VTM Current Multiplier VTM48EF015T115A00 (R) S US C C NRTL US High Efficiency, Sine Amplitude ConverterTM FEATURES * 48 Vdc to 1.5 Vdc 115 A current multiplier - Operating from standard 48 V or 24 V PRMTM regulators * High efficiency (>94%) reduces system power consumption * High density (392 A/in3) * "Full Chip" VI Chip(R) package enables surface mount, low impedance interconnect to system board * Contains built-in protection features against: - Overvoltage - Overcurrent * Provides enable / disable control, internal temperature monitoring * ZVS / ZCS resonant Sine Amplitude Converter topology * Less than 50 C temperature rise at full load in typical applications TYPICAL APPLICATIONS * High End Computing Systems * Automated Test Equipment * High Density Power Supplies * Communications Systems TYPICAL APPLICATION DESCRIPTION The VI Chip(R) current multiplier is a high efficiency (>94%) Sine Amplitude ConverterTM (SACTM) operating from a 26 to 55 Vdc primary bus to deliver an isolated output. The Sine Amplitude Converter offers a low AC impedance beyond the bandwidth of most downstream regulators; therefore capacitance normally at the load can be located at the input to the Sine Amplitude Converter. Since the K factor of the VTM48EF015T115A00 is 1/32, the capacitance value can be reduced by a factor of 1024, resulting in savings of board area, materials and total system cost. The VTM48EF015T115A00 is provided in a VI Chip(R) package compatible with standard pick-and-place and surface mount assembly processes. The co-molded VI Chip(R) package provides enhanced thermal management due to a large thermal interface area and superior thermal conductivity. The high conversion efficiency of the VTM48EF015T115A00 increases overall system efficiency and lowers operating costs compared to conventional approaches. The VTM48EF015T115A00 enables the utilization of Factorized Power ArchitectureTM which provides efficiency and size benefits by lowering conversion and distribution losses and promoting high density point of load conversion. VIN = 26 to 55 V IOUT = 115 A (NOM) VOUT = 0.8 to 1.7 V (NO LOAD) K = 1/32 PART NUMBER DESCRIPTION VTM48EF015T115A00 -40C to 125C TJ Voltage Control Feedback Enable/ Disable Voltage Reference PC PR +IN TM +OUT PC -IN IF RE +OUT1 +OUT2 +IN VTM48EF015T115A00 PRMTM Regulator 38 to 55 Vdc Input Load -IN -OUT SG VC VC Current Sense Constant Vc -OUT1 -OUT2 PC +OUT1 +IN +OUT2 VTM48EF015T115A00 -IN VC VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 1 of 17 09/2015 800 927.9474 -OUT1 -OUT2 VTM48EF015T115A00 1.0 ABSOLUTE MAXIMUM VOLTAGE RATINGS The absolute maximum ratings below are stress ratings only. Operation at or beyond these maximum ratings can cause permanent MIN MAX UNIT MIN MAX UNIT damage to the device. + IN to - IN . . . . . . . . . . . . . . . . . . . . . . . . . . . PC to - IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . TM to -IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . VC to - IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . -1.0 -0.3 -0.3 -0.3 60 20 7 20 VDC VDC VDC VDC IM to - IN......................................................... + IN / - IN to + OUT / - OUT (hipot)................ + IN / - IN to + OUT / - OUT (working)........... + OUT to - OUT............................................... 0 3.15 1500 60 5.5 -1.0 VDC VDC VDC VDC 2.0 ELECTRICAL CHARACTERISTICS Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature range of -40C < TJ < 125C (T-Grade); All other specifications are at TJ = 25 C unless otherwise noted. ATTRIBUTE Input voltage range VIN slew rate VIN UV turn off SYMBOL VIN VIN_UV PNL Inrush current peak IINRP Output current (average) Output current (peak) Output power (average) IIN_DC K VOUT IOUT_AVG IOUT_PK POUT_AVG Efficiency (ambient) hAMB Efficiency (hot) Efficiency (over load range) Output resistance (cold) Output resistance (ambient) Output resistance (hot) Switching frequency Output ripple frequency hHOT h20% ROUT_COLD ROUT_AMB ROUT_HOT FSW FSW_RP Output voltage ripple VOUT_PP Output inductance (parasitic) LOUT_PAR Output capacitance (internal) COUT_INT Output capacitance (external) COUT PROTECTION Overvoltage lockout Overvoltage lockout response time constant Output overcurrent trip Short circuit protection trip current Output overcurrent response time constant Short circuit protection response time Thermal shutdown setpoint Reverse inrush current protection MIN TYP 26 0 dVIN /dt No Load power dissipation DC input current Transfer ratio Output voltage CONDITIONS / NOTES No external VC applied VC applied Module latched shutdown, No external VC applied, IOUT = 115A VIN = 48 V VIN = 26 V to 55 V VIN = 48 V, TC = 25 C VIN = 26 V to 55 V, TC = 25 C VC enable, VIN = 48 V, COUT = 64400 F, RLOAD = 12 m K = VOUT / VIN, IOUT = 0 A VOUT = VIN * K - IOUT * ROUT, Section 11 30C < Tc < 100C, Iout_max = - (3/14) * Tc + 136.43 TC = 30 C TPEAK < 10 ms, IOUT_AVG 115 A IOUT_AVG 115 A VIN = 48 V, IOUT = 115 A VIN = 26 V to 55 V, IOUT = 115 A VIN = 48 V, IOUT = 57.5 A VIN = 48 V, IOUT = 130 A VIN = 48 V, TC = 100C, IOUT = 115 A 23 A < IOUT < 115 A TC = -40C, IOUT = 115 A TC = 25C, IOUT = 115 A TC = 100C, IOUT = 115 A 18 1.5 2.2 7.2 Module latched shutdown TOVLO Effective internal RC filter IOCP ISCP TOCP Effective internal RC filter (Integrative). TSCP From detection to cessation of switching (Instantaneous) TJ_OTP VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 2 of 17 09/2015 800 927.9474 26 V 5.8 6.5 4.2 5.5 W 11 A 4.5 A V/V V 130 200 185 VDC A A W 91.7 % 94.0 90.9 90.7 0.67 0.84 1.00 1.40 2.80 1.0 1.08 1.18 1.50 3.00 % % m m m MHz MHz 150 200 mV 150 pH 420 F 55.1 58.2 138 250 190 64400 F 60 V 0.2 125 Reverse Inrush protection enabled for this product V/s 115 90.0 84.0 91.5 89.5 89.0 80 0.35 0.50 0.64 1.30 2.60 UNIT 55 55 1 1/32 COUT = 0 F, IOUT = 115 A, VIN = 48 V, 20 MHz BW, Section 11 Frequency up to 30 MHz, Simulated J-lead model Effective Value at 1.5 VOUT VTM Standalone Operation. VIN pre-applied, VC enable VIN_OVLO+ MAX s 250 A A 9.1 ms 1 s 130 135 C VTM48EF015T115A00 3.0 SIGNAL CHARACTERISTICS Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature range of -40C < TJ < 125C (T-Grade); All other specifications are at TJ = 25C unless otherwise noted. * Used to wake up powertrain circuit. * A minimum of 11.5 V must be applied indefinitely for VIN < 26 V to ensure normal operation. * VC slew rate must be within range for a successful start. SIGNAL TYPE STATE ATTRIBUTE External VC voltage VTM CONTROL : VC * PRMTM module VC can be used as valid wake-up signal source. * Internal Resistance used in "Adaptive Loop" compensation * VC voltage may be continuously applied SYMBOL VVC_EXT VC current draw IVC Steady ANALOG INPUT VC internal diode rating VC internal resistor VC internal resistor temperature coefficient VC start up pulse VC slew rate VC inrush current CONDITIONS / NOTES Required for start up, and operation below 26 V. See Section 7. VC = 11.5 V, VIN = 0 V VC = 11.5 V, VIN > 26 V VC = 16.5 V, VIN > 26 V Fault mode. VC > 11.5 V MIN TYP 11.5 16.5 115 0 0 60 100 N/A DVC_INT RVC-INT MAX UNIT TVC_COEFF V 150 mA V k N/A ppm/C Tpeak <18 ms 20 V Required for proper start up; 0.02 0.25 V/s VC = 16.5 V, dVC/dt = 0.25 V/s 1 A VIN pre-applied, PC floating, VC to VOUT turn-on delay TON 500 s VC enable, CPC = 0 F Transitional VC = 11.5 V to PC high, VIN = 0 V, VC to PC delay Tvc_pc 75 125 s dVC/dt = 0.25 V/s VC = 0 V 3.2 F Internal VC capacitance CVC_INT PRIMARY CONTROL : PC * The PC pin enables and disables the VTMTM module. * Module will shutdown when pulled low with an impedance When held below 2 V, the VTM module will be disabled. less than 400 . * PC pin outputs 5 V during normal operation. PC pin is equal to 2.5 V * In an array of VTM modules, connect PC pin to synchronize start up. during fault mode given VIN > 26 V or VC > 11.5 V. * PC pin cannot sink current and will not disable other modules * After successful start up and under no fault condition, PC can be used as during fault mode. a 5 V regulated voltage source with a 2 mA maximum current. Start Up SIGNAL TYPE ANALOG OUTPUT STATE Steady Start Up Enable DIGITAL INPUT / OUPUT Disable Transitional ATTRIBUTE PC voltage PC source current PC resistance (internal) PC source current PC capacitance (internal) PC resistance (external) PC voltage PC voltage (disable) PC pull down current PC disable time PC fault response time VVC_SP dVC/dt IINR_VC SYMBOL IPC_OP RPC_INT Internal pull down resistor IPC_EN CPC_INT Section 7 RPC_S VPC_EN VPC_DIS IPC_PD TPC_DIS_T TFR_PC From fault to PC = 2 V CURRENT MONITOR : IM * The IM pin voltage varies between 0.2 V and 0.61 V representing the output current within 25% under all operating line temperature conditions between 50% and 100%. SIGNAL TYPE ANALOG OUTPUT STATE Steady ATTRIBUTE IM Voltage (No Load) IM Voltage (50%) IM Voltage (Full Load) IM Gain IM Resistance (External) CONDITIONS / NOTES VPC SYMBOL VIM_NL VIM_50% VIM_FL A IM RIM_EXT MIN TYP 4.7 5 50 50 150 100 60 2 2.5 MAX UNIT 5.3 2 400 300 1000 3 2 5.1 5 100 V mA k A pF k V V mA s s * The IM pin provides a DC analog voltage proportional to the output current of the VTM module. CONDITIONS / NOTES TJ = 25 C, VIN = 48 V, IOUT = 0 A TJ = 25 C, VIN = 48 V, IOUT = 57.5 A TJ = 25 C, VIN = 48 V, IOUT = 115 A TJ = 25 C, VIN = 48 V, IOUT > 57.5 A MIN TYP MAX UNIT 0.2 0.07 0.28 0.61 6 0.3 V V V mV/A M 2.5 VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 3 of 17 09/2015 800 927.9474 VTM48EF015T115A00 TEMPERATURE MONITOR : TM * The TM pin monitors the internal temperature of the VTM controller IC * The TM pin has a room temperature setpoint of 3 V within an accuracy of 5C. and approximate gain of 10 mV/C. * Can be used as a "Power Good" flag to verify that * Output drives Temperature Shutdown comparator the VTM module is operating. SIGNAL TYPE STATE ANALOG OUTPUT ATTRIBUTE TM voltage TM source current TM gain Steady Disable DIGITAL OUTPUT (FAULT FLAG) Transitional SYMBOL VTM_AMB ITM ATM TM voltage ripple VTM_PP TM voltage TM resistance (internal) TM capacitance (external) TM fault response time VTM_DIS RTM_INT CTM_EXT TFR_TM CONDITIONS / NOTES TJ controller = 27C MIN TYP MAX UNIT 2.95 3.00 3.05 100 V A mV/C 200 mV 50 50 V k pF s 10 CTM = 0 F, VIN = 48 V, IOUT = 115 A 120 Internal pull down resistor 25 From fault to TM = 1.5 V 0 40 10 4.0 TIMING DIAGRAM ISEC 6 7 ISEC ISEC 1 2 3 VC 4 8 d 5 b VVC-EXT a VOVLO VPRI NL 26 V c e f VSEC TM VTM-AMB PC g 5V 3V a: VC slew rate (dVC/dt) b: Minimum VC pulse rate c: TOVLO_PIN d: TOCP_SEC e: Secondary turn on delay (TON) f: PC disable time (TPC_DIS_T) g: VC to PC delay (TVC_PC) 1. Initiated VC pulse 2. Controller start 3. VPRI ramp up 4. VPRI = VOVLO 5. VPRI ramp down no VC pulse 6. Overcurrent, Secondary 7. Start up on short circuit 8. PC driven low Notes: - Timing and voltage is not to scale - Error pulse width is load dependent VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 4 of 17 09/2015 800 927.9474 VTM48EF015T115A00 5.0 APPLICATION CHARACTERISTICS The following values, typical of an application environment, are collected at TC = 25 C unless otherwise noted. See associated figures for general trend data. ATTRIBUTE SYMBOL No load power dissipation Efficiency (ambient) Efficiency (hot) Output resistance (cold) Output resistance (ambient) Output resistance (hot) PNL hAMB hHOT ROUT_COLD ROUT_AMB ROUT_HOT Output voltage ripple VOUT_PP VOUT transient (positive) VOUT_TRAN+ VOUT transient (negative) VOUT_TRAN- CONDITIONS / NOTES TYP UNIT VIN = 48 V, PC enabled VIN = 48 V, IOUT = 115 A VIN = 48 V, IOUT = 115 A, TC = 100 C VIN = 48 V, IOUT = 115 A, TC = -40 C VIN = 48 V, IOUT = 115 A VIN = 48 V, IOUT = 115 A, TC = 100 C COUT = 0 F, IOUT = 115 A, VIN = 48 V, 20 MHz BW, Section 12 IOUT_STEP = 0 A TO 115A, VIN = 48 V, ISLEW = 36 A /us IOUT_STEP = 115 A to 0 A, VIN = 48 V ISLEW = 23 A /us 2.1 91.8 90.3 0.7 0.9 1.0 W % % m m m 116 mV 40 mV 60 mV No Load Power Dissipation vs. Line Voltage Full Load Efficiency (%) 3.5 3.0 2.5 2.0 1.5 92 90 88 86 84 82 80 1.0 26 29 32 35 38 41 43 46 49 52 -40 55 -20 0 -40 C TCASE: 25 C VIN : 100 C 84 PD 76 72 26 39 52 65 78 91 26 V 48 V 55 V 100 48 V 55 V 104 117 48 44 40 36 32 28 24 20 16 12 8 4 0 88 84 80 PD 76 72 130 0 13 26 39 52 65 78 91 104 117 130 Load Current (A) Load Current (A) VIN: 26 V 92 Efficiency (%) 88 13 80 96 Power Dissipation (W) Efficiency (%) 48 44 40 36 32 28 24 20 16 12 8 4 0 0 60 Efficiency & Power Dissipation 25 C Case Efficiency & Power Dissipation -40 C Case 96 80 40 Figure 2 -- Full load efficiency vs. temperature Figure 1 -- No load power dissipation vs. VIN 92 20 Case Temperature (C) Input Voltage (V) Power Dissipation (W) Power Dissipation (W) Full Load Efficiency vs. TCASE 94 4.0 26 V 48 V 55 V VIN: 26 V 48 V 55 V 26 V 48 V Figure 3 -- Efficiency and power dissipation at -40C Figure 4 -- Efficiency and power dissipation at 25C VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 5 of 17 09/2015 800 927.9474 55 V VTM48EF015T115A00 Efficiency & Power Dissipation 100 C Case 84 PD 76 72 0 12 23 26 V VIN: 35 46 58 69 81 Load Current (A) 48 V 55 V 92 1.5 ROUT (m) 88 2.0 Power Dissipation (W) Efficiency (%) 92 80 ROUT vs. TCASE at VIN = 48 V 48 44 40 36 32 28 24 20 16 12 8 4 0 96 1.0 0.5 0.0 -40 104 115 -20 26 V 48 V 55 V I OUT : Output Voltage Ripple vs. Load Output Current (A) VRIPPLE (mV PK-PK) 150 125 100 75 50 25 0 35 46 58 69 81 92 104 115 Load Current (A) VIN: 26 V 48 V 60 80 100 115 A 57.5 A Safe Operating Area 175 23 40 Figure 6 -- ROUT vs. temperature 200 12 20 Case Temperature (C) Figure 5 -- Efficiency and power dissipation at 100C 0 0 220 200 180 160 140 120 100 80 60 40 20 0 Limited by Power < 10 ms, 200 A Maximum Current < 30C TCASE, 130 A Maximum Current Limited by ROUT 115 A Maximum Current Region 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 Output Voltage (V) 55 V Figure 7 -- VRIPPLE vs. IOUT ; No external COUT. Board mounted module, scope setting: 20 MHz analog BW Figure 8 -- Safe operating area Figure 9 -- Full load ripple, 100 F CIN; No external COUT. Board mounted module, scope setting : 20 MHz analog BW Figure 10 -- Start up from application of VIN ; VC pre-applied COUT = 64400 F VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 6 of 17 09/2015 800 927.9474 1.6 1.8 2.0 2.2 VTM48EF015T115A00 Figure 11 -- Start up from application of VC; VIN pre-applied COUT = 64400 F Figure 12 -- 0 A - 115 A transient response: C IN = 100 F, no external COUT IM Voltage vs. Load at VIN = 48 V 0.6 0.5 IM (V) 0.4 0.3 0.2 0.1 0 12 23 35 46 58 69 81 92 104 115 Load Current (A) -40 C TCASE : Figure 13 -- 115 A - 0 A transient response: C IN = 100 F, no external COUT 25 C 100 C Figure 14 -- IM voltage vs. load IM Voltage vs. Load at 25 C Case IM Voltage at 115 A Load vs. TCASE 0.6 0.6 0.5 0.5 IM (V) IM (V) 0.4 0.3 0.4 0.2 0.3 0.1 0.0 0.2 12 23 35 46 58 69 81 92 104 115 -40 -20 Load Current (A) VIN : 26 V 48 V 20 40 60 80 TCASE (C) 55 V Figure 15 -- IM voltage vs. load 0 VIN : 26 V 48 V Figure 16 -- Full load IM voltage vs. TCASE VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 7 of 17 09/2015 800 927.9474 55 V 100 VTM48EF015T115A00 6.0 GENERAL CHARACTERISTICS Specifications apply over all line and load conditions unless otherwise noted; Boldface specifications apply over the temperature range of -40 C < TJ < 125 C (T-Grade); All Other specifications are at TJ = 25C unless otherwise noted. ATTRIBUTE MECHANICAL Length Width Height Volume Weight SYMBOL L W H Vol W CONDITIONS / NOTES MIN 32.25 / [1.270] 21.75 / [0.856] 6.48 / [0.255] No heat sink Nickel Palladium Gold Lead finish TYP 32.5 / [1.280] 22.0 / [0.866] 6.73 / [0.265] 4.81 / [0.294] 14.5 / [0.512] MAX UNIT 32.75 / [1.289] 22.25 / [0.876] 6.98 / [0.275] mm/[in] mm/[in] mm/[in] cm3/[in3] g/[oz] 0.51 0.02 0.003 2.03 0.15 0.051 m -40 N/A 125 N/A C C THERMAL Operating temperature Thermal resistance VTM48EF015T115A00 (T-Grade) VTM48EF015M115A00 (M-Grade) Isothermal heatsink and isothermal internal PCB TJ fJC Thermal capacity ASSEMBLY Peak compressive force applied to case (Z-axis) Storage temperature TST ESDHBM ESDCDM SOLDERING Peak temperature during reflow Peak time above 245C Peak heating rate during reflow Peak cooling rate post reflow MTBF Agency approvals / standards C/W 9 Ws/C 6 5.41 125 N/A Supported by J-lead only ESD withstand SAFETY Working voltage (IN - OUT) Isolation voltage (hipot) Isolation capacitance Isolation resistance 1 VTM48EF015T115A00 (T-Grade) VTM48EF015M115A00 (M-Grade) Human Body Model, "JEDEC JESD 22-A114C.01" Charge Device Model, "JEDEC JESD 22-C101-C" -40 N/A TBD VDC TBD MSL 4 (Datecode 1528 and later) 60 1.5 1.5 VIN_OUT VHIPOT CIN_OUT RIN_OUT 1500 1800 10 Unpowered unit lbs lbs / in2 C C 2000 MIL-HDBK-217 Plus Parts Count; 25C Ground Benign, Stationary, TBD Indoors / Computer Profile Telcordia Issue 2 - Method I Case III; TBD Ground Benign, Controlled cTUVus cURus CE Marked for Low Voltage Directive and RoHS Recast Directive, as applicable VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 8 of 17 09/2015 800 927.9474 245 90 3 6 C s C/s C/s 60 VDC VDC pF M 2200 MHrs MHrs VTM48EF015T115A00 7.0 USING THE CONTROL SIGNALS VC, PC, TM, IM The VTM Control (VC) pin is an input pin which powers the internal VCC circuitry when within the specified voltage range of 11.5 V to 16.5 V. This voltage is required for VTMTM current multiplier start up and must be applied as long as the input is below 26 V. In order to ensure a proper start, the slew rate of the applied voltage must be within the specified range. Some additional notes on the using the VC pin: * In most applications, the VTM module will be powered by an upstream PRMTM regulator which provides a 10 ms VC pulse during start up. In these applications the VC pins of the PRM module and VTM module should be tied together. * The VC voltage can be applied indefinitely allowing for continuous operation down to 0 VIN. * The fault response of the VTM module is latching. A positive edge on VC is required in order to restart the unit. If VC is continuously applied the PC pin may be toggled to restart the VTM module. Primary Control (PC) pin can be used to accomplish the following functions: * Delayed start: Upon the application of VC, the PC pin will source a constant 100 A current to the internal RC network. Adding an external capacitor will allow further delay in reaching the 2.5 V threshold for module start. * Auxiliary voltage source: Once enabled in regular operational conditions (no fault), each VTM PC provides a regulated 5 V, 2 mA voltage source. * Output disable: PC pin can be actively pulled down in order to disable the module. Pull down impedance shall be lower than 400 . * Fault detection flag: The PC 5 V voltage source is internally turned off as soon as a fault is detected. It is important to notice that PC doesn't have current sink capability. Therefore, in an array, PC line will not be capable of disabling neighboring modules if a fault is detected. * Fault reset: PC may be toggled to restart the unit if VC is continuously applied. Temperature Monitor (TM) pin provides a voltage proportional to the absolute temperature of the converter control IC. It can be used to accomplish the following functions: * Monitor the control IC temperature: The temperature in Kelvin is equal to the voltage on the TM pin scaled by 100. (i.e. 3.0 V = 300 K = 27 C). If a heat sink is applied, TM can be used to thermally protect the system. * Fault detection flag: The TM voltage source is internally turned off as soon as a fault is detected. For system monitoring purposes (microcontroller interface) faults are detected on falling edges of TM signal. Current Monitor (IM) pin provides a voltage proportional to the output current of the VTM module. The nominal voltage will vary between 0.07 V and 0.61 V over the output current range of the VTM module (See Figures 14 -16). The accuracy of the IM pin will be within 25% under all line and temperature conditions between 50% and 100% load. 8.0 START UP BEHAVIOR Depending on the sequencing of the VC with respect to the input voltage, the behavior during start up will vary as follows: * Normal operation (VC applied prior to VIN ): In this case the controller is active prior to ramping the input. When the input voltage is applied, the VTM module output voltage will track the input (See Figure 10). The inrush current is determined by the input voltage rate of rise and output capacitance. If the VC voltage is removed prior to the input reaching 26 V, the VTM may shut down. * Stand-alone operation (VC applied after VIN ): In this case the VTM module output will begin to rise upon the application of the VC voltage (See Figure 11). The Adaptive Soft Start Circuit (See Section 11) may vary the ouput rate of rise in order to limit the inrush current to its maximum level. When starting into high capacitance, or a short, the output current will be limited for a maximum of 120 /sec. After this period, the Adaptive Soft Start Circuit will time out and the VTM module may shut down. No restart will be attempted until VC is re-applied or PC is toggled. The maximum output capacitance is limited to 64400 F in this mode of operation to ensure a sucessful start. 9.0 THERMAL CONSIDERATIONS VI Chip(R) products are multi-chip modules whose temperature distribution varies greatly for each part number as well as with the input / output conditions, thermal management and environmental conditions. Maintaining the top of the VTM48EF015T115A00 case to less than 100 C will keep all junctions within the VI Chip(R) module below 125 C for most applications. The percent of total heat dissipated through the top surface versus through the J-lead is entirely dependent on the particular mechanical and thermal environment. The heat dissipated through the top surface is typically 60%. The heat dissipated through the J-lead onto the PCB board surface is typically 40%. Use 100% top surface dissipation when designing for a conservative cooling solution. It is not recommended to use a VI Chip(R) module for an extended period of time at full load without proper heat sinking. VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 9 of 17 09/2015 800 927.9474 PC DVC_INT VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 10 of 17 09/2015 800 927.9474 CIN 1000 pF 3.1 V PC Pull-Up & Source -VIN RVC_INT VC +VIN 100 A 18 V 150 K 5V 2 mA 2.5 V Enable 10.5 V VDD Regulator Supply Enable OVLO UVLO VIN Adaptive Soft Start Enable Modulator Enable Fault Logic Gate Drive Supply Primary Gate Drive Cr VREF (127C) Over Temperature Protection VREF Lr Primary Stage & Resonant Tank Single Ended Primary Current Sensing Q2 Q1 Secondary Gate Drive Power Transformer Temperature Dependent Voltage Source C2 C1 Q3 40 K 1K Q4 102 0.01 F 3 VMAX 240 AMAX Synchronous Rectification TM IM Right J-lead -VOUT COUT +VOUT +VOUT COUT -VOUT Left J-lead VTM48EF015T115A00 10.0 VTM MODULE BLOCK DIAGRAM VTM48EF015T115A00 11.0 SINE AMPLITUDE CONVERTERTM POINT OF LOAD CONVERSION 90 pH IOUT IOUT LIN = 3.7 nH 0.84 m + VIN V IN OUT RROUT R RCIN CIN 6.3 m CCININ 0.98 V*I 1/32 * IOUT 900 nF IIQQ 46 mA + + - - LOUT = 150 pH RRCOUT COUT + 50 1/32 * VIN COUT COUT 420 F VOUT V OUT K - - Figure 17 -- VI Chip(R) product AC model The Sine Amplitude Converter (SACTM) uses a high frequency resonant tank to move energy from input to output. (The resonant tank is formed by Cr and leakage inductance Lr in the power transformer windings as shown in the VTMTM Module Block Diagram. See Section 10). The resonant LC tank, operated at high frequency, is amplitude modulated as a function of input voltage and output current. A small amount of capacitance embedded in the input and output stages of the module is sufficient for full functionality and is key to achieving power density. The VTM48EF015T115A00 SAC can be simplified into the following model: At no load: ROUT represents the impedance of the SAC, and is a function of the RDSON of the input and output MOSFETs and the winding resistance of the power transformer. IQ represents the quiescent current of the SAC control and gate drive circuitry. The use of DC voltage transformation provides additional interesting attributes. Assuming that ROUT = 0 and IQ = 0 A, Eq. (3) now becomes Eq. (1) and is essentially load independent, resistor R is now placed in series with VIN as shown in Figure 18. RR VOUT = VIN * K (1) VIN Vin + - SACTM K SAC = 1/32 K = 1/32 VOUT Vout K represents the "turns ratio" of the SAC. Rearranging Eq (1): K= VOUT VIN (2) Figure 18 - K = 1/32 Sine Amplitude Converter with series input resistor The relationship between VIN and VOUT becomes: In the presence of load, VOUT is represented by: VOUT = (VIN - IIN * R) * K VOUT = VIN * K - IOUT * ROUT (3) Substituting the simplified version of Eq. (4) (IQ is assumed = 0 A) into Eq. (5) yields: and IOUT is represented by: IOUT = (5) IIN - IQ K (4) VOUT = VIN * K - IOUT * R * K2 VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 11 of 17 09/2015 800 927.9474 (6) VTM48EF015T115A00 This is similar in form to Eq. (3), where ROUT is used to represent the characteristic impedance of the SACTM. However, in this case a real R on the input side of the SAC is effectively scaled by K2 with respect to the output. Assuming that R = 1 , the effective R as seen from the secondary side is 1 m, with K = 1/32 as shown in Figure 18. A similar exercise should be performed with the addition of a capacitor or shunt impedance at the input to the SAC. A switch in series with VIN is added to the circuit. This is depicted in Figure 19. SS VVin IN + - C C SACTM SAC K = 1/32 K = 1/32 VVout OUT Figure 19 -- Sine Amplitude ConverterTM with input capacitor A change in VIN with the switch closed would result in a change in capacitor current according to the following equation: IC(t) = C dVIN dt Low impedance is a key requirement for powering a highcurrent, low voltage load efficiently. A switching regulation stage should have minimal impedance while simultaneously providing appropriate filtering for any switched current. The use of a SAC between the regulation stage and the point of load provides a dual benefit of scaling down series impedance leading back to the source and scaling up shunt capacitance or energy storage as a function of its K factor squared. However, the benefits are not useful if the series impedance of the SAC is too high. The impedance of the SAC must be low, i.e. well beyond the crossover frequency of the system. A solution for keeping the impedance of the SAC low involves switching at a high frequency. This enables small magnetic components because magnetizing currents remain low. Small magnetics mean small path lengths for turns. Use of low loss core material at high frequencies also reduces core losses. The two main terms of power loss in the VTMTM module are: - No load power dissipation (PNL): defined as the power used to power up the module with an enabled powertrain at no load. - Resistive loss (ROUT): refers to the power loss across the VTMTM current multiplier modeled as pure resistive impedance. PDISSIPATED = PNL + PROUT (7) (10) Therefore, POUT = PIN - PDISSIPATED = PIN - PNL - PROUT Assume that with the capacitor charged to VIN, the switch is opened and the capacitor is discharged through the idealized SAC. In this case, IC = IOUT * K The above relations can be combined to calculate the overall module efficiency: (8) h = (9) = POUT = PIN - PNL - PROUT PIN PIN Substituting Eq. (1) and (8) into Eq. (7) reveals: IOUT = C K2 * dVOUT dt The equation in terms of the output has yielded a K2 scaling factor for C, specified in the denominator of the equation. A K factor less than unity, results in an effectively larger capacitance on the output when expressed in terms of the input. With a K= 1/32 as shown in Figure 19, C = 1 F would appear as C=1024 F when viewed from the output. (11) VIN * IIN - PNL - (IOUT)2 * ROUT VIN * IIN = 1- ( ) PNL + (IOUT)2 * ROUT VIN * IIN VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 12 of 17 09/2015 800 927.9474 (12) VTM48EF015T115A00 12.0 INPUT AND OUTPUT FILTER DESIGN A major advantage of a SACTM system versus a conventional PWM converter is that the former does not require large functional filters. The resonant LC tank, operated at extreme high frequency, is amplitude modulated as a function of input voltage and output current and efficiently transfers charge through the isolation transformer. A small amount of capacitance embedded in the input and output stages of the module is sufficient for full functionality and is key to achieving high power density. This paradigm shift requires system design to carefully evaluate external filters in order to: 1.Guarantee low source impedance. To take full advantage of the VTMTM current multiplier dynamic response, the impedance presented to its input terminals must be low from DC to approximately 5 MHz. Input capacitance may be added to improve transient performance or compensate for high source impedance. 2.Further reduce input and/or output voltage ripple without sacrificing dynamic response. Given the wide bandwidth of the VTM module, the source response is generally the limiting factor in the overall system response. Anomalies in the response of the source will appear at the output of the VTM module multiplied by its K factor. 3.Protect the module from overvoltage transients imposed by the system that would exceed maximum ratings and cause failures. The VI Chip(R) module input/output voltage ranges must not be exceeded. An internal overvoltage lockout function prevents operation outside of the normal operating input range. Even during this condition, the powertrain is exposed to the applied voltage and power MOSFETs must withstand it. 13.0 CAPACITIVE FILTERING CONSIDERATIONS FOR A SINE AMPLITUDE CONVERTERTM It is important to consider the impact of adding input and output capacitance to a Sine Amplitude Converter on the system as a whole. Both the capacitance value and the effective impedance of the capacitor must be considered. A Sine Amplitude Converter has a DC ROUT value which has already been discussed in section 11. The AC ROUT of the SAC contains several terms: VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 13 of 17 09/2015 800 927.9474 * Resonant tank impedance * Input lead inductance and internal capacitance * Output lead inductance and internal capacitance The values of these terms are shown in the behavioral model in section 11. It is important to note on which side of the transformer these impedances appear and how they reflect across the transformer given the K factor. The overall AC impedance varies from model to model. For most models it is dominated by DC ROUT value from DC to beyond 500 KHz. The behavioral model in section 11 should be used to approximate the AC impedance of the specific model. Any capacitors placed at the output of the VTM reflect back to the input of the VTM module by the square of the K factor (Eq. 9) with the impedance of the VTM module appearing in series. It is very important to keep this in mind when using a PRMTM regulator to power the VTM module. Most PRM modules have a limit on the maximum amount of capacitance that can be applied to the output. This capacitance includes both the PRM output capacitance and the VTM module output capacitance reflected back to the input. In PRM remote sense applications, it is important to consider the reflected value of VTM module output capacitance when designing and compensating the PRM control loop. Capacitance placed at the input of the VTM module appear to the load reflected by the K factor with the impedance of the VTM module in series. In step-down ratios, the effective capacitance is increased by the K factor. The effective ESR of the capacitor is decreased by the square of the K factor, but the impedance of the module appears in series. Still, in most step-down VTM modules an electrolytic capacitor placed at the input of the module will have a lower effective impedance compared to an electrolytic capacitor placed at the output. This is important to consider when placing capacitors at the output of the module. Even though the capacitor may be placed at the output, the majority of the AC current will be sourced from the lower impedance, which in most cases will be the module. This should be studied carefully in any system design using a module. In most cases, it should be clear that electrolytic output capacitors are not necessary to design a stable, well-bypassed system. VTM48EF015T115A00 14.0 CURRENT SHARING The SACTM topology bases its performance on efficient transfer of energy through a transformer without the need of closed loop control. For this reason, the transfer characteristic can be approximated by an ideal current multiplier with some resistive drop and positive temperature coefficient. This type of characteristic is close to the impedance characteristic of a DC power distribution system, both in behavior (AC dynamic) and absolute value (DC dynamic). When connected in an array with the same K factor, the VTM module will inherently share the load current (typically 5%) with parallel units according to the equivalent impedance divider that the system implements from the power source to the point of load. Some general recommendations to achieve matched array impedances: * Dedicate common copper planes within the PCB to deliver and return the current to the modules. * Provide the PCB layout as symmetric as possible. * Apply same input / output filters (if present) to each unit. For further details see AN:016 Using BCM(R) Bus Converters in High Power Arrays. VIN ZIN_EQ1 VTMTM1 ZOUT_EQ1 16.0 REVERSE INRUSH CURRENT PROTECTION The VTM48EF015T115A00 provides reverse inrush protection which prevents reverse current flow until the input voltage is high enough to first establish current flow in the forward direction. In the event that there is a DC voltage present on the output before the VTM module is powered up, this feature protects sensitive loads from excessive dV/dT during power up as shown in Figure 21. If a voltage is present at the output of the VTM module which satisfies the condition VOUT > VIN * K after a successful power up the energy will be transferred from secondary to primary. The input to output ratio of the VTM module will be maintained. The VTM module will continue to operate in reverse as long as the input and output voltages are within the specified range. The VTM48EF015T115A00 has not been qualified for continuous reverse operation. Current Multiplier TM VC PC IM R R VTM VIN (R) +In +Out -In -Out + _ A VOUT B CD E F G H RO_1 VC ZIN_EQ2 VTMTM2 ZOUT_EQ2 VIN RO_2 + - DC Load Supply VIN ZIN_EQn VTMTMn ZOUT_EQn VOUT RO_n VOUT Supply Figure 20 -- VTM current multiplier array TM 15.0 FUSE SELECTION In order to provide flexibility in configuring power systems VI Chip(R) products are not internally fused. Input line fusing of VI Chip(R) products is recommended at system level to provide thermal protection in case of catastrophic failure. The fuse shall be selected by closely matching system requirements with the following characteristics: * Current rating (usually greater than maximum current of VTM module) * Maximum voltage rating (usually greater than the maximum possible input voltage) * Ambient temperature * Nominal melting I2t Figure 21 -- Reverse inrush protection VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 14 of 17 09/2015 800 927.9474 PC A: VOUT supply > 0 V B: VC to -IN > 11.5 V controller wakes-up, PC & TM pulled high, reverse inrush protection blocks VOUT supplying VIN C: VIN supply ramps up D: VIN > VOUT /K, powertrain starts in normal mode E: VIN supply ramps down F: VIN > VOUT /K, powertrain transfers reverse energy G: VOUT ramps down, VIN follows H: VC turns off Supply VTM48EF015T115A00 17.0 LAYOUT CONSIDERATIONS The VTM48EF015T115A00 requires equal current density along the output J-leads to achieve rated efficiency and output power level. The negative output J-leads are not connected internally and must be connected on the board as close to the VTMTTM current multiplier as possible. The layout must also prevent the high output current of the VTM48EF015T115A00 from interfering with the input-referenced signals. To achieve these requirements, the following layout guidelines are recommended: * The total current path length from any point on the V+OUT J-leads to the corresponding point on the V-OUT J-leads should be equal (see Figure 22) . Figure 22 -- Equal current path * Use vias along the negative output J-leads to connect the negative output to a common power plane. * Use sufficient copper weight and number of layers to carry the output current to the load or to the output connectors. * Be sure to include enough vias along both the positive and negative J leads to distribute the current among the layers of the PCB. * Do not run input-referenced signal traces (VC, PC, TM and IM) between the layers of the secondary outputs. * Run the input-referenced signal traces (VC, PC, TM and IM) such that V-IN shields the signals. See AN:005 FPA Printed Circuit Board Layout Guidelines for more details. Figure 23 -- Symmetric layout Equalizing the current paths is most easily accomplished by centering the VTM module output J-leads between the output connections of the PCB and by designing the board such that the layout is symmetric from both sides of the output and from the front and back ends of the output as shown in Figures 23 and 24. Figure 24 -- Symmetric layout VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 15 of 17 09/2015 800 927.9474 VTM48EF015T115A00 17.1 MECHANICAL DRAWING NOTES: mm 1. DIMENSIONS ARE inch . 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com 17.2 RECOMMENDED LAND PATTERN 4 3 2 A B C D E F G H J K L M N Bottom View Signal Name +In -In IM TM VC PC +Out -Out NOTES: mm 1. DIMENSIONS ARE inch . 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 16 of 17 09/2015 800 927.9474 Designation M2, M1 M4, M3 N3 N4 N2 N1 A3-L3, A2-L2 A4-L4, A1-L1 1 VTM48EF015T115A00 Vicor's comprehensive line of power solutions includes high density AC-DC and DC-DC modules and accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom power systems. Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication. Vicor reserves the right to make changes to any products, specifications, and product descriptions at any time without notice. Information published by Vicor has been checked and is believed to be accurate at the time it was printed; however, Vicor assumes no responsibility for inaccuracies. Testing and other quality controls are used to the extent Vicor deems necessary to support Vicor's product warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. Specifications are subject to change without notice. Vicor's Standard Terms and Conditions All sales are subject to Vicor's Standard Terms and Conditions of Sale, which are available on Vicor's webpage or upon request. Product Warranty In Vicor's standard terms and conditions of sale, Vicor warrants that its products are free from non-conformity to its Standard Specifications (the "Express Limited Warranty"). This warranty is extended only to the original Buyer for the period expiring two (2) years after the date of shipment and is not transferable. UNLESS OTHERWISE EXPRESSLY STATED IN A WRITTEN SALES AGREEMENT SIGNED BY A DULY AUTHORIZED VICOR SIGNATORY, VICOR DISCLAIMS ALL REPRESENTATIONS, LIABILITIES, AND WARRANTIES OF ANY KIND (WHETHER ARISING BY IMPLICATION OR BY OPERATION OF LAW) WITH RESPECT TO THE PRODUCTS, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OR REPRESENTATIONS AS TO MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, INFRINGEMENT OF ANY PATENT, COPYRIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT, OR ANY OTHER MATTER. This warranty does not extend to products subjected to misuse, accident, or improper application, maintenance, or storage. Vicor shall not be liable for collateral or consequential damage. Vicor disclaims any and all liability arising out of the application or use of any product or circuit and assumes no liability for applications assistance or buyer product design. Buyers are responsible for their products and applications using Vicor products and components. Prior to using or distributing any products that include Vicor components, buyers should provide adequate design, testing and operating safeguards. Vicor will repair or replace defective products in accordance with its own best judgment. For service under this warranty, the buyer must contact Vicor to obtain a Return Material Authorization (RMA) number and shipping instructions. Products returned without prior authorization will be returned to the buyer. The buyer will pay all charges incurred in returning the product to the factory. Vicor will pay all reshipment charges if the product was defective within the terms of this warranty. Life Support Policy VICOR'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF VICOR CORPORATION. As used herein, life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Per Vicor Terms and Conditions of Sale, the user of Vicor products and components in life support applications assumes all risks of such use and indemnifies Vicor against all liability and damages. Intellectual Property Notice Vicor and its subsidiaries own Intellectual Property (including issued U.S. and Foreign Patents and pending patent applications) relating to the products described in this data sheet. No license, whether express, implied, or arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Interested parties should contact Vicor's Intellectual Property Department. The products described on this data sheet are protected by the following U.S. Patents Numbers: 5,945,130; 6,403,009; 6,710,257; 6,911,848; 6,930,893; 6,934,166; 6,940,013; 6,969,909; 7,038,917; 7,145,186; 7,166,898; 7,187,263; 7,202,646; 7,361,844; D496,906; D505,114; D506,438; D509,472; and for use under 6,975,098 and 6,984,965. Vicor Corporation 25 Frontage Road Andover, MA, USA 01810 Tel: 800-735-6200 Fax: 978-475-6715 email Customer Service: custserv@vicorpower.com Technical Support: apps@vicorpower.com VTM(R) Current Multiplier Rev 3.5 vicorpower.com Page 17 of 17 09/2015 800 927.9474