JAJSSH0 December 2023 BQ77307
PRODUCTION DATA
If the BQ77307 device is used in a system with fewer than 5 series cells, specific cells must be used for connection to real cells, as shown in Table 7-1. The unused cell inputs should be shorted out on the circuit board. The device only implements protections for those cells designated as real cells.
NUMBER OF CELL USED | CELL CONNECTIONS | SHORTED CONNECTIONS |
---|---|---|
7 | VC7‒VC6, VC6‒VC5, VC5‒VC4, VC4‒VC3, VC3‒VC2, VC2‒VC1, VC1‒VC0 | — |
6 | VC7‒VC6, VC6‒VC5, VC5‒VC4, VC3‒VC2, VC2‒VC1, VC1‒VC0 | VC4‒VC3 |
5 | VC7‒VC6, VC5‒VC4, VC3‒VC2, VC2‒VC1, VC1‒VC0 | VC6‒VC5, VC4‒VC3 |
4 | VC7‒VC6, VC5‒VC4, VC3‒VC2, VC1‒VC0 | VC6‒VC5, VC4‒VC3, VC2‒VC1 |
3 | VC7‒VC6, VC5‒VC4, VC1‒VC0 | VC6‒VC5, VC4‒VC3, VC3‒VC2, VC2‒VC1 |
2 | VC7‒VC6, VC1‒VC0 | VC6‒VC5, VC5‒VC4,VC4‒VC3, VC3‒VC2, VC2‒VC1 |
The unused cell input pins should be shorted to adjacent cell input pins, as shown in Figure 8-10 for a 6-series system.
It is also important to note that the range of voltages supported by the different VC pins differs depending on the pin. For example, pins VC5, VC6, and VC7 can only support accurate cell voltage protections if their pin voltage is greater than or equal to 2 V. Thus, if implementing a 2-series system using the top and bottom cell input pins, the upper cell voltage may not be evaluated correctly if the lower cell voltage drops below 2 V, since then VC6 would be below 2 V.
The device data memory must be configured to specify which cell inputs are used for actual cells. The device uses this information to disable cell voltage protections associated with inputs that are not used. See the BQ77307 Technical Reference Manual for further details.