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Analog to Digital Converter (ADC) Resolution - Coggle Diagram
Analog to Digital Converter (ADC) Resolution
Concept
Meaning
Converts analog input to digital output using a binary search method.
Each bit is determined successively from MSB to LSB.
Purpose
Provides fast, accurate, and moderate-cost analog-to-digital conversion.
Application Example
Used in microcontrollers, digital oscilloscopes, and instrumentation systems.
Working Principle
Conversion Process
Input sampled and held constant by S/H circuit.
SAR sets trial bits; DAC converts to analog for comparison.
Binary Search Algorithm
Compares analog input with DAC output iteratively.
Narrows range until all bits are decided.
Step-by-Step Operation
1)Set MSB = 1 2)Comapre. 3)keepl clear 4)move to next bit 5)Final digital output
Major Components
Comparator
Compares input voltage (Vin) with DAC output voltage (Vdac).
Outputs logic high or low based on comparison.
Digital-to-Analog Converter (DAC)
Generates analog voltage from trial digital code.
Determines next step in binary search.
SAR Logic
Stores trial bits and updates them after each comparison.
Controls timing and sequence of conversion.
Sample and Hold (S/H) Circuit
Holds the analog voltage constant during the bit conversion process.
Performance Features
Performance and Features
Speed
Time per conversion = proportional to number of bits.
Faster than integrating ADCs; slower than Flash ADCs.
Resolution
Typically 8–16 bits depending on design.
Accuracy
High accuracy when reference and comparator are stable.
Power Efficiency
Low to moderate power consumption suitable for embedded systems.
Advantages and Disadvantages
Advantages
Excellent accuracy and linearity.
Requires fewer components than Flash ADC.
Deterministic conversion time (fixed number of steps).
Disadvantages
Slower than Flash ADC due to sequential operation.
Needs a stable input voltage (requires S/H circuit).
Practical Implementation
Integrated Features
10-bit SAR ADC with internal multiplexer (ADC0–ADC5).
Internal reference sources: AREF, AVCC, 1.1 V bandgap.
Control Logic
Managed by registers ADMUX and ADCSRA.
Output Handling
Result stored in ADCL and ADCH registers (10-bit digital output).
Applications
Embedded Systems
Sensor data acquisition, analog signal monitoring.
Industrial Electronics
Control systems, automation, feedback loops.
Measurement Systems
Digital multimeters, portable instruments, data loggers.