9.6.13 ChargeOption3 Register (SMBus address = 32h) [reset = 0434h]
      14. 9.6.14 ProchotOption0 Register (SMBus address = 33h) [reset = 4A81h(2S~) 4A09(1S)]
      15. 9.6.15 ProchotOption1 Register (SMBus address = 34h) [reset = 41A0h]
      16. 9.6.16 ADCOption Register (SMBus address = 35h) [reset = 2000h]
      17. 9.6.17 ChargeOption4 Register (SMBus address = 36h) [reset = 0048h]
      18. 9.6.18 Vmin Active Protection Register (SMBus address = 37h) [reset = 006Ch(2s~4s)/0004h(1s)]
      19. 9.6.19 OTGVoltage Register (SMBus address = 3Bh) [reset = 09C4h]
      20. 9.6.20 OTGCurrent Register (SMBus address = 3Ch) [reset = 3C00h]
      21. 9.6.21 InputVoltage (VINDPM) Register (SMBus address = 3Dh) [reset = VBUS-1.28V]
      22. 9.6.22 VSYS_MIN Register (SMBus address = 3Eh) [reset value based on CELL_BATPRESZ pin setting]
      23. 9.6.23 IIN_HOST Register (SMBus address = 3Fh) [reset = 4100h]
      24. 9.6.24 ID Registers
        1. 9.6.24.1 ManufactureID Register (SMBus address = FEh) [reset = 0040h]
        2. 9.6.24.2 Device ID (DeviceAddress) Register (SMBus address = FFh) [reset = 00E1h]
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 ACP-ACN Input Filter
        2. 10.2.2.2 Inductor Selection
        3. 10.2.2.3 Input Capacitor
        4. 10.2.2.4 Output Capacitor
        5. 10.2.2.5 Power MOSFETs Selection
      3. 10.2.3 Application Curves
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
      1. 12.2.1 Layout Example Reference Top View
      2. 12.2.2 Inner Layer Layout and Routing Example
  14. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 サード・パーティ製品に関する免責事項
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 ドキュメントの更新通知を受け取る方法
    4. 13.4 サポート・リソース
    5. 13.5 Trademarks
    6. 13.6 静電気放電に関する注意事項
    7. 13.7 用語集
  15. 14Mechanical, Packaging, and Orderable Information

9.1 Overview

The BQ25720 is a narrow VDC buck-boost charger controller for portable electronics such as notebook, detachable, ultrabook, tablet, and other mobile devices with rechargeable batteries. It provides seamless transition between different converter operation modes (buck, boost, or buck-boost), fast transient response, and high light load efficiency.

The BQ25720 supports a wide range of power sources, including USB-C PD ports, legacy USB ports, traditional AC-DC adapters, and so forth. It takes input voltage from 3.5 V to 26 V and charges a battery of 1 to in series. In the absence of an input source, the BQ25720 supports the USB On-the-Go (OTG) function from a cell battery to generate an adjustable 3 V to 24 V at the USB port with 8-mV resolution.

When only the battery powers the system and no external load is connected to the USB OTG port, the BQ25720 provides the Vmin Active Protection (VAP) feature. In VAP operation, the BQ25720 first charges up the voltage of the input decoupling capacitors at VBUS to store a certain amount of energy. During the system peak power spike, the huge current drawn from the battery introduces a larger voltage drop across the impedance from the battery to the system. The energy stored in the input capacitors will supplement the system, to prevent the system voltage from dropping below the minimum system voltage and leading the system to a black screen. This VAP is designed to absorb system power peaks during the periods of high demand to improve system turbo performance, which is highly recommended by Intel for the platforms with a 1S~2S battery.

The BQ25720 features Dynamic Power Management (DPM) to limit input power and avoid AC adapter overloading. During battery charging, as system power increases, charging current is reduced to maintain total input current below adapter rating. If system power demand temporarily exceeds adapter rating, the BQ25720 supports the NVDC architecture to allow battery discharge energy to supplement system power.

The BQ25720 monitors adapter current, battery current, and system power. The flexibility of the programmable PROCHOT output goes directly to the CPU for throttling back when needed.

The latest version of the USB-C PD specification includes Fast Role Swap (FRS) to ensure power role swapping occurs in a timely fashion so that the device(s) connected to the dock never experience momentary power loss or glitching. The device integrates FRS with compliance to the USB-C PD specification.

The TI patented switching frequency dithering pattern can significantly reduce EMI noise over the entire conductive EMI frequency range (150 kHz to 30 MHz). Multiple dithering scale options are available to provide flexibility for different applications to simplify EMI noise filter design.

In order to be compliant with Intel IMVP8 / IMVP9, the BQ25720 includes a PSYS function to monitor the total platform power from the adapter and battery. Besides PSYS, it provides both an independent input current buffer (IADPT) and a battery current buffer (IBAT) with highly accurate current sense amplifiers. If the platform power exceeds the available power from the adapter and battery, a PROCHOT signal is asserted to the CPU so that the CPU optimizes its performance to the power available to the system.

The SMBus host controls input current, charge current, and charge voltage registers with high resolution, high accuracy regulation limits. It also sets the PROCHOT timing and threshold profile to meet system requirements.