Battery Management Technique to Reduce Standby Energy Consumption in Ultra-Low Power IoT and Sensory Applications

In this paper, we present a battery management technique that significantly increases the battery lifetime of event-based devices that are predominantly in standby mode without requiring off or on chip large power switches. The proposed technique uses a novel battery management technique to remove Wake-Up Receiver (WUR) Low Drop-Out (LDO) unit, while causing minimal change to the system's power supply configuration. This technique manages the system so that it can wake up to a normal battery configuration while sleeping in a different battery set-up. This, as a result, drops standby power consumption significantly, making the proposed technique suitable for IoT sensors and, in general, event-based devices. Battery management comprises of voltage level detector, switches for changing battery configuration, and voltage level shifters. The design was applied to an active Radio Frequency Identification (RFID) tag with an embedded WUR and fabricated using TSMC 180nm technology. Measurements on the test chip showed that the proposed architecture and design leads to 80% standby energy saving, prolonging overall (active plus standby) battery's lifetime by 2.5 times while having negligible area overhead. The advantages and disadvantages of the proposed technique are also presented and discussed.