USER GUIDE | UG:007 Constant Current (CC) Demonstration Board Contents Page Introduction 1 Features 2 General 3-7 Test Procedure 8-15 Bill of Material 16 Ordering Info Summary 17 The Constant Current (CC) Demonstration Board described in this document shows how to use a 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® and a VTM® to drive light-emitting diodes (LEDs) or for general laboratory evaluation. 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 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. Figure 1 CC Demonstration Board Schematic R19 VH TP04 C11 VSENSE C12 R18 R13 + U02A – VH VREF + – R17 VH R6 R16 VH SC TM SG SW01 IL NC1 PS01 R28 PR CD +IN +OUT –IN –OUT R3 C1 C2 –IN C3 SW02 +OUT R10 OS NC2 TP01 F01 +IN TP05 J01 R27 R8 C4 R30 VC PC R12 R23 TP02 R21 R24 U02B TP06 TP07 L01 SLC7530 R32 R33 TP03 TP08 CONN - 10 PIN - MALE Double click the image to see a larger view. –OUT J02 2.1 CC Demonstration Board Description Figure 2 CC Demonstration Board UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 2 2.1.1 General 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 PRM by allowing the PRM PC pin to float. The OFF position disables the PRM by pulling 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 VOUT and VC. As shown 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. C01 R28 R23 D01 R22 R30 C14 C13 R29 TP7 C15 R11 R12 R13 R14 Q01 C12 R7 F01 R5 C5 R6 C8 U01 TP1 C7 R16 R17 R18 R19 C9 SW02 C11 R24 R25 R26 R27 C6 R15 R4 U02 TP6 R10 R9 R8 TP5 TP4 R20 R21 Figure 3 CC Demonstration Board Layout C10 1. C02 R31 R2 R3 PS01 C4 R1 R32 J01 L01 J02 TP2 SWO1 C03 R33 TP3 TP8 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 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 VREF (R10): Provides an adjustable voltage divider in combination with (R6). 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 VMAX (R8): Combined with (R27) VMAX make up the OS resistor referred to in the PRM datasheet. The OS resistor is used to set the output voltage of the PRM. 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: VC PC TM IL NC PR Figure 4 PRM-AL Schematic Symbol Vin UG:007 PR M -AL +In +Out –In –Out vicorpower.com VH SC SG OS NC CD Vout Applications Engineering: 800 927.9474 Page 4 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 ROS resistor required to operate the PRM. Reducing the ROS resistor by turning the potentiometer (R8) clockwise will increase the maximum output voltage. The Fixed resistor (R27) value is chosen to ensure a maximum output voltage of 55 V. Please refer to the PRM P048F048T24AL datasheet for more details on how to choose the appropriate ROS value for the desired PRM maximum output voltage. 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. VSENSE (TP4): Test point voltage sense serves to show the output voltage of the difference 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. (VSENSE = RSENCE x Gain x IOUT _ PRM) 4. VREF (TP5): Test point voltage reference value is being compared with the sensed voltage VSENSE. Op amp B is providing an output voltage to the SC pin in order to retain VSENSE = VREF = IOUT _ PRM assuming that RSENSE x Gain = 1. Turn the potentiometer (R10) 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 Figure 5 Typical Heat Sink 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 Figure 6 PRM & VTM Under-voltage Behavior VTM PC PRM VC VTM VOUT PRM VOUT 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. Figure 7 PRM & VTM Under-voltage Abnormal Behavior VTM PC PRM VOUT PRM VC VTM VOUT 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 (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. • Desired PRM output current. 3.3 Initial CC Demonstration Board Set Up (VREF and VMAX Set) Figure 8 CC No Load Functional Verification DMM Measuring Voltage VREF using test point TP5 DMM + + Measuring Output Current Set to Constant Current mode + +OUT +IN Electronic Load CCBD-CC DC –IN –OUT - - - 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 VREF (R10) potentiometer clockwise gently until it reaches its maximum value of 100 K which corresponds to ≈ 5 V depending on its tolerance. The potentiometer has stops which indicate that it has been turned fully in one direction. Do not wind the potentiometer past the stop, as this may damage the part. 9. Turn VMAX (R8) potentiometer counterclockwise gently until it reaches its maximum value of 5 K 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 VREF at TP5 with reference to SG at TP6. 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 VREF (R10) counterclockwise to lower the PRM output current set point to the desired value. If VREF is not lowered to a reasonable value below the DC current limit, the PRM will start in a fault condition when connected to a load. It will remain in fault until the potentiometer VREF (R10) is turned counterclockwise to lower the 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 Figure 9 CC Electronic / Resistive Load DMM Measuring Voltage VREF using test point TP5 Set to Constant Current mode DMM + + +OUT +IN Electronic Load CCBD-CC DC Figure 10 VREF vs. IOUT PRM Error Margin + Measuring Output Current –IN –OUT - - - 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 PRM P048F048T24AL datasheet. Observe that turning the potentiometer VREF (R10) clockwise increases the voltage measured on test point VREF resulting output current with a max error of 2% as shown in Figure 10. VREF (typ.) vs. IOUT 2.0 1.8 Percentage of Error (%) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 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 VREF (V) UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 10 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. Figure 11 Electronic Load Constant Resistance PRM Start Up Waveform VREF PRM IOUT PRM PC PRM VOUT Figure 12 Electronic Load Constant Voltage PRM Start Up Waveform VREF PRM IOUT PRM PC PRM VOUT UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 11 Figure 13 Resistive Load PRM Start Up Waveform VREF PRM IOUT PRM PC PRM VOUT 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 Figure 14 CC & VTM Electronic / Resistive Load DMM Measuring Voltage VREF using test point TP5 DMM + + +IN +OUT + CCBD-CC DC + Measuring Output Current Set to Constant Resistance mode + VTM-CB –IN –OUT - - - Electronic 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 6. Turn on a fan if necessary. 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 VREF set point. Please refer to the start up sequencing section in the CC application note for more details on the rise 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 VREF. Figure 15 VREF vs. IOUT PRM – VTM Error Margin VREF (typ.) vs. IOUT 3.0 2.8 2.6 Percentage of Error (%) 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 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 VREF (V) 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 IOUT wave in the constant resistance mode. 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 Figure 16 Electronic Load Constant Resistance PRM – VTM Start Up Waveform VREF VTM IOUT PRM PC VTM VOUT Figure 17 Resistive Load PRM – VTM Start Up Waveform VREF VTM IOUT PRM VOUT VTM VOUT UG:007 vicorpower.com Applications Engineering: 800 927.9474 Page 14 Figure 18 Electronic Load CV PRM – VTM VOUT & IOUT Ripple VTM VOUT VTM IOUT Figure 19 Resistive Load PRM – VTM VOUT & IOUT Ripple VTM VOUT VTM IOUT 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 P0.0GDKR-ND RES ZERO OHM 1/10 W 5% 0603 SMD R12, R13, R21, R25, 0Ω DIGI-KEY 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 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 DIGI-KEY 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 490-4779-1-ND CAP CER 0.1 µF 50 V X7R 0603 U02 AD8667 Analog AD8667ARZ Low noise, Precision, 16 V, CMOS, DIGI-KEY Devices SW01, Rail-to-Rail Operational Amplifier DIGI-KEY 563-1024-1-ND Switch Slide SPDT SMD GULL F1150TR-ND Fuse 10 A 125 V Fast Nano 2 SMF SW02 F01 10 A DIGI-KEY 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 output (the factorized bus rail). The PRM – VTM combination provides a high current accuracy, 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