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Cosel is one of the leading power supply manufacturers with a history of 50 years. Cosel manufactures high-quality AC-DC power supplies, DC-DC converters, power modules and EMI filters.

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Modified Power Supply

Cosel is dedicated to providing support for customers requiring additional features or modifications to catalog products.The factory will assign a special identification alphabet to modified units.Please feel free to contact us with your requirements.Following is the list of modified units available:

  • Ex .1 Model designation : R25-5-JDetail of this modification : The input/output terminal is changed to connector type.
  • Ex .2 Model designation : R25-12-CNDetail of this modification : PCB is coated and case cover is attached.

■ Alphabets of modified units and it’s contents of modification ■


No. Alphabets Contents
1 A Power supply that V2(GND) and V3(+) were made common.
2 C Except a certain device(e.g.potentiometer), PCB is coated.
3 D Output voltage is set on request within the output voltage adjustable range.
4 F Fan or Fan unit is additionally included in power supply.
5 G Decreasing a leakage current by reducing the value of earth capacitor at input filtering circuit.
6 H By changing the overcurrent operative point, and make it possible to get peak output current.
7 I Modified as series operation possible those which are not possible to make series operation.
8 J /Jn Terminal block at input/output is changed to connector type.
9 L LED for output confirmation is added.
10 M Silicon rubber is attached to those power supply.
11 N Case cover is attached to those open frame type power supply.
12 P Operative overcurrent point is set to 90-100% of rated output current.
13 R Output remote ON/OFF is made possible.
The logic of output remote ON/OFF is reversed.
14 SN Chassis and cover is attached to PCB type.
15 T Terminal block is changed from horizontal to vertical position against PCB for screwing.
16 V Twisted wire is led from power supply to attach output voltage setting potentiometer externally.
17 Y Potentiometer is attached additionally to those which is not available to standard power supply.


No. Alphabets Contents
1 F Power supply with the addition of a heat sink.
2 G Capacitor between Input and Output is removed.
3 L Input/Output pin are shortened.
4 R The logic of output remote ON/OFF is reversed.
5 S Case connecting pin is cut.
6 T Mounting holes are through-hole type.
7 M Mounting holes are tapping-hole type.


No. Alphabets Contents
1 E Reduce leakage current to the EMI class A lebel.
2 F The wind directions reversed.
3 G Leakage current is reduced.
4 K Low speed fans are used.
5 N Built-in fan is not used. The fan set externally is used to cool the unit.
6 R The logic of remote on/off is reversed.
7 T A fan filter is attached to fan.
8 U Operation stop voltage is set at a lower value than the standard version.
9 W A covers are installed on the terminal block of output modules.

*Some models are not possible for modification mentioned above. Beside the above, we have some other modification. Please feel free to contact us.

Technical Tips

We hope that our tips can contribute to your design, and please do not hesitate to contact us for any technical inquiry.


■ EMC ■

How long should it take for Hi-pot test of LEB150F-0524?
Our test voltage/time is 1.1 times of specs/2 seconds. This is allowed by Safety Standard. We do Hi-pot test for all products.
What is the receiving inspection procedure of isolation test for DPF1000?
The test result is changed by earth capacitor. (= Y capacitor)
If Y capacitor is bigger than our test circuit, this model may not pass.
Because leakage current is increased.
And line pattern and FG pattern should be separated. (distance: 4mm or more)
Please check capacitance of Y capacitor and PCB layout.
Can CDS4004828 meet EMC class B with external circuit?
Please check the attached pdf file.Download
The isolation voltage of PBA150F-15-N between input and output mentioned in catalog is AC3000V. If we need AC4000V isolation, are there any other suggestions?
Isolation voltage of PBA50F-15-N is shown 3,000V on our catalogue.
However, when we tested isolation by 1 sample, the power supply was able to endure 5,000V approximately.
If the guaranteed isolation voltage of 4,000V is needed, we have to evaluate some subject.
For example, if internal component does not meet to this voltage, we will not be able to guarantee it.
Another method we suggested is to add the input isolation transformer.
For SUCS102405B/ZUW252412/PBA50F-9, how long is the isolation voltage DC500V being test?
1 minute
Are there any inrush current level 4 standard of LEB100F-0524?
I think it is surge voltage not inrush current.
Since inrush current level is not decided by IEC directive.
If it is surge voltage, the power supply meets the level 4 of IEC61000-4-5(surge immunity).
Can PBA30 series pass the 4KV isolation test between Input and Output?
We tested one sample for 4KV between input and output and it passed the test.

■ Noise ■

Can the ripple voltage of PBA1000F-36 be reduced to less than 50mVp-p?
Is it possible to reduce the ripple voltage of ZUS152405 to less than 20mVp-p by testing with 20 MHz oscilloscope?
Why CBS2004848-R has sound noise when the load current is zero?
Because the transformer insides makes noise when the load current is zero or very small due to magnetostrictive resonance.
Is it possible for using the external circuit diagram to make the output ripple noise of DBS400B15 less than 10mVp-p?
We recommend to add a common mode coil between output terminals and E2 (electrical capacitor). The value is 1~2mH approximately.
If the coil is added to DBS’s output, the output noise may be reduced to 10mV or less.
Please evaluate under the end-user’s condition before using.
The option G is the capacitor between input and output is removed. Could you explain the function of option G? And why is SUS1R5 series without the option G?
SU1R5 doesn’t have option G which is without the capacitor between input to output.
But SU3, 6 and 10 have its capacitor.
The followings are the advantages and disadvantages of option G:
Advantages: reducing through noise from input to output
Disadvantages : Ripple noise of option G is bigger than normal type.
In order to reduce the ripple voltage, we added a inductor (L) on the output side. But the recommended external circuit doesn’t have inductor at output terminal? What is the advantages and disadvantages of using inductor at output terminal?
External inductor is used to reduce the output noise than no inductor.However, the inductor is bigger and more expensive than a capacitor.Therefore, we recommend the capacitor only without inductor at first.If the noise is not reduced the capacitor only, external inductor must be added.
Can PBA30F-5 PBA30F-9 PBA30F-12 meet the ripple noise level below 80mVp-p?
Those power supply the ripple noise can be smaller than 80mVp-p under testing condition 25 degree and using 20MHz oscilloscope. Please check the attached pdf file.Download
We are using 2 pcs CBS504805 in parallel redundancy operation. Why is the ripple noise so big? It is around 400mVp-p.
After we checked your circuit pattern, we found some mistakes about your mounting method. Please change the circuit pattern , don’t put the input and output pattern underneath the power modules. Please check instruction manual 6.1 Mounting method.

■ Temperature ■

Is it possible for PBA1000 series stored at -40 degree?
Internal component’s storage temperature is guaranteed
The internal fan’s storage temperature is -30 degree C lowest.
So we can guarantee the storage temperature at -30 degree C only.
Is it possible for the storage temperature of CBS series under -50 degree?
It is possible to start-up at -50 degree C. But the specification of ripple and ripple noise is changed between -50 degree C to -40 degree C and they are approximately 1.5 times the specification at -40 degree C.
What is the detailed distribution curve of OTP point for CDS6002428?
Overheat protection of CDS600 works at 115 degree baseplate temperature.
Can DPF1000 and DBS400B24 be auto-recovery from OTP?And what is the OTP point of DPF1000 and DBS400B24?
No, these models don’t have auto-recovery function from OTP and it shuts down only.
OTP operating temp: DBS series — 100 +/-10 degree DPF1000 — 95 degree approximately.
Is it possible for SU series stored at -55 degree C?
SU series can be stored at -55 degree C.
What is the thermal resistance and maximum case temperature of ZUW104812?
Please check the attached pdf file.Download
Can PBA300F-48 operate at -40 degree ?
Unfortunately, our company does not have AC-DC converter to meet at -40 degree.
Because the internal FAN is not guaranteed operation at -40 degree.
However, we confirmed PBA300F-48 can operate at -50 degree by testiing 1 sample. Please find the attached pdf file.Download
Can LDA10F-12-SN work under -25 degree and how big is the ripple voltage?
After the evaluation is finished, we can not guarantee LDA10F-12 working at -25C. When the power supply starts up, we found the output voltage was higher than the rated voltage.
Can LDA30F-15-SN work under -25 degree and how big is the ripple voltage?
Regarding to LDA30F-15, The output voltage was unstable at -25C when AC85V input. So, we guarantee LDA30F-15 at below condition. Download1Temperature: -25C Input voltage: AC170~264V Please take a look at the attached file about ripple noise.Download2
Can DBS150A15 start up at -50 degree?
Yes. Please check the attached file.Download

■ Remote Control ■

How big is the value of input current when DBS400B28 is turned off by remote control with RC terminal?
RC1:3.2mA (Input current) ; RC2+RC3:4.8mA (Input current)
What is the response time of Remote ON/OFF for CDS4004812?
Please check the attached pdf file.Download
What is the maximum input voltage and time that CDS6002428
could withstand when CDS6002428’s remote control function take
affection and no output voltage?
Input pulse voltage: 50Vmax, <100ms Rated input voltage: 36Vmax, duration
Can CBS1002415 / CBS2002415 satisfy the requirement for switch on voltage at DC16V and switch off voltage at DC14V?
These models can be controlled at DC16V and DC14V by using RC terminal of power module

■ Output voltage ■

Is it possible for CDS4004802 to adjust the output voltage from 2VDC to 1VDC?
When using the CDS4004802 in the range of 1-1.2V, there is a possibility that the overshoot occur. And then the overshoot is about 140mV.
For SUCW1R5 and SUCW3 dual outputs converter, if the two loading isn’t same, ie. one is bigger, another one is smaller. What will happen on the output voltage and current?
Output voltage will be changed by load factor because SUCW series is dual output type.
In case of dual output, one voltage decreases by large current, and another output voltage increases.
We call this characteristic “cross regulation”.
The changed value has not decided, however it may be +/- 5% approximately.

■ Input voltage ■

What is the minimum input voltage of CBS1004812,CBS1004805 and CBS2004824-XCMNA that it can work properly ?
The minimum input voltage COSEL guaranteed is DC36V. However, these units have capability to start-up at 31V approximately, and if input voltage reached 33V, the rated output voltage will be generated. However, in the input voltage range between 33V and 36V, the input current is increased due to low input voltage. Therefore, the load should be derated.
The input voltage range of DBS400B modified version is 250VDC-400VDC. If the input voltage is less than 250VDC, is the power module in input undervoltage lockout or not working?
DBS series are using lockout circuit.The start-up voltage of DBS400B28-XTHIA is more than DC180V.
By the way, the start-up input voltage and rated input voltage range is different things.
If DBS400B28-XTHIA and DBS400B12-XMLM are used under DC250Vin, we can not guarantee the specification.
Can PBA1000 series work properly with input voltage AC280V?
We are not able to guarantee AC280V input.
Because the voltage exceeds the maximum rated voltage of components.
PBA1000F could operate at AC280V. However, we don’t recommend this.
Can LCA30S-12 work at 100% load with input voltage range 85V-90Vac?
If the input voltage is AC80V, the load must be decreased to about 94% max. If input voltage range is AC85~90V, it can be worked normally at 100% load.
What is the input surge withstand (input voltage and time) ability of CDS6002428?
50V, <100ms
Can PBA300F-24/PBA300F-48 operate with input voltage range from DC70 to DC166? Because we don’t want to use power module.
U option of PBA300 series can operate at low input voltage by derating of output power.
However this model needs the input voltage of more than DC90V for start-up.
And this models can operate at DC70V after being start-up.
Requirement: DBS series Po=550W; Vo=24V or 28V; Vi=DC200-400V
Can you recommend the suitable power module? Please provide the model no.
The power module of 550W output must be used in Vi=DC250-400V.
Because when input voltage is DC200V, input current will be too big.
So if customer uses the power module in Vi=250-400V, we will be able to recommend the below models.
28V output: DBS400B28-XLPG 28V,19.7A rated
24V output: DBS400B24-XNHMB 24V, 23A rated
Does CBS2002415 has input overvoltage protection ?
No, CBS series doesn’t have overvoltage protection for input.
If CBS2002415 haven’t input overvoltage protection function, how to prevent input overvoltage ?
Rated input voltage range is maximum value for this module.Please use a constant voltage power supply to input power.
If input voltage is abnormal such as DC60V or DC80V, will CBS2002415 burn or explode ?
Smoke and fire will not be caused. External fuse will be blown by breaking internal circuit.
Please provide the external circuit diagram of CBS1002415 with below requirements.
Input overvoltage protection function: the power module will be shut down when input voltage from DC37V to DC60V. When the input voltage becomes normal,it can restart to work automatically. Moreover, the power module must endure input voltage DC500V at 10ms.
Please check the attached pdf file.Download

■ Parallel Operation ■

What is the voltage of CB terminal when using current balance function with CB terminal (load:100%) for DBS400B24/DBS400B24-XNHM?
CB terminal voltage (100% load)
DBS400B24 : 6.6V approximately
DBS400B24-XNHM : 6.2V approximately
* (+/-10% approximately)
Is it possible for 3pcs PBA300F-48 3 pcs in parallel operation with the following functions?
N+1 parallel operation, current sharing and hot swap function. Normally 3 pcs are working with current sharing. When one pcs is broken,the other 2 pcs can also work with current sharing and the broken one can be hot swap.
Please check the attached pdf file.Download
When 2 pcs DBS400B24-XNHM are in parallel operation, CB and VB of 2 pcs DBS400B24-XNHM are connected together for current balance and add diode on the output side of power module.But we found that when the input voltage of 1 pcs DBS400B24-XNHM was turned off, the other DBS400B24-XNHM’s output voltage would drop to 23.1VDC.When we did not connect CB and VB together,the output voltage would be stable at 24VDC even another power module was turned off. But we request the output voltage should be 24VDC (Accuracy:+/- 0.5V) How should we connect in this case?
We want to make parallel operation of one PBA600F-12 and other power source is DC12V like DC generator. What is the connection method of PBA600F-12 output terminal?
This parallel connection is used for redundancy.
Therefore, VB balance and CB balance are not needed to operate.
Please connect like below.
We used 2 pcs CBS1004805 in parallel operation but we worried about CBS series without VB & CB function,only use diode in the catalog. If diode is used, it will make the ambient temperature very high.So are there any other solution?
If it is for increasing output power, CBS1004805 can not be used.
Because the module doesn’t have VB and CB terminal.
So, output current will exceed rated current.
We recommend CDS4004805(400W) or CBS2004805(150W).

If it is for redundancy purpose, CBS1004805 can operate in such condition.
Output current is unbalanced, however output current will not exceed rated current.
Because output power can generate even if one module works only.

■ Series Operation ■

Requirement : Input : 24VDC, Output DC330VDC with 5000W. Is it possible for 12 pcs of CDS6002428 in series operation to meet this requirement?
I’m afraid it’s impossible that CDS6002428 12pcs be in series operation. And we don’t have any power supplies that I can suggest.

■ Others ■

Is the internal current balance circuit of DBS400B24-XNHM or DBS400B24 using Control IC UC3902?
These power supplies don’t have UC3902.
Can DPF1000 and DBS400B24 pass the vibration test in 5-500Hz (0.75G)?
We haven’t tested DBS and DPF. However, CDS passed the same test.
So, we think that DBS and DPF will pass the test.
SUS1R52405 / SUS1R50505 / SUW1R52412 /SUW1R52415 Can you tell me the calculation method of MTBF?
The MTBF is calculated by EIAJ RCR 9102 in our company.
EIAJ RCR 9102 means “Part count reliability on the DC stabilized power supplies”.
In this report, the failure rate of each component are decided as fixed value at all condition.
Therefore, MTBF is same value at all condition.
The formula is the addition of all component’s failure rate
Can DBS100A13R8 be modified to output wattage in the range of 120W to 150W?
It is simply by adjusting DBS150A15 to output voltage13.8V, the module can generate 138W. (13.8V, 10A).
Can the power module withstand 35G impact? (Time: 1000 times in half hour)
It is very hard condition.Power module may break by impact.Please avoid this condition.
It the Vin- and Vo- terminal is short, is the isolation no use ?
Yes, it is not isolation power supply
If PBA50F-9 output current is 1A, will it interfere the input terminal ?
No interfere. The input current decreases only