Arnan Sipitakiat Dept Computer Engineering Chiang Mai Univeristy ADC Methods Direct conversion Flash ADC SuccessiveApproximation Rampcompare ADC Direct Conversion SuccessiveApproximation ID: 722425
Download Presentation The PPT/PDF document "Analog to Digital Converters" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Analog to Digital Converters
Arnan
Sipitakiat
Dept. Computer Engineering, Chiang Mai
UniveristySlide2
ADC Methods
Direct conversion (Flash ADC)
Successive-Approximation
Ramp-compare ADCSlide3
Direct ConversionSlide4
Successive-Approximation
DAC = Digital-to-Analog converter
EOC = end of conversion
SAR = successive approximation
register
S/H = sample and hold circuit
V
in
= input voltage
V
ref
= reference voltageSlide5
Ramp-compare
ADC
Similar to Successive Approximation, but uses a simple circuit to
generate a ramp and measures the time it takes to match the input.
The ramp generation circuit is often sensitive to temperature.Slide6
R1 = 33K, Vin = 5V
ถ้า
Rsensor
= 66K
ค่าที่อ่านจาก
GoGo
Monitor
จะเป็นเท่าใด
Vout
= Vin x R2 / (R1+R2)
Voltage divider:
Measuring ResistanceSlide7
Vo = Vin x R2 / (R1+R2
)
ADC = 1023 x R2 / (R1+R2)
= 1023 x 66 / (33 + 66)
= 1023 x 2/3
= 682Slide8
Successive-Approximation ADC
Voltage DividerSlide9
ADC Parameters
Resolution. 8, 10, 12, … bits
Number of analog ports
ADC speed