Power Supply

Power Sources

The ESP32-S3-DevKitC-1 can be powered through three methods:

1. USB Power (Recommended)

Either USB port provides 5V power:

Port	Connector	IC	Notes
UART (J2)	Micro-USB	CP2102N	Programming + Power
USB (J4)	Micro-USB	Native ESP32-S3	USB-OTG + Power

2. External 5V Supply

Apply 5V directly to the 5V header pin:

Parameter	Value
Voltage Range	4.5 - 5.5V
Maximum Current	800 mA
Protection	D1/D7 Schottky diodes

3. Direct 3.3V Supply

Bypass the LDO by applying regulated 3.3V to the 3V3 pin:

Parameter	Value
Voltage Range	3.0 - 3.6V
Maximum Current	Limited by supply
Notes	Bypasses onboard regulator

Power Path

graph TD
    USB["USB 5V"] --> D1["D1 (Schottky)"]
    EXT["External 5V"] --> D7["D7"]
    D1 --> RAIL["5V Pin"]
    D7 --> RAIL
    RAIL --> LDO["SGM2212 LDO"]
    LDO --> V33["3.3V Rail"]
    V33 --> ESP["ESP32-S3"]

Schottky Diodes (D1, D7)

The 1N5819HW Schottky diodes provide:

Reverse polarity protection
OR-ing between USB and external 5V
Low forward voltage drop (~0.3V)

LDO Regulator

SGM2212-3.3 Specifications

Parameter	Value
Input Voltage	4.5 - 5.5V
Output Voltage	3.3V ±2%
Maximum Current	500 mA
Dropout Voltage	300 mV @ 500 mA
Quiescent Current	65 μA
Thermal Shutdown	150°C

Current Budget

Typical Current Consumption

Component	Current
ESP32-S3 (active, 240 MHz)	70 mA
Wi-Fi TX	+280 mA
Wi-Fi RX	+25 mA
Bluetooth TX	+60 mA
Bluetooth RX	+25 mA
RGB LED (max brightness)	20 mA
Total (worst case)	~450 mA

Budget Example

Planning a project with:

ESP32-S3 running Wi-Fi (150 mA average)
5 external LEDs (10 mA each = 50 mA)
Small sensor (10 mA)
Total: 210 mA

This fits within the 500 mA LDO limit with margin.

Low Power Modes

Sleep Mode Current

Mode	Current	Wake Sources
Active	70-350 mA	-
Modem Sleep	~20 mA	CPU timer, GPIO
Light Sleep	~130 μA	Timer, GPIO, touch
Deep Sleep	~7 μA	Timer, GPIO, ULP
Hibernate	~5 μA	Timer only

Deep Sleep Configuration

#include <esp_sleep.h>

void enterDeepSleep(uint64_t sleepTimeUs) {
    // Configure wake sources
    esp_sleep_enable_timer_wakeup(sleepTimeUs);

    // Optional: GPIO wake
    esp_sleep_enable_ext0_wakeup(GPIO_NUM_4, LOW);

    // Enter deep sleep
    esp_deep_sleep_start();
}

Battery Operation

For battery-powered projects:

LiPo Battery Connection

graph LR
    subgraph "Option A: Via 5V rail"
        LIPO1["LiPo 3.7V"] --> BOOST["Boost/Buck to 5V"] --> PIN5V["5V Pin"]
    end
    subgraph "Option B: Direct 3.3V"
        LIPO2["LiPo 3.7V"] --> LDO["LDO 3.3V"] --> PIN3V3["3V3 Pin<br/>(bypass onboard LDO)"]
    end

Battery Monitoring

Use ADC to monitor battery voltage:

#define BATTERY_PIN 4  // GPIO4 with voltage divider
#define VOLTAGE_DIVIDER_RATIO 2.0  // R1=R2=10K

float readBatteryVoltage() {
    int adcValue = analogRead(BATTERY_PIN);
    float voltage = (adcValue / 4095.0) * 3.3 * VOLTAGE_DIVIDER_RATIO;
    return voltage;
}

Power Design Tips

1. Decoupling Capacitors

The board includes bulk and decoupling capacitors:

10μF on 5V rail
10μF on 3.3V rail
0.1μF near ESP32-S3 power pins

2. High-Current Peripherals

For motors, relays, or high-power LEDs:

Use external power supply
Add isolation (optocouplers, transistors)
Consider separate ground planes

3. Noise Reduction

Keep high-frequency signals away from power lines
Use ferrite beads on noisy loads
Add local decoupling for sensitive analog circuits

4. ESD Protection

The board includes ESD protection diodes (LESD5D5.0CT1G) on:

USB data lines
Boot/Reset buttons
Critical GPIO

Power Consumption Measurement

Using USB Power Meter

Insert USB power meter between USB cable and board
Measure idle current
Trigger various modes (Wi-Fi, BLE, sleep)
Record measurements

Using INA219 Module

#include <Adafruit_INA219.h>

Adafruit_INA219 ina219;

void setup() {
    ina219.begin();
}

void loop() {
    float voltage = ina219.getBusVoltage_V();
    float current = ina219.getCurrent_mA();
    float power = ina219.getPower_mW();

    Serial.printf("%.2fV, %.2fmA, %.2fmW\n", voltage, current, power);
    delay(1000);
}