Polymer Aluminum Electrolytic CapacitorsIoT (UWB) usage examples

Market trends and challenges of IoT (UWB)

Image of IoT (UWB) usage examples
Image of Market trends and challenges

With the advance of digital transformation and rising adoption of cloud services, IoT*1 devices have become more prevalent. UWB*2 wireless communication technology is an example of the IoT technology being used as a communications method that is becoming commonplace. UWB wireless communication technology is utilized in sophisticated compact devices including smart tags and smart keys used for the purpose of loss protection.
As a technology that allows for advanced location measurement and secure communication, UWB wireless communication is expected to be adopted in an even wider array of fields in the future. However, due to the communication load involved in its data transmission and reception, UWB wireless communication technology requires power supplies that can provide sufficient power even in confined spaces. Therefore, one of the issues with the utilization of UWB wireless communication technology is the lack of power storage devices (batteries) that can accommodate the peak communication load output. Because the peak power output is required in data transmission and reception, designing power supplies for devices to accommodate the peak power output also poses the problems of power supplies becoming too large and costs becoming too high.

  • *1IoT: Stands for "Internet of things".
  • *2UWB: Stands for "ultra wide band".
Designing to accommodate the peak power output increases the power supply size

Another challenge is that it is difficult to achieve the peak power output with small batteries such as coin batteries.

The peak power output cannot be achieved when the miniaturization of the power supply size is prioritized

A solution to these issues is the usage of ECAS series capacitors together with the batteries to provide a power assist for the batteries.

Features of Murata's polymer capacitor ECAS series

Murata's conductive polymer aluminum electrolytic capacitors (ECAS series) have a multilayered aluminum foil structure for the anode and conductive polymers for the cathode. These capacitors have low-profile, low-ESR, and high-capacitance features.
Additionally, they are superior for their ripple absorption, smoothing, and transient response performances since there is no DC bias characteristic for capacitance and the temperature characteristic is stable.
Therefore, it is optimal for smoothing purposes in the input/output stage of power circuits and as backup for load fluctuation around the CPU.
This contributes to reducing the number of parts as well as the size of the circuit board area.

Example of applied circuit

The ECAS series can be used in circuits such as shown in the figure below.

Immediately provides a power assist for the peak power output without the need to change the power supply size

Advantages of using the ECAS series

Longer battery life when using coin batteries (CR2032)

Battery voltage was evaluated during UWB communications (4 transmissions and 2 receptions with max. peak current of 130mA) using an evaluation board. Communication operation stops when the voltage drops below 1.4V.

Battery (battery level 100%)
only
Image 1 of Battery only
Battery (battery level 100%)
+ Capacitor (ECAS_100uF)
Image 1 of Battery+Capacitor

Combining with ECAS suppresses peak current during communication, which results in minimizing voltage drops.

Battery only (no capacitor)

Image 2 of Battery only

Battery + ECAS_100uF

Image 2 of Battery+Capacitor

Voltage drops during communication can be minimized, communication is possible at a battery utility rate (DoD) of 80% (improved from 60%), and battery life can be extended by approximately 1.3 times.

Application notes

PDF documents of IoT (UWB) application examples are also available.
Download the documents below to view the materials.

IoT (UWB) application notes (PDF: 0.3 MB)