VTM Current Multiplier VTM48 E x120 y 025A0R S C NRTL US High Efficiency, Bi-directional, Sine Amplitude Converter™ FEATURES • 48 Vdc to 12 Vdc 25 A bi-directional current multiplier • Can power a load connected to either the primary or secondary side • High efficiency (>96%) reduces system power consumption • High density (85 A/in3) • “Full Chip” VI Chip® package enables surface mount, low impedance interconnect to system board • Contains built-in protection features against: - Overvoltage Lockout Overcurrent Short Circuit Overtemperature • Provides enable / disable control, internal temperature monitoring • ZVS / ZCS resonant Sine Amplitude Converter topology • Less than 50ºC temperature rise at full load in typical applications TYPICAL APPLICATIONS • High End Computing Systems • Automated Test Equipment • High Density Power Supplies • Communications Systems VPRI = 26 to 55 V ISEC = 25 A (NOM) VSEC = 6.5 to 13.8 V (NO LOAD) K = 1/4 PART NUMBERING TYPICAL APPLICATION +IN Enable DESCRIPTION The VI Chip® bi-directional current multiplier is a Sine Amplitude Converter™ (SAC™) operating from a 26 to 55 Vdc primary source or a 6.5 to 13.8 Vdc secondary source to power a load. The bi-directional Sine Amplitude Converter isolates and transforms voltage at a secondary:primary ratio of 1/4. The SAC offers a low AC impedance beyond the bandwidth of most downstream regulators; therefore for a step-down conversion; capacitance normally at the load can be located at the source to the Sine Amplitude Converter to enable a reduction in size of capacitors. Since the K factor of the VTM48EF120T025A0R is 1/4, the capacitance value on the primary side can be reduced by a factor of 16 in an application where the source is located on the primary side, resulting in savings of board area, materials and total system cost. The VTM48EF120T025A0R is provided in a VI Chip package compatible with standard pick-and-place and surface mount assembly processes. The co-molded VI Chip package provides enhanced thermal management due to a large thermal interface area and superior thermal conductivity. The high conversion efficiency of the VTM48EF120T025A0R increases overall system efficiency and lowers operating costs compared to conventional approaches. The VTM48EF120T025A0R enables the utilization of Factorized Power Architecture™ which provides efficiency and size benefits by lowering conversion and distribution losses and promoting high density point of load conversion. PART NUMBER VTM48 E x 120 y 025A0R +OUT PACKAGE STYLE F = J-Lead T = Through hole PRODUCT GRADE T = -40 to 125°C M = -55 to 125°C PRM A For Storage and Operating Temperatures see Section 6.0 General Characteristics -IN -OUT +PRI +SEC VTM® +IN Enable +OUT -PRI Battery -SEC PRM B -OUT -IN VTM® Current Multiplier Rev 1.2 vicorpower.com Page 1 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 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 damage to the device. MIN MAX UNIT MIN MAX UNIT + PRI to - PRI . . . . . . . . . . . . . . . . . . . . . -1.0 60 VDC VC to - PRI . . . . . . . . . . . . . . . . . . . . . . . PC to - PRI . . . . . . . . . . . . . . . . . . . . . . . -0.3 20 VDC + PRI / - PRI to + SEC / - SEC (hipot) . . . TM to -PRI . . . . . . . . . . . . . . . . . . . . . . . -0.3 7 VDC + SEC to - SEC ......................................... -0.3 -1.0 20 VDC 2250 VDC 16 VDC 2.0 PRIMARY SOURCE ELECTRICAL CHARACTERISTICS Specifications apply over all line and load conditions when power is sourced from the primary side, unless otherwise noted; Boldface specifications apply over the temperature range of -40°C < TJ < 125°C (T-Grade); All other specifications are at TJ = 25ºC unless otherwise noted. ATTRIBUTE Primary voltage range VPRI slew rate VPRI UV turn off SYMBOL VPRI VPRI_UV PNL Inrush current peak IINRP Efficiency (ambient) Efficiency (hot) Efficiency (over load range) Secondary resistance (cold) Secondary resistance (ambient) Secondary resistance (hot) Switching frequency Secondary ripple frequency IPRI_DC K VSEC ISEC_AVG ISEC_PK POUT_AVG hAMB hHOT h20% RSEC_COLD RSEC_AMB RSEC_HOT FSW FSW_RP Secondary voltage ripple VSEC_PP Secondary inductance (parasitic) LSEC_PAR Secondary capacitance (internal) CSEC_INT Secondary capacitance (external) CSEC_EXT PROTECTION Primary Overvoltage lockout Primary Overvoltage lockout response time constant Secondary overcurrent trip Secondary Short circuit protection trip current Secondary overcurrent response time constant Secondary Short circuit protection response time Thermal shutdown setpoint MIN TYP 26 0 dVPRI/dt No Load power dissipation DC primary current Transfer ratio Secondary voltage Secondary current (average) Secondary current (peak) Secondary power (average) CONDITIONS / NOTES No external VC applied VC applied Module latched shutdown, No external VC applied, IOUT = 25A VPRI = 48 V VPRI = 26 V to 55 V VPRI = 48 V, TC = 25ºC VPRI = 26 V to 55 V, TC = 25ºC VC enable, VPRI = 48 V, CSEC = 1000 µF, RLOAD = 471 mΩ 24 3 5.3 10 K = VSEC/ VPRI, ISEC = 0 A VSEC = VPRI • K - ISEC • RSEC, Section 11 TPEAK < 10 ms, ISEC_AVG ≤ 25 A ISEC_AVG ≤ 25 A VPRI = 48 V, ISEC = 25 A VPRI = 26 V to 55 V, ISEC = 25 A VPRI = 48 V, ISEC = 12.5 A VPRI = 48 V, TC = 100°C, ISEC = 25 A 5 A < ISEC < 25 A TC = -40°C, ISEC = 25 A TC = 25°C, ISEC = 25 A TC = 100°C, ISEC = 25 A Module latched shutdown TOVLO Effective internal RC filter 55.1 26 ISCP_SEC 26 Effective internal RC filter (Integrative). TSCP_SEC From detection to cessation of switching (Instantaneous) TJ_OTP 125 VTM® Current Multiplier Rev 1.2 vicorpower.com Page 2 of 19 07/2015 800 927.9474 26 V 15.0 17 6.5 9 W 20 A 7 A V/V V A A W VDC 96.0 % 95.5 95.6 7.5 9.0 11.5 1.95 3.90 12.0 14.0 16.0 2.05 4.10 % % mΩ mΩ mΩ MHz MHz 150 285 mV 600 pH 47 µF 58.5 1000 µF 60.0 V 8 IOCP_SEC TOCP_SEC V/µs 25 37.5 300 95.0 93.0 94.5 94.5 80.0 4.9 6.3 8.8 1.85 3.70 UNIT 55 55 1 1/4 CSEC = 0 F, ISEC = 25 A, VPRI = 48 V, 20 MHz BW, Section 12 Frequency up to 30 MHz, Simulated J-lead model Effective Value at 12 VSEC VTM Standalone Operation. VPRI pre-applied, VC enable VPRI_OVLO+ MAX 39 µs 55 A A 5.3 ms 1 µs 130 135 ºC VTM48 E x120 y 025A0R 2.1 SECONDARY SOURCE ELECTRICAL CHARACTERISTICS Specifications apply over all line and load conditions when power is sourced from the secondary side, unless otherwise noted; Boldface specifications apply over the temperature range of -40°C < TJ < 125°C (T-Grade); All other specifications are at TJ = 25ºC unless otherwise noted. ATTRIBUTE Secondary voltage range VSEC slew rate VSEC UV turn off SYMBOL VSEC MIN TYP 6.5 0 dVSEC/dt VSEC_UV No Load power dissipation PNL_SEC Inrush current peak INR_SEC_P DC secondary current Primary voltage Primary current (average) Primary current (peak) Primary power (average) ISEC_DC VPRI IPRI_AVG IPRI_PK PPRI_AVG Efficiency (ambient) hAMB Efficiency (hot) Efficiency (over load range) Primary resistance (cold) Primary resistance (ambient) Primary resistance (hot) Primary voltage ripple hHOT h20% RPRI_COLD RPRI_AMB RPRI_HOT VPRI_PP Primary capacitance (external) CPRI_EXT PROTECTION Secondary OVLO Secondary Overvoltage lockout response time constant Primary overcurrent trip Primary Short circuit protection trip current Primary overcurrent response time constant Primary Short circuit protection response time CONDITIONS / NOTES No external VC applied VC applied Module latched shutdown, No external VC applied, IPRI = 6.3 A VSEC = 12 V VSEC = 6.5 V to 13.75 V VSEC = 12 V, TC = 25ºC VSEC = 6.5 V to 13.75 V, TC = 25ºC VC enable, VSEC = 12 V, CPRI = 63 µF, RLOAD = 7 Ω 6.0 3 5.3 40 MAX V/µs 6.5 V 15.0 17.0 6.5 9.0 W 80 A 28.0 A V A A W VPRI = VSEC/K - IPRI • RPRI, Section 11 TPEAK < 10 ms, IPRI_AVG ≤ 6.3 A IPRI_AVG ≤ 6.3 A VSEC = 12 V, IPRI = 6.3 A VSEC = 6.5 V to 13.75 V, IPRI = 6.3 A VSEC = 12 V, IPRI = 3.1 A VSEC = 12 V, TC = 100°C, IPRI = 6.3 A 1.3 A < IPRI < 6.3 A TC = -40°C, IPRI = 6.3 A TC = 25°C, IPRI = 6.3 A TC = 100°C, IPRI = 6.3 A CPRI = 0 F, IPRI = 6.3 A, VSEC = 12 V, 6.5 MHz BW VTM Standalone Operation. VSEC pre-applied, VC enable VSEC_OVLO+ Module latched shutdown TOVLO_SEC Effective internal RC filter 6.3 9.4 300 95 93 94.5 94.5 80.0 145 165 200 14.5 7 ISCP_PRI 7 Effective internal RC filter (Integrative). TSCP_PRI From detection to cessation of switching (Instantaneous) VTM® Current Multiplier Rev 1.2 vicorpower.com Page 3 of 19 07/2015 800 927.9474 95.5 95.6 14.8 9 VDC % 185 225 275 650 % % mΩ mΩ mΩ mV 63 µF 15.0 V 8 IOCP_PRI TOCP_PRI 96.0 165 195 238 UNIT 13.75 13.75 1 µs 14 A A 5.3 ms 1 µs VTM48 E x120 y 025A0R 3.0 SIGNAL CHARACTERISTICS Specifications apply over all line and load conditions when power is sourced from the primary side, unless otherwise noted; Boldface specifications apply over the temperature range of -40°C < TJ < 125°C (T-Grade); All other specifications are at TJ = 25ºC unless otherwise noted. VTM CONTROL : VC • Referenced to -PRI. • VC slew rate must be within range for a succesful start. • Used to wake up powertrain circuit. • PRM® VC can be used as valid wake-up signal source. • A minimum of 11.5 V must be applied indefinitely for VPRI < 26 V • Internal Resistance used in “Adaptive Loop” compensation. to ensure normal operation. • VC voltage may be continuously applied. SIGNAL TYPE STATE ATTRIBUTE External VC voltage VC current draw SYMBOL VVC_EXT IVC Steady ANALOG INPUT • • Required for start up, and operation below 26 V. See Section 7. VC = 11.5 V, VPRI = 0 V VC = 11.5 V, VPRI > 26 V VC = 16.5 V, VPRI > 26 V Fault mode. VC > 11.5 V MIN TYP 11.5 16.5 130 25 115 60 100 0.511 DVC_INT RVC-INT MAX UNIT TVC_COEFF 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 mA V kΩ 900 ppm/°C VVC_SP dVC/dt IINR_VC SYMBOL VPC IPC_OP RPC_INT IPC_EN CPC_INT RPC_S VPC_EN VPC_DIS IPC_PD TPC_DIS_T TFR_PC V 150 Tpeak <18 ms 20 Required for proper start up; 0.02 0.25 VC = 16.5 V, dVC/dt = 0.25 V/µs 1 VPRI pre-applied, PC floating, VC to VSEC turn-on delay TON 500 VC enable, CPC = 0 µF Transitional VC = 11.5 V to PC high, VPRI = 0 V, VC to PC delay Tvc_pc 75 125 dVC/dt = 0.25 V/µs VC = 0 V 3.2 Internal VC capacitance CVC_INT PRIMARY CONTROL : PC Referenced to -PRI. • Module will shutdown when pulled low with an impedance less than 400 Ω. The PC pin enables and disables the VTM. When held below 2 V, the VTM will be disabled. • In an array of VTMs, connect PC pin to synchronize start up. PC pin outputs 5 V during normal operation. PC pin is equal to 2.5 V • PC pin cannot sink current and will not disable other modules during fault mode given VPRI > 26 V or VC > 11.5 V. during fault mode. After successful start up and under no fault condition, PC can be used as a 5 V regulated voltage source with a 2 mA maximum current. Start Up • • VC internal diode rating VC internal resistor VC internal resistor temperature coefficient VC start up pulse VC slew rate VC inrush current CONDITIONS / NOTES CONDITIONS / NOTES Internal pull down resistor Rev 1.2 vicorpower.com Page 4 of 19 07/2015 800 927.9474 µs µF TYP MAX UNIT 4.7 5.0 50 50 150 100 5.3 2 400 300 1000 60 2 2.5 5.1 VTM® Current Multiplier µs MIN Section 7 From fault to PC = 2 V V V/µs A 5 100 3 2 V mA kΩ µA pF kΩ V V mA µs µs VTM48 E x120 y 025A0R TEMPERATURE MONITOR : TM • Referenced to -PRI. • The TM pin has a room temperature setpoint of 3 V • The TM pin monitors the internal temperature of the VTM controller IC and approximate gain of 10 mV/°C. within an accuracy of ±5°C. • Output drives Temperature Shutdown comparator. • Can be used as a "Power Good" flag to verify that the VTM 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 = 27°C MIN TYP MAX UNIT 2.95 3.00 3.05 100 V µA mV/°C 200 mV 50 50 V kΩ pF µs 10 CTM = 0 F, VPRI = 48 V, ISEC = 25 A 120 Internal pull down resistor 25 From fault to TM = 1.5 V 0 40 10 4.0 TIMING DIAGRAM (Power sourced from the primary side) 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® Current Multiplier Rev 1.2 vicorpower.com Page 5 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 5.0 APPLICATION CHARACTERISTICS The following values, typical of an application environment, are collected at TC = 25ºC with power sourced from the primary side unless otherwise noted. See associated figures for general trend data. ATTRIBUTE SYMBOL No load power dissipation Efficiency (ambient) Efficiency (hot) Secondary resistance (cold) Secondary resistance (ambient) Secondary resistance (hot) PNL hAMB hHOT RSEC_COLD RSEC_AMB RSEC_HOT Secondary voltage ripple VSEC_PP VOUT transient (positive) VSEC_TRAN+ VOUT transient (negative) VSEC_TRAN- CONDITIONS / NOTES TYP UNIT VPRI = 48 V, PC enabled VPRI = 48 V, ISEC = 25 A VPRI = 48 V, ISEC = 25 A, TC = 100ºC VPRI = 48 V, ISEC = 25 A, TC = -40ºC VPRI = 48 V, ISEC = 25 A VPRI = 48 V, ISEC = 25 A, TC = 100ºC CSEC = 0 F, ISEC = 25 A, VPRI = 48 V, 20 MHz BW, Section 12 ISEC_STEP = 0 A TO 25 A, VPRI = 48 V, ISLEW = 17 A /us ISEC_STEP = 25 A to 0 A, VPRI = 48 V ISLEW = 212 A /us 5.1 96.1 95.6 7.3 9.3 11.6 W % % mΩ mΩ mΩ 198 mV 650 mV 310 mV Full Load Efficiency vs. Case Temperature 100 Full Load Efficiency (%) 9 7 5 3 98 96 94 92 90 1 26 29 32 35 38 41 43 46 49 52 -40 55 -20 -40°C TCASE: 25°C 100°C V PRI: Efficiency & Power Dissipation -40°C Case 100 96 45 96 Efficiency (%) 35 84 30 80 25 76 20 PD 15 68 10 64 5 60 0.0 0 2.5 5.0 7.5 26 V 48 V 10.0 12.5 15.0 17.5 20.0 22.5 25.0 55 V 60 80 100 26 V 48 V 55 V 32 28 η 24 88 20 84 16 80 12 PD 76 8 4 72 68 0.0 0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 Secondary Load Current (A) Secondary Load Current (A) VPRI: 26 V 92 Efficiency (%) η 40 Power Dissipation (W) 50 72 40 Efficiency & Power Dissipation 25°C Case 100 88 20 Figure 2 — Full secondary load efficiency vs. temperature Figure 1 — No load power dissipation vs. VPRI 92 0 Case Temperature (°C) Primary Voltage (V) 48 V Figure 3 — Efficiency and power dissipation at –40°C 55 V VPRI: 26 V 48 V 55 V 26 V 48 V Figure 4 — Efficiency and power dissipation at 25°C VTM® Current Multiplier Rev 1.2 vicorpower.com Page 6 of 19 07/2015 800 927.9474 55 V Power Dissipation (W) No Load Power Dissipation (W) No Load Power Dissipation vs. Line 11 VTM48 E x120 y 025A0R Efficiency & Power Dissipation 100°C Case 100 24 88 20 84 16 80 12 PD 76 8 72 4 68 0.0 12 RSEC (mΩ) 28 η 92 14 Power Dissipation (W) 96 Efficiency (%) RSEC vs. TCASE at VPRI = 48 V 32 5.0 7.5 8 6 0 2.5 10 4 -40 10.0 12.5 15.0 17.5 20.0 22.5 25.0 -20 Secondary Load Current (A) 26 V VPRI: 48 V 55 V 20 40 60 80 100 Case Temperature (°C) 26 V 48 V 55 V Figure 5 — Efficiency and power dissipation at 100°C I SEC : 12.5 A 25 A Figure 6 — RSEC vs. temperature Secondary Voltage Ripple vs. Load Safe Operating Area 250 45 Secondary Current (A) 225 Ripple (mV pk-pk) 0 200 175 150 125 100 75 50 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 Secondary Load Current (A) VPRI: 26 V 48 V 40 35 10 ms Max 30 25 Continuous 20 15 10 5 0 0 2 4 6 8 10 Secondary Voltage (V) 55 V Figure 7 — VRIPPLE vs. ISEC ; No external CSEC. Board mounted module, scope setting : 20 MHz analog BW Figure 8 — Safe operating area Figure 9 — Full load ripple, 100 µF CPRI ; No external CSEC. Board mounted module, scope setting : 20 MHz analog BW Figure 10 — Start up from application of VPRI ; VC pre-applied CSEC = 1000 µF VTM® Current Multiplier Rev 1.2 vicorpower.com Page 7 of 19 07/2015 800 927.9474 12 14 16 VTM48 E x120 y 025A0R Figure 11 — Start up from application of VC; VPRI pre-applied CSEC = 1000 µF Figure 12 – 0 A– Full load transient response: CPRI = 100 µF, no external CSEC Figure 13 — Full load – 0 A transient response: CPRI = 100 µF, no external CSEC VTM® Current Multiplier Rev 1.2 vicorpower.com Page 8 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 6.0 GENERAL CHARACTERISTICS Specifications apply over all line and load conditions with power sourced from primary side unless otherwise noted; Boldface specifications apply over the temperature range of -40ºC < TJ < 125ºC (T-Grade); All Other specifications are at TJ = 25°C 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] 15.0 / [0.53] 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 µm -40 -55 -40 -55 125 125 125 125 °C °C °C °C THERMAL Operating temperature Thermal resistance VTM48EF120T025A0R (T-Grade) VTM48EF120M025A0R (M-Grade) VTM48ET120T025A0R (T-Grade) VTM48ET120M025A0R (M-Grade) Isothermal heat sink 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 217°C Peak heating rate during reflow Peak cooling rate post reflow MTBF Agency approvals / standards °C/W 5 Ws/°C 6 5.41 125 125 125 125 Supported by J-lead only ESD withstand SAFETY Isolation voltage (hipot) Isolation capacitance Isolation resistance 1 VTM48EF120T025A0R (T-Grade) VTM48EF120M025A0R (M-Grade) VTM48ET120T025A0R (T-Grade) VTM48ET120M025A0R ( M-Grade) Human Body Model, "JEDEC JESD 22-A114-F" Charge Device Model, "JEDEC JESD 22-C101-D" -40 -65 -40 -65 1000 VDC 400 MSL 4 (Datecode 1528 and later) VHIPOT CPRI_SEC RPRI_SEC 2250 2500 10 Unpowered unit lbs lbs / in2 °C °C °C °C 60 1.5 1.5 245 90 3 6 °C s °C/s °C/s 3200 3800 VDC pF MΩ MIL-HDBK-217 Plus Parts Count; 25ºC Ground Benign, Stationary, 6.03 Indoors / Computer Profile Telcordia Issue 2 - Method I Case 1; 7.94 Ground Benign, Controlled cTUVus cURus "CE Marked for Low Voltage Directive and RoHS Recast Directive, as applicable" VTM® Current Multiplier Rev 1.2 vicorpower.com Page 9 of 19 07/2015 800 927.9474 MHrs MHrs VTM48 E x120 y 025A0R 7.0 USING THE CONTROL SIGNALS VC, PC, TM, IM The VTM Control (VC) pin is an primary referenced 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 VTM current multiplier start up and must be applied as long as the primary 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 primary side will be powered by an upstream PRM® regulator which provides a 10 ms VC pulse during start up. In these applications the VC pins of the PRM regulator and VTM current multiplier should be tied together. • In bi-directional applications, the primary of the VTM may also be providing power to a PRM input. In these applications, a proper VC voltage within the specified range must be applied any time the primary voltage of the VTM is below 26 V. • The VC voltage can be applied indefinitely allowing for continuous operation down to 0 VPRI. • 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) is a primary referenced pin that can be used to accomplish the following functions: • Delayed start: Upon the application of VC, the PC pin will source a constant 100 µA 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. • Disable: PC pin can be actively pulled down in order to disable the module. Pull down impedance shall be lower than 400 Ω. • 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) is a primary referenced pin that 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 = 27ºC). 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. 8.0 START UP BEHAVIOR Depending on the sequencing of the VC voltage with respect to the same voltage, whether the source is on the primary or secondary, the behavior during start up will vary as follows: • Normal operation (VC applied prior to the source voltage): In this case, the controller is active prior to the source ramping. When the source voltage is applied, the VTM module load voltage will track the source (See Figure 10). The inrush current is determined by the source voltage rate of rise and load capacitance. If the VC voltage is removed prior to the primary voltage reaching 26 V, the VTM may shut down. • Stand-alone operation (VC applied after VPRI): In this case the VTM secondary 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 secondary voltage rate of rise in order to limit the inrush current to its maximum level. When starting into high capacitance, or a short, the secondary current will be limited for a maximum of 1200 µsec. 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 secondary capacitance is limited to 1000 µF in this mode of operation to ensure a successful start. 9.0 THERMAL CONSIDERATIONS VI Chip® products are multi-chip modules whose temperature distribution varies greatly for each part number as well as with the line/load conditions, thermal management and environmental conditions. Maintaining the top of the VTM48EF120T025A0R case to less than 100ºC will keep all junctions within the VI Chip module below 125ºC 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 module for an extended period of time at full load without proper heat sinking. VTM® Current Multiplier Rev 1.2 vicorpower.com Page 10 of 19 07/2015 800 927.9474 R VC_INT PC PC Pull-Up & Source -VPRI VC +VPRI VTM® Current Multiplier Rev 1.2 vicorpower.com Page 11 of 19 07/2015 800 927.9474 1000 pF 2.5 V V DD D VC_INT CPRI 100 A 18 V V DD Regulator Supply 150 K 1.5 K 10.5 V 5V 2 mA 2.5 V Enable Enable Gate Drive Supply OVLO UVLO V IN Adaptive Soft Start V DD Fault Logic Enable Modulator Enable Slow Current Limit Cr V REF Fast Current Limit Q4 Lr Primary Stage & Resonant Tank Over Current Protection Differential Primary Current Sensing Q2 Overtemperature Protection Primary Gate Drive Q1 Q3 Temperature Dependent Voltage Source V REF Secondary Gate Drive Q6 40 K Power Transformer 1K Q5 0.01 F Synchronous Rectification +VSEC TM -VSEC CSEC VTM48 E x120 y 025A0R 10.0 VTM MODULE BLOCK DIAGRAM VTM48 E x120 y 025A0R 11.0 SINE AMPLITUDE CONVERTERTM POINT OF LOAD CONVERSION The Sine Amplitude Converter (SAC) uses a high frequency resonant tank to move energy from primary to secondary or vice-versa, depending on where the source is located. The resonant tank is formed by Cr and leakage inductance Lr in the power transformer windings as shown in the VTM module Block Diagram (See Section 10). The resonant LC tank, operated at high frequency, is amplitude modulated as a function of primary voltage and secondary current. A small amount of capacitance embedded in the primary and secondary stages of the module is sufficient for full functionality and is key to achieving power density. The VTM48EF120T025A0R SAC can be simplified into the following model: 973 pH ISEC IOUT LPRI = 5.7 nH LSEC = 600 pH 9.0 mΩ + V VPRI SEC RROUT R RCPRI CIN 0.57 mΩ CIN C PRI IN V•I 1/4 • ISEC 2 µF IIQQ 109 mA RRCSEC COUT 3.13 Ω + + – – + 430 µΩ 1/4 • VPRI CSEC COUT 47 µF SEC VVOUT K – – Figure 14 — VI Chip® module AC model At no load: VSEC = VPRI • K (1) The use of DC voltage transformation provides additional interesting attributes. Assuming that RSEC = 0 Ω and IQ = 0 A, Eq. (3) now becomes Eq. (1) and is essentially load independent, resistor R is now placed in series with VPRI as shown in Figure 15. K represents the “turns ratio” of the SAC. Rearranging Eq (1): K= VSEC VPRI (2) R R VVin PRI + – SAC™ SAC 1/32 KK == 1/32 V Vout SEC In the presence of load, VSEC is represented by: VSEC = VPRI • K – ISEC • RSEC (3) Figure 15 — K = 1/32 Sine Amplitude Converter™ with series primary resistor and ISEC is represented by: ISEC = IPRI – IQ K (4) RSEC represents the impedance of the SAC, and is a function of the RDSON of the primary and secondary MOSFETs and the winding resistance of the power transformer. IQ represents the quiescent current of the SAC control and gate drive circuitry. For applications where the source is located on the secondary side, equations 1 to 4 can be re-arranged to represent VPRI and IPRI as a function of VSEC and ISEC. The relationship between VPRI and VSEC becomes: VSEC = (VPRI – IPRI • R) • K (5) Substituting the simplified version of Eq. (4) (IQ is assumed = 0 A) into Eq. (5) yields: VSEC = VPRI • K – ISEC • R • K2 VTM® Current Multiplier Rev 1.2 vicorpower.com Page 12 of 19 07/2015 800 927.9474 (6) VTM48 E x120 y 025A0R This is similar in form to Eq. (3), where RSEC is used to represent the characteristic impedance of the SAC™. However, in this case a real R on the primary side of the SAC is effectively scaled by K2 with respect to the secondary. Assuming that R = 1 Ω, the effective R as seen from the secondary side is 0.98 mΩ, with K = 1/32 as shown in Figure 15. A similar exercise should be performed with the additon of a capacitor or shunt impedance at the primary to the SAC. A switch in series with VIN is added to the circuit. This is depicted in Figure 16. SS VVin PRI + – C C SAC™ SAC K = 1/32 K = 1/32 VVout SEC Figure 16 — Sine Amplitude Converter™ with primary capacitor A change in VPRI with the switch closed would result in a change in capacitor current according to the following equation: IC(t) = C dVPRI dt (7) Assume that with the capacitor charged to VPRI, the switch is opened and the capacitor is discharged through the idealized SAC. In this case, IC = ISEC • K (8) 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 VTM 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 (RSEC): refers to the power loss across the VTM modeled as pure resistive impedance. PDISSIPATED = PNL + PRSEC Therefore, PSEC = PPRI – PDISSIPATED = PPRI – PNL – PRSEC C K2 • h = = dVSEC dt (9) The equation in terms of the secondary 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 secondary when expressed in terms of the primary. With a K= 1/32 as shown in Figure 16, C=1 µF would appear as C=1024 µF when viewed from the secondary. Note that in situations where the souce voltage is located on the secondary side, the effect is reversed and effective valve of capacitance located on the secondary side is divided by a factor of 1/K2 when reflected to the primary. (11) The above relations can be combined to estimate the overall module efficiency: Substituting Eq. (1) and (8) into Eq. (7) reveals: ISEC = (10) PSEC = PPRI – PNL – PRSEC PPRI PPRI VPRI • IPRI – PNL – (ISEC)2 • RSEC VPRI • IPRI = 1– ( ) PNL + (ISEC)2 • RSEC VPRI • IPRI VTM® Current Multiplier Rev 1.2 vicorpower.com Page 13 of 19 07/2015 800 927.9474 (12) VTM48 E x120 y 025A0R 12.0 PRIMARY AND SECONDARY FILTER DESIGN A major advantage of a SAC 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 primary voltage and secondary current and efficiently transfers charge through the isolation transformer. A small amount of capacitance embedded in the primary and secondary 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 VTM module dynamic response, the impedance presented to its primary terminals must be low from DC to approximately 5 MHz. Primary capacitance may be added to improve transient performance or compensate for high source impedance. 2.Further reduce primary and /or secondary 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 secondary 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® module primary/secondary voltage ranges must not be exceeded. An internal overvoltage lockout function prevents operation outside of the normal operating primary or secondary 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 CONVERTER™ It is important to consider the impact of adding 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 RSEC value which has already been discussed in Section 11. The AC RSEC of the SAC contains several terms: • Resonant tank impedance • Primary lead inductance and internal capacitance • Secondary 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 RSEC 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 secondary of the VTM module reflect back to the primary of the module by the square of the K factor (Eq. 9) with the impedance of the module appearing in series. It is very important to keep this in mind when using a PRM® regulator to power the VTM module primary. Most PRM modules have a limit on the maximum amount of capacitance that can be applied to the secondary. This capacitance includes both the PRM output capacitance and the VTM module secondary capacitance reflected back to the primary. In PRM module remote sense applications, it is important to consider the reflected value of VTM module secondary capacitance when designing and compensating the PRM module control loop. Capacitance placed at the primary 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 primary of the module will have a lower effective impedance compared to an electrolytic capacitor placed at the secondary. This is important to consider when placing capacitors at the secondary of the module. Even though the capacitor may be placed at the secondary, 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 secondary capacitors are not necessary to design a stable, well-bypassed system. VTM® Current Multiplier Rev 1.2 vicorpower.com Page 14 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 14.0 CURRENT SHARING The SAC 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 transformer 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 filtering to each unit. • Current rating (usually greater than maximum current of VTM module) • Maximum voltage rating (usually greater than the maximum possible primary or secondary voltage) • Ambient temperature • Nominal melting I2t 16.0 BI-DIRECTIONAL OPERATION The VTM48EF120T025A0R is capable of bi-directional operation. If a voltage is present at the secondary which satisfies the condition VSEC > VPRI • K at the time the VC voltage is applied, or after the unit has started, then energy will be transferred from secondary to primary. The primary to secondary ratio will be maintained. The VTM48EF120T025A0R will continue to operate bi-directional as long as the primary and secondary are within the specified limits. For further details see AN:016 Using BCM® Bus Converters in High Power Arrays. VPRI ZPRI_EQ1 VTM®1 ZSEC_EQ1 VSEC RS_1 ZPRI_EQ2 VTM®2 ZSEC_EQ2 RS_2 + – DC Load ZPRI_EQn VTM®n ZSEC_EQn RS_n Figure 17 — VTM module array 15.0 FUSE SELECTION In order to provide flexibility in configuring power systems VI Chip® products are not internally fused. Line fusing of VI Chip 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: • Direction of power flow: if a power source is located on the primary, there must be a fuse located in the series with the primary source; if a source is located on the secondary, there must also be a fuse located in series with the secondary source. VTM® Current Multiplier Rev 1.2 vicorpower.com Page 15 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 17.1 J-LEAD PACKAGE MECHANICAL DRAWING mm (inch) NOTES: mm 2. DIMENSIONS ARE inch . UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: 3. .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 4. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com 17.2 J-LEAD PACKAGE RECOMMENDED LAND PATTERN +PRI +SEC1 -SEC1 +SEC2 -PRI -SEC2 3. .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] mm 2. DIMENSIONS ARE inch . UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: 4. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com VTM® Current Multiplier Rev 1.2 vicorpower.com Page 16 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 17.3 THROUGH-HOLE PACKAGE MECHANICAL DRAWING mm (inch) NOTES: mm 2. DIMENSIONS ARE inch . UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: 3. .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 4. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com 17.4 THROUGH-HOLE PACKAGE RECOMMENDED LAND PATTERN +PRI +SEC1 -SEC1 +SEC2 -PRI -SEC2 3. .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] mm 2. DIMENSIONS ARE inch . UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: 4. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com VTM® Current Multiplier Rev 1.2 vicorpower.com Page 17 of 19 07/2015 800 927.9474 VTM48 E x120 y 025A0R 17.5 RECOMMENDED HEAT SINK PUSH PIN LOCATION (NO GROUNDING CLIPS) (WITH GROUNDING CLIPS) Notes: 1. Maintain 3.50 (0.138) Dia. keep-out zone free of copper, all PCB layers. 2. (A) Minimum recommended pitch is 39.50 (1.555). This provides 7.00 (0.275) component edge-to-edge spacing, and 0.50 (0.020) clearance between Vicor heat sinks. (B) Minimum recommended pitch is 41.00 (1.614). This provides 8.50 (0.334) component edge-to-edge spacing, and 2.00 (0.079) clearance between Vicor heat sinks. 3. VI Chip® module land pattern shown for reference only; actual land pattern may differ. Dimensions from edges of land pattern to push–pin holes will be the same for all full-size VI Chip® products. 5. Unless otherwise specified: Dimensions are mm (inches) tolerances are: x.x (x.xx) = ±0.3 (0.01) x.xx (x.xxx) = ±0.13 (0.005) 4. RoHS compliant per CST–0001 latest revision. 6. Plated through holes for grounding clips (33855) shown for reference, heat sink orientation and device pitch will dictate final grounding solution. 17.6 VTM MODULE PIN CONFIGURATION 4 3 2 +SEC 1 A A B B C C D D +PRI E E F -SEC G H TM H J J VC K PC K +SEC -SEC L L M M N N P P R R -PRI T T Signal Name +PRI –PRI TM VC PC +SEC –SEC Bottom View VTM® Current Multiplier Rev 1.2 vicorpower.com Page 18 of 19 07/2015 800 927.9474 Pin Designation A1-E1, A2-E2 L1-T1, L2-T2 H1, H2 J1, J2 K1, K2 A3-D3, A4-D4, J3-M3, J4-M4 E3-H3, E4-H4, N3-T3, N4-T4 VTM48 E x120 y 025A0R 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. 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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: [email protected] Technical Support: [email protected] VTM® Current Multiplier Rev 1.2 vicorpower.com Page 19 of 19 07/2015 800 927.9474