Other Parts Discussed in Thread: ADS1293, , TIDA-00318
I have taken on a job to modify a unit already in production to use wireless charging. I am looking at the bq51050B as I need wireless power and the ability to charge a single cell lithium polymer 600mAH battery at 1C. I have no experience with wireless power so I have some questions I hope someone familiar with it can help answer. If I had more time I would work through this but we are on a very tight schedule. The is a multi-day ECG recorder. You can see in the first picture of the bottom of the case the snaps that attach to the electrodes. The electrodes will not be in place during charging. Our first inclination is to put the coil at the center of the snaps. I have two concerns about this placement. First is whether the metal snaps are going to affect the efficiency of the power transfer. Second would be if the traces attached to the snaps could get a voltage induced on them. The snaps run into a TI ADS1293 ECG front end. The inputs have protection on them but this is for transients and not continuous voltage. If this is not a good placement then we could move the coil to the top of the case. In the second picture you can see the battery sits above the PCB under the top of the case. The coil would have to go between the battery and the case. This concerns me because I am wondering if the coil heats up during charge, in which case it would not be good to be under the battery. Out of these two choices I am trying to determine the best place to put the coil. Lastly, because of the size of the unit, we are going to be forced to use a rather small coil, under an inch. I am not sure how this will affect the transfer. Thanks for any insights on these issues.
