BQ51013B: Resonant Capacitor Selection

Den L

Part Number: BQ51013B

Hello,

I need some help on the selection of the resonant capacitors for my specific coils in BQ51013B. As far as I understand I can only select the right capacitors if I know L' which can only be tested/measured. Right now I don't have the means to do the measurements so I wanted to ask TI if they know the approximate values for the capacitors for the following 3 coils:

1) 760 308 101 219 - Ø 15; L = 11.8 μH; Q = 13; IR = 0.7 A; Isat = 1.5 A; RDC = 0.75 Ω

2) 760 308 101 214 - Ø 19; L = 26 μH; Q = 25; IR = 1.1 A; Isat = 2.0 A; RDC = 0.52 Ω

3) 760 308 101 220 - Ø 17; L = 12.6 μH; Q = 20; IR = 1.1 A; Isat = 2.5 A; RDC = 0.34 Ω

Kind Regards,

Den

over 7 years ago

0 Bill Johns over 7 years ago

TI__Guru* 75906 points

This will be difficult to predict.
The coil to coil distance is a factor and amount of metal behind the RX coil.

0 Den L over 7 years ago in reply to Bill Johns

Intellectual 990 points

Hi Bill,

the coil to coil distance should be around 4 mm for all 3 coils and they all have a ferrite plate behind them.

You can find all 3 coils here:

http://katalog.we-online.de/en/pbs/WE-WPCC-RECEIVER/760308101219?_ga=2.92932318.2123676305.1535485703-198739634.1535485703

Kind Regards,

Den

0 Bill Johns over 7 years ago in reply to Den L

TI__Guru* 75906 points

For small coils the coupling will not be good and the inductance will need to high to off set this, Coil #2 is your best option (760308101214).
I will not be able to test coil.
You may try contacting Wurth.

1) 760 308 101 219 - Ø 15; L = 11.8 μH; Q = 13; IR = 0.7 A; Isat = 1.5 A; RDC = 0.75 Ω

2) 760 308 101 214 - Ø 19; L = 26 μH; Q = 25; IR = 1.1 A; Isat = 2.0 A; RDC = 0.52 Ω

3) 760 308 101 220 - Ø 17; L = 12.6 μH; Q = 20; IR = 1.1 A; Isat = 2.5 A; RDC = 0.34 Ω

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BQ51013B: Resonant Capacitor Selection