1.1.2. Power Scheme for Peripherals
Peripherals that require power supply on an audio board include Wi-Fi module, Codec
module, DSP module, PA power amplifier module, Micro SD card module, LED module,
etc. While PA power amplifier is directly powered by USB/Battery, the other modules are
powered through the power management chip, which converts the USB/Battery voltage to
the voltage they require.
For increased reliability, you can reserve a separate power management chip and optional
resistors for each module in case an independent (backup) power supply is needed. During
debugging, you can determine whether some chips can be removed, based on the actual
test results. The power management chip of your choice should meet the circuit
requirements for input and output of current and voltage, low noise, efficiency and other
aspects of the circuit. For example:
!
Figure 1-2. Power Supply Management Circuit for Peripherals
1.1.3. Ground Plane Splitting Scheme
For the above-listed modules (Wi-Fi module, Codec module, DSP module, PA power
amplifier module, Micro SD card module, LED module, etc.), their reference ground planes
should be separated according to the actual situation. For example, the reference ground
plane of Wi-Fi module and Micro SD card is DGND; the reference ground plane for PA
power amplifier and external loudspeaker is AGND; Codec module, DSP module, LED light
and other chips also have their own reference ground planes. It is also recommended to
provide a separate ground plane for the input power module. These planes should be
connected by a short circuit with a 0R resistor (Packaging should be above 0603), such as
at the following figure:
