BCM4330 Preliminary Data Sheet
WLAN Power Management
WLAN Power Management
The BCM4330 has been designed with the stringent power consumption requirements of mobile devices in
mind. All areas of the chip design are optimized to minimize power consumption. Silicon processes and cell
libraries were chosen to reduce leakage current and supply voltages. Additionally, the BCM4330 integrated
RAM is a high Vt memory with dynamic clock control. The dominant supply current consumed by the RAM is
leakage current only. Additionally, the BCM4330 includes an advanced WLAN power management unit (PMU)
sequencer. The PMU sequencer provides significant power savings by putting the BCM4330 into various power
management states appropriate to the current environment and activities that are being performed. The
power management unit enables and disables internal regulators, switches, and other blocks based on a
computation of the required resources and a table that describes the relationship between resources and the
time needed to enable and disable them. Power up sequences are fully programmable. Configurable, free-
running counters (running at 32.768 kHz LPO clock) in the PMU sequencer are used to turn on/turn off
individual regulators and power switches. Clock speeds are dynamically changed (or gated altogether) for the
current mode. Slower clock speeds are used wherever possible.
The BCM4330 WLAN power states are described as follows:
• Active mode—All components in the BCM4330 are powered up and fully functional with active carrier
sensing and frame transmission and receiving. All required regulators are enabled and put in the most
efficient mode (PWM or Burst) based on the load current. Clock speeds are dynamically adjusted by the
PMU sequencer.
• Doze mode—The radio, AFE, PLLs, and the ROMs are powered down. The rest of the BCM4330 remains
powered up in an IDLE state. All main clocks are shut down. The 32.768 kHz LPO clock is available only for
the PMU sequencer. This condition is necessary to allow the PMU sequencer to wake up the chip and
transition to Active mode. In Doze mode, the primary power consumed is due to leakage current. The
external switcher and internal baseband switcher are put into Burst mode (for better efficiency at low load
currents).
• Power-down mode—The BCM4330 is effectively powered off by shutting down all internal regulators. The
chip is brought out of this mode by external logic re-enabling the internal regulators.
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BROADCOM
BCM4330 Preliminary Data Sheet
April 28, 2011 • 4330-DS304-RI
Page 28
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