MAPC-104 Ver la hoja de datos (PDF) - Unspecified
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MAPC-104 Datasheet PDF : 7 Pages
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PC/104-Plus Series
46W, TRIPLE OUTPUT DC/DC CONVERTER
Self-Protection Features
The MAPC-104 contains two systems for protection of out-of-limit voltages,
currents and temperature. These systems control two output lines located on
the Input Power Header connector. Both systems operate independently and
concurrently. The MAPC-104 will respond to both temperature and voltage/
current simultaneously.
The output circuits for both these controls are shown below. Both of them will
drive either an external LED lamp and/or a logic circuit. The Overtemperature
Warning Circuit assumes that an external pullup resistor is supplied by the
user. The Power Good Circuit (“Pwr_LED_Drive Out”) includes an on-board
pullup resistor to drive an external LED with about 15mA.
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Typical External Logic Wiring
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Typical OT Warning External LED Lamp Wiring
Pwr_LED_Drive Out (pin 2, pullup to internal +5V):
HI (transistor off) = Power is normal. LED lamp is illuminated.
LO (transistor on) = Power fault, LED lamp is dark
Overtemperature Operation
The overtemperature system includes a on-board temperature sensor, a local
microcontroller with A/D inputs, a timer and hysteresis so that the user may
take steps to prevent inadvertant shut down. Operation proceeds as follows:
If the on-board temperature exceeds +115°C, the OT_Warn Output is
asserted (LO) by the microcontroller and an internal 30 second software
timer is started. The outputs remain powered on.
If the 30-second timer has not expired and the on-board temperature cools
below +110°C, the OT_Warn Output will be deasserted (HI) and operation
will continue unchanged.
If the 30-second timer has expired and the temperature still exceeds +115°C,
the outputs will shut down. As soon as the on-board temperature cools to
less than +110°C, the MAPC-104 will automatically restart and power will be
restored to the outputs.
The 5 degree hysteresis between 110 and 115°C prevents rapid cycling of
the OT_Warn Output.
If the on-board temperature reaches +125°C, the outputs will shut down,
regardless of the state of the 30-second timer. The temperature must cool to
less than +110°C for autorestart.
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Figure 1. Overtemperature Warning Circuit
The transistors in these outputs are either on (typically less than 0.4 Volts
out) or off (high impedance state). Depending on how the user wires the
external circuit, these indicators have the following sense:
OT_Warn Out (pin 1):
HI (transistor off) = temperature is normal
LO (transistor on) = Over temperature condition
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Typical Power Good External LED Lamp Wiring
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Figure 2. Power Good Circuit
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