Wireless charger using I2c

Yang,

Some wireless receivers contain I2C, some do not.  Those that do have I2C are wireless power supplies and not chargers.  They have registers that have information related to the wireless power system. 

If you need information regarding the battery, you need to go directly to a stand-alone charger (which will work with the wireless power receivers).

What information do you need?

Regards,

Dick

Dear Dick:

Question1：

I have searched for some information on line. The BQ51221 have the register map on page 22, can I use this register map to control the output voltage, frequency or monitor the wireless power supply process is I just use the BQ51221 without stand-alone charger.

Question2：
If I use the stand-alone charger, can you suggest me a chip? Thank you very much.

Fan,

1) Register Map:

A) The registers can be used to change the output voltage (Register 1, bits B0, B1 and B2).  The default value is 500mV (0x01) for this feedback node.  Changing the register will change the voltage appropriately, within its specified output range.

B) Frequency cannot be changed, only monitored.  The TX determines the frequency.

C) Other registers can be used as shown in the register map section starting on page 22.

Note that the bq51221 is a wireless power receiver.  It generates a voltage / current that can be used by the system. It cannot charge batteries on its own.

2) To determine what charger is appropriate, more information is required.  What is the battery type?  What is the charging voltage?  This would possibly a better question for the Charger Forum.

Regards,

Dick

Dear Dick：

Thanks for your kindly reply. I am now doing a project which needs a very small wireless charger circuit for the wearable circuit. It also needs to monitor and control the process of the wireless power transfer process. My battery is shown below in the picture. Do you have any suggestion for the transmitter and receiver type? we should use as less chip as possible. Thank you very much.

Best regards,
Yang Fan

Yang,

Look at the bq51003 as the wireless receiver and the bq25100 as the charger.  See TIDA-00318 for the solution.

Regards,

Dick

Dear Dick:

My Project still need to use I2c to monitor the power transfer process, however, the bq51003 doesn't provide any information about this. Can you kindly give me another suggestion? Thank you very much.

Best regards,
Yang Fan

Yang,

Please look at the bq25120.  It is an I2C enabled charger and Battery Management Unit.  It should provide all the information you need.

Regards,

Dick

Dear Dick,
Thank you for your suggestion. Because I also need a micro controller to control the working process and create a GUI. Which MCU you think can fit for my project? My project is about the wireless charger for the wearable bio-electronic device and I want it as small as possible.

Best regards,
Yang Fan

Yang,

I am not an expert on the TI selection for an MCU.  The MSP430 is a very popular and easy to use solution that I have used in the past for projects.

You can get more information at the Micro-controller E2E forum:  e2e.ti.com/.../

Regards,

Dick

Dear Dick:

Thanks for your kindly reply. Do you have any ideas about the wireless transmitter which can use I2C to control the frequency, voltage or monitor the wireless transfer process? Thank you.

Best regards,
Yang Fan

Yang,

Look at the bq500212A.  There is an application note on how to interface with I2C.  

You cannot set the frequency or voltage on the transmitter.  It will alter its frequency or voltage to deliver the power requested by the receiver.  The items you can monitor are covered in the application note.

Regards,

Dick

Hello Dick,

  Quick question - we have a product that uses multiple BQ500212A devices.  We are doing a revision and I just saw the I2C interface document.  (The datasheet should be updated to indicate that I2C is NOT factory reserved.)

  Just wondering about address - do all devices have the same address or are they different?  I'm wondering about giving us the capability to address individual chargers - it would really add to the functunality.  They are "hardcoded" so I am assuming they are all the same but just wanting to confirm.

Thanks,

Kurt

Kurt,

You are correct, the I2C address is hardcoded into the bq500212A.  The address is 0x14.

I'm sure you are aware of the TCA7408 I2C I/O expander that might help.

Regards,

Dick

Dick

  Thanks!  This would have been a "nice to have" type feature.  We have almost 50 wireless chargers in the product so for now it's not worth it to create any sort of expansion bus.

Cheers,

Kurt