ZHCSCE2I October 2013 – March 2022 BQ76920 , BQ76930 , BQ76940
PRODMIX
The BQ769x0 battery monitors provide low-side FET drivers that work well for many systems. For some systems, high-side FETs may also be beneficial. High-side FETs enable continuous communication between a host controller and the monitor, regardless of whether the FETs are on or off. This allows the controller to read critical pack parameters despite safety faults, enabling the system to access pack conditions before allowing normal operations to resume. The BQ769200 high-side N-channel FET driver can be used with the BQ769x0 monitor in systems where high-side FETs are needed. See Figure 9-4.
| EVENT | [CHG_ON] | [DSG_ON] |
|---|---|---|
| OV Fault | Set to 0 | — |
| UV Fault | — | Set to 0 |
| OCD Fault | — | Set to 0 |
| SCD Fault | — | Set to 0 |
| ALERT Override | Set to 0 | Set to 0 |
| DEVICE_XREADY is set | Set to 0 | Set to 0 |
| Enter SHIP mode from NORMAL | Set to 0 | Set to 0 |
The host microcontroller must initiate all protection recovery. To resume FET operation after a fault condition, the host microcontroller must first clear the corresponding status bit in the SYS_STAT register, which will clear the ALERT pin, and then manually reenable the CHG and/or DSG bit. Certain faults, such as OV or UV, may immediately retoggle if such a condition still persists. Refer to Table 8-3 for details on clearing status bits.
There are no conditions under which the BQ769x0 automatically sets either [CHG_ON] or [DSG_ON] to 1.