Patent ID: 8754720

Claim:
A control apparatus for energizing and de-energizing a device to control an output value of said device according to a predetermined target value, comprising: a switching means controlling an energizing time and a de-energizing time of said device; at least one parameter sensor for providing parameter sensing values indicative to changes in parameters of a transfer function between a ratio of said energizing time to said de-energizing time and said output value; and a pulse signal controller for providing a PWM control signal to said switching means, including a first stage controller providing values of control parameters for a second stage controller according to at least said predetermined target value and said parameter sensing values obtained from said at least one parameter sensor, wherein said second stage controller is further configured to generate a second stage PWM signal, and said first stage controller is further configured to generate a first stage PWM control signal by periodically providing values of control parameters for said second stage controller, and at least two cycles of said second stage PWM signal are generated in one cycle of said first stage PWM signal.