Abstract: A spread spectrum clock generator circuit includes a phase comparator; an oscillator to output an output clock signal; a phase selector to select one of phases equally dividing one cycle of the output clock signal, and to generate a phase shift clock signal having a rising edge in the selected phase; and a phase shift controller to control the phase selector. The phase shift controller generates a variable phase shift amount; determines the phase of the rising edge so that the cycle of the phase shift clock signal has a length changed from the cycle of the output clock signal by the variable phase shift amount added with a fixed phase shift amount; and changes a setting of an SS modulation profile if the selected phase exceeds an upper limit, falls below a lower limit, or is within the upper and lower limits.

Abstract: A spread spectrum clock generator circuit includes a phase comparator; an oscillator to output an output clock signal; a phase selector to select one of phases equally dividing one cycle of the output clock signal, and to generate a phase shift clock signal having a rising edge in the selected phase; and a phase shift controller to control the phase selector. The phase shift controller generates a variable phase shift amount; determines the phase of the rising edge so that the cycle of the phase shift clock signal has a length changed from the cycle of the output clock signal by the variable phase shift amount added with a fixed phase shift amount; and changes a setting of an SS modulation profile if the selected phase exceeds an upper limit, falls below a lower limit, or is within the upper and lower limits.

Abstract: A switching power supply circuit includes a plurality of switching regulators and a timing adjustment circuit. The plurality of switching regulators converts an input voltage input to an input terminal into a plurality of predetermined constant voltages, and outputs the plurality of predetermined constant voltages from a plurality of output terminals, respectively. The timing adjustment circuit adjusts phases of a plurality of pulse signals generated by the plurality of switching regulators so that the phases of the plurality of pulse signals are different from each other, and outputs the plurality of adjusted pulse signals to respective switch circuits of the plurality of switching regulators.

Abstract: A switching power supply circuit includes a plurality of switching regulators and a timing adjustment circuit. The plurality of switching regulators converts an input voltage input to an input terminal into a plurality of predetermined constant voltages, and outputs the plurality of predetermined constant voltages from a plurality of output terminals, respectively. The timing adjustment circuit adjusts phases of a plurality of pulse signals generated by the plurality of switching regulators so that the phases of the plurality of pulse signals are different from each other, and outputs the plurality of adjusted pulse signals to respective switch circuits of the plurality of switching regulators.