Application Note 107
July 2006
Extending the Input Voltage Range of PowerPath
Circuits for Automotive and Industrial Applications
Greg Manlove
INTRODUCTION POWER
SUPPLY The voltage range of Linear Technology’s PowerPath® circuits can be easily extended with just a few components, thus
allowing them to meet the needs of virtually all applications.
This application note presents solutions for circuits that
must withstand large negative voltages, a reverse adapter
input for example, and circuits that must withstand large
positive inputs, such as automotive load-dump.
EXTENDING THE VOLTAGE RANGE
Any of Linear’s PowerPath controller circuits can benefit
from an extended voltage range, even those that already
have wide operating and absolute maximum voltage
ranges. For instance, the LTC4412HV and LTC4414 will
each withstand voltages from –14V to 40V, which can be
extended further using the techniques described here.
Likewise, the LTC4412’s range of –14V to 28V can be
extended. The voltage ranges of monolithic PowerPath
solutions such as the LTC4411, which ranges from –0.3V
to 6V, can also be extended, though not as far. …