CYW20738
1.14 Power Management Unit
The Power Management Unit (PMU) provides power management features that can be invoked by software through power
management registers or packet-handling in the baseband core.
1.14.1 RF Power Management
The BBC generates power-down control signals for the transmit path, receive path, PLL, and power amplifier to the 2.4 GHz trans-
ceiver, which then processes the power-down functions accordingly.
1.14.2 Host Controller Power Management
Power is automatically managed by the firmware based on input device activity. As a power-saving task, the firmware controls the
disabling of the on-chip regulator when in deep Sleep mode.
1.14.3 BBC Power Management
There are several low-power operations for the BBC:
■ Physical layer packet handling turns RF on and off dynamically within packet TX and RX.
■ Bluetooth-specified low-power connection mode. While in these low-power connection modes, the CYW20738 runs on the Low
Power Oscillator and wakes up after a predefined time period.
The CYW20738 automatically adjusts its power dissipation based on user activity. The following power modes are supported:
■ Active mode
■ Idle mode
■ Sleep mode
■ HIDOFF mode
The CYW20738 transitions to the next lower state after a programmable period of user inactivity. Busy mode is immediately entered
when user activity resumes.
In HIDOFF mode, the CYW20738 baseband and core are powered off by disabling power to LDOOUT. The VDDO domain remains
powered up and will turn the remainder of the chip on when it detects user events. This mode minimizes chip power consumption and
is intended for long periods of inactivity.
Document Number: 002-14891 Rev. *C
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