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3. TECHNICAL BRIEF
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3. TECHNICAL BRIEF
For details on pre-charging see the charger chapter. The charger is controlled by an independent state
machine. The pre-charge signal is used to trigger the pre-charge signal is used to trigger the pre-
charge functionality. The charger state machine fully control the pre-charge, the PMU-state machine
now changes to state HPBG on state and the system starts. This state change is indicated to the
charger state-machine to
enable the charger watchdog for safety
3.2.6 Power Supply Start-up sequence
In order to avoid an excessive drop on the battery voltage caused by in-rush current during system
power-on, possibly leading to system instability and “hick-ups” a staggered turn-on approach for the
regulators is implemented. The regulators are turned on in a well defined sequence, thus spreading the
in-rush current transients over time.
The IO’s of X-GOLD TM 213 are isolated in OFF mode (core supply is off). The isolation signal is controlled
by the PMU state machine. This ensures that the PADs are in a well defined state during core supply
settling. This allows to power up the LCORE core regulator and wait for the core to reach reset state
before powering up the I/O supply regulators.