Constant ON-time controller for a buck converter

A system comprising:

• a processor;
• a memory for storing instructions and data for said processor;
• a display interface for coupling signals from said processor to a display device;
• a user interface for coupling signals from a user to said processor;
• and
• a buck regulator receiving a regulator input voltage and generating a regulated output voltage for said system, an ON-time of said buck regulator controlled by a constant ON-time controller having;
• circuitry for sensing said regulated output voltage and generating a sensed output voltage proportional to said regulated output voltage;
• circuitry for adding a first voltage ramp to said sensed output voltage to generate a modified sensed output voltage;
• circuitry for adding a second voltage ramp to a first reference voltage to generate a ripple reference voltage;
• circuitry for processing said ripple reference voltage to generate a modified reference voltage;
• circuitry for comparing said modified sensed output voltage to said modified reference voltage generating a comparator output having a first logic state when said modified sensed output voltage is greater than said modified reference voltage and a second logic state when said modified sensed output voltage is less than said modified reference voltage;
• and
• circuitry for generating a control voltage having a first logic state during said ON-time in response to said comparator output, said regulator input voltage and a second reference voltage, wherein said regulated output voltage receives energy directly from said regulator input voltage during said ON-time and said regulated output voltages receives stored energy from said regulator input voltage after said ON-time terminates.