Small, Low-Energy SoC Released for IoT Devices

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Companies have begun building small, portable medical devices, wearable electronics, asset trackers and home sensors that leverage Silicon Labs' recently released family of Internet of Things (IoT) wireless device system-on-chip (SoC) products. The xG27 family includes the BG27, which offers Bluetooth functionality, as well as the MG27, which supports Zigbee, Bluetooth and proprietary wireless connectivity. Businesses are also using Silicon Labs' BB50 MCU for applications such as personal hygiene, brushless DC motors and LED lighting.

Silicon Labs' goal is to enable companies to offer flexibility in their product portfolio, such as selling one version of a device providing Bluetooth or Zigbee, and an unconnected version that could be lower in cost, all using the same system-on-chip and microcontroller unit (MCU). An SoC is a single chip that contains both an MCU and other components. In the case of the xG27 family, the chips include wireless connectivity. The MCU provides the processing power to capture and manage data on the chip, and users could select a wireless functionality if needed.

For example, an intelligent toothbrush could track an individual's brushing time. One version could simply display the results to the user via the MCU, while the BG27 could provide connectivity via a Bluetooth connection to that person's smartphone, enabling the management of data about the toothbrush's use in the cloud. The MG27's Zigbee functionality will be more often used in applications based on smart lighting, or the monitoring of equipment in an industrial environment, or sensors in an agricultural use case.

Both SoC products are designed to require only low power, with the ability to remain on a shelf for a long period of time without losing battery life. They also feature high security, a relatively low cost and a small size, according to Dhiraj Sogani, Silicon Labs' senior director of wireless product marketing. Both chips have a package that measures 2.3 millimeters by 2.6 millimeters (0.09 inch to 0.1 inch), sized for use in compact medical patches, continuous glucose monitors, wearable electrocardiograms and asset tags in various settings.

The devices are built to reduce battery consumption, the company reports. Both include an integrated DC/DC boost (a switch-mode converter that increases input voltage), and an integrated coulomb counter for battery-level monitoring to avoid battery depletion as products are used. In addition, Sogani says, the device's shelf mode helps it reduce energy usage to less than 20 nanoamperes, so that it can maintain battery life when the device is not in use.

Meeting Challenges for Size and Energy

The security of both SoCs involves Silicon Labs' Secure Vault for secure boot and debugging, to prevent glitch attacks and protect against tampering or remote cyber-threats. Several businesses are now using the SoCs for a wide variety of applications, Sogani reports, including asset tracking, smart homes, industrial equipment management and wearable health monitors.

Traditionally, Sogani says, Silicon Labs' focus has been on wireless connectivity solutions, along with accompanying products such as MCUs. The company builds its products around four fundamental pillars, he says, the first three being low power, security and usability. In the latter scenario, the user experience may not always be emphasized in new technology, he notes, adding that the new SoC family is aimed at enabling "designers to make sure that users get a unified experience."

The fourth pillar is machine learning, Sogani says, though the new SoCs and MCU do not currently come with that function, thereby keeping power consumption low. As wearable and other IoT devices offer greater functionality, often collecting sensor data and transmitting a growing amount of data, both size and energy use are becoming more challenging for the technology and its users, the company explains. "If you look at IoT devices today," he states, "power consumption is becoming more and more important," while there is often no way for users to change batteries on a regular basis.

One example is medical devices, Sogani says. Salivary diagnostics sensor maker Lura Health has developed a preventative health sensor that can be worn within a person's mouth. The device is so small that it can be attached to an individual tooth. The sensor is worn continuously for months, sending data to a smartphone via Bluetooth. With the device, dentists and other clinicians can collect data that can then be used to test for health conditions, including pH acidity, which can cause tooth decay, as well as glucose levels and chronic kidney disease.

Use of Zigbee and BLE with a Single SoC

Developers for such products, Sogani says, require an ultra-small form factor and ultra-low power consumption so that the devices can remain in the mouth without requiring charging. The SoC is designed to offer developers multiple options with a single chip. Sogani points to some device makers that may sell two versions of a product that can work with or without connectivity.

In addition to the connected toothbrush example, the two versions could be offered for intelligent toys or products that may not require connectivity, but simply the intelligence provided by the MCU, such as controlling a switch to turn it on or off based on specific conditions. The MG24 is being built into products such as those used in smart-home applications. Lighting, for instance, could leverage the Zigbee connectivity to create a wireless mesh network within a home, providing remote connectivity so users can manage conditions using that network. A gateway could capture and forward the Zigbee-based data.

With BLE functionality as well, however, users could leverage their smartphone when they were within range of a device such as an LED light, enabling them to adjust settings. The company is providing the technology to switch manufacturers for such applications, for instance. The SoCs can also be used in tags or badges for asset or personnel tracking, with the technology and connectivity built into very small devices. One example of asset tracking might be an industrial environment, with tags attached to equipment and a system managing predictive maintenance.

Silicon Labs predicts that new products will come out later this year with these SoC devices built in, produced in large-volume production. The company already focuses on low-power technology, Sogani says, as well as on security. With the xG27 family of chips, he adds, "We're building on those strengths and adding products to stay on the leading edge of wireless connectivity."

 

Key Takeaways:

• Silicon Labs' xG27 chips offer IoT connectivity in a compact package so developers can build small wireless devices that capture and transmit data without requiring frequent battery replacements.
• The SoCs can use either Bluetooth alone, or Bluetooth and Zigbee, enabling users to simply transmit to area smartphones, or form a wireless mesh of devices such as lighting switches.