A Novel Low-Power High-Order Compensated Voltage and Current Reference Circuit

In this paper, a novel low power consumption and high accuracy bandgap voltage and current reference circuit without amplifier unit for a DC-DC Buck converter is presented. The reference voltage is derived from the bandgap topology, and the reference current is obtained by summing the proportional absolute temperature (PTAT) current and complementary absolute temperature (CTAT) current so that the temperature coefficient of the current reference can be optimized. Higher-order temperature compensation for the reference circuit is accomplished by employing two pairs of MOSFETs operating in the subthreshold region. These MOSFET pairs generate exponential compensation currents tailored for both lowtemperature and high-temperature conditions. This approach ensures the generation of a reference voltage with a minimized temperature coefficient. The circuit is designed based on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.18 \upmu\mathrm{m}$</tex> BCD process with a layout of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.26 ~\text{mm} \times 0.2 ~\text{mm}$</tex>. The maximum <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V_{\text {REF}}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$I_{\text{REF}}$</tex> obtained from the simulation are <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${1.2} \mathrm{V}$</tex> and 114.6 nA, respectively. The temperature coefficient of the reference voltage is only 1.4 ppm/°C in the range of -40 to 125°C. In the range of supply voltages of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.5 \sim 5.5 ~\mathrm{V}$</tex>, the reference voltage varies around 1.01 mV, and the line regulation is 0.028 %. And from the temperature range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0^{\circ} \mathrm{C}$</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 variation of the reference current is only 3 nA.