Ultra low power microcontroller extends battery life

A Norwegian startup is pushing the limits of low power in microcontrollers, cutting power by a factor of four over even 8bit devices.
Energy Micro has developed the EFM32 low power 32bit microcontroller based on the ARM Cortex-M3 architecture with low power clocks and peripherals that consumes less than 180µA per MHz while executing real life code from Flash memory and the lowest active mode current consumption of any microcontroller. Its standby current consumption is also the lowest, at typically 900nA while running real time clock, power-on reset, brown-out detector and full RAM and CPU retention and less than 20nA in its deepest sleep mode. The start-up time of less than 2µs is also the industry’s fastest. The power is lower than traditional 16 or 8bit devices from Silicon Labs, Texas Instruments and Microchip (see chart).

“We are very proud that we have delivered on our mission to provide the world with the most energy friendly microcontrollers,” said Geir Forre, founder and CEO. “By introducing innovative new energy saving features, such as our peripheral reflex system and energy management unit, the potential saving in battery life that can be achieved is immense.”

The low power peripherals include:
a 4x40 segment LCD controller running at less than 900nA;
an 8-channel 12-bit 1M samples/sec ADC running at less than 200µA;
a brown-out detector running at less than 100nA;
a 32kHz real time counter running at 50nA;
and a UART capable of 9600bps at 100nA.

The devices, built in standard low leakage CMOS, are initially targetted at smart metering and home automation, with battery lifetimes of 10 to 15 years with low cycle times. “The EFM32G family of microcontrollers has been specified in close partnership with many world leading companies within, for example, the energy metering, home and building automation and alarm and security industries,” said Øyvind Janbu, co-founder and CTO of Energy Micro. “Working so closely with top engineers in such sectors has enabled us to produce a family of microcontrollers that truly is a perfect fit for a variety of different applications.”
One of Energy Micro’s partner customers is window maker Velux, one of the strongest brands in the global building materials and home improvement industry. It is planning to use the EFM32 in a range of contorllers later this year.
Meter company Kamstrup is also looking to use the device for products next year.
There are 22 different EFM32G microcontroller products which will become available over the next few months, in a variety of packages including QFN32, QFN64, QFP100 and BGA112. The EFM32G operates from a single supply rail of between 1.8 and 3.8V. The operating temperature range is –40degC to +85degC. The microcontrollers provide up to 128KB Flash memory and up to 16KB of RAM.
The first products are being offered by Energy Micro in QFN64 and BGA112 profiles and are currently sampling with lead customers. Pricing for the initial 32-pin devices starts at $1.55 in 100k quantities.