BQ34Z100-G1: Reference schematic question

Jimmy,

1. Q3 and Q8 are parts of a shunt regulator used to provide the 3.3V voltage to power the bq34z100-G1.

2. Yes, the P1 and P2 outputs control the shift registers used to drive the LEDs. The signals are only used when loading data into the shift registers.

3. The formulae and examples for selecting the resistor values can be found on pages 36 and 50 of the datasheet.

4. The LED selection options are discussed on page 5 of the bq34z100EVM User's Guide. (SLUU904A)  There does not appear to be a description of the jumper selection options for the ALERT pin. Here are the options. Use Table 21 in the datasheet to select which pin on the device will be used for the ALERT output.

J3-A: P6 output

J3-B: P2 output

J3-C: P4 output

J3-D: P5 output

5. the VEN pins serves two functions. If outputs a pulse every 1 second to drive the gate of an external FET to switch the scaled battery voltage to BAT input of the device to measure the voltage. It also provides a current sink when the LED activation button is pressed. The gauge will activate the LED sequnce when it detects current going into the pin.

6. No, I so not have any supprot tools for the bq24090.

Tom