Design of Bandgap Reference Source with Composite Current Compensation Strategy

In order to meet the design requirements of MEMS sensor interface circuits, a high power supply rejection ratio (PSRR), low temperature coefficient, low voltage bandgap reference is proposed. The positive and negative temperature coefficient currents are individually generated using an error amplifier. A V-shaped temperature compensation current is then constructed based on the current mirror saturation mirroring principle and the minimum current selection rule for series-connected current sources. The temperature coefficient of the bandgap reference is further reduced by applying a composite current compensation strategy. The circuit design is implemented in a 0.18 μm CMOS process with a layout area of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$320\times 157.7\ \mu \mathrm{m}^{2}$</tex>. The design was simulated, and the post-simulation results demonstrate that the output reference voltage is 474 mV at an operating voltage of 1.8 V, with a power supply rejection ratio of −66.5 dB at 30 kHz. The temperature coefficient is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.5\ \text{ppm}/{}^{\circ}\mathrm{C}$</tex> over the temperature range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-40\ {}^{\circ}\mathrm{C}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$125{}^{\circ}\mathrm{C}$</tex>. The line regulation is 0.05 mV/V across an operating voltage range of 1.2 V to 3.2 V. This bandgap reference exhibits excellent overall performance and is suitable for use in sensor interface circuits.