Power Consumption in IIoT Applications: Linear Regulators vs. DC/DC Buck Converters
Concerning the Internet of Things (IoT), especially Industrial IoT (IIoT) devices, power consumption can be a major hurdle. To overcome this challenge, linear regulators and buck converters can be beneficial.
With the growing demand for enhanced productivity, efficiency, and workplace safety in industrial and manufacturing operations, several industries are adopting IoT systems in their processes.
A high-level image of IoT products. Image used courtesy of Pixabay
More specifically, the IIoT offers several advantages in industrial facilities, including reduced costs, minimal downtime, and enhanced safety of employees and assets. However, a significant hurdle to widespread IIoT adoption is inefficient power conversion and utilization. With proper research and development, engineers can deliver solutions to ramp up power conversion and optimize utilization efficiency.
In this article, we'll cover some of the power utilization challenges of IIoT, the drawbacks of linear regulators, DC/DC buck converters for IIoT applications, and finally ROHM's potential power solutions for IIoT.
Power Utilization Challenges in IIoT
A common IIoT application is remote data monitoring. The real-time data analytics necessary for this application require increasing amounts of power. While large-scale applications such as smart homes and smart factories utilize energy from the grid, many other applications are battery-driven.
Regardless of the power source, power-saving solutions are essential for optimized power conversion and utilization in IIoT systems due to limited power supply. Engineers must therefore address this challenge by designing low-power solutions for IIoT systems to reduce power dissipation and/or extend battery life.
Designing low-power solutions often start at the component level. The configuration of an IIoT sensing application commonly comprises CPUs, sensors, and wireless modules for overall control, environmental data acquisition, and communication.
Block diagram of a typical wireless sensor configuration. Image used courtesy of Sendra et al
Since these devices operate in several power modes, including active and standby, they require constant power for an efficient transition between modes. For instance, IIoT sensing applications can transition from a low power-consuming standby mode to a power-intensive wireless data transmission mode.
By incorporating power ICs, such as DC/DC buck converters, which offer ultra-low-power (ULP) modes, engineers can ensure optimized power consumption in battery-driven IIoT applications.
Challenges with Conventional Power ICs: The Drawbacks of Linear Regulators
Power electronics, including linear voltage regulators and switching converters, are commonly incorporated into battery-driven electronic devices.
Linear regulators modulate the output voltage from a power supply using linear, non-switching techniques. Some benefits of linear regulators in battery-driven applications include low cost, minimized circuit complexity, and low external component count.
Due to these benefits, linear regulators remain an integral component in a host of applications.
Circuit diagram of a linear voltage regulator. Image used courtesy of ROHM
However, linear regulators exhibit several drawbacks, which can adversely impact the efficiency of battery-driven IIoT applications, including:
- High cell counts
- Larger dropout voltages
- Reduced battery life
- Low efficiency
- High heat generation
Let's take a closer look at the relationship between linear regulators and the challenges of heat management and battery cell count.
Heat Generation in Linear Regulators
A major drawback of linear regulators is high heat generation. Generally, extended use of linear regulators to aid in powering electronics causes the IC to produce a significant amount of heat, well above its temperature range. This can, in turn, cause the IC to shut down at intervals.
Moreover, meeting higher input current and voltage requirements in several applications results in the need for bulky heat sinks to ensure the IC remains within a specified temperature range. Consequently, in addition to its constant output voltage capability, excessive heat generation in linear regulators results in high inefficiencies, making it tough to meet the low power-intensive and battery-saving requirements of battery-driven IIoT applications.
Linear Regulators and Battery Cell Count
Another drawback is that the use of linear regulators often results in higher battery cell counts.
Engineers must meet stringent cell count requirements in battery-driven applications that incorporate linear regulators: higher output voltage requires a sufficiently higher number of series-connected cells. For instance, a 3.3 V output requires at least three extra 1–1.5 V alkaline, NiCd, or NiMH battery cells.
Since lithium battery cells offer higher voltages, lithium battery-based applications may require fewer cells. Moreover, while a 5 V output may require at least five extra cells, a 12 V output will have a correspondingly higher cell count requirement.
Thus, linear regulator-based battery-driven applications exhibit high cell counts, regardless of battery type, causing additional issues such as high design costs, large device footprints, and inefficient power utilization.
Based on this assessment of the drawbacks of linear regulators, we can see there is a need for higher efficiency solutions that can ensure high performance and power optimization in IIoT applications.
Power Optimization for IIoT Applications: DC/DC Buck Converters
By incorporating DC/DC buck converters into IIoT devices, designers can achieve higher efficiencies in battery-driven IIoT applications.
Unlike linear regulators, DC/DC buck converters generate low heat, averting the need for bulky heat sinks. With the aid of a switching element, these power ICs can transform the incoming power supply into pulsed voltage. The buck converter smooths the pulsed voltage using inductors, capacitors, and other elements.
Circuit diagram of a typical switching converter. Image used courtesy of ROHM
Incorporating DC/DC buck converters into battery-driven IIoT applications can significantly extend battery life and reduce power dissipation. By maximizing the switching efficiency of the converter, designers can ensure low power dissipation and heat generation.
The power IC ensures optimized power consumption by temporarily storing input energy and releasing it at the required output voltage. Moreover, some buck converters offer additional capabilities such as ultra-low-power (ULP) mode, which provides transient response and optimal constant ON-time control beneficial to IIoT sensing applications.
The ULP-enabled buck converter transitions between normal and ULP modes by monitoring output voltage on a pulse-by-pulse basis. Designers can leverage two comparators—e.g., main and ULP comparators—to monitor the output voltage of the IC. Moreover, by detecting voltage-induced impedance changes in these comparators, the IC can switch from normal to ULP mode, and vice versa.
Transitions between Normal and ULP Modes. Image used courtesy of ROHM.
These seamless transitions are also an essential source of power optimization in IIoT applications.
ROHM Power Solutions for IIoT Applications
One place to look for IIoT solutions is ROHM, which offers high-performance solutions, including Nano Energy technology that provides increased productivity and lower costs in a variety of industrial IoT applications.
Featuring an enhanced analog circuit design, process, and layout, ROHM leverages this technology to develop advanced power IC solutions that offer unprecedented low power consumption capabilities in IIoT applications.
ROHM’s Nano Energy-based BD70522 DC/DC buck converter can efficiently meet remote monitoring needs in various industries while enabling lower power consumption.
Current consumption comparison between ROHM and other companies. Image used courtesy of ROHM.
More specifically, the BD70522 DC/DC buck converter can offer one of the lowest quiescent current (Iq) of 180 nA compared to other buck converters, supporting a standby current down to 50 nA. This specification makes the solution suitable for battery-driven IIoT applications, minimizing power dissipation and extending battery life.
Furthermore, its ultra-low-power (ULP) mode and constant ON-time (COT) control capabilities can provide a transient response and power savings.
These capabilities also provide advanced light load efficiency for minimized load range down to 10μA.
All in all, ROHM’s power solutions are also suitable for use in other applications, including wearable devices, thermostats, smoke detectors, energy harvesters, and standby switcher-free low-Iq applications.
For more information about ROHM’s IIoT power solutions, visit our website.
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