Espressif Systems ESP32 Series, Руководство по дизайну

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1. Schematic Design
1. Schematic Design
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.
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Figure 1-1. USB/Battery Power Supply Circuit
D-
D+ USB_DP
USB_DN
TEMP
GND GND GND
VBUS
GND
GND
GND
GND
VBUS
VBAT
GND
DCIN
GND
VBAT
VBUS
GND GND
VBUS
BATTERY
Charge Circuit:
USB:
1.When USB is plugged in,
DCIN will be only powered by USB.
2.Otherwise, DCIN is powered by VBAT.
USB/Battery Switch:
R174 100K(1%)
D6
LESD5D5.0CT1G
U11
AP5056
TEMP
1
PROG
2
GND
3
VCC
4
BAT
5
STDBY
6
CHRG
7
CE
8
PGND
9
J5
USB_CON8
VBUS
1
D-
2
D+
3
GND
5
NC
4
GND
6
GND
7
GND
8
GND
9
R175
100K(1%)
Q5
AO3401
J6
CON2
2
1
C117
10uF/16V(20%)
R135 0R(5%)
D4 RED LED
D14 SS24
D7
LESD5D5.0CT1G
R134 0R(5%)
R133 1K(1%)
C129
10uF/16V(20%)
C116
100uF/6.3V(20%)
C130
0.1uF/16V(10%)
D8 GREEN LED
R137 0R(5%)
R136 1K(1%)
D5
LESD5D5.0CT1G
D3
1N5819HW-7-F
C115
10uF/16V(20%)
R132 1K(1%)
Espressif ! /19 1 2019.01