Vicor Constant Current Demonstration Board User Manual

USER GUIDE | UG:007

Constant Current (CC) Demonstration Board

The Constant Current (CC) Demonstration Board described in this document shows how to use a

Contents Page

Introduction 1

PRM regulator as a constant current source. The CC demonstration board is not designed for
installation in end-user equipment. The system demonstrates the use of a PRM
drive light-emitting diodes (LEDs) or for general laboratory evaluation.

®

and a VTM®to

Features 2

General 3-7

Test Procedure 8-15

Bill of Material 16

Ordering Info 17
Summary

Please read this document before setting up a customer demonstration board.

The User’s Guide is not comprehensive and is not a substitute for common sense and good
practice. For example:

1. When testing electronic products always use approved safety glasses.

2. Provide a strain relief for wires and place the system on the bench in such a way as to prevent
accidental dislodgment from the bench top.

3. Remove power and use caution when connecting and disconnecting test probes and interface
lines to avoid inadvertent short circuits and contact with hot surfaces.

4. Never use a jumper in place of the fuse. Replace the fuse only with its equivalent type and rating.

5. Never attempt to disconnect the CC demonstration board from a VTM customer board while
power is applied. This system is not designed to demonstrate hot plug capability. Additional
components would be required to implement a hot plug capable system.

1.0 Introduction

The PRM Regulator can be set to either regulate its output in a Local Loop mode or regulate the
output of a VTM Voltage Transformer at the point of load in an Adaptive Loop. Adaptive Loop
regulation is realized through the addition of a compensation resistor to the CD pin. Please refer
to the

Factorized Power Architecture (FPA™) white paper for more details. The CC demonstration

board is designed to provide a precise regulated current. This is particularly useful in LED driving
applications where the intensity and brightness are controlled by regulating the current through
the LED.

The VI Chip solution provides an efficient, power dense means of powering high current opto­semiconductor LEDs such as Enfis products UNO and Quattro arrays as well as OSRAM product
OSTAR.

The P048F048T24AL-CC board may be used to provide up to 5 A when employed as a standalone
non-isolated source. A PRM–VTM combination provides isolated current multiplication up to 100
A. Separate VTM boards allow customers to choose a desired output current and voltage range.
To obtain a VTM customer board, simply add “-CB to the VTM part number.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 1

2.0 Features

+IN

J01

+

–

+

–

–IN

–OUT

+

OUT

R33

J02

TP08

TP06

TP04

TP05

TP07

TP02

TP01

TP03

S

W01

F01

C4

C1

C2 C3

R3

VH

C

12

L01

R28

R27

R8

R32

R30 R23

R12

R13R18

R

17

R16

R19

VH

C11

U02A

U02B

R21

R24

VSENSE

VREF V

H

SW02

R10

SLC7530

PS01

V

C

PC

TM

IL

NC1

P

R

+IN

–IN

V

H

SC

SG

OS

NC2

C

D

+

OUT

–OUT

R6

CONN - 10 PIN - MALE

The CC Demonstration Board contains the following:

1. High power density PRM.

2. Adjustable current output of up to 5 A (if no VTM is used).

• Adjustable current output of up to 100 A with the use of a VTM customer board.

3. Adjustable PRM maximum output voltage.

4. Kelvin connections for measuring the efficiency of the VI Chip components independent
of load connect losses.

5. Oscilloscope probe jacks for measuring output voltage, including output voltage ripple.

6. Fused PRM input.

7. Provision for mounting optional VI Chip pushpin heat sink.

8. System enable and disable.

CC Demonstration

Figure 1

Board Schematic

Figure 2

CC Demonstration

Board

Double click the image to see a larger view.

2.1 CC Demonstration Board Description

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 2

2.1.1 General

C01

C02

C03

J01

C6

R

15

C7
R16
R17
R18
R19
C9

C8

R11
R12
R13
R14

C5
R

6

R7

R20

R21

R4

R5

U01

U02

T

P6

TP2

TP3

TP1

TP4

T

P5

T

P7

TP8

L01

R33

R32

J02

R30

C14

C15

R31

R24

R25

R26

C11

R27

R22

R23

R28

C12

C13
R29

C10

R10

R8

R9

SW02

Q

01

F01

C4
R

1

R2
R3

SWO1

PS01

D01

1. Source voltage DC input points (+IN, –IN): Designed to accommodate #10 hardware and
Panduit ring lugs. The PRM has no reverse power protection so be sure to observe correct
polarity.

2. Toggling switch (SW01): Used to enable or disable the PRM. The ON position enables the

RM by allowing the PRM PC pin to float. The OFF position disables the PRM by pulling

P
the PRM PC to signal ground (SG).

3. Toggling switch (SW02): Used to open or close the connection between the reference
voltage produced from the potentiometer (R10) and the positive input of the comparator
op amp. This is provided as an added feature to allow the use of an external shunt
regulator. The recommended component is TLV431B. For further details refer to application
note

AN: 018 Providing a Constant Current for Powering LEDs using the PRM and VTM

Make sure to turn this switch to the "open" position when a shunt regulator is in use.

4. Output voltage points (+OUT, –OUT).

5. Output connector (J01): Used for mating with VTM-CB providing V
dedicated to the +OUT, four for the –OUT, and two for the VC. Each contact is rated for
3 A. The excess capacity afforded by these pins can facilitate testing multiple VTM-CBs
from a single PRM-CC using appropriate wiring harness and mating connector. This may
also be achieved using the large pads of the output voltage points.

and VC. As shown

OUT

CC Demonstration

Figure 3

Board Layout

Double click the image to see a larger view.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 3

2.1.2 CC Demonstration Board Components

+Out

–Out

+In

–In

VC
PC
TM
IL

VH

PR

NC

SG

SC

PRM -AL

OS
NC
CD

Vout

Vin

1. Input capacitors (C01, C02, C03): A 22 µF capacitance assuming a low input source
impedance.

2. Fast-acting fuse (F01): Rated for 10 A.

3. Potentiometer V

(R10): Provides an adjustable voltage divider in combination with (R6).

REF

This divider achieves the reference voltage used to set the value of the PRM output
current. Please refer to the application note

AN: 018 Providing a Constant Current for

Powering LEDs using the PRM and VTM for more details on start up sequencing precautions.

4. Potentiometer V
to in the

PRM datasheet. The OS resistor is used to set the output voltage of the PRM.

(R8): Combined with (R27) V

MAX

make up the OS resistor referred

MAX

In this case it is used to limit the PRM maximum output voltage the CC feedback can drive
in order to source more current.

5. Dual op amp (U02): U02A shown in Figure 1 is used as a difference amplifier sensing the
voltage produced by the current flowing though the PRM output sense resistor (R33).
Op amp (U02B) regulates the output of op amp (U02A) against the manually set reference
using the potentiometer (R10) or an external shunt regulator.

6. Output inductor (L01): The PRM soft switches at a frequency greater than 1 MHz while the
VTM soft switches at a frequency of 1.7 MHz. L01 is used to reduce the high frequency
current ripple produced by the high frequency switching inside the PRM.

7. Sense resistor (R33): The voltage across the sense resistor is captured by the difference
amplifier then fed back to the PRM SC pin through the error amplifier in order to maintain
the current regulation. R33 is a 1 w, ±0.1% tolerance, 10 mΩ high precision metal strip
current sense resistor positioned at the –OUT of the PRM.

8. PRM connection highlights:

PRM-AL Schematic Symbol

Figure 4

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A. Auxiliary voltage (VH): The op amp is powered using the VH pin. This pin is a 9 V ±0.3 V

regulated voltage capable of sourcing up to 5 mA. Do not exceed the current rating
for VH. Exceeding the current limit will render the unit inoperative. To increase VH
capability an external circuit scheme using a power transistor can be used as described in
application note

AN: 018 Providing a Constant Current for Powering LEDs using the PRM

and VTM.

B. Secondary control (SC): The output of the comparator op amp (U02B) is connected to the

SC pin. This pin will be driven high to drive the PRM output voltage high and vice versa.
The resistor divider formed by (R23 & R30) controls the maximum voltage at the input of
this SC pin. The output of the comparator is about 9 V. Care must be taken when selecting
values different than the recommended (R23 & R30). Please refer to the application note

AN: 018 Providing a Constant Current for Powering LEDs using the PRM and VTM.

C. Output set resistor (R27): This pin defines the maximum output voltage of the PRM when

the error amplifier output drives the SC pin to its maximum. The combination of both
resistors (R27 & R8) forms the R
R

resistor by turning the potentiometer (R8) clockwise will increase the maximum

OS

resistor required to operate the PRM. Reducing the

OS

output voltage. The Fixed resistor (R27) value is chosen to ensure a maximum output
voltage of 55 V. Please refer to the
how to choose the appropriate R

PRM P048F048T24AL datasheet for more details on

value for the desired PRM maximum output voltage.

O

S

D. VTM control pin (VC): This PRM output pin provides a 10 ms pulse during start up enabling

the downstream VTM. VC is connected to pin (3 & 4) on (J01) connector.

2.1.3 Test Points

1. Input & output Kelvin test points –IN, +IN (TP1 & TP3) and –OUT, +OUT (TP7 & TP8):
These input/output access points of the PRM enable accurate efficiency measurements of
the VI Chip independent of the interconnection losses.

2. PC (TP3): Test point primary control signal. During normal operation this pin is internally
pulled high to 5 V. Drive this pin low by moving (SW01) to the OFF position to disable the
PRM output. This pin will pulsate under fault conditions.

3. V

(TP4): Test point voltage sense serves to show the output voltage of the difference

SENSE

amplifier (U02A). This voltage is proportional to the actual PRM-sensed output current.
The constant of proportionality is equal to the difference amplifier gain formed by the
resistors (R16-R18). If the recommended gain of 100 is used in combination with the
10 mΩ sense resistor the outcome is a one-to-one relationship between the measured
voltage at this test point and the PRM output current. (V

4. V

(TP5): Test point voltage reference value is being compared with the sensed voltage

REF

V

. Op amp B is providing an output voltage to the SC pin in order to retain V

SENSE

V

REF

= I

OUT_ PRM

assuming that R

x Gain = 1. Turn the potentiometer (R10)

SENSE

SENSE

= R

SENCE

x Gain x I

OUT_ PRM

SENSE

clockwise to increase the required output current set point.

5. SG (TP6): Test point signal ground is the ground reference for the internal control IC.

6. Output voltage oscilloscope probe jack (J02): Accepts most oscilloscope probes and
enables precision measurement of the output voltage ripple.

)

=

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 5

2.2 Mounting a Heat Sink

Typical Heat Sink

Figure 5

A pushpin VI Chip heat sink is included with the CC demonstration board to allow extended

bench top testing at full power and lower airflow.

The PRM is equipped with an over-temperature shut down feature. Please refer to the data
sheet for more details.

2.3 No Load Connection

The CC demonstration board relies on the feedback provided by the current flowing through
the sense resistor (R33). If no load is connected to the module output the CC loop will detect a
no-current flow and will steer the SC pin accordingly to the maximum value. The output
voltage of the PRM will be driven to its highest set point. The resistor (R27) can prevent the
PRM from going into an output over-voltage fault during this condition by limiting the
maximum PRM output voltage. The PRM is equipped with over-voltage protection. However, if
the circuit drives the PRM into over-voltage with no load, the PRM may be damaged. Please
refer to the appropriate section for guidelines on properly setting the maximum PRM output
voltage.

2.4 VTM Shut Down

The PRM initiates a VC pulse at start up for the downstream VTM. The VC pulse is used to
synchronize the output of the VTM with the PRM output voltage. If the PRM detects a fault
condition, it will initiate the 12 V, 10 ms pulse to the downstream VTM. Adjusting the (R10)
counterclockwise to limit the output current will drive the PRM output voltage low. It is
possible to manually trigger the under-voltage mechanism where the PRM goes into fault
condition as shown in Figure 6.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 6

PRM & VTM Under-voltage

Figure 6

Behavior

VTM PC

PRM VC

TM V

V

OUT

PRM V

OUT

It is also possible to adjust (R10) clockwise fast enough before a PRM under-voltage event.
The PRM will aptly recover without registering an error. However, the VTM may have already
detected an under-voltage condition which will force it into shut down. Reset the VTM by
toggling the (SW01). The VTM requires a VC voltage if its input is lower than 26 V. An additional
circuit is required to provide a permanent solution in the special case where the PRM recovers
from a lower than 26 V. This circuit will detect a VTM fault and will force a PRM restart. Please
contact Vicor applications engineering for further details.

PRM & VTM Under-voltage

Figure 7

Abnormal Behavior

VTM PC

PRM V

OUT

PRM VC

VTM V

OUT

2.5 Measurement Precautions

The DC current limit protection uses a shunt resistor in the path of –IN and –OUT. Although
this is a non-isolated system, be advised that shorting –IN to –OUT disables this valuable
feature of the PRM. This warning extends to the use of multiple scope probes on the input
and output simultaneously.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 7

The CC sense resistor (R33) is located right before the output voltage oscilloscope probe jack

DC

+ +

- -

CCBD-CC

+

-

Electronic Load

+OUT

DMM

Measuring

Output Current

Set to Constant Current mode

DMM

Measuring Voltage V

R

EF

using test point TP5

–OUT

+IN

–IN

(J02). Probing the input pins while connecting a probe to (J02) will introduce another low
resistance return path. The amount of current circulating through that path is difficult to
predict. The current through the added path will not be sensed by the CC circuit. The CC
circuit will require the PRM to compensate for this loss. The current through the load will be
equal to the user set reference current and the unknown variable current through the scope.
In short, this may damage the load and equipment used due to excess current.

3.0 Test Procedure

3.1 Recommended Equipment

• DC power supply – 0-100 V; 500 W

• DC electronic load – pulse capable; 0-100 V; 100 A minimum

• Two digital multi-meters (DMMs)

• Oscilloscope

• Fan (if the PRM-VTM to be operated for extended periods of time or at an elevated

ambient temperature we recommend the supplied heat sink be installed)

• Safety glasses

• datasheet for the requisite PRM / VTM

3.2 Prerequisites

• Maximum desired output voltage.

CC No Load Functional

Figure 8

Verification

• Desired PRM output current.

3.3 Initial CC Demonstration Board Set Up (V

REF

and V

MAX

Set)

1. Have the latest PRM datasheet in hand.

2. Install heat sink if desired.

3. Assure that the DC supply is set to 0.0 Vdc prior to turning the unit on.

4. Set the supply current limit to a higher value than the chosen PRM DC current limit.

5. Set the DC load to 0.0 A, constant current mode.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 8

6. Verify proper power supply to CC board connections.

7. Connect DMM to measure the output voltage using the output Kelvin test points.

8. Turn V

(R10) potentiometer clockwise gently until it reaches its maximum value of

REF

100 K which corresponds to ≈ 5 V depending on its tolerance. The potentiometer has

tops which indicate that it has been turned fully in one direction. Do not wind the

s
potentiometer past the stop, as this may damage the part.

9. Turn V

(R8) potentiometer counterclockwise gently until it reaches its maximum value

MAX

of 5K which corresponds to an output voltage of ≈ 30 V depending on its tolerance.
The potentiometer has stops which indicate that it has been turned fully clockwise /
counterclockwise. Do not wind the potentiometer past the stop as this may damage the part.

10. Connect DMM to measure V

at TP5 with reference to SG at TP6.

REF

11. Make sure (SW02) is in "close" position.

12. Turn on a fan if desired.

13. Raise the DC input voltage to the nominal value of 48 V as indicated on the

PRM
P048F048T24AL datasheet. The output voltage should read approximately 30 V if the

potentiometer has been turned fully counterclockwise as directed in step 9.

14. Set the load in constant current mode to 50% of the PRM’s rated output (2.5 A for the
P048F048T24AL-CC). With the load in this setting, the circuit will have no control and will
drive the PRM to its maximum value provided that the load current is less than the
reference set point. This allows for adjusting the maximum PRM output voltage.

15. Turn the potentiometer (R8) clockwise to set the maximum PRM output voltage. When
setting the maximum PRM output, keep in mind that the CC feedback can drive the
output voltage up to this maximum limit in order to maintain the required current. Due to
component tolerances, turning (R8) fully clockwise can result in the circuit driving the PRM
above its maximum voltage. If this is done with no load, the PRM may be damaged.
Do not set the maximum PRM voltage above 55 V.

16. Turn off the electronic load

17. Turn the potentiometer V
point to the desired value. If V

(R10) counterclockwise to lower the PRM output current set

REF

is not lowered to a reasonable value below the DC

REF

current limit, the PRM will start in a fault condition when connected to a load. It will
remain in fault until the potentiometer V

(R10) is turned counterclockwise to lower the

REF

set reference. An undesirable clicking sound will be audible in this case. Although
continuous operation in this mode will not damage the unit, it is not recommended.

18. Decrease the input voltage to low line.

You have now verified the operation of the CC and set the desired output current and
maximum output voltage.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 9

3.4 CC Demonstration Board with an Electronic / Resistive Load

DC

+ +

- -

CCBD-CC

+

-

E

lectronic Load

+OUT

DMM

M

easuring

Output Current

Set to Constant Current mode

DMM

Measuring Voltage V

REF

u

sing test point TP5

–OUT

+IN

–

IN

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.2 0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 6.2

V

REF

(V)

Percentage of Error (%)

V

REF

(typ.) vs. I

OUT

CC Electronic / Resistive Load

Figure 9

1. Make sure that the power is removed from the unit prior to making adjustment.

2. Connect DMM in series with the electronic load. Make sure DMM can handle the
maximum PRM output current then set it to read DC current.

3. Set the Electronic Load to constant resistance mode of 0.16 Siemens.

4. Verify proper DMM and electronic load connections to the CC board output.

5. Connect an oscilloscope to the test point provided to monitor output voltage. Remove the
plastic cover of the scope probe and position it in the test jack (J02). The oscilloscope is
now referenced to the –OUT ground. Be careful not to create a ground loop by
connecting any other probes to the –IN. Shorting the –IN and –OUT of the PRM will
defeat the PRM current limit feature as the current shunt is in this path. Please refer to the
measurement precaution section for more details.

6. Turn on a fan if necessary.

7. Turn on the electronic load.

8. Raise the DC input voltage to the nominal value of 48 V as indicated on the

P048F048T24AL datasheet.

Observe that turning the potentiometer V
measured on test point V
shown in Figure 10.

Figure 10

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 10

V

vs. I

REF

PRM Error Margin

OUT

(R10) clockwise increases the voltage

REF

resulting output current with a max error of 2% as

REF

PRM

The following Figures 11 - 13 are a start up comparison between what the user should see when
using an electronic load and an actual equivalent power resistor. Figure 11 shows a delay in the
PRM output current introduced by the electronic load set to 0.16 s along with a current overshoot.

Note: do not set the electronic load in a constant voltage mode is not recommended for stability
reasons. If the electronic load is set to a constant voltage, a lengthier delay and an unstable
behavior is observed as in Figure 12. These plots are presented to inform the user of the possible
occurrence of this issue when exploring the CC demo board.

The current overshoot occurs within that instant where the CC senses and corrects its response.

Using a resistive load equivalent to 7 Ω, Figure 13 shows the expected waveform where both the
reference voltage and the PRM output current agree. Please refer to the start up sequencing
section in the

CC application note for more details on the rise time limitations.

Electronic Load Constant

Figure 11

Resistance PRM

Start Up Waveform

Figure 12

Electronic Load Constant

Voltage PRM

Start Up Waveform

V

R

EF

PRM I

PRM PC

PRM V

OUT

OUT

V

REF

PRM I

OUT

PRM PC

PRM V

OUT

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 11

Resistive Load PRM Start Up

DC

+ +

- -

CCBD-CC

+

-

Electronic Load

+OUT

DMM

Measuring

Output Current

Set to Constant Resistance mode

DMM

M

easuring Voltage V

REF

using test point TP5

+ +

- -

VTM-CB

–OUT

–IN

+IN

Figure 13

Waveform

V

REF

RM I

P

OUT

PRM PC

PRM V

OUT

Figures 11 – 13 are taken in reference to –IN. Figures 15 – 19, showing the output voltage and
current ripple, were captured in reference to –OUT by using the scope jack (J02) for better accuracy.

3.5 CC Demonstration Board / VTM with an Electronic /
Resistive Load

CC & VTM Electronic /

Figure 14

Resistive Load

1. Make sure that the power is removed from the unit prior to making adjustment.

2. Use output connector (J01) to connect the CC to the VTM-CB.

3. Connect DMM and a resistor network or electronic load in series with the output of the
VTM customer board. Make sure DMM can handle the maximum PRM output current
then set it to read DC current.

4. Verify proper electronic load and VTM connections.

5. Connect an oscilloscope to the test point provided to monitor output voltage on the
VTM-CB. The VTM provides current multiplication and source isolation. Grounding the
oscilloscope probe at the VTM –OUT and the PRM –IN will only provide a short path for
the AC current which will not affect the functionality of the system.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 12

. Turn on a fan if necessary.

0.2

0

.4

0.6

0

.8

1

.0

1.2

1.4

1.6

1

.8

2.0

2

.2

2.4

2.6

2.8

3

.0

0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 6.2

V

R

EF

(V)

Percentage of Error (%)

V

REF

(typ.)

vs. I

OUT

6

7. Turn on the electronic load.

8. Raise the DC input voltage to the nominal value indicated on the datasheet.

It was observed that in some cases the VTM does not start due to a low V

efer to the start up sequencing section in the

r

C application notefor more details on the rise

C

set point. Please

REF

time limitations.

Figure 15 shows the accuracy of the PRM output current as seen at the VTM output versus the
set reference. The measured VTM output current is divided by the typical VTM k factor and
then compared to the set reference V

REF

.

V

vs. I

REF

PRM – VTM

OUT

Error Margin

Figure 15

Figures 16 – 19 show current and voltage ripple at start up in both a pure resistive and electronic
load. Again, note the delay introduced in the VTM I

wave in the constant resistance mode.

OUT

If these plots are observed using an electronic load, it is possible to experience an unacceptable
wave such as the ones in Figure 18. This slight fluctuation is due to the electronic load enhancing
or opposing the work of the CC control loop.

The resistive load, Figures 17 and 19, show the accurate constant current waveforms.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 13

Electronic Load Constant

Figure 16

Resistance PRM – VTM

Start Up Waveform

V

REF

VTM I

PRM PC

VTM V

OUT

OUT

Resistive Load PRM – VTM

Figure 17

Start Up Waveform

V

REF

VTM I

PRM V

VTM V

OUT

OUT

OUT

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 14

Electronic Load CV

Figure 18

PRM – VTM

& I

O

UT

Ripple

V

UT

O

V

V

TM V

TM I

OUT

OUT

Resistive Load PRM – VTM

Figure 19

& I

O

UT

Ripple

V

UT

O

TM V

V

VTM I

OUT

OUT

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 15

4.0 Bill of Material*

Ref Des Value Supplier Supplier Part # Description

R3 10 kΩ DIGI-KEY P10.0KHDKR-ND RES 10 KOHM 1/10 W 1% 0603 SMD

R6 63.4 kΩ DIGI-KEY P63.4KHCT-ND RES 63.4 KOHM 1/10 W 1% 0603 SMD

R8 5 kΩ DIGI-KEY 490-2655-6-ND TRIMPOT 5 KOHM 1 TRN 3 MM SMD

R10 100 kΩ DIGI-KEY 490-2645-6-ND TRIMPOT 100 KOHM 1 TRN 3 MM SMD

R12, R13, 0 Ω DIGI-KEY P0.0GDKR-ND RES ZERO OHM 1/10 W 5% 0603 SMD

R21, R25,

R28

R16, R19 100 kΩDIGI-KEY P100KHDKR-ND RES 100 KOHM 1/10 W 1% 0603 SMD

R17, R18 1 kΩ DIGI-KEY P1.00KHDKR-ND RES 1.00 KOHM 1/10 W 1% 0603 SMD

R23 2.15 kΩ DIGI-KEY P2.15KHDKR-ND RES 2.15 KOHM 1/10 W 1% 0603 SMD

R24 16.2 kΩDIGI-KEY P16.2KHDKR-ND RES 16.2 KOHM 1/10 W 1% 0603 SMD

R27 5 kΩ DIGI-KEY P4.99KHCT-ND RES 4.99 KOHM 1/10 W 1% 0603 SMD

R30 1.24 kΩDIGI-KEY P1.24KHDKR-ND RES 1.24 KOHM 1/10 W 1% 0603 SMD

R32 10 Ω  DIGI-KEY P10.0FDKR-ND RES 10 OHM ¼ W 5% 1206 SMD

R33 10 mΩ VISHAY CSM25120R010B 10 m OHM SMD Shunt

C1,C2,C3 22 µF DIGI-KEY PCE3207CT-ND CAP 22 µF 100 V ELECT VS SMD

C4, C11 0.01 µF DIGI-KEY 478-1227-1-ND CAP CERM 0.01 µF 10% 5 0V X7R 0603

C12 0.1 µF DIGI-KEY 490-4779-1-ND CAP CER 0.1 µF 50 V X7R 0603

U02 AD8667 Analog AD8667ARZ Low noise, Precision, 16 V, CMOS,

Devices Rail-to-Rail Operational Amplifier

SW01, DIGI-KEY 563-1024-1-ND Switch Slide SPDT SMD GULL

SW02

F01 10 A DIGI-KEY F1150TR-ND Fuse 10 A 125 V Fast Nano 2 SMF

L01 0.1 µH COILCRAFT SLC7530D-101MLC IND 0.1 µH/20%/20 A dual 3026

J01 CONN 10POS 90 DEG through hole

female 0.100 SPC

J02 Jack vertical mech through hole

PS01 VI Chip P048F048T24AL 48 V to 48 V 240 W PRM

*Above-mentioned components are populated parts only.

UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 16

5.0 Summary

In this user guide we have discussed the impact of adding the CC circuit to a PRM regulator

utput (the factorized bus rail). The PRM – VTM combination provides a high current accuracy,

o
high efficiency, high power density solution for high power LED applications.

6.0 Ordering Information

The PRM Constant Current demo part number is P048F048T24AL-CC. The relevant VTM board
(if required) is specified by adding the suffix “-CB” to the chosen VTM model number. For any
questions, comments or further design support, please contact your local Field Applications Engineer.

Go to:

http://www.vicorpower.com/contact-us for ordering information and application

support.

12/2013

vicorpower.com Applications Engineering: 800 927.9474 Rev 1.2 Page 17