A Low-Power CMOS Bandgap Voltage Reference for Supply Voltages Down to 0.5 V

• Main Authors: Andrea Ria, Alessandro Catania, Paolo Bruschi, Massimo Piotto
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Electronics
• Subjects: voltage reference; CMOS bandgap; low-voltage; low-power; inverter-like
• Online Access: https://www.mdpi.com/2079-9292/10/16/1901

A voltage reference is strictly required for sensor interfaces that need to perform nonratiometric data acquisition. In this work, a voltage reference capable of working with supply voltages down to 0.5 V is presented. The voltage reference was based on a classic CMOS bandgap core, properly modified to be compatible with low-threshold or zero-threshold MOSFETs. The advantages of the proposed circuit are illustrated with theoretical analysis and supported by numerical simulations. The core was combined with a recently proposed switched capacitor, inverter-like integrator implementing offset cancellation and low-frequency noise reduction techniques. Experimental results performed on a prototype designed and fabricated using a commercial 0.18 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>m CMOS process are presented. The prototype produces a reference voltage of 220 mV with a temperature sensitivity of 45 ppm/°C across a 10–50 °C temperature range. The proposed voltage reference can be used to source currents up to 100 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>A with a quiescent current consumption of only 630 nA.