SLUUC54C February 2020 – March 2024 BQ27Z558 , BQ27Z561 , BQ27Z561-R2
Another method available in the BQ27Z561-R2 gauge is to estimate an accurate OCV reading. After a set wait time (OCV Pred Transient T) in RELAX mode, the gauge begins to accumulate voltage readings. Once OCV Pred Measure Time has passed, the gauge uses a fast OCV algorithm to predict the final OCV value. This fast OCV method is enabled by setting IT Gauging Ext[FOCV_EN] = 1. This method provides the benefit of reduced relaxation requirements for QMax updates. If at any time the requirements for the conventional OCV method are achieved (dV/dt of < 1 μV/s requirement) after a fast OCV estimation, the device updates the OCV measurement accordingly. For a fast OCV estimate, entry into RELAX mode must be preceded by at least OCV Pred Active T Limit of a charge or discharge current large enough for the BQ27Z561-R2 to exit RELAX mode.
| Class | Subclass | Name | Type | Min | Max | Default | Unit | Description |
|---|---|---|---|---|---|---|---|---|
| Gas Gauging | IT Cfg | OCV Pred Active T Limit | U2 | 100 | 65535 | 200 | s | This is the minimum time the gauge must be in CHARGE or DISCHARGE mode before entering into RELAX mode for a fast OCV estimate. |
| Gas Gauging | IT Cfg | OCV Pred Transient T | U2 | 100 | 65535 | 300 | s | This is the minimum time the gauge must be in RELAX mode before fast OCV voltage readings start to accumulate. |
| Gas Gauging | IT Cfg | OCV Pred Measure Time | U2 | 0 | 65535 | 200 | s | This is the time in RELAX mode when fast OCV voltage readings are accumulated and fast OCV is predicted. |