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3. TECHNICAL BRIEF
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LGE Internal Use Only
Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.3.6 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 215 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.