Low temperature coefficient and low line sensitivity subthreshold curvature‐compensated voltage reference

A subthreshold nano-power voltage and current reference with high-order temperature compensation is proposed by taking advantage of the channel length modulation of MOS devices. Curvature compensation is implemented by providing proper compensating drain-source voltages for the core devices of a first-order CMOS reference such that the output nonlinear temperature factors can be compensated over a wide temperature range. In-depth mathematical analysis is carried out to model the temperature dependency of the reference signals before and after compensation. As part of the analysis, Taylor expansion of the threshold voltage of MOS devices has been evaluated in a generalized fashion, enabling to clarify the complicated relationship between the high-order temperature-related terms of the output and design parameters. Simulated in a standard 0.18-μm CMOS process, the minimum supply voltage of a proof-of-concept design is 1.0 V, providing 345 mV voltage reference with minimum temperature coefficient (TC) of 2.0 ppm/ C across the range of -40-140 C. The active area is 0.45 mm 2 with around 200 nA current consumption. The DC line regulation is 0.23%/V, and the power supply rejection ratio (PSRR) is À63 dB at 10 Hz.

Section: Discussionmentioning

confidence: 99%

Subthreshold reference circuit with curvature compensation based on the channel length modulation of MOS devices

Aminzadeh

2021

“…A solution to reduce supply voltage and power consumption is to replace BJT transistors with MOSFETs in the subthreshold region for temperature compensation. However, this approach results in larger temperature coefficient (TC) and generally worse performance 5 . Various effects, such as diode leakage currents and the dependence of the reference voltage on the threshold voltages, are responsible for this degradation.…”

Section: Introductionmentioning

confidence: 99%

pMOS‐only pW‐power voltage reference with sub‐10 ppm/°C trimmed temperature coefficient and sub‐100 ppm/V line sensitivity

Azimi

Habibi

Crovetti

2023

In this paper, a new ultra-low-power voltage reference based on a two-stage, all-pMOS topology operating in the subthreshold region is proposed to uniquely meet the pW-power range power consumption requirements of emerging Internet-of-Things applications without significantly compromising the temperature coefficient (TC) and the line sensitivity (LS) performance. The proposed circuit consists of the LS regulator, TC corrector, and TC trimming sections. Based on post-layout Monte Carlo simulations in 180-nm CMOS, the proposed circuit operates with 0.8-to 2.4-V supply potential and generates a reference voltage of 206 mV with a process spread of 7.8%, achieving an average calibrated TC of 4.4 ppm/ C in the temperature range of À20 C to 80 C, and an average LS of 51.5 ppm/V with a power consumption of 25.9 pW at 25 C (469.1 pW at 80 C).

A high‐precision voltage reference with a curvature‐compensated bandgap for fluorescence detection

Xiong,

Mo,

Yan

et al. 2024

SummaryFluorescent optical fiber temperature sensors require accurate online temperature monitoring in hazardous environments with strong electromagnetic fields, high voltages, flammability, or explosiveness. This imposes stringent requirements on the temperature coefficient stability of the bandgap reference (BGR) circuit. To address these challenges, this paper proposes a high‐order curvature compensation bandgap reference (HCC_BGR) circuit fabricated using a 0.18‐μm bipolar‐CMOS‐DMOS (BCD) process. A traditional first‐order bandgap reference (TRA_BGR) circuit is also fabricated for comparison. Experimental results demonstrate that the proposed HCC_BGR circuit generates a stable 1.22‐V reference voltage with a low‐temperature coefficient of 5.56 ppm/°C from −20°C to 85°C. Compared to the TRA_BGR circuit, the HCC_BGR reduces the temperature coefficient by 3.07 times. Furthermore, the low‐dropout regulator (LDO) using the proposed HCC_BGR exhibits excellent line sensitivity of 1.52%/V from 3.4 to 5 V.