Over-current protection apparatus and method for a switching mode regulator

A switching mode regulator with an over-current protection, comprising:

• a pair of a high-side switch and a low-side switch connected by a common output node;
• an inductor connected between the common output node and a regulator output;
• a PWM comparator for comparing an error signal with a ramp signal to thereby generate a control signal having on-duty cycles and off-duty cycles;
• a driver for generating a first driving signal to turn on the high-side switch in the on-duty cycles and a second driving signal to turn on the low-side switch in the off-duty cycles, to thereby generate a current through the inductor and derive an output voltage at the regulator output;
• a voltage sense circuit for sensing the output voltage to thereby generate a feedback signal;
• an error amplifier for comparing the feedback signal with a first reference signal to thereby determine an error signal;
• and
• a current sense circuit for sensing the inductor current in the off-duty cycles, wherein a next on-duty cycle is blanked when the inductor current exceeding a threshold.

A method for generating a regulator voltage, comprising the steps of:

• connecting a pair of a high-side switch and a low-side switch by a common output node therebetween;
• connecting an inductor between the common output node and a regulator output;
• comparing an error signal with a ramp signal for generating a control signal having on-duty cycles and off-duty cycles;
• generating a first driving signal for turning on the high-side switch in the on-duty cycles and a second driving signal for turning on the low-side switch in the off-duty cycles to thereby produce a current flowing through the inductor and derive the regulator voltage at the regulator output;
• sensing the regulator voltage for generating a feedback signal;
• comparing the feedback signal with a reference signal for determining the error signal;
• sensing the inductor current for generating a current sense signal in the off-duty cycles;
• and
• blanking a next on-duty cycle when the current sense signal exceeding a threshold.