Minimizing quiescent current (IQ) is a key factor to reduce power consumption and manage battery life. An Internet-of-Things (IoT) sensor node is one of the best examples of why it’s important to minimize IQ to extend battery life. For example, in the low-power IoT application shown in Figure 1, the SimpleLink™ MCU controls a door lock via Bluetooth®, a Wi-Fi® connection or both.
Because these types of systems spend the majority (>99%) of the time in standby mode, as shown in Figure 2, the IQ in standby or sleep mode tends to be the limiting factor for battery life. Careful optimization of low-IQ power-management blocks makes it possible to extend battery life from two years to more than five years.
Standby IQ has long been a concern, but historically solutions were limited to a narrow set of low-power systems. Recent breakthroughs reduced the IQ in power-management building blocks like DC/DC converters, power switches, low-dropout regulators (LDOs) and supervisors, widening the use of these blocks to end equipment such as industrial meter applications, automotive sensors and personal wearables.
As Figure 3 illustrates, the IQ in 5-V LDOs has approximately reduced 90% every three years over the past 10 years. Both circuit improvements and optimized process technologies have enabled the reduction of solution area and improved transient-noise performance, while simultaneously reducing IQ.
Keith Kunz
Distinguished Member Technical Staff
Design Engineer & Technologist, Linear Power
Stefan Reithmaier
Distinguished Member Technical Staff
Analog Design Manager, Boost & Multi Channel/Phase DCDC