board power consumption (L0, v3pwr, nucleo stm32l053r8)
Questions are at the end
I did some measurements with nucleo stm32l053r8, stlinkv2 cut off, led3 removed
power supply form v3pwr via
- 3.3V cn6 pin4
- GND cn6 pin6
Tools used
- stm cubemonitor power v1.2.1 & stlinkv3pwr
- multimeter (should still count as factory calibrated, price roughly 2x stlinkv3pwr -> values should be OK)
Measuring current
- via IDD
- in power wire
Code Basis: cubemx stm32 project for stm32l053r8 with
- all free pins analog
- MSI clock 1MHz
- USART2 9600 Bit/s
Measurement settings : voltage 3.3V, sampling frequency 100 Hz
Full Power Code:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
while(1) {
}
/* USER CODE END 2 */
…
stm cubemonitor power, multiple measurements
- between 370 uA and 380 uA
- sometimes more ripple, sometimes less
- several times jumps in current, see one example image
multimeter in power line
- value continuously changing, from 371 uA to 377ua with 3.3 uA to 3.7uA AC
multimeter in IDD
- value continuously changing, from 206 uA to 214uA with 6.6 uA to 6.9 uA AC
- value seems to follow the sawtooth pattern
Expected for MCU at 3.3V and 1 MHz, see “Table 28. Current consumption in Run mode, code with data processing running from Flash”
-> Should fit for 1MHz run from Flash
Standby Code:
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
HAL_PWR_EnterSTANDBYMode();
…
stm cubemonitor power, multiple measurements
- between 158 uA and 159 uA
multimeter in power line
- value continuously changing, from 161.9 uA to 162.1 uA with 0.1uA AC
multimeter in IDD
- value continuously changing, from 1.78 uA .. 1.80 uA with no AC
Expected; see "Table 36. Typical and maximum current consumptions in Standby mode"
No IWDG / LSI OFF TA = − 40 to 25°C 0.29 0.6 uA
IWDG / LSI ON TA = − 40 to 25°C 1.3 1.7 uA
Should be OK as not configured to use LSE
Question 1
Given Run Mode
~375uA Board incl MCU - ~210uA MCU —> ~165uA board
UART2 is configured but not in action
Given Standby Mode
~162uA Board incl MCU - ~2uA MCU —> ~160uA board
Where is the ~160uA going on the board
Question 2
A current jump as in the screenshot has happened to me quite often. Is this OK for the v3pwr ?
