SLUSE48B May 2021 – November 2023 BQ79652-Q1 , BQ79654-Q1 , BQ79656-Q1
PRODUCTION DATA
The device implements a power supply BIST (Built-In Self-Test) function to test the primary power supply failure diagnostic paths that cover the following detections:
The power supply BIST is essentially a check on the checker and it is a command base function initiated by host.
The power supply BIST, once started, will force a fault on failure detection path on each supply. Take AVDD OV diagnostic path as an example, when the BIST engine tests the AVDD OV path, the following occur:
Start power supply BIST by sending DIAG_PWR_CTRL[PWR_BIST_GO] = 1. The BIST run will not abort even if a failure is detected during the run. At the end of the BIST run, the result is indicated by the FAULT_PWR2[PWRBIST_FAIL] flag.
The power supply BIST forces a failure and ensures the diagnostic path triggers the fault accordingly. A failure on the BIST run indicates a diagnostic path is unable to trigger in a fault condition. To further examine which path is unable to indicate a failure, host can set the DIAG_PWR_CTRL[BIST_NO_RST] = 1. This bit disables the reset step during the BIST run. Re-start power supply BIST with this option enabled. At the end of the BIST run, examine the FAULT_PWR1 and FAULT_PWR2 registers. Any register flag that remains 0 indicates it is unable to flag a failure.