A Sub-200nW All-in-One Bandgap Voltage and Current Reference Without Amplifiers
Wenbin Huang, Lianxi Liu, Zhangming Zhu
Abstract
This brief presents a low-power and high-precision bandgap voltage and current reference (BGVCR) in one simple circuit for battery-powered applications. All the amplifiers have been eliminated in the proposed circuit. The voltage reference is derived from the bandgap topology, and the current reference is obtained by summing a proportional-to-absolute-temperature (PTAT) current and a complementary-to-absolute-temperature (CTAT) current. Therefore, the temperature coefficient of the current reference can be optimized. Besides, a pseudo-cascode structure and a simple line sensitivity enhancement circuit are adopted to improve the current mirror accuracy and line sensitivity. The proposed circuit is fabricated in a 0.18-μm deep N-well CMOS process with an active area of 0.063 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measured VREF and IREF are 1.2 V and 51 nA, respectively. The VREF and IREF show measured average temperature coefficients of 32.7 ppm/°C and 89 ppm/°C at a temperature of -45 to 125°C and standard deviations of 0.17 % and 1.15 %, respectively. In the supply voltage range of 2 to 5 V, the line sensitivities of voltage and current are 0.058%/V and 1.76%/V, respectively. The minimum supply voltage is 2 V with a total power consumption of 192 nW at room temperature.