| Summary: | 碩士 === 國立清華大學 === 電機工程學系 === 102 === In recent years , due to the rapid development of medical technology , human
Life is extended . This makes the rapid growth of biomedical electronic market , and
also let the needs of the physiological signals measurement systems promoted grad-
ually .A high precision analog-to-digital (A/D) converter is an important block in the
physiological signals measurement systems ; we generally choose the delta-sigma
A/D converter as the main architecture for the data converter . To be matching requ
irements for the plan , a delta-sigma modulator which is applied in the bio-sensing
system that could handle the signal capturing by the devices is implemented in this
thesis .
This thesis presents a one-bit second-order discrete-time delta-sigma modulator
(DT-ΔΣM) , and to be implemented with TSMC 0.18-μm 1P6M process . By using CIFB
architecture make the STF to have better filtering performance at high frequency ,
and make the modulator to have better stability ; the input stage of the operational
amplifier use the rail to rail architecture to raise the reliability of the system and ma-
ke the modulator still function work even though the outpu swing of the integrat-
or is larger . Also using the CDS technique in the first intergrator stage help to reduce
the offset of component mismatches and suppress the 1/f noise . The whole delta-
sigma modulator operating at 1.8V supply voltage , with 20KHz signal bandwidth ,
and oversampling ratio of 256 , the designed modulator achieved signal to noise and
distortion ratio(SNDR) of 93.26 dB , equivalent to the effective number of bits (ENOB
) 15.26 bits .The power consumption is 2.732 mW , the figure of merit (FoM) is 1.782
pJ/conv. , and the core chip area is 668 x 278μm2 .
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