Patent ID: 8836307

Claim:
A voltage regulator comprising: a first comparator, for comparing a first ramp signal with an output sense signal to output an ON-time trigger signal for a pulse width modulation signal, wherein the output sense signal comprises an output voltage error signal varied along with a difference between an output voltage of the voltage regulator and a first reference voltage; a flip-flop, for outputting the pulse width modulation signal and determining a start point of an ON-time of the pulse width modulation signal according to the triggering of the ON-time trigger signal; and a second comparator, for comparing a second ramp signal with the output sense signal to determine whether to reset an output of the flip-flop and thereby determining an end point of the ON-time of the pulse width modulation signal; wherein a first input terminal of the first comparator is electrically coupled to receive the output sense signal and further electrically coupled to a second input terminal of the first comparator through a resistor, and the second input terminal of the first comparator is electrically coupled to receive the first ramp signal and further electrically coupled to a second reference voltage; wherein the first ramp signal is reset to the second reference voltage at the start point of the ON-time of the pulse width modulation signal and then is maintained at the second reference voltage, and further ramps down starting from the end point of the ON-time of the pulse width modulation signal; wherein the second ramp signal ramps up starting from the start point of the ON-time of the pulse width modulation signal, and then is reset at the end point of the ON-time of the pulse width modulation signal.