SLVAE87A December 2020 – October 2023 BQ79600-Q1 , BQ79612-Q1 , BQ79614-Q1 , BQ79616-Q1 , BQ79652-Q1 , BQ79654-Q1 , BQ79656-Q1
The BQ79616-Q1 provides high-accuracy cell voltage measurements for 6S to 16S battery modules in <200 µs. The integrated front end filters enable the system to implement simple, low-cost, differential RC filters on the cell input channels. The integrated, post-ADC, low-pass filters enable filtered, DC-like, voltage measurements for better SOC calculation. This device supports autonomous internal cell balancing with temperature monitoring to auto-pause and resume balancing to avoid an overtemperature condition.
The inclusion of the isolated, bidirectional, daisy chain ports supports both capacitor- and transformer-based isolation, allowing the use of the most effective components for centralized or distribution architectures commonly found in the xEV powertrain system. This device also includes eight GPIOs/auxiliary inputs that can be used for NTC thermistor measurements.
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The device is powered by BAT pin and the LDOIN pin, with which the LDOIN pin is regulated by the pre- regulation circuit form with an external NPN. The device can be powered by a battery module with as low as 9V (without OTP programming) on the BAT pin.
The BAT and LDOIN pins should be filtered separately from the cell. This is to protect against hotplug, in-rush current, and other relevant noise. Recommended filters are RBAT = 30 Ω / .25 W, CBAT = 0.01 µF / 100 V for the BAT pin, two resistors in series for best thermal performance: RNPNC1 = 100 Ω / .75W, RNPNC2 = 200 Ω / .75 W and capacitor CNPNC = 0.22 µF / 100 V for the collector. LDOIN is the input for the external LDO supply for the BQ79616-Q1. Figure 1-1 shows the typical circuit.
The resistor values and NPN can be further optimized from the reference schematic values based on the min and max module voltages for different projects.
Select the NPN Transistor based on the following criteria:
The resistor RNPNB in Figure 1-1 serves several purposes:
where
Connect the filter on the LDOIN supply (CLDOIN ) for stability. Use CLDOIN = 0.1 µF with a voltage rating of 10 V.