A DC-DC converting apparatus including a step-up and step-down circuit
stepping up/down an input voltage to generate an output voltage and a PWM
control circuit. The PWM control circuit generates an error signal, first
to third voltages, a first triangular wave signal varying between the
first and second voltages, and a second triangular wave signal varying
between the third voltage and a fourth voltage determined based on the
first to third voltages. The PWM control circuit compares the error
signal with the first and second triangular wave signals and causes the
step-up and step-down circuit to step up/down the input voltage based on
the comparison. The first to fourth voltages V1 to V4 satisfy
V1