ZHCSJR3B February 2019 – November 2019 BQ25887
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
-
8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 Device Power-On-Reset
- 8.3.2 Device Power Up from Input Source
- 8.3.3 Input Current Optimizer (ICO)
- 8.3.4 Battery Charging Management
- 8.3.5 Integrated 16-Bit ADC for Monitoring
- 8.3.6 Status Outputs
- 8.3.7 Input Current Limit on ILIM Pin
- 8.3.8 Voltage and Current Monitoring
- 8.3.9 Thermal Regulation and Thermal Shutdown
- 8.3.10 Battery Protection
- 8.3.11 Serial Interface
- 8.4 Device Functional Modes
- 8.5
Register Maps
- 8.5.1 Cell Voltage Regulation Limit Register (Address = 00h) [reset = A0h]
- 8.5.2 Charger Current Limit Register (Address = 01h) [reset = 5Eh]
- 8.5.3 Input Voltage Limit Register (Address = 02h) [reset = 84h]
- 8.5.4 Input Current Limit Register (Address = 03h) [reset = 39h ]
- 8.5.5 Precharge and Termination Current Limit Register (Address = 04h) [reset = 22h]
- 8.5.6 Charger Control 1 Register (Address = 05h) [reset = 9Dh]
- 8.5.7 Charger Control 2 Register (Address = 06h) [reset = 7Dh]
- 8.5.8 Charger Control 3 Register (Address = 07h) [reset = 00h]
- 8.5.9 Charger Control 4 Register (Address = 08h) [reset = 0Dh]
- 8.5.10 Reserved Register (Address = 09h) [reset = 00h]
- 8.5.11 ICO Current Limit in Use Register (Address = 0Ah) [reset = XXh]
- 8.5.12 Charger Status 1 Register (Address = 0Bh) [reset = XXh]
- 8.5.13 Charger Status 2 Register (Address = 0Ch) [reset = XXh]
- 8.5.14 NTC Status Register (Address = 0Dh) [reset = 0Xh]
- 8.5.15 FAULT Status Register (Address = 0Eh) [reset = XXh]
- 8.5.16 Charger Flag 1 Register (Address = 0Fh) [reset = 00h]
- 8.5.17 Charger Flag 2 Register (Address = 10h) [reset = 00h]
- 8.5.18 FAULT Flag Register (Address = 11h) [reset = 00h]
- 8.5.19 Charger Mask 1 Register (Address = 12h) [reset = 00h]
- 8.5.20 Charger Mask 2 Register (Address = 13h) [reset = 00h]
- 8.5.21 FAULT Mask Register (Address = 14h) [reset = 00h]
- 8.5.22 ADC Control Register (Address = 15h) [reset = 30h]
- 8.5.23 ADC Function Disable Register (Address = 16h) [reset = 00h]
- 8.5.24 IBUS ADC 1 Register (Address = 17h) [reset = 00h]
- 8.5.25 IBUS ADC 0 Register (Address = 18h) [reset = 00h]
- 8.5.26 ICHG ADC 1 Register (Address = 19h) [reset = 00h]
- 8.5.27 ICHG ADC 0 Register (Address = 1Ah) [reset = 00h]
- 8.5.28 VBUS ADC 1 Register (Address = 1Bh) [reset = 00h]
- 8.5.29 VBUS ADC 0 Register (Address = 1Ch) [reset = 00h]
- 8.5.30 VBAT ADC 1 Register (Address = 1Dh) [reset = 00h]
- 8.5.31 VBAT ADC 0 Register (Address = 1Eh) [reset = 00h]
- 8.5.32 VCELLTOP ADC 1 Register (Address = 1Fh) [reset = 00h]
- 8.5.33 VCELLTOP ADC 0 Register (Address = 20h) [reset = 00h]
- 8.5.34 TS ADC 1 Register (Address = 21h) [reset = 00h]
- 8.5.35 TS ADC 0 Register (Address = 22h) [reset = 00h]
- 8.5.36 TDIE ADC 1 Register (Address = 23h) [reset = 00h]
- 8.5.37 TDIE ADC 0 Register (Address = 24h) [reset = 00h]
- 8.5.38 Part Information Register (Address = 25h) [reset = 28h]
- 8.5.39 VCELLBOT ADC 1 Register (Address = 26h) [reset = 00h]
- 8.5.40 VCELLBOT ADC 0 Register (Address = 27h) [reset = 00h]
- 8.5.41 Cell Balancing Control 1 Register (Address = 28h) [reset = 2Ah]
- 8.5.42 Cell Balancing Control 2 Register (Address = 29h) [reset = F4h]
- 8.5.43 Cell Balancing Status and Control Register (Address = 2Ah) [reset = 81h]
- 8.5.44 Cell Balancing Flag Register (Address = 2Bh) [reset = 00h]
- 8.5.45 Cell Balancing Mask Register (Address = 2Ch) [reset = 00h]
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12器件和文檔支持
- 13機械、封裝和可訂購信息
9.2.2.1 Inductor Selection
The device has 1.5-MHz switching frequency to allow the use of small inductor and capacitor values. The inductor saturation current should be higher than the input current (IIN) plus half the ripple current (IRIPPLE):
Equation 5. 
The inductor ripple current (IRIPPLE) depends on input voltage (VVBUS), duty cycle (D = VBAT/VBUS), switching frequency (fSW) and inductance (L):
Equation 6. 
The maximum inductor ripple current happens in the vicinity of D = 0.5. Usually inductor ripple is designed in the range of (20 – 40%) maximum charging current as a trade-off between inductor size and efficiency for a practical design.