Product # BQ57120QEx50

Phone 1-888-567-9596

www.synqor.com

Doc.# 005-0006201 Rev. C

07/21/15

Page 10

Input:

40-65 V

Output:

9.3-16.25 V

Current:

50A

Package:

Quarter-brick

Applications Section

Applications Section

BusQor

Converter

Converters

Loads

Front End

Typical User Board

Vin(+)

TTL

On/Off

Vin(-)

Figure A: Example of Intermediate Bus Architecture using BusQor bus converter

and NiQor non-isolated converters

52.5Vdc

40-65V

13.1Vdc

Figure B: Internal ON/OFF pin circuitry

5V

124K

49.9K

100k

5V

3.3V

2.5V

1.8V

1.5V

0.9V

CONTROL FEATURES

REMOTE ON/OFF (Pin 2): The ON/OFF input, Pin 2,

permits the user to control when the converter is on or off.

This input is referenced to the return terminal of the input

bus, Vin(-). There are two versions of the converter that

differ by the sense of the logic used for the ON/OFF input.

In the positive logic version, the ON/OFF input is active

high (meaning that a high turns the converter on). In the

negative logic version, the ON/OFF signal is active low

(meaning that a low turns the converter on). Figure B is a

detailed look of the internal ON/OFF circuitry.

BASIC OPERATION AND FEATURES

With voltages dropping and currents rising, the economics of

an Intermediate Bus Architecture (IBA) are becoming more

attractive, especially in systems requiring multiple low voltages.

IBA systems separate the role of isolation and voltage scaling

from regulation and sensing. The BusQor series bus converter

provides isolation and a coarse voltage step down in one

compact module, leaving regulation to simpler, less expensive

non-isolated converters.

In Figure A below, the BusQor module provides the isolation

stage of the IBA system. The isolated bus then distributes power

to the non-isolated buck regulators to generate the required

voltage levels at the point of load. In this case, the bucks are

represented with SynQor’s NiQor series of non-isolated dc/dc

converters. In many applications requiring multiple low voltage

outputs, significant savings can be achieved in board space

and overall system costs.

When designing an IBA system with bus converters, the

designer can select from a variety of bus voltages. While there

is no universally ideal bus voltage, most designs employ one of

the following: 12 V, 9 V, 7.5 V, 5 V, or 3.3 V. Higher bus voltages

can lead to lower efficiency for the buck regulators but are

more efficient for the bus converter and provide lower board

level distribution current. Lower bus voltages offer the opposite

trade offs.

SynQor’s 12 Vout BusQor module acts as a true dc transformer.

The output voltage is proportional to the input voltage, with a

specified “turns ratio” or voltage ratio, plus minor drop from

the internal resistive losses in the module. When used in

IBA systems, the output variation of the BusQor must be in

accordance with the input voltage range of the non-isolated

converters being employed.

The BusQor architecture is very scalable, meaning multiple bus

converters can be connected directly in parallel to allow current

sharing for higher power applications.