ZHCSN83A june   2020  – january 2021 BQ25731

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  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(BQ25731)
    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  Two-Level Battery Discharge Current Limit
      3. 9.3.3  Fast Role Swap Feature
      4. 9.3.4  CHRG_OK Indicator
      5. 9.3.5  Input and Charge Current Sensing
      6. 9.3.6  Input Voltage and Current Limit Setup
      7. 9.3.7  Battery Cell Configuration
      8. 9.3.8  Device HIZ State
      9. 9.3.9  USB On-The-Go (OTG)
      10. 9.3.10 Converter Operation
      11. 9.3.11 Inductance Detection Through IADPT Pin
      12. 9.3.12 Converter Compensation
      13. 9.3.13 Continuous Conduction Mode (CCM)
      14. 9.3.14 Pulse Frequency Modulation (PFM)
      15. 9.3.15 Switching Frequency and Dithering Feature
      16. 9.3.16 Current and Power Monitor
        1. 9.3.16.1 High-Accuracy Current Sense Amplifier (IADPT and IBAT)
        2. 9.3.16.2 High-Accuracy Power Sense Amplifier (PSYS)
      17. 9.3.17 Input Source Dynamic Power Management
      18. 9.3.18 Input Current Optimizer (ICO)
      19. 9.3.19 Two-Level Adapter Current Limit (Peak Power Mode)
      20. 9.3.20 Processor Hot Indication
        1. 9.3.20.1 PROCHOT During Low Power Mode
        2. 9.3.20.2 PROCHOT Status
      21. 9.3.21 Device Protection
        1. 9.3.21.1 Watchdog Timer
        2. 9.3.21.2 Input Overvoltage Protection (ACOV)
        3. 9.3.21.3 Input Overcurrent Protection (ACOC)
        4. 9.3.21.4 System Overvoltage Protection (SYSOVP)
        5. 9.3.21.5 Battery Overvoltage Protection (BATOVP)
        6. 9.3.21.6 Battery Discharge Overcurrent Protection (BATOC)
        7. 9.3.21.7 Battery Short Protection (BATSP)
        8. 9.3.21.8 System Undervoltage Lockout (VSYS_UVP)
        9. 9.3.21.9 Thermal Shutdown (TSHUT)
    4. 9.4 Device Functional Modes
      1. 9.4.1 Forward Mode
      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 I2C Serial Interface
        1. 9.5.1.1 Timing Diagrams
        2. 9.5.1.2 Data Validity
        3. 9.5.1.3 START and STOP Conditions
        4. 9.5.1.4 Byte Format
        5. 9.5.1.5 Acknowledge (ACK) and Not Acknowledge (NACK)
        6. 9.5.1.6 Target Address and Data Direction Bit
        7. 9.5.1.7 Single Read and Write
        8. 9.5.1.8 Multi-Read and Multi-Write
        9. 9.5.1.9 Write 2-Byte I2C Commands
    6. 9.6 Register Map
      1. 9.6.1  ChargeOption0 Register (I2C address = 01/00h) [reset = E70Eh]
      2. 9.6.2  ChargeCurrent Register (I2C address = 03/02h) [reset = 0080h]
        1. 9.6.2.1 Battery Low Voltage Current Clamp
      3. 9.6.3  ChargeVoltage Register (I2C address = 05/04h) [reset value based on CELL_BATPRESZ pin setting]
      4. 9.6.4  ChargerStatus Register (I2C address = 21/20h) [reset = 0000h]
      5. 9.6.5  ProchotStatus Register (I2C address = 23/22h) [reset = B800h]
      6. 9.6.6  IIN_DPM Register (I2C address = 25/24h) [reset = 4100h]
      7. 9.6.7  ADCVBUS/PSYS Register (I2C address = 27/26h)
      8. 9.6.8  ADCIBAT Register (I2C address = 29/28h)
      9. 9.6.9  ADCIIN/CMPIN Register (I2C address = 2B/2Ah)
      10. 9.6.10 ADCVSYS/VBAT Register (I2C address = 2D/2Ch)
      11. 9.6.11 ChargeOption1 Register (I2C address = 31/30h) [reset = 3F00h]
      12. 9.6.12 ChargeOption2 Register (I2C address = 33/32h) [reset = 00B7]
      13. 9.6.13 ChargeOption3 Register (I2C address = 35/34h) [reset = 0434h]
      14. 9.6.14 ProchotOption0 Register (I2C address = 37/36h) [reset = 4A81h(2S~5s) 4A09(1S)]
      15. 9.6.15 ProchotOption1 Register (I2C address = 39/38h) [reset = 41A0h]
      16. 9.6.16 ADCOption Register (I2C address = 3B/3Ah) [reset = 2000h]
      17. 9.6.17 ChargeOption4 Register (I2C address = 3D/3Ch) [reset = 0048h]
      18. 9.6.18 Vmin Active Protection Register (I2C address = 3F/3Eh) [reset = 006Ch(2s~5s)/0004h(1S)]
      19. 9.6.19 OTGVoltage Register (I2C address = 07/06h) [reset = 09C4h]
      20. 9.6.20 OTGCurrent Register (I2C address = 09/08h) [reset = 3C00h]
      21. 9.6.21 InputVoltage(VINDPM) Register (I2C address = 0B/0Ah) [reset =VBUS-1.28V]
      22. 9.6.22 IIN_HOST Register (I2C address = 0F/0Eh) [reset = 2000h]
      23. 9.6.23 ID Registers
        1. 9.6.23.1 ManufactureID Register (I2C address = 2Eh) [reset = 40h]
        2. 9.6.23.2 Device ID (DeviceAddress) Register (I2C address = 2Fh) [reset = D6h]
  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 Input Snubber and Filter for Voltage Spike Damping
        2. 10.2.2.2 ACP-ACN Input Filter
        3. 10.2.2.3 Inductor Selection
        4. 10.2.2.4 Input Capacitor
        5. 10.2.2.5 Output Capacitor
        6. 10.2.2.6 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 第三方产品免责声明
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    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

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订购信息

12.1 Layout Guidelines

Proper layout of the components to minimize high frequency current path loop (see Section 12.2) is important to prevent electrical and magnetic field radiation and high frequency resonant problems. Here is a PCB layout priority list for proper layout.

Table 12-1 PCB Layout Guidelines
RULES COMPONENTS FUNCTION IMPACT GUIDELINES
1 PCB layer stack up Thermal, efficiency, signal integrity Multi- layer PCB is suggested. Allocate at least one ground layer. The BQ257XXEVM uses a 4-layer PCB (top layer, ground layer, signal layer and bottom layer).
2 CBUS, RAC, Q1, Q2 Input loop High frequency noise, ripple VBUS capacitors, RAC, Q1 and Q2 form a small loop 1. It is best to put them on the same side. Connect them with large copper to reduce the parasitic resistance. Move part of CBUS to the other side of PCB for high density design. After RAC before Q1 and Q2 power stage recommend to put 10 nF + 1 nF (0402 package) decoupling capacitors as close as possible to IC to decoupling switching loop high frequency noise.
3 RAC, Q1, L1, Q4 Current path Efficiency The current path from VBUS to VSYS, through RAC, Q1, L1, Q4, has low impedance. Pay attention to via resistance if they are not on the same side. The number of vias can be estimated as 1 to 2A/via for a 10-mil via with 1 oz. copper thickness.
4 CSYS, Q3, Q4 Output loop High frequency noise, ripple VSYS capacitors, Q3 and Q4 form a small loop 2. It is best to put them on the same side. Connect them with large copper to reduce the parasitic resistance. Move part of CSYS to the other side of PCB for high density design.
5 RSR Current path Efficiency, battery voltage detection Place RSR near the battery terminal. The current path from VBAT to VSYS, through RSR, has low impedance. Pay attention to via resistance if they are not on the same side. The device detects the battery voltage through SRN near battery terminal.
6 Q1, Q2, L1, Q3, Q4 Power stage Thermal, efficiency Place Q1, Q2, L1, Q3 and Q4 next to each other. Allow enough copper area for thermal dissipation. The copper area is suggested to be 2x to 4x of the pad size. Multiple thermal vias can be used to connect more copper layers together and dissipate more heat.
7 RAC, RSR Current sense Regulation accuracy Use Kelvin-sensing technique for RAC and RSR current sense resistors. Connect the current sense traces to the center of the pads, and run current sense traces as differential pairs.
8 Small capacitors IC bypass caps Noise, jittering, ripple Place VBUS cap, VCC cap, REGN caps near IC.
9 BST capacitors HS gate drive High frequency noise, ripple Place HS MOSFET boost strap circuit capacitor close to IC and on the same side of PCB board. Capacitors SW1/2 nodes are recommended to use wide copper polygon to connect to power stage and capacitors BST1/2 node are recommended to use at least 8mil trace to connected to IC BST1/2 pins.
10 Ground partition Measurement accuracy, regulation accuracy, jitters, ripple Separate analog ground(AGND) and power grounds(PGND) is preferred. PGND should be used for all power stage related ground net. AGND should be used for all sensing, compensation and control network ground for example ACP/ACN/COMP1/COMP2/CMPIN/CMPOUT/IADPT/IBAT/PSYS. Connect all analog grounds to a dedicated low-impedance copper plane, which is tied to the power ground underneath the IC exposed pad. If possible, use dedicated COMP1, COMP2 AGND traces. Connect analog ground and power ground together using power pad as the single ground connection point.