Temperature Process Compensation Technology Research

Because the performance of semiconductor devices will generally change with the variations of process and temperature, errors appears between simulation and measured results. However, these errors can be eliminated by adding corresponding compensation mechanism at the beginning of the circuit design, keeping the performances stable.This thesis firstly gives the analysis of influences caused by the variations of temperature and process. Then, typical temperature/process compensation techniques are summarized and divided into two kinds: general techniques and custom ones.For the general techniques, temperature sensor and process detector are studied. The corresponding modules with digital outputs are designed, especially a novel process detector, which can produce different outputs according to different process offsets. For the custom techniques, two key analog modules in digital DC-DC controller, the windowed-ADC based on ring oscillator and Digital Pulse-Width Modulator (DPWM), are studied.A new temperature compensation technique for the ring-oscillator-based ADC is proposed. It employs a novel fixed-number-based algorithm and a CTAT current biasing technology to compensate the temperature-dependent variations of the output, thus eliminates the need of digital calibrations. Simulation results prove that, with the proposed technique, the resolution under the temperature range of 0℃to 100℃can reach a 2-mV quantization bin size with an input voltage span of 120mV, at the sampling frequency fs=100KHz.A new hybrid DPWM is also presented, which employs a ring-oscillator/counter structure. Based on a temperature/process compensation technique and a novel digital controller, it is able to not only offer temperature/process-independent pulse widths, but also operate at much higher clock frequency compared with the existing delay-line/counter DPWM structure. Simulation results show that with our DPWM, the system clock frequency reaches 157.7MHz while the worst variation, across a temperature range of 0℃to 100℃under all process corners, is only±5.7%.