cancel
Showing results for 
Search instead for 
Did you mean: 

Problems setting up the STWLC38

ggeorge_42
Associate II

Hello,

We plan to use the STWLC38 for power in a new wearable design.

We purchased the STEVAL-WLC38RX and STEVAL-WBC86TX kits to get familiar and experiment with the ICs.

Now we are trying to adapt the Rx of the STEVAL-WLC38RX as used in a wearable device and followed the application diagram from the STWLC38 datasheet (Figure 13. STWLC38 basic application diagram in Rx mode), using the recommended coil (Wurth 760308101219). We also changed the Cs and Cd capacitors as recommended.

The STEVAL-WBC86TX board was not modified.

The problem is that the power reception from the STEVAL-WBC86TX is not enough to reach 5V at the output.

We tried changing the Cs according to STDES-WLC38WA (TN1440) as well as some other values with better results, but not enough. In the  chart of WPSTUDIO Vrect looks unstable, with lots of ripple and Vout is OFF.

Do you have any suggestions on how to tune the Rx circuit with the new coil?

Thank you,

G.Giannopoulos

10 REPLIES 10
willzhou
ST Employee

Hi
1.You can google FT260 driver or find at this link
https://github.com/STwirelesscharger/Python_FT260_ST_WLC

2.TX SS TO (Signal Strength or Ping Timeout). This probably has to do with the coupling of Tx/Rx coils (very different diameters)
Yes it is, coupling is bad and tx can not decode SS packet

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.