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2. Power Supplies and Power Management
2.1 Power Supply Topology
One core buck regulator, multiple LDO regulators, and a power management unit (PMU) are integrated into the CYW43903. All
regulators are programmable via the PMU. These blocks simplify power supply design for application and WLAN functions in
embedded designs.
A single VBAT (3.0V to 4.8V DC maximum) and VIO supply (1.8V to 3.3V) can be used, with all additional voltages being provided
by the regulators in the CYW43903.
The REG_ON control signal is used to power up the regulators and take the appropriate sections out of reset. The CBUCK, CLDO,
LNLDO, and other regulators power up when any of the reset signals are deasserted. All regulators are powered down only when
REG_ON is deasserted. The regulators may be turned off/on based on the dynamic demands of the digital baseband.
The CYW43903 provides a low power-consumption mode whereby the CBUCK, CLDO, and LNLDO regulators are shut down. When
in this state, the low-power linear regulator (LPLDO1) supplied by the system VIO supply provides the CYW43903 with all required
voltages.
2.2 CYW43903 Power Management Unit Features
The CYW43903 supports the following Power Management Unit (PMU) features:
VBAT to 1.35Vout (550 mA maximum) core buck (CBUCK) switching regulator
■
VBAT to 3.3Vout (450 mA maximum) LDO3P3
■
1.35V to 1.2Vout (350 mA maximum) CLDO with bypass mode for deep-sleep
■
1.35V to 1.2Vout (55 mA maximum) LDO for
■
Additional internal LDOs (not externally accessible)
■
PMU internal timer auto-calibration by the crystal clock for precise wake-up timing from the low power-consumption mode.
■
Figure 3
and
Figure 4
show the regulators and a typical power topology.
Document Number: 002-14826 Rev. *G
PRELIMINARY
BBPLL
CYW43903
Page 8 of 65
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