BQ79616-Q1: Thermistor multiplexing and power LED indicator

Samuel Mazur

Part Number: BQ79616-Q1
Other Parts Discussed in Thread: TMUX1574, TMUX4051

Hello,

I would like to ask about possibility to multiplex 14 thermistors to 8 GPIO pins. Do you have any recomendation for switch that could be used that will not violate 5mA output limit on CVDD? 7 GPIOs for measurements 1 GPIO for switching.

Also I would like to ask if there is possibility to add somewhere LED to indicate ACTIVE state of BQ chip? In evaluation design it is connected to AVDD but in design guideline is stated that we cannot connect any load to AVDD. Could you please clarify if we could put there LED?

Thank you

over 2 years ago

+1 Wayne Liu over 2 years ago

TI__Expert 8705 points

Hi,

Replying your questions:

1. Please refer to the switch https://www.ti.com/lit/ds/symlink/tmux4051-q1.pdf?ts=1676923519495&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTMUX4051-Q1, whose current is tens of uA.

2. AVDD supplies 30mA typically, so it's OK to drive a LED rather than noisy loads.

0 Samuel Mazur over 2 years ago in reply to Wayne Liu

Prodigy 30 points

Thank you for your answer.

Could you please confirm that https://www.ti.com/product/TMUX1574 would be also suitable? as TMUX4051 would need at least 4 cycles to get all temperatures instead of 2 cycles for TMUX1574.

+1 Wayne Liu over 2 years ago in reply to Samuel Mazur

TI__Expert 8705 points

Hi,

1574 also works for you but please choose a Q100 device and get the confirmation from this switch product line since I am only covering BQ. Have a good day.

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BQ79616-Q1: Thermistor multiplexing and power LED indicator