rev. description features The VHK50W series of rugged DC-DC converters are designed for high reliability applications, featuring integral heat sink, over-temperature protection, over-current protection and input transient voltage protection. With an external input fuse, the converter can protect accidental input polarity reversal. The wide 4:1 input range (9-36V or 1875V) is very useful to stabilize an input source like batteries in various discharging and charging conditions. Additionally, high efficiency, fast response, tight regulations, remote sense and remote On/Off control make these converters very useful in many industrial and communications applications. ·25-50W isolated output ·Efficiency to 84% ·RoHS Compliant ·4:1 input range ·Regulated output ·Continuous short circuit protection ·Metal enclosure with integrated heatsink ·Rugged design ·Over-temperature shutdown input voltage nominal range (V dc) (V dc) VHK50W-Q24-S3R3 VHK50W-Q24-S5 VHK50W-Q24-S12 VHK50W-Q24-S15 VHK50W-Q24-S24 VHK50W-Q48-S3R3 VHK50W-Q48-S5 VHK50W-Q48-S12 VHK50W-Q48-S15 VHK50W-Q48-S24 notes: 1 of 9 date date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W MODEL page page 24 24 24 24 24 48 48 48 48 48 9.0~36.0 9.0~36.0 9.0~36.0 9.0~36.0 9.0~36.0 18.0~75.0 18.0~75.0 18.0~75.0 18.0~75.0 18.0~75.0 output voltage (V dc) 3.3 5 12 15 24 3.3 5 12 15 24 output current 1 (A) 10 10 4.16 3.33 2.08 10 10 4.16 3.33 2.08 input current no load full load (mA) (mA) 50 50 50 50 50 50 50 50 50 50 1785 2570 2510 2510 2510 880 1270 1240 1240 1240 efficiency typ. (%) 77 81 83 83 83 78 82 84 84 84 1. see output derating curve (page 4) INPUT parameter input voltage range conditions/description under voltage lockout 24 Vin power up 24 Vin power down 48 Vin power up 48 Vin power down section 15 in the application notes PI type remote on/off control 2 input filter notes: min 9 18 nom 24 48 8.8 8 17 16 max 36 75 units V dc V dc V dc V dc V dc V dc 2. add suffix “N” to the model number for negative logic on/off control *V-Infinity reserves the right to make changes to its products or to discontinue any product or service without notice, and to advise customers to verify the most up-todate product information before placing orders. V-Infinity assumes no liability or responsibility for customer’s applications using V-Infinity products other than repair or replacing (at V-I’s option) V-Infinity products not meeting V-I’s published specifications. Nothing will be covered outside of standard product warranty. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 2 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W OUTPUT parameter voltage accuracy transient response external trim adj. range ripple & noise (20MHz BW) conditions/description min nom 25% step load change 3.3V, 5V 12V& 15V 24V temperature coefficient short circuit protection continuous line regulation 3 load regulation 4 over voltage protection trip range, % Vo nom. over current protection nominal output max ±1 500 ±10 40 100 60 150 100 240 units % μ sec % mV RMS mV pk-pk mV RMS mV pk-pk mV RMS mV pk-pk %/°C ±0.2 ±0.2 140 160 % % % % max units KHz °C °C °C ±0.03 115 110 GENERAL SPECIFICATIONS parameter switching frequency operating ambient temp. 5 storage temperature thermal shutdown case temp. case material conditions/description min nom 300 -40 -55 85 105 85 aluminum / steel ISOLATION SPECIFICATIONS parameter isolation voltage conditions/description input/output input/case output/case isolation resistance notes: 3. 4. 5. min 1500 1500 1500 100 nom max units V dc V dc V dc MΩ measured from high line to low line at full load measured from full load to zero load at nominal input see output derating curve (page 4) *V-Infinity reserves the right to make changes to its products or to discontinue any product or service without notice, and to advise customers to verify the most up-todate product information before placing orders. V-Infinity assumes no liability or responsibility for customer’s applications using V-Infinity products other than repair or replacing (at V-I’s option) V-Infinity products not meeting V-I’s published specifications. Nothing will be covered outside of standard product warranty. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 REV. A DESCRIPTION NEW DRAWING DATE 4/22/2008 108.0 4.252 86.3 3.398 38.00 1.496 16.0 0.630 (TYP) 101.76 4.006 91.0 3.583 (2 PLCS) 6 9.7 0.382 (TYP) 7 8 9 19.0 0.748 70.0 2.756 RoHS TOLERANCE: ±0.3mm UNLESS OTHERWISE SPECIFIED 1 26.18 1.031 2 3 4 5 9.7 0.380 (TYP) PC FILE NAME: VHKXXW Series COPYRIGHT 2008 BY CUI INC. Material Aluminum/Steel Terminal # Description 1 2 3 4 5 6 7 8 9 - V out -S Trim +S + V out Case Remote - V in + V in 20050 SW 112th Ave. Tualatin, OR 97062 Phone: 503-612-2300 800-275-4899 Fax: 503-612-2383 Website: www.cui.com TITLE: REV: VHK PART NO. VHKXXW Series DRAWN BY: ZRJ A UNITS: MM [INCHES] APPROVED BY: SCALE: 1:2 page 4 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W APPLICATION NOTES 1. OUTPUT DE-RATING The operating ambient temperature range for VHK50W is -40 ~ +85°C, with the actual output power subject to the following de-rating curves at free-air convection and at forced air conditions. To ensure long-term reliability, it is important to ensure proper cooling at the worst operating conditions. VHK50W Power Derating Curves 115% Natural Convection 100% Relative Output Power - % of nominal output 0.5 m/S (100LFM) 1.0 m/S (200LFM) 80% 1.5 m/S (300LFM) 60% 2.0 m/S (400LFM) 40% 2.5 m/S (500LFM) 3.0 m/S (600LFM) 20% 3.5 m/S (700LFM) 0% -40 55 60 65 70 Ambient Temperature - degrees C 75 80 85 FIGURE 1. OUTPUT DERATING 2. INPUT VOLTAGE RANGE It is important to ensure the input voltage measured at the converter input pins is within the range for that converter. Make sure wire losses and voltage ripples are accounted for. One possible problem is driving the converter with a linear unregulated power supply. For example, if the average voltage measured by a DMM is 9V, with a voltage ripple of 3Vpp, the actual input can swing from 7.5V to 10.5V. This will be outside the specified input range of 9-36V and the converter may not function properly. On the other end, make sure the actual input voltage does not exceed the highest voltage of 36V or75V. 3. LEAD WIRES Make sure the input and output wires are of adequate AWG size to minimize voltage drop, and ensure the voltage across the input terminals is above the converter's rated minimum voltage at all times. It is recommended to have the wire pairs twisted, respectively for the input pair and the output pair, so as to minimize noise pickup. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 5 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W 4. INPUT CURRENT The input voltage source must be able to provide enough current to the converter, otherwise it may not start up or operate properly. A typical symptom is not starting or unusually low output voltage. In general, it is recommended to be able to provide at least: η *Vmin) where Pout is the maximum output power, Vmin is the minimum input voltage and η is the converter's Ipeak = 150%*Pout/(η efficiency. As an example, for VHK50W-Q24-S5 to operate with 9~36V input, 50W output and an efficiency of 81%, the minimum source current is recommended to be: Ipeak = 150% * 50 / (81% * 9) = 10.29A. 5. INPUT FUSE To limit the input current and to facilitate input reversal protection and input OVP protection, a fast-acting input fuse is recommended for the input line. The fuse rating will depend on the input range and should allow for the maximum current at the lowest input voltη *Vmin). age, as shown in this equation: Ipeak = 150%*Pout/(η In the previous example of VHK50W-Q24-S5, the peak input current at 9V was calculated to be 10.29A. A 10A or a 15A fuse may be suitable for this application. Make sure the fuse voltage rating is higher than the maximum input voltage. 6. INPUT OVP It is important to ensure the input voltage does not exceed the maximum rated input voltage for that model. To suppress voltage transients of short durations, the converter includes a transient voltage suppression device (TVS) at the input. The built-in TVS has a rated breakdown voltage of 39V for the VHK50W-Q24-XX models and 82V for the VHK50W-Q48 models. With small transients of short-durations, the TVS will limit the input voltage without interrupting the converters operations. For large transients, the TVS may conduct a large amount of current that may trip the input fuse. Without the input fuse, the converter may suffer permanent damages. When the fuse is open, replace it with one of same type and ratings. 7. INPUT REVERSAL PROTECTION If the input voltage is reversed for any reason, the built-in protection circuits in the converter will limit the reverse voltage to one diode drop which is no more than 1V. With an external input fuse connected, the fuse will open and thus remove power from the converter. Check the wiring and make corrections as needed. The input fuse will need to be replaced. Make sure the new fuse is of the same type and rating. Without the input fuse, the converter may suffer permanent damages. 8. REMOTE SENSE The converter provides regulated outputs at the output terminals. When there is a large current and/or the output cable is of some length, the voltage at the end of the output cable may be noticeably lower than at the terminals. The converter can compensate up to 0.5V of voltage drop through remote sense terminals. To ensure accurate regulation, run two separate wires (twisted) from the desired regulation points to the remote sense terminals, as shown below. +Vo +S (+) Load Trim (-) -S -Vo FIGURE 2. REMOTE SENSE 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 6 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W 9. OUTPUT TRIMMING (OPTIONAL) The output voltages are preset to nominal values as indicated by the models table at the factory. If desired, the output voltage may optionally be trimmed to a different value (+/- 10%) with external resistors and/or potentiometer as shown below. +Vo +Vin +S FIGURE 3. TRIMMING WITH 10KΩ Trimpot Trim EXTERNAL POTENTIOMETER R load -S -Vin -Vo To trim the output voltage with fixed resistors, the output voltage can be calculated as follows. Trim-Up +Vin Trim-Down +Vo +Vin +S +Vo +S R trim-down Trim Trim R load R load R trim-up -S -Vin -S -Vin -Vo -Vo FIGURE 4: TRIM-UP VOLTAGE SETUP FIGURE 5: TRIM-DOWN VOLTAGE SETUP The value of R trim-up is defined as: The value of R trim-down is defined as: Where: R trim-up is the external resistor in K Ω . V o,nom is the Where: R trim-down is the external resistor in K Ω . V o,nom is the nominal output voltage. V o is the desired output voltage. R 1 , nominal output voltage. V o is the desired output voltage. R 1 , R 2 , R 3 , V r , and V f are internal to the unit and are defined in R 2 , and V r are internal to the unit and are defined in Table 1. For example, to trim-up the output voltage of 5.0V Table 1. For example, to trim-up the output voltage of 5.0V module (VHK50W-Q48-S5) by 8% to 5.4V, R trim-up is calculated module (VHK50W-Q48-S5) by 8% to 4.6V, R trim-down is calculated as follows: as follows: Ω Ω Ω Table 1 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 7 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W 10. OUTPUT OCP AND SHORT-CIRCUIT PROTECTION Output overload and short circuit conditional will cause the output voltage to decline or shutdown altogether. If the case temperature is not over 85°C, the output recovers automatically when the short or OCP conditions are removed. In the case of slight overloading, the output voltage may not shut down, but the converter may build up heat over time, causing over-temperature shutdown. 11. OVER-TEMPERATURE PROTECTION When the case temperature reaches about 85°C, the converter's built-in protection circuit will shut down the output. When the temperature is reduced enough to a safe operating level, the converter will recover to normal operations automatically. 12. OUTPUT OVP In case the output voltage exceeds the OVP threshold, the converter shuts down. 13. OUTPUT PARALLEL CONNECTIONS The converter is not designed for load share on the output. However, for redundancy, the outputs of two or more converters can be connected in parallel through O-Ring diodes, as shown below. +Vin -Vin FIGURE 6. OUTPUT +Vo -Vo PARALLEL CONNECTIONS +Vin -Vin +Vo -Vo 14. OUTPUT SERIES CONNECTIONS Two or more converters can be connected in series to obtain a higher output voltage. To prevent output reverse biasing each other in case of a short, add a Schottky diode on each output in reverse polarity, as shown in the diagram. In the event of a short, the converters will forward-bias the diodes and the output reversal will be limited to one diode drop (about 0.5V) only, so as not to damage the converters. The forward current will cause each converter to go into short-circuit protection. For proper diode selection, make sure that: 1) the diodes voltage rating is higher than each converter output; 2) the rated diode current can carry the short-circuit current; 3) the diodes do not overheat before the short is removed. +Vin -Vin FIGURE 7. OUTPUT +Vo -Vo SERIES CONNECTIONS +Vin -Vin +Vo -Vo 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 8 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W 15. REMOTE OUTPUT ON/OFF CONTROL The converter output can be enabled or disabled through the On/Off pin. The control logic is shown in this table. A common control circuit is shown below. REM +Vo REM (pin 2) SW SW High signal here disable output -Vin -Vin (pin 4) -Vo FIGURE 8. REMOTE ON/OFF CONTROL FIGURE 9. REMOTE ON/OFF CONTROL WITH TRANSISTOR SWITCH Logic Table Negative logic SW Closed (V REM <0.8 V) Output on SW Open (V REM >2.4 V) Output off Positive logic Output off Output on 16. ISOLATION The input and output of the converter are electrically isolated. If needed, an output terminal can be connected to an input terminal, resulting in the converter non-isolated. 17. INPUT FILTERING AND EMI INTERFERENCE The VHK50W converters have input capacitors that control input current ripple and the associated EMI interference. However, it has not been tested to a formal standard for conducted emissions. Additional filtering may be needed to ensure compliance to an EMI standard. Refer to FIGURE 10 for a reference circuit. L1 C1 L2 C2 +Vin +Vo -Vin CASE -Vo C3 FIGURE 10. EMI FILTER FOR VHK50W C4 VHK50W Series EMI to meet class A EMI to meet class B C1 NC C2 47µF/50V ESR<0.60 C3 47µF/50V ESR<0.60 C4 2200pF/2KV L1 Short L2 2.5µH NC 220µF/50V ESR<0.120 220µF/50V ESR<0.120 2200pF/2KV Short 1.5µH NOTE: The recommended components are a starting point but not guaranteed for meeting these EMI requirements. More or less filtering may be required for a specific application or to meet other EMI standards, e.g. MIL-STD-461. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 9 of 9 date 04/2008 DESCRIPTION: chassis mount dc-dc converter PART NUMBER: VHK50W 18. OUTPUT FILTERING The converter has built-in capacitors at the output to control ripple and noise. If desired, additional output capacitance can be introduced at the input to the powered equipment. Recommended starting point: one 10μF tantalum and one 1μF ceramic capacitor in parallel at the output. 19. OUTPUT NOISE MEASUREMENT SCHEMATIC For proper output ripple and noise measurement, connect a 10μF tantalum and a 1μF ceramic capacitor across the output. Set the scope bandwidth to 20MHz. Probe directly off of one of the capacitors, using a small ground clip to minimize measurement error. +Vin +Vo Ceramic 1.0µF +S Trim + Resistor Load -S -Vin -Vo Solid Tantalum 10µF To Scope FIGURE 11. OUTPUT NOISE MEASUREMENT CIRCUIT 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382