Novel Current-Sharing IC Balances Two Supplies with Ease
Pinkesh Sachdev Failure is not an option. That’s the likely motto for the architects of today’s alwaysup electrical infrastructure—think telecommunications networks, the Internet and
the electrical grid. The problem is that the bricks of this infrastructure, from the
humble capacitor to the brainy blade-servers, have a limited lifetime usually ending
at the most Murphy of moments. The usual workaround to the mortality problem is
redundancy—backup systems ready to take over whenever a critical component fails.
For instance, high availability computer
servers typically ship with two similar
DC supplies feeding power to each individual board. Each supply is capable of
taking on the entire load by itself, with
the two supplies diode-ORed together
via power diodes to create a single 1В +В 1
redundant supply. That is, the higher
voltage supply delivers power to the load,
while the other supply idly stands by. If the
active supply voltage drops or disappears,
due to failure or removal, the once lowervoltage supply becomes the higher voltage
supply, so it takes over the load. The
diodes prevent back-feeding and crossconduction between supplies while protecting the system from a supply failure. 5A
12.2V NC Supply lifetimes are extended if each
takes on half the load, spreading the
supply heat and reducing thermal
stresses on supply components. A rule …