Digital-to-analog converter and method of digital-to-analog conversion

Abstract

A digital-to-analog convertor, and a methods of digital-to-analog conversion employ first and second PWM generators providing first and second PWM signals, said first PWM generator being controlled by a most significant word of the digital signal, and said second PWM generator being controlled by a least significant word of the digital signal. First and second switches are controlled by the first and the second PWM signals and first and second current sources have first and second currents, switched by the first and the second switches, thereby providing first and second switched currents, whereby an analog signal is obtained by the combination of the first and second switched currents.

1 . A digital-to-analog convertor comprising:
 first and second PWM generators providing first and second PWM signals respectively, said first PWM generator being controlled by a most significant word of the digital signal, and said second PWM generator being controlled by a least significant word of the digital signal;   first and second switches controlled by the first and the second PWM signals, respectively; and   first and second current sources having first and second currents, respectively, the first and second currents being switched by the first and the second switches thereby providing first and second switched currents, respectively, whereby the analog signal is obtained by the combination of the first and second switched currents.   
   
   
       2 . The digital-to-analog converter as claimed in  claim 1 , wherein the first current is greater in magnitude than the second current. 
   
   
       3 . The digital-to-analog converter as claimed in  claim 1 , wherein the first and second switches are each one of a solid state switch or a mechanical switch. 
   
   
       4 . The digital-to-analog converter as claimed in  claim 1 , wherein the first and the second current sources comprise resistors. 
   
   
       5 . A method of providing a method of digital-to-analog conversion comprising the steps of:
 providing a first PWM signal having a duty cycle corresponding to a most significant word of the digital signal;   providing a second PWM signal having a duty cycle corresponding to a least significant word of the digital signal;   providing a first electrical signal, said first electrical signal having a duty cycle equal to the duty cycle of the first PWM signal;   providing a second electrical signal, said second electrical signal having a duty cycle equal to the duty cycle of the second PWM signal; and   combining the first the second electrical signals to provide the analog signal.   
   
   
       6 . The method of digital-to-analog conversion as claimed in  claim 5 , wherein the step of providing the first PWM signal includes the step of controlling a first PWM generator with the most significant word of the digital signal. 
   
   
       7 . The method of digital-to-analog conversion as claimed in  claim 5 , wherein the step of providing the first electrical signal includes the step of controlling a switch with the first PWM signal.