|
 |
Circuits designed by David Johnson,
P.E.
Last Updated on:
Tuesday, December 26, 2017 04:22 AM
Master Category List - Dave's Circuits
The contents &
graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB
SITE server |
|
|
|
More
Photovoltaic Circuits, Rectifier Circuits
|
|
Ideal
Blocking Diode Circuit for Photovoltaic Solar Panels |
Most photovoltaic solar panels are used to charge a battery during the daytime.
Nearly all panels come equipped with a blocking diode. The diode prevents DC
current from flowing backwards from the battery bank into the panel at night.
The usual blocking device of choice is a schottky diode with a typical 0.5v
voltage drop. In some large panels, which can often source over 4 Amps of
current, the power loses due to this voltage drop can add up. As an example
a 4KW solar power system made of 20 200 watt panels will dissipate some 40 watts
of power in the diodes. The circuit below uses a new high voltage ideal
diode IC from Linear Technology. The LTC4357 contains all the circuitry
needed to control an external n-channel FET. The circuit shown below
performs a standard diode function with a much lower 0.06 voltage drop at 4 Amps.
When current tries to flow in the other direction, the IC turns off the FET,
blocking the current. |
|
|
|
The LTC4357 contains a charge pump
circuit to provide the needed gate-source voltage for the n-channel device. An
n-channel is used since they tend to have much lower channel resistances and higher
voltages than p-channel parts. The 100v device picked has an on resistance of
only 0.015 ohms. The circuit is good for over 10 Amps but I would recommend that
the FET be mounted to a heat sink if the current exceeds 8 Amps. |
|
|
Click on Drawing Below to view PDF version of Schematic |
|
 |
|
|
|
|
