Silicon Labs is producing ARM M0-based USB-enabled MCUs called Happy Gecko which aim to lower USB power drain and simplify USB connectivity.
Adding USB interfaces to portable, battery-powered connected devices can double the application current consumption, says Silicon Labs.
Happy Gecko USB MCUs have five energy modes enabling applications to remain in an energy-optimal state by spending as little time as possible in active mode.In deep-sleep mode, Happy Gecko MCUs have 0.9 μA standby current consumption (with a 32.768 kHz RTC, RAM/CPU state retention, brown-out detector and power-on-reset circuitry active).
Active-mode power consumption drops down to 130 µA/MHz at 24 MHz with real-world code (prime number algorithm). The USB MCUs further reduce power consumption with a 2-microsecond wakeup time from standby mode.
Like all EFM32 MCUs, the Happy Gecko family includes the six-channel Peripheral Reflex System (PRS) feature, which monitors complex system-level events and allows different MCU peripherals to communicate autonomously with each other without CPU intervention.
The PRS watches for specific events to occur before waking the CPU, thereby keeping the Cortex-M0+ core in an energy-saving standby mode as long as possible, reducing system power consumption and extending battery life.
Peripherals include an analogue comparator, supply voltage comparator, on-chip temperature sensor, programmable current digital-to-analog converter (IDAC), and a 12-bit analog-to-digital converter (ADC) with 350 μA current consumption at a 1 MHz sample rate. On-chip AES encryption enables the secure deployment of wireless connectivity for IoT applications such as smart meters and wireless sensor networks.
The Happy Gecko family eliminates external discretes like crystals and regulators with a crystal-less architecture featuring a full-speed USB PHY, an on-chip regulator and resistors. Happy Gecko MCUs are available QFN, QFP and chip-scale package (CSP) options small enough for use in USB connectors and thin-form-factor wearable designs.
For more detail: Happy Gecko ARM M0-based USB MCUs from Si Labs