ZHCSTD3B June 2022 – October 2023 BQ756506-Q1
PRODUCTION DATA
Related Pins | Components | Value | Description |
---|---|---|---|
VC0 to VC6 | Filter resistor | 100 Ω | Only differential RC filters are needed for VC channels. Besides serving for input signal filtering, these components are required to support hot-plug events during cell module insertion. Hence, it is highly recommended to use the component values as suggested. |
Filter capacitor | 0.47 μF/16 V or 1 μF/16 V | ||
CB0 to CB6 | Filter resistor | Depends on system’s balancing current requirements | The filter resistor on CB pins sets the maximum balancing current. See Section 8.3.3 for details. Only differential RC filters are needed for CB channels. Besides serving for input signal filtering, these components are required to support hot-plug events during cell module insertion. Hence, it is highly recommended to use the component values as suggested. |
Filter capacitor | 0.47 μF/16 V or 1 μF/16 V |
Cell Connections
It is recommended to populate the battery cells from bottom channels (both VC and CB channels) and up, leaving upper channels as unused channels if cell module size is smaller than the maximum channel size of the device. Unused channel(s) will be connected as shown in Figure 9-3.
Fuse and Relay Status Detection
For systems that require fuse and relay monitoring, the GPIOs can be used for this measurement, as shown in Figure 9-5. The GPIOs provide single-ended ADC measurements of the fuse and relay nodes via a resistor divider, and the difference between these measurements can be used to determine the status of the fuse and the relay. See the fuse and relay diagnostics table for how to detect each case.
RDIV1 and RDIV2 should be sized so that the maximum module voltage does not cause the GPIO voltages to exceed 5V.
Fuse and Relay Diagnostic
In the table below, GPIO8 is used for fuse diagnostics and GPIO7 is used for relay diagnostics. SW1 and SW2 are real voltages at the fuse and relay nodes, calculated from the GPIO resistor dividers. VC4 is the cell voltage measurement of cell 4.
Diagnostic | Open/Blown | Close |
---|---|---|
Fuse | Indicated when (SW1-VC4) <<0V. Open Fuse causes SW1 to be pull down towards ground by the load. | Indicated when (SW1-VC4) = ~0V This IR drop depends on current flow and fuse impedance (e.g. +/-0.3V) |
Relay | Indicated when (SW2-SW1) <<0V Open Relay causes SW2 to be pull down towards ground by the load. | Indicated when (SW2-VC4) = ~ 0V This IR drop depends on current flow and fuse impedance (e.g. +/-0.3V) |