Power Management Features of STMicro STM32L Family

The first thing that has an overall effect in keeping power consumption low is that ST Micro used a process technology that keeps the leakage current low as far as possible. The 130nm proprietary technology is optimized for ultra-low leakage to maximize efficiency when the microcontroller is active or when sleeping. The ST Micro has also succeeded in bringing down the power consumption by on-board Flash memory. Additional feature that help is an integrated DMA which can keep the peripherals active when the processor and the flash can be turned off.

The STM32L series provides many additional features for optimizing the power consumption. Several ultra low power modes are available that can help minimize power consumption.

• Low-Power Run mode at 32kHz, typical consumption is 10 micro-amps
• Low-Power Sleep mode with one timer active, typical consumption at about 6 micro-amps
• STOP mode: Real-Time Clock (RTC), context preserved, RAM retention at 1.3 micro-amps
• STOP mode: no RTC, context preserved, RAM retention at 0.5 micro-amps
• Stand-By mode: RTC, back-up register preserved, at 1.0 micro-amps
• Stand-By mode: no RTC, Back-up register preserved, at 270 nanoamps 

The family uses dynamic voltage scaling to reduce the internal operating voltage for medium and low operating frequencies. The STM32L circuitry is can deliver high performance at low voltages.Analog features available on the family devices are capable of operating at supply voltages as low as 1.8V. The digital devices can go as low as 1.65V saving battery life.