Author_Institution :
Philos. at San Francisco State Univ., San Francisco, CA, USA
Abstract :
Design of a sub-1V, low power, fractional bandgap voltage reference (Vr ~ 0.6V) conjoined with a current reference (Ir ~ 1μA) in standard 90 nm digital CMOS is proposed, utilizing standard parasitic substrate PNPs. A positive temperature coefficient (TC) voltage is generated across a feed-back resistor, Rf, via a negative TC emitter-base voltage (VEB) on one side of Rf and the looped-back Vr output on the other side, which has a near zero TC. The resulting current, Ix = (Vr - VEB) /Rf, has a zero current crossing point that can be set roughly around the mid-point of minimum and maximum operating temperatures. As such, Ix supplies the needed positive TC current to the bandgap´s proportional to absolute temperature (PTAT) current loop that facilitates generating the residual zero TC current, Ir, which is concurrently fed to Ro to produce Vr. Simulations show Vr of about 0.6V at TC of about ±10ppm/°C (with trim) can be achieved over span of -50°C <; T <; 150°C. Accordingly, simulating for bandgap´s operation for +0.9V > VDD > +5V, indicates that IDD of about 5μA, and voltage coefficient (VC) of about ±50 ppm/V are achievable.
Keywords :
CMOS integrated circuits; integrated circuit design; low-power electronics; reference circuits; voltage regulators; current reference; digital CMOS; feedback resistor; fractional CMOS bandgap voltage reference; negative TC emitter base voltage; positive temperature coefficient voltage; proportional to absolute temperature current loop; standard parasitic substrate; CMOS integrated circuits; Low voltage; Photonic band gap; Resistors; Semiconductor device modeling; Topology; Transistors; CMOS reference voltage; bandgap; battery power; current reference; energy harvesting; extended temperature range; fractional bandgap; half bandgap; low power; low voltage; reference; regulator; sub 1 volt; subthreshold; ultra low power;
