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V•I Chip Bus Converter Module

B048K030T21

Rev. 1.0

Page 13 of 15

V•I Chip Bus Converter Module

PRELIMINARY

Input Impedance Recommendations

To take full advantage of the BCM capabilities, the impedance presented

to its input terminals must be low from DC to approximately 5 MHz. The

source should exhibit low inductance (less than 100 nH) and should have a

critically damped response. If the interconnect inductance exceeds 100 nH,

the BCM input pins should be bypassed with an RC damper (e.g., 47 µF in

series with 0.3 ohm) to retain low source impedance and stable

operations. Given the wide bandwidth of the BCM, the source response is

generally the limiting factor in the overall system response.

Anomalies in the response of the source will appear at the output of the

BCM multiplied by its K factor. The DC resistance of the source should be

kept as low as possible to minimize voltage deviations. This is especially

important if the BCM is operated near low or high line as the over/under

voltage detection circuitry could be activated.

Input Fuse Recommendations

V•I Chips are not internally fused in order to provide flexibility in

configuring power systems. However, input line fusing of V•I Chips must

always be incorporated within the power system. A fast acting fuse should

be placed in series with the +IN port.

Application Circuits

-In

PC

RSV

TM

+In

-Out

+Out

-Out

+Out

BCM

K

Ro

NiPOL

1

NiPOL

2

NiPOL

3

NiPOL

4

LOAD

1

LOAD

2

LOAD

3

LOAD

4

Figure 27—The BCM provides an isolated output from a narrow range input ideal for driving non-isolated point of load converters (niPOLs)

Vo = 2.38 - 3.43 V

48 Vin

(38 - 55 Vdc)

FPA Local Loop

+Out

–Out

+In

–In

VC

PC

TM

IL

VH

PR

NC

SG

SC

PRM-AL

OS

NC

CD

L

O

A

D

Factorized

Power Bus

K

-In

PC

RSV

TM

+In

-Out

+Out

-Out

+Out

BCM

K

Ro

Figure 28—The PRM regulates its output to provide a constant factorized bus voltage. The output voltage is the nominal load voltage, Vo, at no

load and decreases with load at a constant rate equal to the BCM output resistance Ro.

In the following figure;

K = BCM Transformation Ratio

48 Vin

(36 - 75 Vdc)

B048K030T21

Ω)