A Low Power Low Supply MOS-Only Subthreshold Voltage Reference for Wide Temperature Range

Pratosh Kumar Pal,Rajendra Kumar Nagaria

doi:10.15598/aeee.v17i2.3197

Abstract

A Sub-1V, MOS-only Voltage Reference Circuit (VRC) has been proposed with the utmost of transistors working as subthreshold region for low-supply and low-power applications. A supply-insensitive current is passed to Active Load Circuit (ALC) for supply and temperature independence at the output reference voltage. It has four current mirrors connected in a closed loop configuration to generate a supply-independent current which is passed through the ALC resulting supply and temperature insensitive output reference voltage. The ALC has a combination of two subthreshold NMOS transistors having different threshold voltages. The presented VRC is simulated using standard 90 nm CMOS model for 0.25-1 V supply voltage range. The simulation result gives minimum operating voltage required as 0.25 V for which all transistors work in their respective region of operation. For the supply range of 0.25-1 V, the obtained mean voltage reference is 100.4 mV with the line regulation of 0.186 mV/V. The temperature coefficient (TC) of 51ppm/°C is achieved for a wide temperature range of -50 to 135°C with the given minimal operating supply voltage. The power dissipation for minimal supply voltage at room temperature is 33 nW. The proposed VRC exhibits a high PSRR of -52.5 dB at 100Hz and -29 dB at 1 MHz.

Highlights

The reference voltage generator circuits are the vital block of analog as well as the mixed analog System on Chip (SoC)
The proposed Sub-1V, subthreshold MOS-only Looped Current Mirror Voltage Reference (LCMVR) is implemented in 90 nm CMOS technology
From the results shown in Tab. 2, it is concluded that the proposed LCMVR has better performance in terms of PSRR, and LR than work reported in [21]

Summary

Introduction

The reference voltage generator circuits are the vital block of analog as well as the mixed analog System on Chip (SoC). For the need of ultra-low-power and lowvoltage applications like portable multimedia devices and compact medical devices, the use of BJTs for conventional bandgap references is restricted as it cannot satisfy the demand of low-power, as well as compact area requirements of today’s need of technology as it has bulky size and higher bandgap voltage i.e. in the range of around 1.2 [1] This demand of low-voltage and low-power applications is fulfilled by a Sub-1V VRCs with most of the MOS transistors of the designed circuit operating in the subthreshold region. Another CMOS subthreshold VRC for low-voltage and low-power without resistor and BJT is presented in [21] It has used a bulk driven technique to generate the supply independent current where most of the transistors are working in the subthreshold region. They have high power supply noise effect at the output

Methods

Results

Conclusion