Short-circuit protection circuit, chip and system for switched-mode power supply

A short-circuit protection circuit for a switched-mode power supply, the short-circuit protection circuit comprising:

• a sampling module configured for sampling an input voltage and producing a first voltage from the input voltage;
• a generation module configured for generating a second voltage from a reference voltage, the second voltage having a predetermined period and a sawtooth waveform;
• a comparison module configured for comparing the first voltage and the second voltage;
• and
• an output module configured for outputting, from a result of the comparison performed by the comparison module, a control signal for controlling an external power transistor in the event of a short circuit in the switched-mode power supply, wherein:
• the result of the comparison comprises a first comparison result indicating that the first voltage is higher than the second voltage during a first time interval within the predetermined period, the output module outputs, from the first comparison result, a first control signal for causing the external power transistor to be out of operation within the first time interval;
• the result of the comparison further comprises a second comparison result indicating that the first voltage is lower than the second voltage during a second time interval within the predetermined period, the output module outputs, from the second comparison result, a second control signal for causing the external power transistor to operate within the second time interval, wherein the predetermined period consists of the first time interval and the second time interval;
• and
• a duration of the second time interval decreases with increase of the first voltage, wherein a hiccup-mode duty cycle decreases with increase of the first voltage and increases with decrease of the first voltage.