Method of optimum current blanking time implementation in current sense circuit

A method of sensing a current flowing through a power switch of a switching regulator, the method comprising:

• turning on the power switch to enable the current to flow, the turning on causing an initial transient spike in the current;
• controlling a sense switch to turn on after the occurrence of the initial transient spike, the sense switch being operable to sense a portion of the current;
• wherein the controlling includes:
• disposing a buffer between a gate of the power switch and a gate of the sense switch;
• and configuring the buffer to have an input high threshold (Vih) voltage greater than a worst case Miller plateau voltage of the power switch, thereby disabling the buffer to turn on the sense switch during the occurrence of the initial transient spike.

An electronic system comprising:

• a load;
• and
• a switching regulator operable to provide power to the load, the switching regulator including:
• an energy storage element coupled to receive a voltage input at an input terminal;
• a current sensing circuit including:
• a power switch coupled to receive a current from the energy storage element, the power switch being controlled by a gate signal, wherein an inrush of the current causes an initial transient spike;
• a buffer having a buffer input and a buffer output, the buffer input being coupled to receive the gate signal and provide a buffered gate signal at the buffer output;
• a sense switch coupled to receive a portion of the current from the energy storage element, the sense switch being turned on by the buffered gate signal after the initial transient spike;
• a sense resistor coupled to receive the portion of the current from the sense switch;
• an amplifier operable to convert the portion of the current through the sense resistor to a feedback signal;
• a controller coupled to receive the feedback signal derived as a function of the current flowing through the energy storage element, wherein the controller provides the gate signal in response to the feedback signal.