A fully integrated RC oscillator with adaptive-body-biasing

Abstract

A fully integrated CMOS RC oscillator is presented. The oscillator is inverter-based. An adaptive body biasing(ABB) scheme is proposed to regulate the trip point of the decision inverter adaptively, thus alleviating the frequency variation over PVT. To achieve low power consumption all components are in the sub-threshold region. The circuit is designed in a 55-nm CMOS process with an area of 0.052 mm 2 . The simulation result shows a temperature sensitivity of 59 ppm/℃ from -40~125℃ which achieves a 72 ppm/℃ reduction as compared to an oscillator without ABB. the oscillator operates at 33kHz and consumes 183 nW from a 0.6V supply.

High-precision Low-power Low-temperature Drift Dropout Voltage Cancellation Oscillator

“…Figure 1 shows the basic structure of the single comparator RC oscillator of this design, which consists of a comparator, two-branch capacitor charging and discharging circuits, and multiple switching controls [2] . Vref is the reference voltage, V1 is the output oscillation waveform, I1 and I3 are the charging current sources, I2 and I4 are the capacitor discharge current sources, and I1-I4 current source current size is the same so that the two capacitors charge and discharge the same time to achieve the effect of 50% duty cycle [3] .…”