Part Number:BQ24770EVM-540
I've got my bq24770EVM setup connected. As I'm running through the power-up and initial checks, I notice that my ACOK LED (D5) is not lit. I have 19.5V at the input. I'm targeting a 3-cell battery line up. After trial and error I selected R26=100kOhms, R30=1MOhm to get 3.123V at CELLS (TP11). Here are my initial measurements:
TP11 (CELLS): 3.12V (should be > 3V for 3 cells) OK
TP7 (ACDET): 2.59V (should be 2.6V +/- 0.1V) right on the edge of the range...
D5 LED (ACOK): NOT LIT (however, it lights after turning on PS1=3.31V)
TP15 (REGN): 5.33V (should be 5.5V +/- 0.5V) OK
J3 (BAT, GND): 8.89V (should be 1V +/- 1.1V) WAY OFF!
TP6 (ACDRV) to TP5 (CMSRC): 6.45V (should be 6V +/- 0.5V) OK
Measure System Voltage for 3 cell setting: J2 (SYS, GND): 13.62V (should be 13.5V +/- 0.6V) OK
Also, after turning on PS2=3.3V, and running bqStudio, for the bq24770 charger, then trying to read the registers, I get no read back and an error message: “Device ACK Error”
-any ideas on how to bring my initial measurements in line with the expected values and also get bqStudio reading properly? Please let me know. Thanks,
Carl Olen