How the esp32 deep sleep current is lower than 10uA

Chen Tuo 2022/05/26-2022/05/29

1. summary

This article is based on official routines , experiment ESP32 Modules in Deep-sleep Implementation of ultra low power consumption in mode .

1.1 Deep sleep Deep-sleep

Official documents ：

https://docs.espressif.com/projects/esp-idf/zh_CN/latest/esp32/api-reference/system/sleep_modes.html

ESP32 have Light-sleep and Deep-sleep Two sleep saving modes .

stay Light-sleep In mode , Digital peripherals 、CPU、 And for the most part RAM All use clock gating , At the same time, the power supply voltage decreases . After exiting this mode , Digital peripherals 、CPU and RAM Resume operation , The internal state remains unchanged .

stay Deep-sleep In mode ,CPU、 Most of the RAM、 And all by the clock APB_CLK All the digital peripherals driven will be powered off . The part of the chip that continues to be in the power supply state only includes ：

• RTC controller
• RTC peripherals
• ULP Coprocessor
• RTC High speed memory
• RTC Low speed memory

Light-sleep and Deep-sleep There are multiple wake-up sources in this mode . These wake-up sources can also be combined , At this time, any wake-up source can trigger wake-up .

[APB_CLK（APB The clock ）]

ESP32 Of CPU Master clock CPU_CLK The main frequency can reach 160MHz, Too high for external devices , Can't be used directly , Frequency division required .ESP32 A variety of clock options with different frequencies are provided , It can be configured flexibly CPU, peripherals , as well as RTC Working frequency of , To meet different power consumption and performance requirements .

Peripheral clocks include APB_CLK,REF_TICK,LEDC_SCLK,APLL_CLK and PLL_D2_CLK.

1.2 Power consumption of different modes

1.3 The awakening source of this experiment

To test the minimum current consumption , This experiment does not use touch to wake up 、ULP Wake up and GPIO Wake up the , Only use the timer to wake up . Other ways to wake up , Future articles will cover .

1.4 Official routine domestic mirror

The main content of this article comes from the official routine Deep Sleep Example

https://gitee.com/EspressifSystems/esp-idf/tree/master/examples/system/deep_sleep

1.5 Test circuit board

The following are common in the market ESP32 The development board cannot be used in this experiment because of its peripheral circuit .

The circuit schematic diagram of this development board is attached at the back of this paper .

In order to reduce the influence of additional circuit on measurement , We need to make a test circuit board by ourselves . Production methods ：1 individual ESP32-S The module is welded on a base plate , Add 2 Button （RESET and IO0）,2 Buttons each with 1 individual 10k The pull-up resistance of , As shown on the right side of the figure below .

use 2 A current meter measures the current . High current 2 Two meter heads shall be connected in parallel, otherwise uA The internal resistance of the meter is too large to move , In addition, I can type a watch . Remove it when the current is low mA Header .

Cheap and effective measurement methods ：

Burn program and view serial port LOG I need one more USB To serial port downloader ：

2. development environment

《 Use Lexin domestic Gitee Image building ESP32 development environment 》

https://zhuanlan.zhihu.com/p/348106034

https://blog.csdn.net/chentuo2000/article/details/113424934?spm=1001.2014.3001.5501

3. Build the project

This example demonstrates how to use esp_sleep.h API Enter deep sleep mode , Then wake up from the timer source .

Timer is a kind of RTC Timer , Programmable to trigger wakeup after a preset time . This example will every 20 Seconds triggers a wake-up .

• Copy official routine

Copy the official example project to ESP-IDF Beyond development tools ：

cd ~/esp

cp -r esp-idf/examples/system/deep_sleep/ ~/esp/esp32_deep_sleep

• Project tree

cd esp32_deep_sleep

4. Build the project

• Refresh esp-idf Environmental Science

get_idf

• Set the target chip

idf.py set-target esp32

• Configuration items

idf.py menuconfig

1) Set up Flash The memory size is 4MB

2) To test the minimum current consumption , Wake up without touch 、ULP Wake up and GPIO Wake up the

3) choice Skip image validatin when exiting deep sleep

Use this option , It allows you to reduce the boot time of the boot loader when you wake up from deep sleep . The boot loader stores the address of the running partition in rtc In the memory , And use it when you wake up . This example allows you to skip all image checks and speed up boot .

preservation , sign out .

• Compile the project

idf.py build

• Burn project

see USB Serial port COM slogan ：

burning ：

idf.py -p /dev/ttyS3 -b 115200 flash

Write operation （ You can send the above command before or after ）：

1) Hold down IO0 Button

2) Press down RST Button , Let go again

3) Release IO0 Button

If not, power on again and try again .

• Enable monitor

idf.py monitor -p /dev/ttyS3

（Ctrl+] You can exit the monitor program ）

First run

Subsequent operation

• Wake up current （ parallel connection mA surface ）

• deep sleep electric current （ To break off mA surface ）

deep sleep The current is 66uA, Distance from... In the manual 20uA The difference is too far .

5. Reduce deep-sleep electric current

• Main reference

https://electronics.stackexchange.com/questions/530151/esp32-wroom32-consuming-77-%c2%b5a-much-too-high-in-deep-sleep

• Modify the program

stay deep_sleep_example_main.c Of app_main Add the following statement at the beginning of the function ：

void app_main(void)
{
    gpio_reset_pin(GPIO_NUM_0);
    gpio_reset_pin(GPIO_NUM_2);
    gpio_reset_pin(GPIO_NUM_4);
    gpio_reset_pin(GPIO_NUM_12);
    gpio_reset_pin(GPIO_NUM_13);
    gpio_reset_pin(GPIO_NUM_14);
    gpio_reset_pin(GPIO_NUM_15);
    gpio_reset_pin(GPIO_NUM_25);
    gpio_reset_pin(GPIO_NUM_26);
    gpio_reset_pin(GPIO_NUM_27);
    gpio_reset_pin(GPIO_NUM_32);
    gpio_reset_pin(GPIO_NUM_33);
    gpio_reset_pin(GPIO_NUM_34);
    gpio_reset_pin(GPIO_NUM_35);
    gpio_reset_pin(GPIO_NUM_36);
    gpio_reset_pin(GPIO_NUM_37);
    gpio_reset_pin(GPIO_NUM_38);
    gpio_reset_pin(GPIO_NUM_39);

explain ：

gpio_reset_pin Function will gpio The pin is reset to the default state （ choice gpio function , Enable pull-up and disable input and output ）.

recompile 、 burning 、 perform .

• Wake up current （ parallel connection mA surface ）

• deep sleep electric current （ To break off mA surface ）

The current is less than 10uA.

6. Add one LED As gpio The load of

6.1 add to gpio load

• Add load to the power supply （ Fill with electricity sink current）

GPIO_NUM_2,GPIO_NUM_4 and GPIO_NUM_15 These pins add a load to ground （ Pull the current source current） It will increase the deep sleep current to 60uA above . Connect as shown in the attached circuit diagram LED1 You can't , To put LED The positive pole of is connected to 3.3v On the power supply ,LED The negative pole of the is grounded GPIO Pin , That is, the current filling connection method , In this way, the sleep current can be reduced .

• Be careful not to use GPIO_NUM_2

Use current filling connection GPIO2 It will affect firmware burning .

• We use GPIO4 Connect LED

6.2 Modify the program

stay deep_sleep_example_main.c The statements with changes in are as follows , Please check the original code .

#define GPIO_OUTPUT_IO_LED 4 // LED Connect to gpio Pin 4

void led_init(void)
{
    gpio_pad_select_gpio(GPIO_OUTPUT_IO_LED);
    gpio_set_direction(GPIO_OUTPUT_IO_LED, GPIO_MODE_OUTPUT); // Set the GPIO as a push/pull output
}

void led_on(void) {
    gpio_set_level(GPIO_OUTPUT_IO_LED, 0);
}

void led_off(void) {
    gpio_set_level(GPIO_OUTPUT_IO_LED, 1);
}

void app_main(void)
{
    //  After making the following settings, the current changes from 63uA Down to 3uA
    gpio_reset_pin(GPIO_NUM_0);
    gpio_reset_pin(GPIO_NUM_2);
    gpio_reset_pin(GPIO_NUM_4);
    gpio_reset_pin(GPIO_NUM_12);
    gpio_reset_pin(GPIO_NUM_13);
    gpio_reset_pin(GPIO_NUM_14);
    gpio_reset_pin(GPIO_NUM_15);
    gpio_reset_pin(GPIO_NUM_25);
    gpio_reset_pin(GPIO_NUM_26);
    gpio_reset_pin(GPIO_NUM_27);
    gpio_reset_pin(GPIO_NUM_32);
    gpio_reset_pin(GPIO_NUM_33);
    gpio_reset_pin(GPIO_NUM_34);
    gpio_reset_pin(GPIO_NUM_35);
    gpio_reset_pin(GPIO_NUM_36);
    gpio_reset_pin(GPIO_NUM_37);
    gpio_reset_pin(GPIO_NUM_38);
    gpio_reset_pin(GPIO_NUM_39);

    led_init();
    led_off();

    struct timeval now;
    gettimeofday(&now, NULL);
    int sleep_time_ms = (now.tv_sec - sleep_enter_time.tv_sec) * 1000 + (now.tv_usec - sleep_enter_time.tv_usec) / 1000;

    switch (esp_sleep_get_wakeup_cause()) {
#ifdef CONFIG_EXAMPLE_EXT1_WAKEUP
        case ESP_SLEEP_WAKEUP_EXT1: {
            uint64_t wakeup_pin_mask = esp_sleep_get_ext1_wakeup_status();
            if (wakeup_pin_mask != 0) {
                int pin = __builtin_ffsll(wakeup_pin_mask) - 1;
                printf("Wake up from GPIO %d\n", pin);
            } else {
                printf("Wake up from GPIO\n");
            }
            break;
        }
#endif // CONFIG_EXAMPLE_EXT1_WAKEUP
#if SOC_GPIO_SUPPORT_DEEPSLEEP_WAKEUP
        case ESP_SLEEP_WAKEUP_GPIO: {
            uint64_t wakeup_pin_mask = esp_sleep_get_gpio_wakeup_status();
            if (wakeup_pin_mask != 0) {
                int pin = __builtin_ffsll(wakeup_pin_mask) - 1;
                printf("Wake up from GPIO %d\n", pin);
            } else {
                printf("Wake up from GPIO\n");
            }
            break;
        }
#endif //SOC_GPIO_SUPPORT_DEEPSLEEP_WAKEUP
        case ESP_SLEEP_WAKEUP_TIMER: {
            printf("Wake up from timer. Time spent in deep sleep: %dms\n", sleep_time_ms);
            //led_init();
            led_on();
            vTaskDelay(150 / portTICK_RATE_MS); //  Time delay 150ms
            led_off();
            break;
        }
#ifdef CONFIG_EXAMPLE_TOUCH_WAKEUP

6.3 test result

deep sleep The current is the same as before , Less than 10uA.

attach ：ESP32 Development board circuit schematic diagram

Reference documents

1. https://docs.espressif.com/projects/esp-idf/zh_CN/latest/esp32/api-reference/system/sleep_modes.html?highlight=apb_clk
2. https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/sleep_modes.html#wakeup-sources
3. https://lastminuteengineers.com/esp32-sleep-modes-power-consumption/