A low‐voltage band‐gap reference circuit with second‐order analyses

A voltage reference consisting of only two nMOS transistors with different threshold voltages is presented. Measurements performed on 23 samples from a single batch show a mean reference voltage of 275.4 mV. The subthreshold conduction and the low number of transistors enable to achieve a mean power consumption of only 40 pW. The minimum supply voltage is 0.45 V, which coincides with the lowest value reported so far. The mean TC in the temperature range from 0 to 120 C is 105.4 ppm/ C, while the mean line sensitivity is 0.46%/V in the supply voltage range 0.45-1.8 V. The occupied area is 0.018 mm 2 . The power supply rejection rate without any filtering capacitor is À48 dB at 20 Hz and À29.2 dB at 10 kHz. Thanks to large area transistors and to a careful layout, the coefficient of variation of the reference voltage is only 0.62%. We introduce as a new figure of merit, the voltage temperature parameter (VTP), which gives a direct measure of the overall percentage variation of the reference voltage on the typical 2D domain of supply voltage and temperature. For the proposed circuit, the average VTP is 1.70% with a standard deviation of 0.21%. In order to investigate the effect of transistor area on process variability, a 4X replica of the proposed configuration has been fabricated and tested as well. Except for LS, the 4X replica doesn't exhibit any appreciable improvement with respect to the basic voltage reference.

Section: Operating Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A picopower temperature‐compensated, subthreshold CMOS voltage reference

Albano

Crupi

Cucchi

et al. 2013

“…The temperature behavior of V BE is the key term in the BGR circuit design. It is relative to the collector current and the junction temperature . Provided the collector current is proportional to some power of absolute temperature, the analytical form of V BE can be expressed by

V_{italicBE} (T) = V_{G} (T) + [V_{italicBE} (T_{0}) - V_{G} (T_{0})] \frac{T}{T_{0}} - (α - m) \frac{k T}{q} ln (\frac{T}{T_{0}})

where V G is the bandgap voltage of silicon, T is the absolute temperature in degree kelvin (°K), α is a constant depending on the CMOS technology and the bipolar structure, m is the temperature order of the collector current.…”

Section: Proposed Curvature‐corrected Bgrmentioning

confidence: 99%

“…The temperature behavior of V BE is the key term in the BGR circuit design. It is relative to the collector current and the junction temperature [15,16]. Provided the collector current is proportional to some power of absolute temperature, the analytical form of V BE can be expressed by [15]…”

Section: The Temperature Characteristics Of V Bementioning

confidence: 99%

A high‐order curvature‐corrected CMOS bandgap voltage reference with constant current technique

Geng

Zhao

2012

SUMMARY A high‐order curvature‐corrected complementary metal–oxide–semiconductor (CMOS) bandgap voltage reference (BGR), utilizing the temperature‐dependent resistor and constant current technique, is presented. Considering the process variation, a resistor trimming network is introduced in this work. The circuit is implemented in a standard 0.35‐µm CMOS process. The measurement results have confirmed that the proposed BGR operates with a supply voltage of 1.8 V, consuming 45 μW at room temperature (25 °C), and the temperature coefficient of the output voltage reference is about 5.5 ppm/°C from −40 °C to 125 °C. The measured power supply rejection ratio is −38.8 dB at 1 kHz. The BGR is compatible with low‐voltage and low‐power circuit design when the structure of operational amplifiers and all the devices in the proposed bandgap reference are properly designed. Copyright © 2012 John Wiley & Sons, Ltd.

“…The accuracy of this method is limited by the non-linearities of the bipolar junction transistor. In order to deal with this issue, some designs utilize a curvature temperature compensation method, thus achieving improved temperature drift (TD) performance [6][7][8][9][10][11][12][13][14][15][16][17][18]. Subsequent architectures focus on using only MOS devices to generate a reference voltage [19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

A 0.75‐V, 4‐μW, 15‐ppm/°C, 190 °C temperature range, voltage reference

Andreou

Georgiou

2015

A low-voltage, low-power, low-area, wide-temperature-range CMOS voltage reference is presented. The proposed reference circuit achieves a measured temperature drift of 15 ppm/°C for an extremely wide temperature range of 190°C (À60 to 130°C) while consuming only 4 μW at 0.75 V. It performs a high-order curvature correction of the reference voltage while consisting of only CMOS transistors operating in subthreshold and polysilicon resistors, without utilizing any diodes or external components such as compensating capacitors. A trade-off of this circuit topology, in its current form, is the high line sensitivity. The design was fabricated using TowerJazz semiconductor's 0.18-μm standard CMOS technology and occupies an area of 0.039 mm 2 . The proposed reference circuit is suitable for high-precision, lowenergy-budget applications, such as mobile systems, wearable electronics, and energy harvesting systems.