rev. page date page date description: chassis mount dc-dc converter 1 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w features 50-75w 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 description the vhk75w 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 18- 75v) 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. model input voltage output output input current efficiency nominal range voltage current 1 no load full load typ. (v dc) (v dc) (v dc) (a) (ma) (ma) (%) vhk75w-q24-s3r3 24 9.0~36.0 3.3 15 50 2679 77 vhk75w-q24-s5 24 9.0~36.0 5 15 50 3906 80 vhk75w-q24-s12 24 9.0~36.0 12 6.25 50 3834 81.5 vhk75w-q24-s15 24 9.0~36.0 15 5 50 3788 82.5 vhk75w-q24-s24 24 9.0~36.0 24 3.12 50 3900 83 VHK75W-Q24-S48 24 9.0~36.0 48 1.56 50 3811 82 vhk75w-q48-s3r3 48 18.0~75.0 3.3 15 50 1322 78 vhk75w-q48-s5 48 18.0~75.0 5 15 50 1929 81 vhk75w-q48-s12 48 18.0~75.0 12 6.25 50 1894 82.5 vhk75w-q48-s15 48 18.0~75.0 15 5 50 1871 83.5 vhk75w-q48-s24 48 18.0~75.0 24 3.12 50 1857 84 vhk75w-q48-s48 48 18.0~75.0 48 1.56 50 1860 84 notes: 1. see output derating curves (page 4) 2. input currents are measured at nominal input voltage 3. efficiency is measured at nominal line, full load *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-to- date product information before placing orders. v-infinity assumes no liability or responsibility for customer?s applications u sing 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. input parameter conditions/description min nom max units input voltage range 9 24 36 v dc 18 48 75 v dc under voltage lockout 24 vin power up 8.8 v dc 24 vin power down 8 v dc 48 vin power up 17 v dc 48 vin power down 16 v dc remote on/off control 4 section 15 in the application notes input filter pi type notes: 4. add suffix ?n? to the model number for negative logic on/off control
page date description: chassis mount dc-dc converter 2 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w output parameter conditions/description min nom max units voltage accuracy 1 % transient response 25% step load change 500 sec external trim adj. range 10 % ripple & noise (20mhz bw) 3.3v, 5v 40 mv rms 100 mv p-p 12v& 15v 60 mv rms 150 mv p-p 24v 100 mv rms 240 mv p-p 48v 200 mv rms 480 mv p-p temperature coefficient 0.03 %/c short circuit protection continuous line regulation 5 0.2 % load regulation 6 1 % over voltage protection trip range, % vo nom. 115 140 % over current protection % nominal output current 110 160 % general specifications parameter conditions/description min nom max units switching frequency 300 khz operating ambient temp. 7 derated from 50 to 85c -40 85 c storage temperature -55 105 c thermal shutdown case temp. 85 c case material aluminum / steel isolation specifications parameter conditions/description min nom max units isolation voltage input/output 1500 v dc input/case 1500 v dc output/case 1500 v dc isolation resistance 100 m notes: 5. measured from high line to low line at full load 6. measured from full load to zero load at nominal input 7. see output derating curves (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-to- date product information before placing orders. v-infinity assumes no liability or responsibility for customer?s applications u sing 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.
b b b b rev. description date a new drawing 4/22/2008 b dimension updates 8/27/2008 *din rail mounting kit available (part# vhk-din) + v out case remote trim - s - v out 0.3mm unless otherwise + s - v in + v in terminal # 9 8 7 6 5 4 3 2 1 material tolerance: specified b description website: www.cui.com rohs 20050 sw 112th ave. tualatin, or 97062 phone: 503-612-2300 800-275-4899 fax: 503-612-2383 aluminum/steel vhkxxw series vhk copyright 2008 by cui inc. title: mm [inches] scale: vhkxxw series pc file name: approved by: drawn by: units: part no. zrj 1:2 rev: 107.5 4.232 86.3 3.398 (typ) 0.614 101.76 4.006 15.6 38.0 1.496 45 69 87 12 3 b 26.50 18.75 0.382 (typ) 1.043 (2 plcs) (2 plcs) 0.738 2.756 3.583 91.0 70.0 9.70 9.5 0.374 (typ)
page date description: chassis mount dc-dc converter 4 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w application notes 1. output de-rating the operating ambient temperature range for vhk75w is -40 ~ +85c, with the actual output power subject to the following de-rat ing 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. please note the derating curves may improve if the converter is mounted on a metal surface to a llow heat conduction. 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 su pply. for example, if the average voltage measured by a dmm is 9v, with a voltage ripple of 3vpp, the actual input can swing from 7.5 v 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, respe ctively for the input pair and the output pair, so as to minimize noise pickup. vhk75w power derating curves @ nominal input 0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00% -40 3540455055606570758085 ambient temperature - degrees c relative output power - % of nominal output natural convection 0.5 m/s (100lfm) 1.0 m/s (200lfm) 1.5 m/s (300lfm) 2.0 m/s (400lfm) 2.5 m/s (500lfm) 3.0 m/s (600lfm) 3.5 m/s (700lfm)
page date description: chassis mount dc-dc converter 5 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 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 prop erly. a typical symptom is not starting or unusually low output voltage. in general, it is recommended to be able to provide at least: ipeak = 150%*pout/( *vmin) where pout is the maximum output power, vmin is the minimum input voltage and is the converter's efficiency. as an example, for vhk75w-q24-s5 to operate with 9~36v input, 75w output and an efficiency of 82%, the minimum source current is recommended to be: ipeak = 150% * 75 / (82% * 9) = 15.24a . 5. input fuse to limit the input current and to facilitate input reversal protection and input ovp protection, a fast-acting input fuse is rec ommended for the input line. the fuse rating will depend on the input range and should allow for the maximum current at the lowest inpu t voltage, as shown in this equation: ipeak = 150%*pout/( *vmin) . in the previous example of vhk75w-q24-s5, the peak input current at 9v was calculated to be 15.24a. 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 voltag e 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 vhk75w-q24-xx models and 82v for the vhk75w-q48 models. with small transients of short-durations, the tvs will limit the input voltage without interrupting the converters operations. for large transients, th e tvs may conduct a large amount of current that may trip the input fuse. without the input fuse, the converter may suffer permanent dam ages. 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 volta ge 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 conver ter. check the wiring and make corrections as needed. the input fuse will need to be replaced. make sure the new fuse is of the sa me type and rating. without the input fuse, the converter may suffer permanent damages in a reversal situation. 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 s ome 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. even if the load current is low, still connect +vo to +s and -vo to -s. +vo +s trim -s -vo (-) (+) load figure 2. remote sense
page date description: chassis mount dc-dc converter 6 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 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 volta ge may optionally be trimmed to a different value (+/- 10%) with external resistors and/or potentiometer as shown below. to trim the output voltage with fixed resistors, the output voltage can be calculated as follows. trim-up trim-down 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 . v o,nom is the where: r trim-down is the external resistor in k . v o,nom is the nominal output voltage. v o is the desired output voltage. nominal output voltage. v o is the desired output voltage. r 1 and r 2 are internal to the unit and are defined in table 1. r 1 and r 2 are internal to the unit and are defined in table 2. for example, to trim-up the output voltage of 5.0v module for example, to trim-down the output voltage of 5.0v module (vhk75w-q48-s5) by 8% to 5.4v, r trim-up is calculated (vhk75w-q48-s5) by 8% to 4.6v, r trim-down is calculated as follows: as follows: r load 10k trimpot +vin -vin -vo -s trim +s +vo r load r trim-up +vin -vin +vo +s trim -s -vo r load r trim-down +vin -vin +vo +s trim -s -vo figure 3. trimming with external potentiometer r2 = 8.2 k r1 = 5.8 k o o, nom = 5.4 - 5.0 = 0.4 v v - v = = 6.3 (k ) r 0.4 trim-up 5.8 - 8.2 x 0.4 v - v = = 3.98 (k ) r 0.4 trim-down 5.8 - 10.52 x 0.4 r2 = 10.52 k r1 = 5.8 k o o, nom = 5.0 - 4.6 = 0.4 v = (k ) r o o, nom v - v o o, nom trim-up r1 - r2 x (v - v ) = (k ) r o o, nom v - v o o, nom trim-down r1 - r2 x (v - v ) 13.0476 74.514 48v 16.67 14.76 13.304 8.2 7.2 42.33 25.474 19.656 5.8 3.168 24v 15v 12v 5v 3.3v table 1 295.527 1569.6 48v 120 94 60.1 10.52 15 430 150 86.45 5.8 6.18 24v 15v 12v 5v 3.3v table 2
page date description: chassis mount dc-dc converter 7 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 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 te mperature is not over 85c, the output recovers automatically when the short or ocp conditions are removed. in the case of slight overloa ding, 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 85c, 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. one may be inclined to use this circuit to force current sharing b y trimming the output voltages for each converter. however, this circuit me not reliably or accurately divide the load current, as the device characteristics of the converters or the diodes may not be balanced over a range of operating conditions. we generally do not recommend this circuit to increase power output over a single converter. instead, we recommend this setup for redundancy only, having one converter as a backup in case of a failure. make sure the or-ing diodes can handle the voltage and full load curren t. +vin -vin +vo -vo +vin -vin +vo -vo figure 6. output parallel connections
page date description: chassis mount dc-dc converter 8 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 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 ot her 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, th e 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 s election, make sure that: 1) the diodes voltage rating is higher than each converter output; 2) the rated diode current can carry the sho rt-circuit current; 3) the diodes do not overheat before the short is removed. 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 con trol circuit is shown below. the standard version defaults to positive logic. for negative logic, indicate the selection when orderi ng. 16. isolation the input and output of the converter are electrically isolated. if needed, an output terminal can be connected to an input te rminal, resulting in the converter non-isolated. logic table negative logic positive logic sw closed (v <0.8 v) output on output off sw open (v >2.4 v) output off output on rem rem sw high signal here disable output -vin (pin 4) rem (pin 2) rem -vin sw rem -vin -vo +vo figure 8. remote on/off control figure 9. remote on/off control with transistor switch +vin -vin +vo -vo +vin -vin +vo -vo figure 7. output series connections
page date description: chassis mount dc-dc converter 9 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 17. input filtering and emi interference the vhk75w 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 a n emi standard. refer to figure 10 for a reference circuit. v-infinity offers a line of dc input filter modules designed to help reduce common and differential mode noise. the table belo w provides a list of dc-dc converter models within the series and the mating dc input filter. 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 c4 case +vo -vo +vin -vin l2 c3 c2 emi to meet class a vhk75w series c2 c3 c4 l2 47f/50v esr<0.60 47f/50v esr<0.60 2200pf/2kv 2.5h emi to meet class b 220f/50v esr<0.120 220f/50v esr<0.120 2200pf/2kv 1.5h figure 10. emi filter for vhk75w series mating filter module notes vhk75w-q24-sxx vfm-10a vhk75w-q48-sxx vfm-10a
page date description: chassis mount dc-dc converter 10 of 10 04/2011 20050 sw 112 th ave. tualatin, oregon 97062 p h o n e phone 503.612.2300 f a x www.v-infinity.com fax 503.612.2383 part number: vhk75w 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 10 f tantalum and one 1 f ceramic capacitor in parallel at the output. 19. output noise measurement schematic for proper output ripple and noise measurement, connect a 10 f tantalum and a 1 f 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 . resistor load to scope solid tantalum 10f ceramic 1.0f +vin -vin -vo -s trim +s + +vo figure 11. output noise measurement circuit
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