Zero current detection system used in switching regulator comprising an inductor

A zero current detection system, applicable to a switching regulator comprising an inductor, and the inductor having a terminal coupled to an output terminal of the switching regulator, and the zero current detection system comprising:

• a comparator having a positive input coupled to other terminal of the inductor opposite to the output terminal of the switching regulator, and a negative input coupled to a low voltage terminal, and an output terminal configured to output a comparison result signal;
• a first signal latch circuit having a clock terminal configured to receive the comparison result signal, and an output terminal configured to output a latched output signal;
• a delay line module configured to start counting time according to the latched output signal, and output a zero current detection signal after counting a delay time;
• a voltage sampling module configured to sample in response to the zero current detection signal, the node voltage at different time points, to generate two sampling voltages;
• and
• a delay control module configured to adjust a delay time of the delay line module according to voltage levels of both of the two sampling voltages, wherein when the voltage levels of the two sampling voltages are different, the delay control module keeps the delay time of the delay line module, and when voltage levels of the two sampling voltages are the same, the delay control module adjusts the delay time of the delay line module.