HIGH INTEREST IN LOW-ENERGY
IoT devices implementing wireless charging might get juice through a pick-up coil like this unit from TDK-Lambda. The modules are just 1.0 mm thick. Three small Rx coils target wearables; their dimensions are as small as 22 × 12 mm and the coils are designed for a maximum output of 2 W.
RF ICs, and the BM70 module from Microchip Technology. The power profile of these devices minimizes current consumption, and form factors are as small as 4 × 4 mm for the RF ICs and 15 × 12 mm for the module. The module options include RF regulatory certifications, or non-certified (unshielded/antenna-less) for smaller and more remote antenna designs that will undergo end-product emission certifications. To handle beacon applications, the module supports standalone “hostless” operation—in other words, it boots from a Flash memory so there’s no need for an external host processor to download code or run a driver. Microchip’s BLE devices include an integrated, certified Bluetooth 4.2 firmware stack that facilitates communications at up to 2.5 times faster data transfer speeds and connection security, with government-grade (FIPS-based) secure connection support. On another front, power supply maker TDK-Lambda Americas has devised a number of components with low-power IoT and BLE applications in mind. These devices include RF components and modules based on surface acoustic wave (SAW), bulk acoustic wave (BAW) and SESUB (semiconductor embedded in substrate) technology, tiny and flat multilayer inductors, a variety of advanced sensor technologies, and miniaturized ultra-flat coils for wireless charging.
Consider one particular BLE module. With its miniature footprint of just 3.5 × 3.5 mm and slim insertion height of 1.0 mm, the SESUB-PAN-D14580 is billed as the world’s smallest BLE module. It is nearly 65% smaller than modules that employ discrete components and consumes about a quarter of the power needed by classic Bluetooth devices. It works from 3-V supply voltage and consumes just 5.0 mA when transmitting, 5.4 mA when receiving and 0.8 µA in standby mode. Based on TDK SESUB integration technology, the module incorporates a DA14580 Bluetooth 4.1 chip from Dialog Semiconductor. Its substrate layers optimally route all the I/Os to a BGA on the module’s bottom surface, to better let designers access the integrated Bluetooth IC. The module makes available all terminals of the discrete chip. The quartz oscillator, capacitors and various other peripheral components mount on the same substrate. The miniature size and low current consumption lets the Bluetooth module handle battery-powered wearable applications where small size, light weight and low power consumption are essential. Mass production started in July 2015. It isn’t just communication chips that are getting attention. Power supply makers are designing low-power components specifically for wearable devices such as smart watches. An example is the TDK µdc-dc converters, which have a relatively small 2.9 × 2.3-mm footprint with an insertion height of 1 mm. The integrated power modules occupy 65% of the space taken up by conventional discrete components. They have a 92% power efficiency and under light loads, the modules go into a power-save mode using pulse frequency modulation with a typical quiescent current of 24 µA. It also looks as though a lot of low-power communication electronics will get juice through some kind of wireless charging scheme. A complicating factor is that there is no such thing as a wireless charging standard. Several technologies are in use, The Microchip BM70 BLE module block diagram. Module options include RF regulatory certifications, or non-certified (unshielded/ antenna-less) for smaller and more remote antenna designs that will undergo end-product emission certifications.
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