ZHCSKH8C December 2009 – December 2019 BQ24072T , BQ24075T , BQ24079T
PRODUCTION DATA.
- 1 特性
- 2 应用
- 3 说明
- 4 修订历史记录
- 5 说明 （续）
- 6 Device Options
- 7 Pin Configuration and Functions
- 8 Specifications
-
9 Detailed Description
- 9.1 Overview
- 9.2 Functional Block Diagram
- 9.3
Feature Description
- 9.3.1 Undervoltage Lockout (UVLO)
- 9.3.2 Overvoltage Protection (OVP)
- 9.3.3 Dynamic Power-Path Management
- 9.3.4 Battery Charging
- 9.3.5 Charge Current Translator
- 9.3.6 Battery Detection and Recharge
- 9.3.7 Termination Disable (TD Input, BQ24072T)
- 9.3.8 Battery Disconnect (SYSOFF Input)
- 9.3.9 Dynamic Charge Timers (TMR Input)
- 9.3.10 Status Indicators (PGOOD, CHG)
- 9.3.11 Thermal Regulation and Thermal Shutdown
- 9.3.12 Battery Pack Temperature Monitoring
- 9.4 Device Functional Modes
-
10Applications and Implementation
- 10.1 Application Information
- 10.2
Typical Applications
- 10.2.1
Using the BQ24075T, BQ24079T to Disconnect the Battery from the System
- 10.2.1.1 Design Requirements
- 10.2.1.2
Detailed Design Procedure
- 10.2.1.2.1 Program the Fast Charge Current (ISET):
- 10.2.1.2.2 Program the Input Current Limit (ILIM):
- 10.2.1.2.3 Program 6.25-hour Fast-Charge Safety Timer (TMR):
- 10.2.1.2.4 TS Function:
- 10.2.1.2.5 CHG and PGOOD LED Status:
- 10.2.1.2.6 Processor Monitoring Status:
- 10.2.1.2.7 System ON/OFF (SYSOFF):
- 10.2.1.2.8 Selecting IN, OUT and BAT Capacitors
- 10.2.1.3 Application Curves
- 10.2.2 BQ24072T in a Host Controlled Charger Application
- 10.2.1
Using the BQ24075T, BQ24079T to Disconnect the Battery from the System
- 11Power Supply Recommendations
- 12Layout
- 13器件和文档支持
- 14机械、封装和可订购信息
10.2.1.2.4 TS Function:
Using a 10 kΩ NTC thermistor in the battery pack (103AT-2). Connect a resistor divider from VIN to VSS with the thermistor and TS connected to the center tap (R6 and R7 in Figure 23).
- RHOT = 4.086 kΩ; 50°C threshold from NTC data sheet
- RCOLD = 28.16 kΩ; 0°C threshold from NTC data sheet
- VCOLD = 0.25 x VIN = 0.25 x 5 V = 1.25 V
- VHOT = 0.125 x VIN = 0.125 x 5 V = 0.625 V
Equation 6. 
Equation 7. 
Since the calculated values for R6 is less than 100 kΩ, a 100 kΩ resistor for R8 must be used. Choose the closest standard values, which for this case are R7 = 8.25 kΩ and R6 = 19.1 kΩ.
For applications that do not require the TS monitoring function, set R6 = 200 kΩ and R7 = 49.9 kΩ to set the TS voltage at a valid level and maintain charging.