Design of Translinear Circuit-Based Temperature-Independent Reference Current

When designing analog circuits, performance stability is an essential aspect, especially against temperature variations. The reference current, which is widely used to bias the analog circuits at an appropriate operating point, is one of the parameters that should be stable versus the temperature changes. This paper aims to design a stable and temperature-independent reference current with a low cost of fabrication and low power consumption, where the total consumption of power was only 1uW at 1V supply voltage. Since the mobility of carriers in the MOS devices is a temperature-dependent parameter, the new design uses the translinear principle-based square root circuit combined with two current source circuits to cancel the thermal effect of the carriers’ mobility on the produced current. The square root circuit of the proposed reference current circuit was designed to operate in the weak inversion region to achieve the linear property and was implemented by a 0.1μm CMOS technology. The simulation results recorded an output current of 25.06μA over a temperature range from 0 to 100 ℃ with a temperature coefficient of 92 ppm/°C. Thus, the proposed design of the reference current is suitable for low-power applications, especially for ultra-low-power op-amps