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This paper presents a bandgap reference (BGR) with the characteristics of curvature-compensation and high power supply rejection ratio (PSRR). To achieve a better performance, the base current of BJT is injected to a small segment of resistor string to flatten the temperature variation, and a pre-regulator of the power supply is implemented to improve the PSRR. The circuits, designed in 0.18$\mu$m BCD technology, exhibit an average voltage of 1.212V with temperature coefficient of 2.0ppm/${}^{\circ }\text{C}$ in the range from $-40^{\circ }\text{C}$ to 110${}^{\circ }\text{C}$ at typical condition, and a power supply rejection ratio of $-175.7$dB at low frequency. After 4-bit trimming, Monte Carlo simulation results show that the proposed design gets an accuracy of 0.29%, with a variation of $\pm 3.5$mV. The active design area is 160$\mu \mathrm{\text{m}}\times 206\mu$m, and the power supply current is about 8.2$\mu$A.

This paper presents a novel low-voltage bandgap reference with improved power supply rejection (PSR). The proposed circuit adopts a complementary loop locking approach for stabilizing the drain-source voltages of the current mirrors, which gives rise to a boost of the PSR performance by more than 30dB over $-20$–110^∘C and at 1-V supply. An analysis shows that the PSR of the proposed bandgap reference is typically characterized with its insensitivity to temperature variations. The circuit is designed with a commercial 0.18-$\mu$m CMOS process. The experiment results of Monte Carlo simulation demonstrate that the average PSR with 1-V supply is $-106$dB at DC and is $-93.8$dB at 1kHz (attained under a room temperature condition of 27^∘C). And the temperature coefficient of the DC-based PSR is about 0.83%/^∘C at 1-V supply, significantly decreased by three–six folds compared to other conventional designs. The quiescent current consumed is only about 13.5$\mu$A.

The role of complimentary to absolute temperature (CTAT) circuit in current mode bandgap has been described. Loop-gain problems with the existing self-bias MOS-based CTAT generator were discussed. A simple modification to the existing circuit was proposed to enhance the loop-gain by $\sim$20dB without adding additional circuitry leading to zero additional power consumption. Power Supply Rejection and sensitivity to $V_{\mathrm{\text{DD}}}$ will be improved due to the higher loop-gain. A prototype has been developed to demonstrate the proposal robustness across PVT corners. Simulation results show 20.5dB PSRR improvement and 7.5% improvement in sensitivity to $V_{\mathrm{\text{DD}}}$. The proposed solution consumes 180nW power from 1V power supply voltage and occupies 3300$\mu$m² silicon area.

A new PVT compensated voltage reference is presented by using switched-capacitor (S.C.) technique. In the proposed bandgap voltage reference (BGR), a p–n junction is biased with different currents during two different phases and required PTAT and CTAT voltages generated and held by two capacitors. Using a capacitive voltage divider, the PTAT voltage is weighted such that the sub-1V bandgap voltage is achievable. In order to cancel the effect of op-amp offset and to relax the design of op-amp, the offset voltage of the op-amp is sampled by a capacitor during a specified phase and inversely is added to the final bandgap voltage in next phase. The analysis of the proposed S.C. BGR is supplemented by simulation of a 0.5-V BGR with 28$\mu$W power consumption in a standard 0.18$\mu$m CMOS technology. Simulation results show that the average temperature coefficient of the S.C. BGR is 17ppm/^∘C and it is robust against the process variations. Applying an arbitrary 100-mV op-amp offset results in a lower than 1.1mV deviation in generated reference voltage. Due to the better matching of MIM capacitors in CMOS process (rather than resistors used in conventional BGR) the proposed S.C. bandgap provides good accuracy without any post trimming. Monte–Carlo analysis shows that $\sigma$/$\mu$ of the generated reference voltage is as low as 0.7%. The sensitivity of the proposed BGR to supply variation is also less than 1%/V.