USER GUIDE | UG:013 VI Chip® PRM Evaluation Board Written by: Ankur Patel Applications Engineer February 2013 ContentsPage Introduction Introduction1 The PRM® evaluation boards described in this document are designed to use with the PRM family of PRM regulators and demonstrate the benefits of the Factorized Power Architecture™. These evaluation boards are not designed for installation in end user equipment. The system demonstrates the use of a PRM (the pre-regulator module) and a VTM (the current multiplier or the voltage transformation module) for general laboratory evaluation only. Contents3 Features3 Board Description 4 General Components 5 Test Points 7 Sockets8 Schematic9 Assembly Drawings 11 Bill of Materials 13 VTM Evaluation Boards 16 Recommended Test Equipment 17 Board Operating Modes Common Features 18 19 Default/Adative Loop Operating Mode: PRM Trim Control AL Control 20 Apative Loop Operating Mode: PRM & VTM 21 Remote Sense Operating Mode: PRM 21 Be sure to read this design guide manual thoroughly before using this product. Pay attention to all cautions and warnings. Remote Sense Operating Mode: PRM & VTM Trim and Soft Start Adjustment Current Limit Adjustment 23 This user guide is not comprehensive and is not substitute for common sense and good practice. For example: Slave Operating Mode 26 20 20 IMPORTANT NOTICE: n When testing electronic product always use approved safety glasses. 24 25 Paralleling26 Conclusion27 n Provide a strain relief for wires and place the system on the bench in such a way as to prevent accidental displacement from bench top. n Remove the power and use caution when connecting and disconnecting test probes and interface lines to avoid unintentional short circuits and contact with hot surfaces. n Never use a jumper in place of the fuse. Replace the fuse only with its equivalent type and rating. n Never attempt to disconnect the evaluation board from a VTM® evaluation board while power is applied. This system is not designed to demonstrate the hot plug capability. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 1 The PRM® evaluation board can be used to demonstrate a stand-alone buck-boost regulator or in conjunction with a VTM evaluation board to enable evaluation of a Factorized Power Architecture™ (FPA) system. There are many combinations possible using PRM and VTM evaluation boards, but the focus in this user guide is using one PRM evaluation board and one VTM evaluation board, with a brief overview of how to parallel boards. The PRM module evaluation board can be used to configure various modes of regulation depending upon the application requirements. (1) AL Operation: the PRM uses a unique feed-forward scheme that enables precise regulation of an isolated POL voltage without the need for remote sensing and voltage feedback. (2) Remote Sense Operation: the internal regulation circuitry is disabled and an external control loop and current sensor maintain regulation. This affords flexibility in the design of both voltage and current compensation loops to optimize performance in the end application. In Remote Sense Operation, PRM can be set in local sense mode or in non-isolated remote sense mode depending on the application. Table 1. Evaluation board numbers and their ratings PRM Part Number (PS10) Evaluation Board Number PRM48AF480T400A00 PRD48AF480T400A00 PRM48BF480T500A00 PRD48BF480T500A00 MPRM48NF480M500A00 MPRD48NF480M500A00 Description Input Voltage (V) Output Voltage (V) 48 V 48 V (36 V to 75 V) (20 V to 55 V) Full-Chip 48 V 48 V PRM (38 V to 55 V) (20 V to 55 V) Evaluation 48 V 48 V Board (45 V to 55 V) (20 V to 55 V) PRM48JF480T500A00 PRD48JF480T500A00 PRM2A01-xxxxxx PRD2A01-xxxxxx User Configured User Configured PRM2A02-xxxxxx PRD2A02-xxxxxx PRM48BH480T250A00 PRD48BH480T250A00 48 V 48 V MPRM48NH480M250A00 MPRD48NH480M250A00 (38 V to 55 V) (20 V to 55 V) PRM48AH480T200A00 PRD48AH480T200A00 PRM48JH480T250A00 PRD48JH480T250A00 Half-Chip 48 V 48 V PRM (36 V to 75 V) (20 V to 55 V) Evaluation 48 V 48 V Board (45 V to 55 V) (20 V to 55 V) PRM2A03-xxxxxx PRD2A03-xxxxxx User Configured PRM2A04-xxxxxx PRD2A04-xxxxxx User Configured Output Power (W) 400 W 500 W 500 W 250 W 200 W 250 W Refer to the specific PRM data sheet for detail ratings of the device. It is important to remain within the device limits when testing. These boards make it convenient to evaluate the performance of Vicor’s PRM products. All evaluation boards include sockets to allow easy "plug and play" insertion and removal of through-hole components and wires while providing kelvin voltage measurements test points of all pins of the PRM. Evaluation boards are designed to simplify testing of the product by providing test points and sockets for easy connection to standard test-equipment, lugs for input/output connections, connectors to allow easy insertion and removal of the PRM evaluation board and VTM evaluation board. Please note that Not all evaluation board part numbers have been listed here. Full chip and half chip PRMs of different output power level may be using common full chip and half chip evaluation boards. Design specific components have been arranged in table 5 based on PRM output power level. It is recommended that the user should, first, find out which PRM part number is mounted on evaluation board. Second, please refer to appropriate data sheet for pin functions of PRM and modes of operation. Third, follow the appropriate section of the user guide to use the PRM evaluation board in specific modes of operation. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 2 Contents All PRM evaluation boards arrive with the following contents. (The user guide can be downloaded from the www.vicorpower.com) n n n n n n n n n 1 x PRM evaluation board 1 x VI Chip push pin heat sink 2 x VI Chip push pins for heat sink installation 2 x VI Chip push pin heat sink grounding clips 1 x hardware kit 1 x through-hole aluminum-electrolytic input capacitor (CIN) 1 x through hole resistor for default compensation (R28) 1 x through hole capacitor for default compensation (C20) 2 x jumpers Features 1. Input and output lugs for source and load connections 2. Input fuse (appropriately rated) 3. Input filtering and sockets to place through-hole input aluminum-electrolytic capacitor for source decoupling 4. Output filtering and sockets to place through-hole output aluminum-electrolytic capacitor 5. Switch for enabling and disabling the PRM through the ENABLE pin 6. Open drain MOSFET for enabling and disabling the PRM using external source 7. Mode selection switch for various PRM® configurations 8. Trim control selection: a. Using potentiometer b. Using fixed resistor c. Using external voltage source 9. Adaptive Loop control selection: a. Using potentiometer b. Using fixed resistor c. Using external voltage source 10. Output current sensing for output current measurement and current feedback in Remote Sense Operation 11. Sockets and circuits to optimize the external control circuits in Remote Sense Operation. 12. Voltage reference to trim pot for adjusting output voltage set point in Remote Sense Operation. 13. Dual output connectors for transferring the power and signal connections to downstream VTM® evaluation board 14. Oscilloscope probe jack for making accurate output voltage measurements 15. Dual paralleling connectors for ENABLE, SHARE and SGND signal connections to other PRM evaluation board 16. Kelvin voltage test points and sockets for all pins of PRM 17. Test points for current sensing and AC signal injection (RS mode) 18. Provision for installing the heat sink UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 3 Board Description The following section provides a detailed description of the evaluation board components, test points and sockets. Figure 1. Board Description Figure 2. Power/signal connectors pinout, front view -OUT 10 VC 8 -OUT +OUT +OUT 6 4 2 -S 10 9 -OUT 7 VC 5 3 1 -OUT +OUT +OUT 9 +S J13 Power/signal connector UG:013 vicorpower.com V T M_-IN 4 2 8 6 7 5 3 1 V _T M V _PC V _IM J10 Signal connector Applications Engineering: 800 927.9474 Page 4 General Components 1. PRM (PS10) 2. Input lugs: Sized for #10 hardware. Use these for making connection to the input source. This board does not contain reverse polarity protection. Check for proper polarity before applying the power. 3. Input fuse (F10): Appropriately rated. 4. Input filtering: Input capacitor (CIN) and filtering (inductor and ceramic capacitors) allows for stable operation with most input sources. Sockets can be used for easy installation of aluminum-electrolytic input capacitor. It is recommended to place the 22 uF, 100 V input electrolytic capacitor in the sockets at the input of the PRM®. 5. Enable/Disable switch (S11) and FET switch: When actuator is in top position towards “ON” text on the board, the ENABLE pin will be open and PRM device will be enabled. When actuator is in bottom position towards “OFF” text on the board, the ENABLE pin will be connected to SGND and PRM device will be disabled. When switch S11 is ON, open drain FET can be selected to control the ENABLE pin using external source. 6. Header-jumper for Adaptive Loop control (P10): Provides the option to select and enable Adaptive Loop control: a. Using potentiometer (R39) b. Using fixed resistor c. Using external voltage source 7. Header-jumper for trim control (P11): Provides the option to select and enable the trim control: a. Using potentiometer (R40) b. Using fixed resistor c. Using external voltage source 8. Operating Mode selection switch (S10): For selecting one of the following operating modes: a. Default/Adaptive Loop b. Slave Operation (used in PRM paralleling) c. Remote Sense: Local sensing (single ended) d. Remote Sense: Non-isolated remote sensing (differential) 9. Output lugs: Sized for #10 hardware. Use these lugs to connect the output directly to the load. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 5 General Components (Cont.) 10. Signal connector (J10): Used to transfer VTM® PC, IM, TM, -IN and Output Sense signals between the PRM and VTM boards. TM pin of VTM provides feedback to VT pin of PRM to enable temperature compensation in Adaptive Loop Operation of PRM and VTM. 11. Power/Signal connector (J13): Used to transfer power (+OUT/-OUT) and VC to downstream VTM board when used. 12. Output oscilloscope probe Jack (J14): Used for making the accurate scope measurements of the output voltage (i.e. ripple). Remove scope grounding lead and insert probe directly into jack ensuring a good connection between the jack and the probe ground barrel. Do not attempt to install while power is applied. May not be compatible with all scope probes. 13. Output capacitor (COUT) and output filtering (inductor and ceramic capacitors): Helps to minimize the switching ripple of the output voltage. Sockets can be used for easy installation of aluminum-electrolytic output capacitor. 14. High-side current-sense resistor and current-sense IC (R25 and U10): Current- sense shunt monitors the output current and IC provides the feedback to the IFB pin for constant current limit protection in Remote Sense Operation. Gain is programed using resistor R26. Constant current limit is set at ~10% above the rated output current of the PRM® on all boards. 15. Voltage sense and error amplifier: Dual op-amp provides the voltage sensing and error amplifier function. It can be configured for local voltage sensing at the PRM output or a differential amplifier to allow for non-isolated remote sensing at the VTM® output or load in Remote Sense Operation. Sockets are provided for compensation components. 16. Voltage reference and output voltage trim pot (R44) for external voltage control loop: Remote Sense Operation trim pot adjusts the output voltage by increasing and decreasing the error amplifier reference voltage (VREF). Turn clockwise to increase the output voltage and counterclockwise to decrease the output voltage. Sockets can be used for easy installation of soft start ceramic capacitor. 17. Dual paralleling wire to board connectors (J17 and J18): Used for transferring signal pins (ENABLE, SHARE and SGND) in parallel operation from one board to other board. Provides simple strip and insert option. Accepts 18-24AWG solid wires. Spring loaded contact will grab solid wire with no need for soldering. Connection requires for parallel regulator operation are grouped together. 18. Push-pin heat sink and grounding clip mounting holes: Use these holes for installing the optional push pin heat sink and grounding clips included with the board. Use of the heat sink with fan is highly recommended for appropriate cooling of the PRM module. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 6 Test Points Description Each test point has a socket which accepts 0.015 – 0.025 inch diameter leads for easy installation of solid wires and through-hole components. All the test points are brought out to the edge of the board to allow for easy measurement and/or connection to the user’s external circuitry. All test points are labeled and routed to the edge of the board. Each test point is accompanied with an adjacent socket for adding a test lead or to facilitate wiring to external circuitry. Table 2. Test points description Reference Functional Functional Designator Name Description TP30,+IN, TP33-IN Input voltage test points provide kelvin connection to input pins of the PRM®. Use these test points for measuring the input voltage of the PRM to avoid error due to interconnect losses. TP31,+OUT, TP32-OUT Output voltage test points provide kelvin connection to output pins of the PRM. Use these test points for measuring the output voltage of the PRM to avoid error due to interconnect losses. TP34, Signal Ground (SGND) test points are the ground reference for all control circuitry and TP21, SGND signal pins of the PRM. TP22 TP28, CS+, Used to measure the output current of the PRM across shunt resistor R25. TP29 CS- TP35, IM, Used to measure the output of current sense IC with reference to SGND. TP36 SG SHARE/ Used to measure the SHARE/CONTROL NODE signal of the PRM with reference to TP10 CONTROL SGND test point. NODE TP11AL Used to measure the AL signal of the PRM with reference to SGND test point in Adaptive Loop Operation. TP12TRIM Used to measure the TRIM signal of the PRM with reference to SGND test point in Adaptive Loop Operation. Used to measure the VAUX signal of the PRM with reference to SGND test point. TP13 VAUX REF/ TP14 Used to measure the REF/REF_EN signal of the PRM with reference to SGND. REF_EN TP15VT Used to measure the VT signal when connected to VTM® TM pin with reference to SGND in Adaptive Loop Operation. TP16 ENABLE Used to measure the ENABLE signal with reference to SGND. TP17 VC Used to measure the VC signal with reference to SGND. TP18IFB Used to measure the IFB signal of the PRM with external constant current circuit with reference to SGND in Remote Sense Operation. TP43, VREF TP44 Used to measure the voltage reference signal of the error amplifier with reference to SGND in Remote Sense Operation TP19, NC, NC No connect. For internal use only. TP20 TP37, TP38 Can be used to inject the isolated signal of network analyzer for bode plot measurement to measure the stability in Remote Sense Operation. TP23, TP24 VG, SG Can be used to connect function generator to control the open drain MOSFET in ENABLE control. TP39, TP41 EXT AL, SG Can be used to enable Adaptive Loop control using external source when AL control is selected using header P10 and jumper. TP40, TP42 EXT TRIM, SG Can be used to enable TRIM control using external source when TRIM control is selected using header P11 and jumper. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 7 Sockets Description Each socket accepts 0.015 – 0.025 inch diameter leads for easy installation of solid wires and through-hole components for use with external circuit and test equipment. Table 3. Sockets description Reference Functional Functional Designator Name Description Input H57, Sockets are used for easy installation of through-hole 100 V rated H58Capacitor aluminum-electrolytic capacitor. (CIN) H32, H33 Output Capacitor (COUT) Sockets are used for easy installation of through-hole 100 V rated aluminum-electrolytic capacitor. Ensure proper polarity with short leads while installing. H49, AL Resistor H53 (R37) Used for easy installation of fixed through-hole resistor between AL and SGND pins of the PRM when jumper is placed on pin1 and pin2 of the P10 header. Used only with Adaptive Loop and default switch S10 configuration. H50, H54 Trim Used for easy installation of fixed through-hole resistor between TRIM Resistor (R38) and SGND of the PRM® when jumper is placed on the pin1 and pin2 of the P11 header. Used only with Adaptive Loop and default switch S10 configuration. H41, H43 Compensation Capacitor (C20) Used for easy installation of through-hole compensation capacitor C20 in feedback path of error amplifier. Default through-hole 4700 pf capacitor is added in the box. Used only with Remote Sense Operation. H42, H44 Compensation Resistor (R28) Used for easy installation of the through-hole compensation resistor R28 in feedback path of the error amplifier. Default through-hole 20 K resistor is added in the box. Used only with Remote Sense Operation. Integrator H39, Capacitor Used for easy installation of through-hole compensation capacitor C19. H40 (C19) Differential H47, Input Used for easy installation of through-hole resistor R33 for non-isolated H48 Resistor differential sensing in Remote Sense Operation. (R33) Differential H51, Input Used for easy installation of through-hole resistor R41 for non-isolated H52 Resistor differential sensing in Remote Sense Operation. (R41) H55, H56 Soft-start Used for easy installation of the through-hole capacitor on top of default 0.1uF Capacitor to soft-start the PRM output voltage in Remote Sense Operation. (C24) H46, H45 Used to insert wires to hook up the network analyzer measuring probes to measure stability in Remote Sense Operation. H30, CS+ Used to insert test leads to measure the voltage across R25. H31 CS- UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 8 UG:013 vicorpower.com J15 J11 H26 T P24 T P23 H23 T P62 T P61 G SGND Q10 SOT 23_3 F10 C16 2220 C15 2220 PIN i ON/OFF CONTROL R2 1 0603 PIN i T P66 T P65 D S 2220 C17 L1 0 1206 R2 4 1 S11 2 3 H58 T P58 Cin H57 PIN T P56 i T P55 T P53 T P51 T P49 T P47 H35 T P33 2220 C25 T P30 H28 NC2 NC1 SHA R E/CO NT R OL NODE AL T RIM H22 TP21 R1 4 0603 H34 PRM2 _HALF_ JLEAD -IN +IN CL DA GND T P60 SGND SGND T P34 SGND SHAR E / CONTR OL NODE AL TR IM E NAB L E HS10 PRM V AUX PS10 TP22 R1 6 0603 T P17 ENABLE H11 -OUT +OUT VC VT IF B R EF/ R EF_E N T P16 R1 5 0603 VT H10 SIGNAL PIN TEST POINTS AND FIXED RESIST ORS SGND H18 T P15 REF/REF_EN H17 T P14 R1 3 0603 VAUX H16 T P13 R1 2 0603 TRIM H15 T P12 R1 1 0603 AL T P45 T P11 R1 0 0603 EN ABLE T P10 SHAR E/CONT R OL NODE H14 T P18 T P52 T P50 T P48 H36 H29 Applications Engineering: 800 927.9474 T P36 T P35 H37 -OUT H38 IMON T P59 T P32 2220 C26 1206 R2 2 T P20 POU T i R1 9 0603 SGND V OUT V- V+ RG -IN T SOT 23_6 U10 +IN 6 5 4 0603 20 19 18 17 16 15 14 13 12 11 POU T i ON SGND VCC C18 T P68 H31 T P29 REF/REF_ EN IF B CURRENT SENSE AMPLIFIER 1 2 3 2512 R2 5 T P28 T P67 H30 TRIM SGND EAO IMON REF_ EN_ B SHARE/CONTROL NODE VC_ OUT R20 0603 NC2 H20 T P57 PRM_ +OUT VC VT IFB REF/REF_ EN VAUX T P31 T P54 T P19 NC1 H19 R1 8 0603 IFB H21 T P46 R1 7 0603 VC H12 R2 6 1206 L1 1 1206 R2 3 MODE SELEC T 1210 C11 H27 C13 T P26 C14 T P27 T P25 2 9 -OUT -OUT 10 3 7 VC 5 +SENSE 4 2 4 6 8 10 2 4 6 8 10 7 V C_ OUT 1 3 5 7 9 J13 1 3 5 7 9 J10 6 9 9 +S -S 10 -SENSE 8 7 8 T P64 J16 J12 V T M_-IN 4 2 J14 5 3 1 V _T M V _PC V _IM 6 -OUT T P63 VTM_-IN 10 SLAVE REMOTE SENSE (Differential) LOCAL SENSE (Single Ended) ADAPTIVE LOOP DEFAULT CONNECTOR FRONT VIEW 5 3 1 -OUT +OUT +OUT -OUT +OUT +OUT 6 4 2 H33 VC 8 H32 V TM_TM V TM_PC V T M_IM H24 1 1210 1210 1210 Cout C12 POU T i H25 VAUX VT i +S i -S PRM_ +OUT -SENSE +SENSE S10 SW_ 21910MST i POU T LOCA L SENSE_ + i POU T +SENSE_B -SENSE_B VCC V T M_T M PRM evaluation board schematic 1 2 3 4 5 6 7 8 9 10 H13 Schematic Schematic for half-chip and full-chip PRM® evaluation board is same. Figure 3a. Page 9 ENABLE H54 R3 8 1206 T P70 T P42 T P40 SGND R46 0603 SGN D P11 2 4 6 T P72 CN 6_DIGIKEY_95278 1 3 5 CO NN3PIN J17 CONN3PIN J18 TRIM CONT ROL SELECT R3 5 0603 R4 0 SIGNALS FOR PARALLELING SHARE/CONT ROL NODE SGND TRIM POT EXT TRIM T P71 3 2 1 H50 3 2 1 T P69 T RIM EXT AL SGND AL POT H53 R3 7 1206 T P74 T P41 T P39 H49 T P73 SGND P10 2 4 6 AL T P76 CN6_DIGIK EY_95278 1 3 5 AL CONTROL SELECT R3 4 0603 R3 9 T P75 REF_ EN_ B EAO 0603 C23 H43 1 U12 3 2 U11A SO8 R28 1206 H42 H40 R4 3 1206 SGND R4 5 1206 R4 4 1 1206 C19 H56 1206 C24 H55 1206 C22 H44 VREF T P43 T P44 R36 1206 1206 R3 2 SGND VOLTAGE SENSE AND ERROR AMPLIFIER 7 6 5 U11B R42 1206 R31 1206 REMOTE SENSE CONTROL CIRCUITRY VOLTAGE REFERENCE SGN D SOT 23_3 C21 0603 VCC C20 1206 H41 H39 SGND IN 2 OUT vicorpower.com G ND UG:013 3 8 H51 R41 1206 R3 3 1206 R2 9 H47 1206 R2 7 1206 T P37 H52 H48 H46 T P38 -SENSE_B +SENSE_ B R3 0 1206 IMON LOCA L SENSE_+ H45 PRM evaluation board schematic 4 ADAPT IVE LOOP CONTR OL CIRCUITRY Schematic (Cont.) Figure 3b. Applications Engineering: 800 927.9474 Page 10 Assembly Drawings H57 C17 L10 PS10 PF43 PF44 H56 PF46 R23 J13 H32 J14 C14 C13 C11 C12 PF19 H35 PF49 H33 H36 H27 H25 H24 H11 H17 H34 H12 H16 H18 H13 H21 H10 H22 H15 H19 H14 PF16 J16 PF17 TP26 TP25 PF15 TP27 PF14 TP17 PF13 PF12 TP14 PF11 TP34 PF10 TP18 PF09 TP13 PF08 TP15 PF07 TP21 TP16 PF06 TP10 PF05 TP12 PF04 TP22 PF03 TP11 TP19 PF02 PF01 TP20 J17 J18 R46 H20 TP33 FID01 TP31 H44 H43 C20 R28 H42 J10 L11 PF18 J15 PF41 PF38 H41 C19 H29 R26 PF45 R25 PF20 TP44 TP43 H55 H40 U11 R32 U10 C18 PF39 PF40 FID02 PF37 PF48 H58 C16 R29 PF36 PF35 C21 R36 J12 PF42 H26 R24 C15 R27 R15 R13 R18 R14 R17 R22 HS10 PF32 TP37 PF47 TP32 Q10 PF22 R10 R16 R12 R19 R20 R11 R30 TP38 S11 R21 PF23 TP24 F10 TP23 H23 H45 PF33 H39 P11 PF31 P10 H28 R33 PF30 H48 PF50 H51 R41 PF29 TP29 H31 H52 TP30 R31 C22 R42 C24 PF28 TP36 H38 R35 S10 PF27 PF34 TP39 R34 TP41 PF26 R43 H46 H47 PF24 R45 R44 TP28 H30 R38 PF25 U12 C23 TP35 H37 R37 H53 R40 TP40 H50 J11 H49 R39 TP42 Top view: Half-chip evaluation board assembly drawing H54 Figure 4a. C17 H57 H31 H30 TP44 H56 J13 L11 H32 UG:013 vicorpower.com PF16 H27 PF17 J16 TP27 H25 H24 PF15 TP26 PF14 TP25 H11 H17 PF13 TP17 PF12 TP14 H34 H12 PF11 TP34 PF10 TP18 H16 H18 PF09 TP13 H21 PF08 TP15 PF07 TP21 H13 H10 PF06 TP10 PF05 TP16 H15 H22 PF04 TP12 PF03 TP22 H14 H19 PF02 TP11 TP20 PF01 TP19 H20 J18 R46 J17 PF42 H36 TP33 J14 TP32 PF49 H33 C14 C13 C12 C11 PF19 H35 FID01 PF41 FID02 R28 C20 R23 PF18 J15 TP31 H44 H43 H40 C19 H42 J10 PF46 R25 PF20 PF38 R26 PF45 TP29 R22 PS10 PF44 U10 H29 PF48 H58 C16 C15 C18 PF39 PF40 R36 R32 R29 PF43 R24 L10 R27 TP28 PF22 F10 TP24 H26 R15 R13 R18 R14 R17 H37 R10 R16 R12 R19 R20 R11 PF37 C21 TP37 TP35 Q10 PF23 S11 R21 TP23 H23 R30 TP38 HS10 J12 H41 H45 PF32 P11 PF31 PF36 PF35 H39 PF30 R33 PF33 PF50 P10 C24 H55 H51 R41 PF29 U11 H52 R31 C22 R42 H48 H28 PF47 PF28 H38 S10 TP30 TP43 R43 TP36 R35 PF27 H46 H47 TP41 TP39 R34 PF26 PF34 R38 PF24 PF25 R45 R44 U12 H50 R37 H53 C23 R40 TP40 J11 H49 R39 TP42 Top view: Full-chip evaluation board assembly drawing H54 Figure 4b. Applications Engineering: 800 927.9474 Page 11 Assembly Drawings (Cont.) Figure 4c. Bottom view: Half-chip/Full-chip evaluation board assembly drawing TP73 TP69 TP70 TP74 TP61 TP63 TP72 TP76 TP71 TP75 TP65 TP68 TP67 TP57 C25 C26 TP66 TP59 TP56 TP58 TP64 TP62 TP46 TP48 TP54 UG:013 TP50 vicorpower.com TP60 TP52 TP49 TP45 TP51 TP47 TP55 TP53 Applications Engineering: 800 927.9474 Page 12 Bill of Materials Following table describes the most common components of all four versions of PRM® evaluation boards. Table 4. Common components Reference Manufacturer Description Manufacturer Part Number Designator C11, C12, C13, C14 CAP X7R 2.2uF 10% TDK CORP OF AMERICA C3225X7R2A225KT5LOU 100V 1210 .102 MAX HT C15, C16, C17 CAP X7R 4.7uF 20% 100V 2220 TDKC5750X7R2A475M C18, C21, C23 CAP X7R .01uF 10% 100V 0603 MURATAGRM188R72A103KA01J C20* not applied– use sockets CAP X7R 4700pF 10% 50V RADIAL AVX CORP SR155C472KAR CAP X7R .10uF 10% AVX CORP 12061C104KATMA C24 100V 1206 CIN CAP ALEL 22uF 20% 100V RADIAL 8 X 11.5 PANASONICEEU-FC2A220 F10 Design Specific – see Table 5 H10 to H58 PIN RECPT .015/.025 DIA 0667 SER TH MILL-MAX MFG CORP J10, J13 CONN 10 PINS 2.54MM PITCH DUAL ROW SM HO GCTBG225-10-A-N-A J14 JACK VERTICAL MECH THRU HOLE TEKTRONIX131-5031-00 J17, J18 CONN 3 POS WIRE TO BOARD SMD AVX CORP 478-6170-2-ND JUMPER_HEADER JUMPER SOCKET XJ8A OMRON ELECTRONICS XJ8A-0211 L10, L11 IND 0.1uH 20% 32.5A 2525 VISHAY/DALEIHLP2525CZERR10M01 P10, P11 HEADER 6 PIN STRAIGHT SMT FCI95278-101A06LF 0667-0-57-15-30-27-10-0 PCB Design Specific – see Table 5 PS10 Design Specific – see Table 5 Q10 FET 2N7002 SOT-23 ON SEMICONDUCTOR 2N7002LT1G R21 RES 10K OHM 1/10W 1% 0603 KOA SPEER RK73H1J1002FTD R22 RES ZERO OHM JUMPER 2A 1206 KOA SPEER RK73Z2BTTD R23, R24 RES 1 OHM 1/4W 5% 1206 KOA SPEER RK73B2BTTE1R0J R25 UG:013 Design Specific – see Table 5 vicorpower.com Applications Engineering: 800 927.9474 Page 13 Bill of Materials (Cont.) Following table describes the most common components of all four versions of PRM® evaluation boards. Table 4 (Cont.). Common components Reference Manufacturer Manufacturer Description Designator Part Number R26 Design Specific – see Table 5 – Remote Sense Operation – set the constant current limit R28* – not applied – use sockets RES 20K OHM 1/4W 1% AXIAL KOA SPEER MF1/4DCT52R2002F R29 RES 54.9K OHM 1/4W 1% SMD 1206 KOA SPEER RK73H2BTTE5492F R30 RES 20 OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTD20R0F R31, R42 RES 1.27K OHM 1/4W 1 % SMD 1206 KOA SPEER RK73H2BTTE1271F R34 RES 0 OHM JUMPER 1A 0603 KOA SPEER RK73Z1JTTD R35 RES 4.32K OHM 1/10W 1% 0603 KOA SPEER RK73H1J4321FTD R36 RES 1K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE1001F R39, R40 RES TRIM POT 100K OHM 1/2W 10% TH MURATAPV36Y104C01B00 R43 RES 10K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE1002F R44 RES TRIM POT 10K OHM 1/2W 10% TH COPAL ELECTRONIC CT94EY103 R45 RES 5.62K OHM 1/4W 1% KOA SPEER RK73H2BTTE5621F SMD 1206 R46 RES 1 OHM 1/10W 1% 0603 PANASONIC ERJ-3RQF1R0V S10 MECH SMD 10-POS DIP SWITCH CTS ELECTROCOMPONENTS 219-10MSTRF S11 SW TOGGLE SPDT C & K COMPONENTS GT11MSCBE 1 POS SMD TP10 to TP44 TEST POINT, SURFACE MOUNT KEYSTONE U10 IC HV I SENSE LMP8645HV TSOT-6 NATIONAL SEMICONDUCTOR LMP8645HVMKE/NOPB U11 IC DUAL OPAMP LM6142AIM 8PIN SO NATIONAL SEMICONDUCTOR LM6142AIMNOPB U12 IC VREF 1.25V REF3312 SOT23 3 TI 5017 REF3312AIDBZT Please note that R28 and C20 are through-hole default compensation components required for Remote Sense operation. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 14 Bill of Materials (Cont.) Following table describes the design specific components of all four versions of PRM® evaluation boards. Table 5. Design specific components Reference Manufacturer Description Manufacturer Designator Part Number Evaluation board numbers: PRD48AF480T400A00 and PRD2A02-xxxxxx PS10 PRM2A FULL VICOR WIDE 400W PRM48AF480T400A00 or PRM2A02-xxxxxx (User Configured) R26 RES 215K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE2153F R25 RES I SENSE 5m OHM 1W 1% 2512 VISHAYWSL25125L000FEA F10 FUSE 20A 125VAC FAST 10.1X3.1 SMD LITTELFUSE0456020.ER PCB SNGLTD PCB FULL PRM CONFIG CB VICOR39573 Evaluation board numbers: PRD48BF480T500A00, PRD2A01-xxxxxx, PRD48JF480T500A00 and MPRD48NF480M500A00 PRM2A FULL PS10 VICOR NARROW 500W PRM48BF480T500A00 or PRM2A01-xxxxxx (User Configured) or PRM48JF480T500A00 or MPRM48NF480M500A00 R26 RES 174K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE1743F R25 RES I SENSE 5m OHM 1W 1% 2512 VISHAYWSL25125L000FEA F10 FUSE 20A 125VAC FAST 10.1X3.1 SMD LITTELFUSE0456020.ER PCB SNGLTD PCB FULL PRM CONFIG CB VICOR39573 Evaluation board numbers: PRD48AH480T200A00 and PRD2A04-xxxxxx PS10 PRM2A HALF VICOR WIDE 200W PRM48AH480T200A00 or PRM2A04-xxxxxx (User Configured) R26 RES 215K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE2153F R25 RES I SENSE 10m OHM 3W 1% 2512 BOURNSCRA2512-FZ-R010ELF F10 LITTLE FUSE 10 AMP R451010.MRL LITTELFUSE0451010.MRL PCB SNGLTD PCB HALF PRM CONFIG CB VICOR38693 Evaluation board numbers: PRD48BH480T250A00, PRD2A03-xxxxxx , PRD48JH480T250A00 and MPRD48NH480M250A00 PRM2A HALF NARROW PS10 VICOR 250W PRM48BH480T250A00 or PRM2A03-xxxxxx (User Configured) or PRM48JH480T250A00 or MPRM48NH480M250A00 R26 RES 174K OHM 1/4W 1% 1206 KOA SPEER RK73H2BTTE1743F R25 RES I SENSE 10m OHM 3W 1% 2512 BOURNSCRA2512-FZ-R010ELF F10 LITTLE FUSE 10 AMP R451010.MRL LITTELFUSE0451010.MRL PCB SNGLTD PCB HALF PRM CONFIG CB VICOR38693 UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 15 VTM® Evaluation Boards The PRM® evaluation board is designed to work with all types of VTM evaluation boards to facilitate testing of virtually any PRM/VTM combination. The VTM evaluation board contains dual connectors designed to mate with J10 and J13 on PRM evaluation board. The additional signal connector is used to transfer VTM signal pins, as well as S+ and S- signals between boards. The S+ and S- signals are tied to the VTM output using local sense resistors and can be used for implementing non-isolated remote sense as described in a later section. Board also provides the ability to inject an AC signal for measuring the loop response and break the isolation for non-isolated remote sense using PRM and VTM. The TM feedback of the VTM is also transferred through the additional signal connector to make connection with VT pin of the PRM to enable temperature compensation in Adaptive Loop configuration. Figure 5. VTM evaluation board Figure 6. VTM evaluation board connector pin out (front view) VTM -IN NC VS- +IN +IN -IN VC -IN IM-VTM TM-VTM NC PC-VTM VS+ +IN +IN -IN VC -IN VTM evaluation board signal connector UG:013 vicorpower.com VTM evaluation board power/signal connector Applications Engineering: 800 927.9474 Page 16 Figure 7. PRM evaluation board connection to VTM evaluation board Recommended Test Equipment The following is a list of recommended test equipment. 1. DC power supply: 0 - 80 V, 600 W minimum 2. Load: Rated appropriately based on output voltage, current and power requirements. 3. Digital multi-meters (DMMs) 4. Oscilloscope + probes 5. Function generator (for external enable/disable and trim control) 6. Auxiliary bench voltage supply (for external trim and AL control) 7. Network analyzer (Remote Sense Operation) 8. Interconnect wires, cables and fastening hardware. 9. Calibrated input and output shunts, appropriately rated (for efficiency measurements) 10. Trim pot screwdriver 11.Fan 12. Datasheets of requisite PRM® and VTM® device used. 13. Safety glasses 14. Thin bladed tool for wire extraction from paralleling connectors (AVX part number: 06-9276-7001-01-000) Push pin heat sink installation Each PRM® and VTM® evaluation board comes with its own heat sink and push pins for installation. Before testing, it is highly recommended that heat sinks be installed in the appropriate location for each board. When installing the push pin heat sink, use caution not to exceed the maximum compressive on the device listed in the data sheet. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 17 Line and Load connections n Make sure that input power supply is OFF. n Connect the input power supply positive lead to the +IN input lug of the evaluation board. n Connect the input power supply return lead to the –IN input lug of the evaluation board. n Connect the output lug +OUT to the positive terminal of the electronic load. n Connect the output lug –OUT to the return terminal of the electronic load. n Verify proper polarity of the connections. n Place the input capacitance 22 uF, 100 V. n Turn the FAN ON. n Have the latest version of the datasheet. Board Operating Modes PRM evaluation board supports both Adaptive Loop and Remotes Sense Operation. Therefore, operating mode selection switch S10 is provided on the board for selection of the following operating modes: n Default / Adaptive loop using PRM n Adaptive loop using PRM and VTM n Remote Sense: local sensing (single ended) n Remote Sense: non-isolated remote sense (differential) n Slave (for array operation) Figure 8. Mode select switch VCC REF_ EN_ B V T M_T M i POU T LOCA L SENSE_ + i POU T +SENSE_B -SENSE_B IMON ON S10 SW_ 21910MST 1 2 3 4 5 6 7 8 9 10 SGND 20 19 18 17 16 15 14 13 12 11 EAO i -S -SENSE +SENSE TRIM SHARE/CONTROL NODE IF B REF/REF_ EN UG:013 PRM_ +OUT i +S VT VAUX vicorpower.com Applications Engineering: 800 927.9474 Page 18 Figure 9. Switch configuration ON OFF DEFAULT / ADAPTIVE LOOP using PRM ON OFF ADAPTIVE LOOP using PRM and VTM ON OFF LOCAL SENSE (Single Ended) using PRM ON OFF REMOTE SENSE (Differential) using PRM and VTM ON OFF SLAVE using PRM Postion number 1 2 3 4 5 6 7 8 9 10 Figure 9 provides the illustration for how to configure the switch for each operating mode. Common features in all modes of operations n On / off control to enable and disable the PRM® in the presence of input power. n Using switch S11 or n Open drain MOSFET using external circuitry or function generator n Input filtering (inductor and ceramic capacitors) n Output filtering (inductor and ceramic capacitors) n Sockets for easy installation of input and output electrolytic capacitor n Test points for current sensing n Kelvin test points for measurement of input voltage, output voltage and all signal pins of the PRM. n Sockets for each test point for easy installation of through-hole components and solid wires to facilitate the wiring to external circuitry and test equipment. Figure 10. H23 1 S11 2 3 T P65 ENABLE D ON / OFF control G Q10 SOT 23_3 R2 1 0603 S T P23 T P24 T P66 SGND H26 ON / OFF CONTROL UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 19 Default / Adaptive Loop operating mode using PRM® Mode select switch S10 setting: keep the switch OFF at all positions as shown in following illustration. Please note that switch S10 is 10 positions switch. ON OFF Postion number DEFAULT / ADAPTIVE LOOP 1 2 3 4 5 6 7 8 9 10 In default operation, PRM maintains its own output voltage using active internal voltage sensing. Also internal current sensing circuit is active for constant current limit. In Adaptive Loop Operation, AL control programs the load line to compensate resistive drops from the PRM output voltage to point of Load. Trim control sets the output voltage other than the default 48 V in the range of 20 V to 55 V. Default/Adaptive Loop controls Trim control: Jumper and header select either external trim, trim POT, Trim to SGND option or none. Place jumper across correct position in P11 to enable trim control. Please note that R38 – 1206 resistor footprint is not populated in trim control. Instead, External trim provides option to select sockets for easy installation of fixed resistor or surface mount test points to apply external voltage source. Trim control provides the option to select the potentiometer R40 using proper jumper setting on header P11 in default / Adaptive Loop Operation. Rotate POT R40 clockwise to increase the TRIM pin voltage and counterclockwise to decrease the TRIM pin voltage. Trim control allows setting the TRIM pin voltage in the range of 1 V to 2.75 V to set the output voltage between 20 V and 55 V. Figure 11. Trim control selection TP69 H50 P11 TP40 1 2 3 4 TRIM 5 6 CN6_DIGIKEY_95278 EXT TRIM TRIM POT R38 1206 SGND TP72 TP71 R35 0603 R40 TP42 TP70 H54 SGND TRIM CONTROL SELECT Adaptive Loop control: Jumper and header select either external AL, AL POT, AL to SGND option or none. Place jumper across correct position in P13 to enable AL control. Please note that R37 – 1206 resistor footprint is not populated in AL control. Instead, External AL provides option to select sockets for easy installation of fixed resistor or surface mount test points to apply external voltage source. AL control provides the option to select potentiometer R39 using proper jumper setting on header P10. Rotate POT R39 clockwise to increase the AL pin voltage and counterclockwise to decrease the AL pin voltage. AL control allows setting the AL pin voltage in the range of 0 V to 3 V to program the PRM load line for Adaptive Loop Operation. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 20 Figure 12. Adaptive Loop selection TP73 H49 TP76 TP75 P10 TP39 1 2 3 4 AL 5 6 CN6_DIGIKEY_95278 EXT AL AL POT R34 0603 R37 1206 SGND R39 TP41 SGND TP74 H53 AL CONTROL SELECT Adaptive Loop operating mode using PRM® and VTM® Mode select switch S10 setting: keep the switch S10 setting at all positions as shown in following illustration. ON OFF Postion number PRM and VTM ADAPTIVE LOOP 1 2 3 4 5 6 7 8 9 10 For use when VTM evaluation board is connected to PRM evaluation board. Switch at position 6 is ON, the TM signal of the VTM is transferred through the additional signal connector to make connection with VT pin of the PRM to enable temperature compensation in Adaptive Loop Operation. Other features remain the same in this mode of operation as mentioned in previous mode of operation. Remote Sense operating mode using PRM®: local sensing (single ended) Mode select switch S10 setting: keep the switch S10 setting at all positions as shown in following illustration. ON OFF Postion number LOCAL SENSE (Single Ended) 1 2 UG:013 3 4 5 6 7 8 9 10 vicorpower.com Applications Engineering: 800 927.9474 Page 21 The following table describes the switch configuration. Table 6. Switch configuration in local sensing Switch Position Number ON or OFF Connection 1 ON TRIM pin is shorted to GND and PRM is configured for Remote Sense Operating mode. CONTROL NODE pin is connected to output of external error amplifier. 2 ON 3 ON IFB pin is connected to output of external current sense amplifier to set constant current limit. 4 ON REF_EN pin is connected to input of the external voltage reference circuit to generate voltage reference for external error amplifier. 5 ON VAUX pin is connected to power VCC of the op-amp and current sense IC. 6 OFF TM pin of the VTM is not connected to VT pin of the PRM. 7 ON PRM +OUT pin is connected to local sense (single ended) of the remote sense control circuitry. 8 Don’t care 9 OFF See next Remote Sense Operation 10 OFF See next Remote Sense Operation Figure 13. Remote Sense: local sensing (single ended) control circuitry BLUE highlight = Pre-installed component GREEN highlight = user installed component H39 Preinstalled component and connections H43 H41 H40 1206 C19 H42 OPEN 1206 C22 VCC SGND OPEN 1206 R32 4 3 5 7 2 1 R29 H47 1206 54.9K R31 1206 1.27K SGND C21 0603 8 To CONTROL NODE through S10 TP38 H45 H46 R28 1206 20K C20 1206 4.7nF AC signal injection IMON OPEN TP37 User installed component EAO R27 1206 H44 VREF U11A SO8 SGND R36 1206 1K 6 H51 H48 R33 OPEN 1206 H52 U11B R41 OPEN 1206 R30 1206 20Ω To PRM +OUT through S10 LOCAL SENSE_+ +SENSE_B -SENSE_B R42 1206 1.27K In this configuration, PRM operates in Remote Sense. PRM module output voltage is sensed through divider formed by R29 and R31. U11B is configured as buffer as shown in figure 13 and provides the sense voltage to error amplifier U11A. R33, R41 and R27 are left open, reserved for differential sensing and current sensing. R29 is set to limit the upper trim range based on a maximum reference voltage of 1.25 V. Note that by default compensation components are not installed and required for operation. Default compensation components are provided with the board as described in a later section. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 22 Remote Sense operating mode using PRM® and VTM®: non-isolated remote sensing (differential sensing) Mode select switch S10 setting: keep the switch S10 setting at all positions as shown in the following illustration. ON OFF Postion number REMOTE SENSE (Differential) 1 2 3 4 5 6 7 8 9 10 Note: To use this configuration, the VTM isolation must be broken by tying VTM -IN and VTM -OUT together. The following table describes the switch configuration. Table 7. Switch configuration in differential sensing Switch Position Number ON or OFF Connection 1 ON TRIM pin is shorted to GND and PRM is configured for Remote Sense Operating mode. CONTROL NODE pin is connected to output of external error amplifier. 2 ON 3 ON IFB pin is connected to output of external current sense amplifier to set the constant current limit. 4 ON REF_EN pin is connected to input of the external voltage reference circuit to generate voltage reference for external error amplifier. 5 ON VAUX pin is connected to power VCC of the op-amp and current sense IC. 6 OFF TM pin of the VTM is not connected to VT pin of the PRM. 7 OFF 8 PRM +OUT pin is NOT connected to local sense (single ended) of the remote sense control circuitry. Don’t care 9 ON VTM +OUT (+SENSE) pin is connected to positive input (+SENSE_B) of the differential buffer of remote sense control circuitry. 10 ON VTM –OUT (-SENSE) pin is connected to negative input (-SENSE_B) of the differential buffer of remote sense control circuitry. Figure 14. Remote Sense: non-isolated remote sensing (differential) control circuitry BLUE highlight = Pre-installed component GREEN highlight = user installed component H39 Preinstalled component and connections H43 H41 H40 1206 C19 H42 OPEN 1206 C22 VCC SGND 1 4 3 R29 H47 1206 R31 1206 1.27K 5 7 2 VREF U11A SO8 SGND UG:013 OPEN 1206 R32 SGND C21 0603 8 To CONTROL NODE through S10 TP38 H45 H46 R28 1206 20K C20 1206 4.7nF IMON OPEN TP37 User installed component EAO R27 1206 H44 vicorpower.com R36 1206 1K 6 H51 R33 1206 U11B R41 1206 H48 R30 1206 LOCAL SENSE_+ +SENSE_B To VTM ouput (+S/–S) through S10 and J10 H52 -SENSE_B R42 1206 1.27K Applications Engineering: 800 927.9474 Page 23 In this configuration, the PRM® and VTM® evaluation boards are connected together to form a PRM / VTM pair and regulation is performed at the VTM module output. The +SENSE and -SENSE connections are made at the VTM output through connector J10. This is a non-isolated configuration and therefore the VTM isolation must be broken by tying the VTM -OUT and VTM -IN pins together. The VTM evaluation board has provisions for easily breaking the isolation. U11B is configured as a differential amplifier with gain set for appropriate output voltage. R33 and R41 set the gain. POT R44 can be used to set the required voltage at the VTM output. Maximum output voltage can be set for maximum 1.25 V reference voltage. R33 and R41 is calculated using following equation. R33 = R41 = VOUT_SET (MAX) • 1.27kΩ 1.25 V Equation 1 Where: VOUT_SET (MAX) is the maximum VTM output trim voltage Please note that R33 and R41 are not populated by default. Sockets can be used to populate through-hole resistors R33 and R41. In order to configure the evaluation boards for non-isolated remote sense the following steps must be taken: Connect the PRM and VTM evaluation boards together 1. 2. Configure the operating mode switch as described 3. Break the isolation by connecting VTM-IN and -OUT together 4. Calculate and install the appropropriate differential sense resistors(R33 and R41) 5. Install compensation components C20 and R28 Remote Sense Compensation components By default, compensation components are not populated, and are required for operation. Please note that board comes with default through-hole compensation components C20 and R28 that can be used to get a baseline for Remote Sense operation. Sockets can be used for easy installation of C20 and R28. These components are not optimized and will have low bandwidth response. Transient response can be improved by adjusting the compensation components as outlined in the PRM datasheet. It is recommended to use a network analyzer to measure the closed loop frequency response when adjusting compensation. The PRM and VTM boards provide test points which can be used to inject the network analyzer AC signal and measure the closed loop response. For PRM Remote Sense mode (single ended local sense), test points TP37/TP38 and H46/ H45 are in series between the PRM +OUT and the voltage sense resistors and should be used. For PRM-VTM Remote Sense mode (differential sense) test points are provided on the VTM board in series with the +S connections (Labeled “AC Sig Inj +/-“) and should be used. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 24 Trim and soft-start adjustment in Remote Sense Operation Trim and soft start adjustment in Remote Sense Operation is set by the reference voltage network shown below. The PRM evaluation board is normally configured for a 20 V to 55 V trim range. Trim POT R44 is used to trim the output voltage in Remote Sense Operation. The slew rate of the output voltage during startup may be controlled by controlling the rate-of-rise of the voltage at VREF node. This can be achieved using soft-start capacitance C24. By default, C24 is populated with 0.1uF ceramic capacitance. Sockets H55 and H56 can be used for installation of additional through-hole soft-start capacitance. It is not recommended to extend the soft start beyond 10msec. Figure 15. Voltage Reference circuit H55 REF_EN_B OUT 2 1 IN 3 0603 TP43 R44 C24 R45 1206 GND C23 VREF R43 1206 U12 1206 SOT23_3 TP44 SGND H56 VOLTAGE REFERENCE Current limit adjustment in Remote Sense Operation In Remote Sense Operation, current feedback is provided externally. The current limit set point is a function of the current sense amplifier gain, the shunt resistor and the internal current limit threshold of PRM. Full chip PRM evaluation board has 5 mΩ current shunt whereas half chip PRM evaluation board has 10mΩ current shunt. The IFB current limit threshold is fixed at 2.0V. The gain of the current sense amplifier can be changed per Equation 2 in order to adjust the current limit. Resistor R26 set the gain of the current sense amplifier. R25 is the current shunt. GCS = VIFB_IL ILIMIT (SET) • R25 Equation 2 By default, R26 is installed for the current limit approximately 10% above rated output current. The current limit setpoint can be changed by adjusting the value of R26 and appropriately setting the gain of the current sense IC. UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 25 Slave operating mode (Arrays) Mode select switch S10 setting: keep the switch S10 setting at all positions as shown in following illustration. Slave configuration for Adaptive Loop Master. Master/Slave configured PRM parallel arrays ON OFF Postion number Slave configuration for Remote Sense Operation. Slave configured PRM parallel arrays 1 2 3 4 5 6 7 8 9 10 ON OFF Postion number 1 2 3 4 5 6 7 8 9 10 Slave operation is required for constructing arrays of parallel devices as described in the next section. Switch at position 1 is ON and switch at rest of the positions are OFF. When switch at position 1 is ON, TRIM pin of the PRM is shorted to SGND and PRM is configured as a slave. When a PRM is configured as slave, the internal voltage and current sensing circuitry are disabled and slave PRMs receive their control signal (SHARE) from a master PRM or external remote sense circuit. For Remote Sense operation parallel array where all PRMs are configured as slave, switch at position 3 should be ON to enable the constant output current limit. Paralleling The paralleling and current sharing capability of the devices can be demonstrated by stacking multiple evaluation board and interconnecting the inputs and outputs with standoffs of sufficient current rating to create a parallel array. See Figure 16 below. One board should be configured normally for Adaptive Loop or Remote Sense operation and placed on top for easy access to control circuitry. The remaining PRMs should be configured as Slaves and placed underneath. When paralleling PRMs, the ENABLE, SHARE and SGND pins should be connected together. Dual paralleling wire to board connectors (J17 and J18) are used for transferring signal pins (ENABLE, SHARE and SGND) in parallel operation from board to board. These connectors provide simple strip and insert option and accept 18-24AWG solid wires. SHARE and SGND wires can be twisted to minimize noise pick-up. Note that when using J17 and J18, SGND pins will be connected together through an on board 1 OHM series resistors to decouple signal grounds. VTM boards can also be connected in parallel to create high power PRM-VTM arrays. VTM input and outputs need to be connected in parallel using same size standoffs. Each VTM requires a VC signal from a PRM in order to start and it is recommended to connect one PRM VC to one VTM VC using the connector J13 when possible. If needed a single PRM VC can be used to drive up to two VTMs (will require additional off board connections). UG:013 vicorpower.com Applications Engineering: 800 927.9474 Page 26 Figure 16. Paralleling of PRM evaluation board Top - Master Bottom - Slaves Interconnect signals Conclusion The PRM® evaluation board is a flexible tool which allows users to implement and perform basic testing on various configurations, including PRM-VTM® module combinations. This user guide covers some basic topics; however, it cannot describe every scenario. If additional information required, please contact Vicor Applications Engineering. The Power Behind Performance Rev 1.4 12/14 vicorpower.com Applications Engineering: 800 927.9474 Page 27