
Description
The LPD150 Series of DC-to-DC converters
feature the highest power density, delivering up to 100 watts of power on
the half-size industry standard footprint and all that in a package which is only 0.50
inch high. In addition, the Model LPD150 offers thermal shutdown,
over-temperature and over-voltage protection that so far, have been available typically in
modules twice the size.
When applied correctly, the Model LPD150
is virtually indestructible. If an abnormal and/or potentially
destructive condition occurs, the protection circuits Current Limit, Over-Voltage
Protection (OVP), and Thermal Shutdown cause the Logic Control to "turn-off" the
MOSFET, thus turning off the DC-to-DC converter. The converter can also be turned off
externally by applying a Logic Low signal to "Gate In" pin.
Over-Current Protection: Two independent output current detection circuits protect the
LPD150 Series converters from any damage if the output is overloaded or shorted. The
LPD150 module uses straight-line current limiting at module temperatures below 80°C and
automatically switches to foldback current limiting above 80°C. The output voltage
remains constant and within its specified limits up to the current limit set point. If the
current at rated voltage is greater than the current limit set point, the output voltage
will decrease in order to limit the output current. The module will automatically resume
normal operation after the overload or short-circuit condition is removed.
Over-Voltage Protection: This is an important feature that protects the user's circuit
when output voltage increases to an undesirable level. The output of the LPD150 module is
continuously monitored and fed back to the control circuit (through an isolation
transformer). The module shuts itself down if the output rises above 125% of the rated
voltage. In order to turn the module on, the input power must be turned off and reapplied.
Over-Temperature Protection
(Thermal Shutdown): When the temperature of
the module reaches 115°C, the LPD150 module shuts down. A negative temperature
coefficient thermistor is used as a sensor. The thermistor essentially reduces the current
limit trip point, thereby turning the module off when the junction temperature of the
thermistor reaches 130°C, which corresponds to the base plate temperature of
115°C. The module automatically restarts once the temperature is reduced.
High Reliability
Components: The LPD150 design utilizes the
latest technology for the power ferrite material for the transformer, aluminum PC board
for efficiently removing the heat from the power components, and ceramic capacitors for
input and output filtering. No aluminum electrolytic capacitors are used in the design.
The power MOSFETs and output rectifiers are selected based only on their superior
performance. Together with simple design and superior components, the Powercube LPD150
Series converters offer users one of the highest reliability DC-to-DC converters in the
industry.
|