Current Consumption Test for ESP32 in Deep sleep
ESP32 has 18 RTC GPIOs and 10 touchpads, which can all be configured as the wake-up source to wake up the chip from deep sleep.
Description
Purpose: measure the current consumptions of ESP32 in Deep_sleep mode, under different wake-up setups;
Tool: ESP32_ULP_EB V1 evaluation board.
Scope: The current consumption of all the RTC GPIOs and touchpads of ESP32 are measured in this test, except for RTC GPIO_37 and RTC GPIO_38.
Note
GPIO_37 and GPIO_38 are not tested here, because these two pads are not led out to the pin header of the board.
RTC GPIO
External events can trigger level signals of the RTC GPIO, which has been configured as the wake-up source of the chip, and wake up the chip from deep sleep.
Wake-up source
EXT(0): wake up the chip when a specific GPIO pad, which has been configured as the wake-up source of the chip, meets certain requirement regarding electrical level. This GPIO can be configured as “high-level” triggered or “low-level” triggered;
EXT(1): wake up the chip when a set of specified GPIO pads, which have been configured as the wake-up sources of the chip, all meet certain requirements regarding electrical level. One GPIO can also be seen as a set of specified GPIOs (In this case, EXT(1) has no difference with EXT(0)).
Configuration
Set a RTC GPIO as the wake-up source of the chip, and configure it to input floating mode;
Resistors:
when the GPIO is configured as high-level triggered, a 10 kΩ pull-down resistor should be used;
when the GPIO is configured as low-level triggered, a 10 kΩ pull-up resistor should be used;
Note
To achieve lower power consumption, external resistors, instead of internal ones, are recommended in this case.
Test Result
Wake-up source: EXT(0)
GPIO NUM |
Low-level triggered |
High-level triggered |
|---|---|---|
GPIO_0 |
6.3 uA |
6.2 uA |
GPIO_2 |
6.3 uA |
6.2 uA |
GPIO_4 |
6.4 uA |
6.2 uA |
GPIO_12 |
6.4 uA |
6.4 uA |
GPIO_13 |
6.3 uA |
6.3 uA |
GPIO_14 |
6.3 uA |
6.3 uA |
GPIO_15 |
6.4 uA |
6.4 uA |
GPIO_25 |
6.3 uA |
6.5 uA |
GPIO_26 |
6.6 uA |
6.3 uA |
GPIO_27 |
6.4 uA |
6.4 uA |
GPIO_32 |
6.4 uA |
6.4 uA |
GPIO_33 |
6.4 uA |
6.4 uA |
GPIO_34 |
6.4 uA |
6.2 uA |
GPIO_35 |
6.4 uA |
6.3 uA |
GPIO_36 |
6.4 uA |
6.3 uA |
GPIO_37 |
||
GPIO_38 |
||
GPIO_39 |
6.4 uA |
6.3 uA |
Wake-up source: EXT(1)
GPIO NUM |
Low-level triggered |
High-level triggered |
|---|---|---|
GPIO_0 |
5.2 uA |
5.3 uA |
GPIO_2 |
5.2 uA |
5.2 uA |
GPIO_4 |
5.2 uA |
5.2 uA |
GPIO_12 |
5.2 uA |
5.3 uA |
GPIO_13 |
5.3 uA |
5.2 uA |
GPIO_14 |
5.3 uA |
5.3 uA |
GPIO_15 |
5.3 uA |
5.2 uA |
GPIO_25 |
5.2 uA |
5.3 uA |
GPIO_26 |
5.3 uA |
5.2 uA |
GPIO_27 |
5.3 uA |
5.3 uA |
GPIO_32 |
5.3 uA |
5.3 uA |
GPIO_33 |
5.3 uA |
5.3 uA |
GPIO_34 |
5.3 uA |
5.7 uA |
GPIO_35 |
5.3 uA |
5.7 uA |
GPIO_36 |
5.3 uA |
5.3 uA |
GPIO_37 |
||
GPIO_38 |
||
GPIO_39 |
5.4 uA |
5.5 uA |
Conclusion
The current consumptions of the chip are basically the same and extremely low during the deep sleep, when different RTC GPIOs are configured as the wake-up sources；
The current consumptions of the chip in EXT1 mode are about 1 uA lower than that in EXT0 mode.
Pad Num |
Current |
|---|---|
Pad0 (GPIO_4) |
37.3 uA |
Pad1 (GPIO_0) |
35.7 uA |
Pad2 (GPIO_2) |
36.6 uA |
Pad3 (GPIO_15) |
35.6 uA |
Pad4 (GPIO_13) |
36.5 uA |
Pad5 (GPIO_12) |
36.1 uA |
Pad6 (GPIO_14) |
36.7 uA |
Pad7 (GPIO_27) |
35.7 uA |
Pad8 (GPIO_33) |
36.7 uA |
Pad9 (GPIO_32) |
36.3 uA |
Touchpad
Touchpad can be enabled as the wake-up source to wake up the chip from deep sleep.
Configuration
Set a touchpad as the wake-up source of the chip, and initialize this pad;
Set up the touchpad’s trigger threshold.
Test Result
Wake-up source: touchpad
Pad Num |
Current |
|---|---|
Pad0 (GPIO_4) |
37.3 uA |
Pad1 (GPIO_0) |
35.7 uA |
Pad2 (GPIO_2) |
36.6 uA |
Pad3 (GPIO_15) |
35.6 uA |
Pad4 (GPIO_13) |
36.5 uA |
Pad5 (GPIO_12) |
36.1 uA |
Pad6 (GPIO_14) |
36.7 uA |
Pad7 (GPIO_27) |
35.7 uA |
Pad8 (GPIO_33) |
36.7 uA |
Pad9 (GPIO_32) |
36.3 uA |
Note
touch_pad_set_meas_time can be used to adjust the charging/discharging cycle and the detection period of the touch sensor accordingly, so as to optimize the response time and achieve even lower power consumption.