Patent ID: 7570034

Claim:
A step-up/down DC-DC converter, comprising: a voltage step-up/down part configured to generate and output a predetermined output voltage by stepping up or down an input voltage in accordance with a control signal input to the voltage step-up/down part; and a control part configured to generate an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, compare the error signal and first and second triangle wave signals, and cause the voltage step-up/down part to perform a step-up or step-down operation based on a result of the comparison, wherein the control part includes: a first triangle wave generator circuit configured to generate the first triangle wave signal compared with the error signal to determine whether to cause the voltage step-up/down part to perform the step-down operation; and a second triangle wave generator circuit configured to generate the second triangle wave signal compared with the error signal to determine whether to cause the voltage step-up/down part to perform the step-up operation, the first triangle wave generator circuit being configured to generate a clock signal synchronized with the generated first triangle wave signal, and output the generated clock signal to the second triangle wave generator circuit, the second triangle wave generator circuit being configured to generate the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal, and output the second triangle wave signal.