Infineon has released a new programmable 32-bit ARM® Cortex®-M0 microcontroller (MCU) for developing cost-effective smart actuators such as passive locks.

For most of the current smart locks, their "smart" can only work when there is a power supply. This MCU from Infineon can solve the problem of battery limitation very well.

Infineon Unveils an NFC Actuation Controller

The IC consists of an NFC transceiver with an associated harvesting module and an integrated half-bridge capable of delivering up to 250mA peak current for motor control and drive. The NAC1080 MCU is embedded in the near-field communication (NFC) front end, allowing the device to be controlled directly from a smartphone. Advanced on-premises and cloud capabilities can be extended in mobile apps provided by regional marketing partners.

Infineon NAC1080

The NAC1080 supports multiple modes of operation. The first is an active power supply mode, and the second is a passive power supply mode.

In active mode, the device is powered by an external 3V power supply. In passive mode, no external power supply is required, the chip uses the energy harvested from the external NFC RF field to be stored in an external capacitor (sized to store the energy needed to start the actuator).

Designing a smart lock without batteries, the lock can work directly with a smartphone. When collecting a tap on the smart lock, the lock will collect the event NFC energy from the phone to unlock or lock the door. In addition to passive NFC lock applications, NAC1080 can also be used as emergency backup power applications.

The energy storage requirement of the system is an important factor to be considered in the design process of the smart lock. In the above smart lock design, the total energy collected by the system must exceed the requirements of the MCU and actuator, and the storage capacitor must be properly sized to provide the required energy.

Other design factors include antenna impedance matching, coupling coefficients between the transmitter and receiver antennas, and the electrical-mechanical power conversion efficiency of the motor itself.

The NAC1080 also provides an integrated AES128 accelerator and a true random number generator for data encryption/decryption in an ultra-low power environment.

Applications include low-power locks such as in gyms, hospitals, office furniture, bicycles, and mailboxes, as well as more complex locks designed to protect front doors. The chip is expected to enable battery-free operation of IoT devices by integrating NFC acquisition, H-bridge control, and an ARM core into a single device.