Page 8 - PEN eBook July 2023

Cover Story — Design

Considering the main requirements for the DC/DC converter of the described applications, these
can be summarized into the following four categories:

▶ Wide input voltage range
▶ Adaptive switching behavior
▶ High efficiency
▶ Power sequencing

WIDE INPUT VOLTAGE RANGE
The input voltage range of the described applications extends from a 5-V point-of-load (PoL) supply
via a 12-V intermediate voltage, generated in the device itself for a direct connection to the 24-V DC
bus. Each rail voltage has its own tolerance range. If one were to use a separate DC/DC converter

for each rail voltage, the respective design would have to be conceived, configured, tested, checked
for EMI conformity, built and logistically handled.

The VDLM series 171013801, 171023801 and 171033801 (Figure 2) come with an input voltage range
from 3.5 to 38 V. This makes the power modules suitable to cover all common voltage rails.

Figure 2: Typical rail voltages with tolerances

ADAPTIVE SWITCHING BEHAVIOR

Battery-powered applications like portable devices do not always operate under full-load conditions.
For example, a measurement application has a higher power demand during measurement and a
lower power demand between measurements.

8 JULY 2023 | www.powerelectronicsnews.com