Low-Power Analog Baseband Circuits for Wake-Up Receivers

Abstract

Wireless sensor networks require ultra-low power consumption. To avoid wasting power consumption, wake up receiver system is applied to main receiver system. The wake up receiver continuously watch a wake up signal from other nodes. If it detects a wake up signal, it activates the main receiver to receive data. The baseband circuit for wake up receiver is composed of envelope detector, programmable gain amplifier and comparator. The enveloped detector converts the high frequency signal to baseband signal. The output signal of envelope detector is amplified through the programmable gain amplifier suitably. The comparator determines that the output signal of the programmable gain amplifier is high or low. This baseband circuit uses fully differential structure to strong from environment noise and coupling noise. The gain of programmable gain amplifier is defined by the ratio of capacitor value through negative feedback network. Moreover, the comparator not only consume power only when the input signal cross the threshold voltage, but also apply a replica biasing circuit with negative feedback to achieve low power consumption and be strong from PVT variation. This system is designed in 180nm technology and the total current consumption is under 14μA, when the supply voltage is 1.8V. ⓒ 2017 DGIST