ZHCSG63C December 2013 – July 2018
PRODUCTION DATA.
- 1 特性
- 2 應(yīng)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 Details of a Qi Wireless Power System and bq51003 Power Transfer Flow Diagrams
- 8.3.2 Dynamic Rectifier Control
- 8.3.3 Dynamic Efficiency Scaling
- 8.3.4 RILIM Calculations
- 8.3.5 Input Overvoltage
- 8.3.6 Adapter Enable Functionality and EN1/EN2 Control
- 8.3.7 End Power Transfer Packet (WPC Header 0x02)
- 8.3.8 Status Outputs
- 8.3.9 WPC Communication Scheme
- 8.3.10 Communication Modulator
- 8.3.11 Adaptive Communication Limit
- 8.3.12 Synchronous Rectification
- 8.3.13 Temperature Sense Resistor Network (TS)
- 8.3.14 3-State Driver Recommendations for the TS-CTRL Pin
- 8.3.15 Thermal Protection
- 8.3.16 WPC v1.2 Compliance – Foreign Object Detection
- 8.4 Device Functional Modes
- 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
封裝選項
機械數(shù)據(jù) (封裝 | 引腳)
- YFP|28
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
訂購信息
8.3.13 Temperature Sense Resistor Network (TS)
bq51003 includes a ratiometric external temperature sense function. The temperature sense function has two ratiometric thresholds which represent a hot and cold condition. TI recommends an external temperature sensor to provide safe operating conditions for the receiver product. This pin is best used for monitoring the surface that can be exposed to the end user (that is, place the NTC resistor closest to the user).
Figure 28 allows for any NTC resistor to be used with the given VHOT and VCOLD thresholds.
Figure 28. NTC Circuit Used for Safe Operation of the Wireless Receiver Power Supply The resistors R1 and R3 can be solved by resolving the system of equations at the desired temperature thresholds (see Equation 3 and Equation 4).
where
- TCOLD and THOT are the desired temperature thresholds in degrees Kelvin
- RO is the nominal resistance
- and β is the temperature coefficient of the NTC resistor
- RO is fixed at 20 kΩ
An example solution is provided:
- R1 = 4.23 kΩ
- R3 = 66.8 kΩ
where the chosen parameters are:
- %VHOT = 19.6%
- %VCOLD = 58.7%
- TCOLD = –10°C
- THOT = 100°C
- β = 3380
- RO = 10 kΩ
Figure 29 shows the plot of the percent VTSB vs temperature.
Figure 29. Example Solution for an NTC resistor with RO = 10 kΩ and β = 4500 Figure 30 illustrates the periodic biasing scheme used for measuring the TS state. The TS_READ signal enables the TS bias voltage for 24 ms. During this period the TS comparators are read (each comparator has a 10-ms deglitch) and appropriate action is taken based on the temperature measurement. After this 24-ms period has elapsed, the TS_READ signal goes low, which causes the TS-Bias pin to become high impedance. During the next 35 ms (priority packet period) or 235 ms (standard packet period), the TS voltage is monitored and compared to 100 mV. If the TS voltage is greater than 100 mV then a secondary device is driving the TS-CTRL pin and a CTRL = ‘1’ is detected.
Figure 30. Timing Diagram for TS Detection Circuit