GE

Data Sheet

CAR2548DC series dc-dc converters

Input: -36Vdc to -75Vdc; Output: 48Vdc @ 2500W; 3.3Vdc or 5 Vdc @ 1A

December 6, 2013

©2013 General Electric Company. All rights reserved.

Page 7

Control and Status

can be controlled both through hardware and firmware. For

example, the output voltage is controlled both by the signal pin

(Vprog) and the PMBus command, (Vout_command) .

Using output voltage as an example; the Vprog signal pin has

ultimate control of the output voltage until the Vprog is either >

3Vdc or a no connect. When the programming signal via Vprog

is either a no connect or > 3Vdc, it is ignored, the output

voltage is set at its nominal 12Vdc and the unit output voltage

can be controlled via the PMBus command, (Vout_command).

this data sheet under Signal Definitions.

Output return. These include ‘Vstb return’ and ‘Signal return’.

Control Signals

signal can vary the output voltage from 43.2Vdc to

56Vdc. The equation of this signal is:

Vout = 42.67 + (Vprog * 5.33) where Vprog = 0.1 to 2.5V

For Vprog > 2.5V the output reverts back to 48Vdc.

generated and acted upon automatically by power supplies

connected in parallel. The Ishare pins should be tied together

for power supplies if active current share among the power

supplies is desired. No resistors or capacitors should get

connected to this pin.

Able to current share with CAR2548FP rectifiers.

voltage. This is an open collector, TTL level control signal that

needs to be pulled HI externally through a resistor.

A turn OFF command either through this signal (Remote

ON/OFF) or firmware commanded would turn OFF the 48V

output.

the 48Vdc main output. This pin should be connected to

‘output return’ on the system side of the output connector. The

purpose of this pin is to ensure that the output turns ON after

engagement of the power blades and turns OFF prior to

disengagement of the power blades.

EEPROM from accidental over writing. When left open the

EEPROM is write protected. A LO (TTL compatible) permits

writing to the EEPROM. This signal is pulled HI internally by the

power supply.

Status signals

the delivered output current is present on this pin. The signal

level is 0.1V per amp ± 0.25V.

whether the input voltage is within the anticipated range. This

signal needs to be pulled HI externally through a resistor.

the output voltage is present. This signal needs to be pulled HI

externally through a resistor.

representing whether an over temperature exists. This signal

needs to be pulled HI externally through a resistor.

If an over temperature should occur, this signal would pull LO

approximately 10 seconds prior to shutting down the power

supply. The unit would restart if internal temperatures recover

within normal operational levels. At that time the signal reverts

back to its open collector (HI) state.

Fault occurred. This signal needs to be pulled HI externally

through a resistor.

This signal activates for OTP, OVP, OCP, INPUT fault or No

output.

power supply. Its intent is to indicate to the system that a

power supply is present. This signal may need to be pulled HI

externally through a resistor.

representing the SMBusAlert# feature of the PMBus compatible

HI externally through a resistor.

Serial Bus Communications

The I²C interface facilitates the monitoring and control of

various operating parameters within the unit and transmits

these on demand over an industry standard I²C Serial bus.

All signals are referenced to ‘Signal Return’.

have the following addresses:

Device

Address

Address Bit Assignments

(Most to Least Significant)

MCU

0xBx

1

0

1

1

A2

A1

A0

R/W

Broadcast

0x00

0

0

0

0

0

0

0

0

EEPROM

0xAx

1

0

1

0

A2

A1

A0

R/W

The Global Broadcast instruction executes a simultaneous

write instruction to all power supplies. A read instruction

cannot be accessed globally. The three programmable address

power supply.

(8) modules to be addressed on a single I²C bus. The pins are

pulled HI internal to the power supply. For a logic LO these pins

should be connected to ‘Output Return’

by the host that initiates communications across the I²C Serial

bus. This signal is pulled up internally to 3.3V by a 10kΩ

resistor. The end user should add additional pull up resistance

as necessary to ensure that rise and fall time timing and the