ZHCSGX4C June 2017 – April 2021 BQ40Z50-R2
PRODUCTION DATA
The chemical fuse (Dexerials, Uchihashi, and so on) is ignited under command from either the bq294700 secondary voltage protection IC or from the FUSE pin of the gas gauge. Either of these events applies a positive voltage to the gate of Q5, shown in Figure 9-3, which then sinks current from the third terminal of the fuse, causing it to ignite and open permanently.
It is important to carefully review the fuse specifications and match the required ignition current to that available from the N-channel FET. Ensure that the proper voltage, current, and Rds(on) ratings are used for this device. The fuse control circuit is discussed in detail in Section 9.2.2.2.5.