bq34z110 led modes

You can use the single LED mode with the I2C interface. You will need to use an external FET to switch the LED and pin 3 on the bq34z100 will drive the gate of the FET. You should be able to use the 1 and 4 LED modes with the HDQ interface and you must use the HDQ interface when using the 4 LED option without using the external shift register..

Thank you very much for your reply. 

If I switch to 0 led mode then I use I2C for programming bq and after that switch back to 4 led mode, there would be any conflicts? (ecept for the ones appearing when I set led mode register)

There should not be any conflicts, but you may have to reset the device for the change to take effect.

As far as I know I can't use single or four led indication and i2c in the same time - I need to use jumper to choose. Can I use single or four led indication with hdq communication in the same time without using any jumpers, right?

Another thing that I am not sure... When I am using external diodes Can I use i2c (according figure 8. of bq34z110 datasheet) in the same time without using any jumpers, right?

In all cases I will use 3 cell battery or more.

ionut Fasola, are you from Poland?

You can only select one LED configuration setup. Are you referring to the jumpers on the TI EVM? If so, at least one jumper will be required for any of the LED configurations. This is covered in a section in the EVM User's Guide.

The 4-LED mode is the only one that requires that you use HDQ mode for communications.

I know that I can select only one LED configuration. I am making "my own" version EVM of this gauge to measure how much current will be needed in various LED modes. So my questions are still actual. As I understand it, if I want to compare single led mode with any multi led I have to select single led mode and external diodes. I have to refuse with 4 led mode because I want to use i2c communication only, right?

thanks for reply

You are correct that the I2C interface cannot be used when selecting the 4-LED option, because the I2C pins are used to drive LEDs. If you are trying to measure the current required to drive an LED, then you should be able to place a jumper on position A and place a current meter across the J1 (I2C) jumper.

Thanks. I have another question. I can't figure out  why there is two different mos transistors Q4 in multi cell application and EVM application (2N7002 or BSS138). How it works?

Another thing is with single led mode, transistor Q1: why there is 2SK3019? Because of gate protection diode? Can I replace it with 2N7002?

Appreciate any answer, thank you

The gate threshold was lower on the BSS138 and Vds-max is higher on the 2N7002. If your pack voltage is lower than 50V, then you should be able to use the BSS138 in both locations. The 2SK3019 was chosen because of its gate protection features.

Hi,

I am also trying to use the BQ34 in the led configuration : 5 leds ,I2C bus

- Pack Configuraton = 0x0141

- Pack Configuration  B = 0xFF

- Pack Configuration C  = 0x30

- Led_Comm Configuration = 0x43

- Number of cells = 0x01

The schematic to enable the I2C communication is quite similar to the one shown at page 46 of the  Bq34Z100 - G1 data sheet but when I press the button no communication occurs.Really  I don't understand what is my mistake .

Moreover the VEN pin goes high every 1 sec. for about 150 mS and when the button is pressed I can detect the 2,5 V on one side of 1K resistor but on the other side (VEN)  I only see the 1 second transition of VEN pin

Thanks

Giuliano