Patent ID: 7990121

Claim:
A switching regulator of a synchronous rectification type converting an input voltage input to an input terminal into a predetermined constant voltage and outputting the predetermined constant voltage to a load connected to an output terminal, the switching regulator comprising: a first switching element configured to perform switching in accordance with a control signal input thereto; an inductor configured to be charged with the input voltage by the switching of the first switching element; a second switching element for synchronous rectification configured to perform switching in accordance with a control signal input thereto so as to discharge the inductor; a control circuit part configured to control the switching of the first switching element so that an output voltage output from the output terminal is the predetermined constant voltage, and to cause the second switching element to perform the switching inversely to the first switching element; and a reverse current prevention circuit part configured to interrupt a current that flows into the second switching element by cutting off a selected connection of the second switching element that is different from a connection for said control signal input to the second switching elements so as to prevent generation of a reverse current that flows in a direction of the second switching element from the output terminal, the reverse current prevention circuit part comprising a reverse current detector circuit configured to detect the reverse current, by selectively carrying out a voltage comparison operation to compare (i) voltage at the connection of the first switching element and the inductor and (ii) a ground voltage, and latching and outputting a cut-off signal to interrupt the current that flows into the second switching element by cutting off the selected connection of the second switching element, when the reverse current has been detected, wherein said reverse current detector circuit stops the voltage comparison operation when the reverse current has been detected, and resumes the voltage comparison operation when the second switching element turns off.