Inverting DC/DC Controller Converts a Positive Input to a
Negative Output with a Single Inductor – Design Note 523
David Burgoon
There are several ways to produce a negative voltage
from a positive voltage source, including using a
transformer or two inductors and/or multiple switches.
However, none are as easy as using the LTC В®3863,
which is elegant in its simplicity, has superior efficiency
at light loads and reduces parts count compared to
alternative solutions.
Advanced Controller Capabilities
The LTC3863 can produce a –0.4V to –150V negative
output voltage from a positive input range of 3.5V to
60V. It uses a single-inductor topology with one active
P-channel MOSFET switch and one diode. The high
level of integration yields a simple, low parts-count
solution.
The LTC3863 offers excellent light load efficiency,
drawing only 70ВµA quiescent current in user-programmable Burst Mode В® operation. Its peak current
mode, constant frequency PWM architecture provides
positive control of inductor current, easy loop compensation and superior loop dynamics. The switching
frequency can be programmed from 50kHz to 850kHz
with an external resistor and can be synchronized to …