Datasheet

3. FUNCTIONAL DESCRIPTION
3.4 RTC and Low-Power Management
With the use of advanced power-management technologies, ESP32 can switch between different power modes.
• Power modes
– Active mode: The chip radio is powered on. The chip can receive, transmit, or listen.
– Modem-sleep mode: The CPU is operational and the clock is configurable. The Wi-Fi/Bluetooth base-
band and radio are disabled.
– Light-sleep mode: The CPU is paused. The RTC memory and RTC peripherals, as well as the ULP
co-processor are running. Any wake-up events (MAC, host, RTC timer, or external interrupts) will wake
up the chip.
– Deep-sleep mode: Only RTC memory and RTC peripherals are powered on. Wi-Fi and Bluetooth
connection data are stored in the RTC memory. The ULP co-processor is functional.
– Hibernation mode: The internal 8-MHz oscillator and ULP co-processor are disabled. The RTC recovery
memory is powered down. Only one RTC timer on the slow clock and certain RTC GPIOs are active.
The RTC timer or the RTC GPIOs can wake up the chip from the Hibernation mode.
The power consumption varies with different power modes and work statuses of functional modules. Please see
Table 4 for details.
Table 4: Power Consumption by Power Modes
Power mode Description Power consumption
Active (RF working)
Wi-Fi Tx packet
Please refer to ESP32 Datasheet.Wi-Fi / BT Tx packet
Wi-Fi / BT Rx and listening
Modem-sleep The CPU is powered on.
Max speed 240 MHz: 30 mA ~ 50 mA
Normal speed 80 MHz: 20 mA ~ 25 mA
Slow speed 2 MHz: 2 mA ~ 4 mA
Light-sleep - 0.8 mA
Deep-sleep
The ULP co-processor is powered on. 150 µA
ULP sensor-monitored pattern 100 µA @1% duty
RTC timer + RTC memory 10 µA
Hibernation RTC timer only 5 µA
Power off CHIP_PU is set to low level, the chip is powered off 0.1 µA
Note:
• When Wi-Fi is enabled, the chip switches between Active and Modem-sleep mode. Therefore, power consumption
changes accordingly.
• In Modem-sleep mode, the CPU frequency changes automatically. The frequency depends on the CPU load and
the peripherals used.
• During Deep-sleep, when the ULP co-processor is powered on, peripherals such as GPIO and I2C are able to
operate.
• When the system works in the ULP sensor-monitored pattern, the ULP co-processor works with the ULP sensor
periodically; ADC works with a duty cycle of 1%, so the power consumption is 100 µA.
Espressif Systems 7 ESP32-WROOM-32 Datasheet V2.5