Schematic Design; Power Supply And Gnd Plane; Usb/Battery Power Scheme - Espressif Systems ESP32 Design Manuallines

!
1.
The circuit design of an audio product, based on the ESP module provided by Espressif,
can be broken down into three major sections:

• Power supply and GND plane.

• Design rules of audio chips.
• Pin configuration of the ESP32 module.
1.1. Power Supply and GND Plane

1.1.1. USB/Battery Power Scheme

When the module works in Wi-Fi mode, peak current in the circuit is very high. The
suggested output current for the module's power supply is no less than 500 mA. As audio
boards generally require an external battery, your design may need a charging management
chip, for example AP5056, to charge the battery. You can choose a chip according to your
actual needs.
If the battery is used to power the whole system, please make sure that it is connected to
the circuit and that the VBAT pin of the charging management chip, serving as the input of
the system power supply, is connected to the positive terminal of the battery. As soon as
the charging management chip detects the battery, it starts supplying current of the
nominal value identified in its specification, but if the battery is not detected, the output
current is very small, and power supply for the circuit may be insufficient.
You can avoid this problem by adding a USB/Battery power supply switch circuit into the
design (as shown in Figure 1-1). For example, if a USB cable is plugged in, VBAT pin is cut
off from the system and the power is supplied over USB; otherwise, the power will be
supplied over VBAT.
!
Espressif
USB:
J5
D3 1N5819HW-7-F
6 1
GND VBUS
7 2 D-
GND D-
8 3 D+
GND D+
9 4
GND NC
5
GND
D5 D6
USB_CON8
GND GND GND GND
Charge Circuit:
VBUS
U11
R134 0R(5%) TEMP 1
TEMP
R136 1K(1%) 2
PROG
3
GND
4
VCC
AP5056
C115
10uF/16V(20%)
J6
GND GND
CON2
BATTERY
Figure 1-1. USB/Battery Power Supply Circuit

Schematic Design

VBUS
USB_DN
USB_DP
D7
LESD5D5.0CT1G
LESD5D5.0CT1G
LESD5D5.0CT1G
R132 1K(1%)
R133 1K(1%)
R135 0R(5%)
8
CE
7 D4 RED LED
CHRG
6 R137 0R(5%) D8 GREEN LED
STDBY
5
BAT
9
PGND
GND
VBAT
2
C116 C117
1
100uF/6.3V(20%) 10uF/16V(20%)
GND
! /19 1
1. Schematic Design
USB/Battery Switch:
VBUS DCIN
D14 SS24
VBAT
Q5
VBUS
AO3401
R174 100K(1%)
C129 C130
10uF/16V(20%) 0.1uF/16V(10%)
R175
100K(1%)
GND GND GND
1.When USB is plugged in,
DCIN will be only powered by USB.
2.Otherwise, DCIN is powered by VBAT.
2019.01