Switching power supply device having pulse-by-pulse type overcurrent protection function

A switching power supply device, comprising:

• a switching output circuit configured to generate an output voltage from an input voltage;
• an oscillation circuit configured to generate a clock signal;
• a control circuit configured to control driving of the switching output circuit in synchronization with the clock signal;
• a pulse-by-pulse type overcurrent protection circuit configured to detect an overcurrent flowing through the switching output circuit to generate an overcurrent protection signal for forcibly stopping a switching operation of the switching output circuit;
• and
• a pulse skip circuit configured to perform a pulse skip operation of the clock signal in response to the overcurrent protection signal, the pulse skip circuit including:
• a timer part configured to start a counting operation in response to the overcurrent protection signal to generate a mask period expiration signal;
• an RS flipflop configured to generate a mask signal set to a first logic level in response to the overcurrent protection signal and reset to a second logic level in response to the mask period expiration signal;
• and
• a logic gate configured to block the clock signal over a mask period during which the mask signal is set to the first logic level,
• wherein the timer part is configured to extend the mask period as the output voltage is lowered.