Switching regulator and comparator-based zero current detection method used by the switching regulator

A comparator-based zero current detection method used by a switching regulator, the method comprising:

• setting an offset of a comparator, which has a value from 1 to n, to m;
• and
• if it is required to increase the offset to (m+1):
• setting the offset of the comparator to (m+1) if the offset of the comparator was set to m by being increased from (m−1), and
• maintaining the offset of the comparator at m for P times and then setting the offset of the comparator to (m+1) if the offset of the comparator was set to m by being decreased from (m+1),
• wherein 1≦m≦n, m and n are natural numbers of digital bits, and P is a natural number.

A switch controller, comprising:

• a comparator comprising a first input terminal and a second input terminal, and configured to compare a first voltage applied to the first input terminal connected to an external switching node through which an inductor current flows with a second voltage applied to the second input terminal connected to a first terminal of an external switch;
• and
• a control logic configured to receive a comparison signal of the comparator based on the comparison of the first voltage and the second voltage, and control an offset of the comparator to adjust a turn-off time of the external switch,
• wherein the control logic is configured to reduce the offset of the comparator if the comparison signal indicates that the turn-off time is before the inductor current becomes zero and increase the offset of the comparator if the comparison signal indicates that the turn-off time is after the inductor current becomes zero.