US 12,574,126 B2 · Ultra low power wake up radio architecture

Abstract

A radio frequency (RF) signal strength detection technique is disclosed with a received signal strength indicator (RSSI) circuit, which can be deployed in an internet-of-things (IoT) network. The RSSI circuit is based on a direct conversion of RF to digital code indicating the signal strength. The direct conversion is achieved by the repeated switching of a rectifier's output voltage using an ultra-low power comparator. A 5-bit programmable feedback circuit can be used to correct detection inaccuracies. The RSSI circuit can be implemented in a 65-nm CMOS process and consumes 15 nW power. It can have a linear dynamic range of 26 dB and exhibit an error of ±0.5 dB with a wide bandwidth of 500 MHz. The technique has been verified with simulation and measurement results. The high detection accuracy with ultra-low power consumption of the proposed RSSI circuit is favorable for IoT applications including, e.g., biomedical, localization, and other low-power applications.

Claims20

Dependent claims

A method of detecting radio frequency (RF) signal strength using a Receiver Signal Strength Indicator (RSSI) circuit in a wake up radio of an RF receiver, the method comprising the steps of:

(a) receiving an incoming RF signal;
(b) rectifying the RF signal in a multi-stage passive rectifier to generate an output voltage;
(c) comparing the output voltage to a threshold voltage in a comparator and generating a toggle signal when the output voltage exceeds the threshold voltage;
(d) feeding the toggle signal to the multi-stage passive rectifier to discharge a capacitor for each stage of the multi-stage passive rectifier to enable another charging cycle;
(e) repeating steps (b) to (d) a plurality of times during a duration of the RF signal;
and
(f) counting the toggle signals from the comparator to generate a digital code indicative of the detected strength of the RF signal;
and
(g) outputting the digital code.

6 more elements

Dependencies are inferred from the claim text.

Ultra low power wake up radio architecture

Life of this patent

Ultra low power wake up radio architecture

Life of this patent

Abstract

Claims20