SLUSBC8C December   2013  – July 2018

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Wireless Power Consortium (WPC or Qi) Inductive Power System
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
      1. 8.1.1 A Brief Description of the Wireless System
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Details of a Qi Wireless Power System and bq51003 Power Transfer Flow Diagrams
      2. 8.3.2  Dynamic Rectifier Control
      3. 8.3.3  Dynamic Efficiency Scaling
      4. 8.3.4  RILIM Calculations
      5. 8.3.5  Input Overvoltage
      6. 8.3.6  Adapter Enable Functionality and EN1/EN2 Control
      7. 8.3.7  End Power Transfer Packet (WPC Header 0x02)
      8. 8.3.8  Status Outputs
      9. 8.3.9  WPC Communication Scheme
      10. 8.3.10 Communication Modulator
      11. 8.3.11 Adaptive Communication Limit
      12. 8.3.12 Synchronous Rectification
      13. 8.3.13 Temperature Sense Resistor Network (TS)
      14. 8.3.14 3-State Driver Recommendations for the TS-CTRL Pin
      15. 8.3.15 Thermal Protection
      16. 8.3.16 WPC v1.2 Compliance – Foreign Object Detection
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 bq51003 Wireless Power Receiver Used as a Power Supply
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Using the bq51003 as a Wireless Power Supply
          2. 9.2.1.2.2 Series and Parallel Resonant Capacitor Selection
          3. 9.2.1.2.3 COMM, CLAMP, and BOOT Capacitors
          4. 9.2.1.2.4 Control Pins and CHG
          5. 9.2.1.2.5 Current Limit and FOD
          6. 9.2.1.2.6 RECT and OUT Capacitance
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Dual Power Path: Wireless Power and DC Input
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

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.

bq51003 NTC_circuit_lusay6.gifFigure 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).

Equation 3. bq51003 eq2_Vcold_Vhot_lusay6.gif
Equation 4. bq51003 eq3_RNTC_lusay6.gif

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.

bq51003 example_solution_graph_lusay6.pngFigure 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.

bq51003 Timing_diagram_lusay6.pngFigure 30. Timing Diagram for TS Detection Circuit