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VTM™ Current Multiplier

V048F160T015

Rev. 3.0

Page 5 of 11

Pin / Control Functions

+In / -In DC Voltage Ports

The VTM™ current multiplier input should be connected to the

PRM™ regulator output terminals. Given that both the regulator and

current multiplier have high switching frequencies, it is often good

practice to use a series inductor to limit high frequency currents

between the PRM module output and VTM module input capacitors.

The input voltage should not exceed the maximum specified. If the

input voltage exceeds the overvoltage turn-off, the VTM module will

shutdown. The VTM module does not have internal input reverse

polarity protection. Adding a properly sized diode in series with the

positive input or a fused reverse-shunt diode will provide reverse polarity

protection.

TM – For Factory Use Only

VC – VTM Control

upstream PRM regulator, synchronizing the output rise of the VTM

module with the output rise of the regulator. Additionally, the VC port

provides feedback to the PRM to compensate for the current multiplier

output resistance. In typical applications using VTM modules powered

from PRM regulators, the regulators VC port should be connected to

the VTM module VC port.

The VC port is not intended to be used to supply V

VTM module for extended periods of time. If VC is being supplied from

a source other than the PRM regulators, the voltage should be removed

after 20 ms.

PC – Primary Control

The Primary Control (PC) port is a multifunction port for controlling the

current multiplier as follows:

Disable – If PC is left floating, the VTM module output is enabled.

To disable the output, the PC port must be pulled lower than 2.4 V,

referenced to -In. Optocouplers, open collector transistors or relays

can be used to control the PC port. Once disabled, 14 V must be

re-applied to the VC port to restart the VTM module.

Primary Auxiliary Supply – The PC port can source up to 2.4 mA

at 5 Vdc.

+Out / -Out DC Voltage Output Ports

The output and output return are through two sets of contact

locations. The respective +Out and –Out groups must be connected in

parallel with as low an interconnect resistance as possible. Within the

specified input voltage range, the Level 1 DC behavioral model shown

in Figure 16 defines the output voltage of the VTM module. The

current source capability of the VTM module is shown in the

specification table.

To take full advantage of the VTM current multiplier, the user should

note the low output impedance of the device. The low output

impedance provides fast transient response without the need for bulk

POL capacitance. Limited-life electrolytic capacitors required with

conventional converters can be reduced or even eliminated, saving cost

and valuable board real estate.

-In

PC

VC

TM

+In

-Out

+Out

-Out

+Out

Bottom View

A

B

C

D

E

F

G

H

J

K

L

M

N

P

R

T

4

3

2

1

A

B

C

D

E

H

J

K

L

M

N

P

R

T

Figure 9 — VTM™ current multiplier pin configuration

Signal Name

Pin Designation

+In

A1-E1, A2-E2

–In

L1-T1, L2-T2

TM

H1, H2

VC

J1, J2

PC

K1, K2

+Out

A3-D3, A4-D4,

J3-M3, J4-M4

–Out

E3-H3, E4-H4,

N3-T3, N4-T4