Hello World,
I have completed a sophisticated Highly Efficient Hot Qi Dog Cape. The boards are on their way! The Hot Qi Dog Cape is a Qi/Battery powered/Qi Charger for the BeagleBone!
Presenting the Hot Qi Dog Cape..In Red, Green, Black and Moldy Purple!
This Hot Qi Dog Cape has the following:
Full Evaluation Board Qi Receiver- Has a solder jumper to allow for either a Qi 5V pass through voltage or battery charging functions, comes with lots of test points!
EEPROM-This is needed for ALL Capes on the BeagleBone. This tells the BeagleBone all the information about the Cape that was plugged in. I allowed different addresses by the means of solder jumpers. I also allowed your option of write protecting the cape!
Battery Charger with a GUI Using I2C-A complete charger module for charging compact, flexible, high efficiency, switch-mode charge management for single-cell, Li-ion and Li-polymer batteries.
GUI-Yes this has a GUI. You can download and look at it now right from TI.com! bq2427xEVM_SW_V0001.zip
IC Controlled NexFET Power MOSFET-The NexFET power MOSFET has been designed to minimize losses in power conversion load management applications. The SON 3x3 package offers excellent thermal performance for the size of the package! I had to custom make a SON-8 package for Eagle!
Low Input Voltage Synchronous Boost Converter with 1.3A Switches-More than 90% efficient, Automatic Transition between Boost Mode and Down Conversion Mode, Quiescent Current less than 55 uA. Operating Range from 0.3V to 5.5V, Output short circuit protection under all operating conditions, Power Save Mode, Overtemperature Protection.
PMIC Access Points-I left this open for anyone to use this shield and use the PMIC function of the BeagleBone.
Cape Powered BeagleBone-Just plug the Cape in and set the coil either built into the case or other place and the BeagleBone is powered from the Cape!
I will say it again, It isn't just a battery charger, it is a complete High-Efficiency Switch Mode Charger with Separate Power Path Control with EEPROM!
What is Power Path Management,
-It allows the device to power the system from a high efficiency DC to DC converter while simultaneously and independently charging the battery. The charger monitors the battery current at all times and reduces the charge current when the system load requires current above the input current limit. This allows for proper charge termination and timer operation. The system voltage is regulated to the battery voltage and will not drop below 3.5V. This minimum system voltage support enables the system to run with a defective or absent battery pack and enables instant system turn on even with a totally discharged battery or no battery! Try that with your iPhones or Droids! The power path management architecture also permits the battery to supplement the system current requirements when the adapter cannot deliver the peak system currents. This enables the use of a smaller adapter.
-The battery is charged in three phases:
---conditioning, constant current, and constant voltage
The charger also offers the a voltage based battery pack thermistor monitoring input (TS) that monitors battery temperature for safe charging.
Here are the details if you want or just skip ahead:
-Instantly Startup the system from a deeply discharged battery or no battery
-Integrated FETs for up to 2.5A charge rate, even though I limited this rate to 1A
-Highly integrated Battery N-Channel MOSFET controller for Power Path Management
-Safe and accurate battery management functions
----0.5% Battery Regulation Accuracy
----10% Charge Current Accuracy
-Voltage based, NTC monitoring input (TS) for measuring the temperature of the battery, I also used a solder jumper for this option to be either enabled or disabled
-Thermal regulation protection for output current control
-Battery Short Circuit Protection
-Soft start feature to reduce inrush current
-Thermal shutdown and protection
-Battery charging status LEDs and signal LEDs
Best of all I included the connections for a USB kit from Ti so you can program your own battery charger from the default settings and monitor the battery charging process on a computer. So with this Hot Qi Dog Cape you are basically getting a BQ24272 Evaluation Module from Ti embedded on a Cape!
This Hot Qi Dog Cape isn't for everyone! This is a kit for the people that want to experiment with different battery types, different charging patterns, different voltages, efficiencies, etc. I wanted to make a kit that includes two of the most efficient, best products that TI has on the market right now. I wanted to include functionality to expand to other devices if needed. This board and design will be easy to transfer over to other designs and boards such as the Raspberry Pi in which I already did as the Qi Lime Pi Shield, and many others!
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I will make a Qi Lime Pi Slice Shield soon that will have just a basic Qi Receiver, battery charger and buck boost for simplicity with EEPROM.
I will post my design files in a later post when I have fully tested this design and have a fully working prototype! Again, The boards are on their way!
Thank you TI and Wurth for most of the hard work on making Great Eval Boards and Great Documentation!
Thank You,
Chad
