The definition and characterization of different attributes are very important for the business and for the consumer, making it necessary to establish norms of classification and standardization, thus making commercial trading more efficient and allowing for higher awareness on the part of consumers.
Based On The Driver's Request For The Ideal Relationship Between Steering Wheel Torque And Vehicle Velocity, The Vehicle Speed Proportional Coefficient Of The Assist Characteristic Can Be Determined By Making Steering Wheel Torque At Different Vehicle Lateral Acceleration Agree With The Request Of The Driver At A Certain Velocity.
This thesis presents a high gain, low noise and low power dynamic residue amplifier and a low power, low noise dynamic comparator designed in TSMC 28nm process for a two step Pipelined SAR-ADC. The cascoded integrator dynamic residue amplifier (CIDRA) achieves a gain of 30dB with THD of 47dB (11 mV pp input). The input referred noise across tem- perature and process corner is 55 µV and it operates at a frequency of 500MHz while the energy consumption is 390 fJ. The low power and low noise pseudo-latch preamp dynamic comparator (PLPDC) shows a delay of 250pSec for a differential input of 16 pV and consumes 91 fJ (current is 91 µA for 100 MHz clock) of energy. The input referred offset is 4 mV (?).
The final circuit, consisting of an analog chain and a 14-bit SAR ADC realized in fully-differential configuration followed by a digital module for the computation of an FFT, has a power consumption of less than 20μW, an integrated noise in the 1-50Hz bandwidth lower than 1μV and state of the art performances for this type of systems.
With the latest advancement in field-programmable gate array (FPGA) technology,the analog-to-digital converter (ADC) can now be integrated within the FPGA digitalfabric without the need for an external ADC chip. Realization of the ADC is possible by utilizing the low voltage differential signaling (LVDS) pin pair available on the FPGA chip along with some external passive components. The implementation of ADC in the FPGA chip has a few advantageous where the cost, board space and components are reduced. The FPGA no longer needs an external ADC to beintegrated with the analog interfaces. FPGA implementation of ADC structures such as successive approximation register (SAR) and sigma-delta ADC are considered and their performances are evaluated. Ina close loop digital controller application such as motor controller, it requires a fast ADC conversion to drive a motor with a quick feedback response. SAR ADC is capable of fast conversion time while the sigma-delta ADC sacrifices a fast conversion time for accuracy. However, the SAR ADC conversion contains errors in FPGA implementation and sigma-delta ADC is too slow for a practical close loopsystem. A dual-sampling sigma-delta (DSSD) ADC is proposed utilizing the potential of the sigma-delta ADC and maximizing the usage of FPGA. The proposed ADC is capableof sampling both clock edges instead of the conventional single edge sampling. The sampled analog signal is feedback through an RC filter network which will be tracked and compared with the analog input signal. The result for each clock edges are summed to obtain the final converted digital word. Thus, the workload is distributed since the sampling data is divided into two clock edges. It allows faster data processing and maximizing data throughput. The aim of this research is to reduce the ADC conversion time while maintaining the quality of the signal converted. The performance of the DSSD ADC is compared with other ADCstructures implemented in FPGA. The performance of the proposed ADC structure is written in verilog hardware description language (HDL) and evaluated using the Altera Cyclone II FPGA chip on a Development and Education (DE) II board. The results show the proposed 8-bit DSSD ADC with 27 MHz sampling clock provides the ADC with 1 least significant bit (LSB) error, 4.8 μs conversion time and a bandwidth of 104.1 kHz. The DSSD ADC structure has improved from the conventional sigma-delta structure which is 3 LSBs, 9.4 μs conversion time and bandwidth of 53.2 kHz.
For the 12-bit SAR ADC, the differential nonlinearity (DNL) is +0.576/-0.96 least significant bit (LSB), and the integral nonlinearity (INL) is +0.534/-0.655 LSB.
Il circuito finale, costituito da una catena analogica e un ADC SAR a 14 bit in configurazione fully-differential seguiti un modulo digitale per il calcolo di una FFT, presenta un consumo inferiore ai 20μW, un rumore integrato sulla banda tra 1 e 50Hz inferiore ad 1μV e prestazioni allo stato dell’arte per questa categoria di sistemi.