With bus bar connected to BBP/BBN pins, it is intended to allow a single cell channel (VC channel) to be shared with a cell + a bus bar (see Figure 9-52 (a) connection). Usually, such connection introduced additional IR error to the cell measurement to the system. The dedicated bus bar channel through BBP/BBN pins supported in the device allows the host to measure the bus bar voltage to obtain the actual cell measurement.

Figure 9-52 (a) connection applies to bus bar connecting to any middle VC channel. That is, in a single device, there is a cell connected above and below the BBP/BBN channel. To support hotplug on the bus bar channel, the device only requires a 400-Ω filter resistor each on the BBP/N pins and a 0.47-µF/16-V differential capacitor across the BBP/N pins.

If the bus bar connected to BBP/N is placed at the top of a module (see Figure 9-52 (b) connection), such connection is the exception in the BBP/N case that a cell channel is not being shared. In this connection, actual cell measurements are made through the VC channels and host does not require additional calculations.

Figure 9-52 (b) connection applies to bus bar connected to top of the module, where in a single device, no cell is connected above the bus bar. To support hotplug on the bus bar channel, besides the 400-Ω filter resistor each on BBP/N pins and a 0.47-µF/16-V differential capacitor across BBP/N pins, and additional 0.47-µF/16-V differential capacitor is needed to connect from BBN to the top CB pins. This additional capacitor forms a complete capacitor ladder from all cells in the module to the bus bar, allowing high spike voltage during hotplug to distributor across the capacitor ladder.

Figure 9-52 Bus Bar Connected Across BBP and BBN Pins