SWITCHED CURRENT SOURCE TYPE

D to A CONVERTER Prepared by

KETAN NAYAK (140413117005) HARSH PARMAR (140413117006)

INDEX• Introduction• Types of Converters -A to D Converter -D to A Converter • D to A Converter• Types of D to A Converter• Switch Current Source Type DAC • Applications of DAC

INTRODUCTION• A Digital to Analog converter (DAC) is a

device that converts digital numbers (binary) into an analog voltage or current output.

DAC101010101010101010101010

Input/Output Characteristics

5

Digital Input Signal

Ana

log

Out

put S

igna

l

Types of Converters1. Analog to Digital Converters

2. Digital to Analog Converters

Analog to Digital Converter

Digital to Analog Converter

Types of D/A Converters1. R-2R ladder type DAC

2. Weighted resistor type DAC

3. Switched current source type DAC

4. Switched capacitor type DAC

R-2R Ladder Type DAC

Weighted Resistor Type DAC

Switched Capacitor Type DAC

Switch Current Source Type DAC Introduction

• The R-2R Ladder Type Network DAC and the Weighted Resistor DAC can be Regarded as a Switch Voltage Source Type DAC.

• Because when the Input Position goes HIGH, the High Voltage is Effectively Switched into Circuit.

• Most of IC’s DAC use a form of Current Switching Rather than Voltage Switching Because Current can be Switched out Faster than Voltage.

Switch Current Source type DAC

Applications of DAC• Generic use• Digital Audio • Function Generators/Oscilloscopes• Motor Controllers

Generic Use• Used when a continuous analog signal is

required.• Signal from DAC can be smoothed by a

Low pass filter

0 bit

nth bit

n bit DAC011010010101010100101101010101011111100101000010101010111110011010101010101010101010111010101011110011000100101010101010001111

Digital Input

Filter

Digital Audio• CD Players• MP3 Players• Digital Telephone/Answering Machines

Function Generators• Digital Oscilloscopes

– Digital Input– Analog Ouput

• Signal Generators– Sine wave generation– Square wave generation– Triangle wave generation– Random noise generation

Motor Controllers• Cruise Control• Valve Control • Motor Control