SLUA748A December   2015  – April 2016 BQ25120 , BQ51003 , TPS61046 , TPS61240 , TPS62743

 

  1.   Trademarks
  2.   Power Management Reference Design for a Wearable Device with Wireless Charging Using the bq51003 and bq25120
    1. 1 Wearable Power Design
      1. 1.1 Wireless Charging Input
      2. 1.2 Battery Charger, MCU, Radio, and Sensor Power
      3. 1.3 Second Buck Output for MCU, Radio or Sensor
    2. 2 PMOLED Display Power Design
    3. 3 Heart Rate Monitor or e-Ink Power Design
    4. 4 Layout Guidelines for Wearable Design
      1. 4.1 Wireless Receiver (bq51003)
      2. 4.2 Linear Charger (bq25120)
      3. 4.3 Buck Converter (TPS62743/6)
      4. 4.4 Boost Converters (TPS61046 and TPS61240)
      5. 4.5 General Considerations
    5. 5 References
  3. AExperimental Results
    1. A.1 Experimental Results
  4.   Revision History

4.4 Boost Converters (TPS61046 and TPS61240)

  • The switching node should be as short as possible.
  • It is recommended to place the input capacitor close not only to the VIN and GND pins.
  • The output capacitor must be placed close to the IC and it is recommended to be close to the ground pin. If possible, the ground for the input and output capacitor should be on the same plane. In the TPS61046 it was not possible to follow this rule due to the placement for reduced size. Therefore, a solid ground with vias was provided on the next layer making sure the connection is adequate.
PCB_cap_gnd_TPS61046_slua748.gifFigure 10. Capacitor Grounding TPS61046
PCB_layout_TPS61240_slua748.gifFigure 11. TPS61240 Layout