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Original question:

BQ24610: Accidental connection of a battery the wrong way (Battery Polarity Protection)

BQ24610: Advise on powering the LEDs on the BQ24610 and reducing power consumption of the LEDs

Mome_MGE
Intellectual 270 points
Part Number: BQ24610

Hello,

I've been thinking of a way to reduce the power consumption of the BQ24610 with its LED's, while keeping them bright enough.

My system uses 24V Power Supply and the battery attached is a 5S1P Giving a voltage range from 13V to 21V.

I have a DCDC Converter which is an LMZM33606RLX which outputs 12V for my motor.

I thought of dedicated LED drivers but all I have seen are LED drivers which takes full control of the LED's and you need to send a control signal to the LED driver.

I was thinking I could go two other ways:

1) As I have an LMZM33606RLX at 12V, I could connect and power the LED's for CE, PG, STAT1, STAT2, ACDRV and BATDRV with the correct resistor values in series, but the worry I forsee is possible issues of the BQ24610 signal pins might get damaged from using the 12V supply (I could be completely wrong, because part of me is saying it can't be true as your resistor will limit it, but somewhere in my mind its saying there is a reason why they use 3.3V from VREF to power the LED's on the BQ24610), this option would be great as then I don't have to add extra components to the system at all, excepts some BAT54 diodes so I can run the LED's from the VREF or when the 12V activates.

2) Is to run all the leds from a dedicated buck DC-DC converter instead of a linear DC-DC converter from either 3.3V output or 12V output.

I hope to hear from you guys soon!

I have attached a picture of the simulation I ran quickly on multisim for idea 1, with worst case senariro if both VREF and LMZM33606RLX ran as the same time to power the LED

 

Best regards

Mo

  • 0
    TI__Mastermind 24075 points
    Hi Mo,
    CE, STAT1/2, PG pin has an abs. max of 33V, and if you look at figure 19. in the d.s, this shows a typical application schematic with STAT1/2, PG pulled up to adapter voltage and not VREF. Tying to VREF helps customers who are using MCU to monitor fault status, so having pull up to VREF allows fault monitoring on the EVM board, as well as allows us to use the same pullup for the ISET1/2,ACSET pins (max rated for 3.6V), so there is no problem with using 12V. You want to keep current into internal FET (can be seen in functional block diagram of d.s) < 5mA ((VPULLUP - Vfwd (forward voltage drop of LED))/series resistor)