A switching DC-to-DC converter includes multiple power supply channels, coupled
in parallel between a DC voltage source and ground, for converting the DC voltage
source into multiple DC output voltages that are separate from each other. An oscillator
outputs multiple oscillating signals to render each of the multiple power supply
channels make at least one switching transition differently in the time domain
from others of the multiple power supply channels, thereby improving transient
noise. The multiple oscillating signals include two triangular wave signals with
a phase difference of 180 degrees and two pulse wave signals with a-phase difference
of 180 degrees. Rising edges of the two pulse wave signals occur simultaneously
with either a peak or a valley of the two triangular wave signals, respectively.
