Abstract
Lock-in amplifiers are versatile measuring instruments for extracting a narrow-bandwidth signal with a known carrier from noisy environments. The lock-in amplifier presented here has therefore been designed to provide an efficient readout of the second harmonic of fluxgate sensors. However, existing analog lock-in amplifiers use band-pass filters with increased component count or even omit them altogether. Therefore, the proposed lock-in amplifier takes advantage of the N-path filter principle to minimize chip area and power consumption. The lock-in amplifier consists of a low noise programmable gain preamplifier and a passive band-pass filter that uses a switched-capacitor topology. In this way, the filter achieves a high level of power efficiency and reconfigurability in terms of a tunable center frequency and bandwidth. The complete circuit is integrated on chip using a 180nm CMOS technology and occupies a total area of only 0.42mm^2. Moreover, the lock-in amplifier achieves a simulated input-referred noise voltage of 5.5nV /\sqrtHz at 10kHz while consuming less than 1mA under a 1.8V supply voltage.
Original language | English |
---|---|
Title of host publication | 2023 21st IEEE Interregional NEWCAS Conference (NEWCAS) |
Number of pages | 4 |
ISBN (Electronic) | 9798350300246 |
DOIs | |
Publication status | Published - 2023 |
Event | 21st IEEE Interregional NEWCAS Conference: NEWCAS 2023 - Edinburgh, United Kingdom Duration: 26 Jun 2023 → 28 Jun 2023 |
Conference
Conference | 21st IEEE Interregional NEWCAS Conference |
---|---|
Abbreviated title | NEWCAS 2023 |
Country/Territory | United Kingdom |
City | Edinburgh |
Period | 26/06/23 → 28/06/23 |
Keywords
- Analog lock-in amplifier
- CMOS integrated circuit
- fluxgate magnetometer
- n-path filter
- sensor interface
ASJC Scopus subject areas
- Safety, Risk, Reliability and Quality
- Instrumentation
- Electrical and Electronic Engineering
- Hardware and Architecture
- Computer Networks and Communications
- Modelling and Simulation