Patent ID: 7554310

Claim:
A voltage regulator comprising: at least one power switch adapted to convey power between respective input and output terminals of said voltage regulator; and a digital controller adapted to control operation of said at least one power switch responsive to an output of said voltage regulator, said digital controller comprising: a first digital control loop including a first analog-to-digital converter providing a first digital measurement of said voltage regulator output, a digital filter providing a digital control output based on a first digital error signal and a second digital error signal, and a digital pulse width modulator providing a control signal to said at least one power switch based on said digital control output, the first digital error signal comprising a difference between the first digital measurement and a digital reference value, the second digital error signal comprising a sum of the first digital error signal and a time varying portion of the digital reference value; and a second digital control loop including a second analog-to-digital converter providing a second digital measurement of said voltage regulator output, said second analog-to-digital converter having greater resolution than said first analog-to-digital converter, said second digital control loop providing the digital reference value based on a desired output voltage setpoint, said second digital control loop providing said time varying portion of the digital reference value based on a difference between said second digital measurement and said output voltage setpoint.