- 《Q302》 I have purchased and mounted the TMH0512S. I connected a 5V light bulb to +Vin, but 16V of voltage is discharged from +Vout.
- The TMH series are for non stable isolation DC-DC converters. Therefore the change in output current will change the output voltage, and change in input voltage will change the output voltage as well. In the specifications it is regulated for output currents 20 to 100% and the load change to 10%. Therefore when no load is connected, discharging 16V is not a problem.
- 《Q301》 The temperature of my DC-DC converter is extremely high, is there a problem?
- The DC-DC converter is a transistor so it may heat up according to the efficiency rate. Of course products with higher efficiency will have a lower heat radiation. Heat is radiated when it does not get transfered, so at max output a normal product may have a temperature of 30℃~40℃. Also it varies from model to model but the lighter the load, the less the temperature will rise. After taking in these to account, and you still think it is too hot, then there may be a problem.
- 《Q201》 After mounting the PCB, can it be washed while with an organic solvent? Or with a liquid of any kind?
- We recommend a non-scrub flux type washing. When the product must be washed, wash only the soldered side using IPA and a hand brush. We don’t recommend something other than IPA.
- 《Q122》 Are there any countermeasure I could take to lower the power supply output below 10μV, like a noise filter circuit?
- To lower the power supply noise to below 10μV, truthfully would be impossible. Connecting a filter to lower the noise would only lower the noise level a fraction and more importantly, mounting and wiring would be more efficient in lowering the noise level. For this, it is probably better to look for texts on lowering noise. Either way noise can be lowered only so much so problems do not occur while in use. For power supply noise, there are a few types which are are not only superimposed noises, however we have listed the types of noise below, however lowering all the noise would be impossible
① Magnetic noise inside the converter which occurs from currents flowing continuously.
② Noise which includes input voltage from the converter
③ Noise which includes output voltage from the converter
④ From the input of the converter to the output while going through the GND and back to the input is common mode noise
⑤ When the converter case is dropped to GND and the current noise which flows
First off for ①, since the converter is using rapid switching the current that flows into the pattern will create a magnetic state, especially around coils and trance. You may think a magnetic shield will help, however in a magnetic state it leaks into the air and will not be held back by the shield.
First off, use a converter with small noise, next mount the converter’s position as far as possible from the analog circuit (magnetic noise is an inverse proportion of the distance squared. To farther lower the noise, a magnetic shield may also be used.
Magnetic shields make an eddy current, which compared to the magnetic flux goes in the opposite direction and hold the magnetic flux from getting past. The converter’s case will have an affect from the magnetic shield, however setting up another shield externally is also recommended.
For ②, attaching a low impedance capacitor to the input pin , and a filter to the input line is recommended.
For the output noise in ③, the same can be said as above, using a capacitor and filter to lower the noise.
Next for ④, common mode noise which occurs from the converter travels from the converter’s primary circuit with the voltage change which from there goes through the converter’s isolation transistor and secondary side, and finally coming back to the primary circuit, this is because the high frequency current makes a loop. The converter with a small noise, the voltage change in the primary circuit is smooth, and the isolation transistor between the primary and secondarry has a small capacity. The way to reduce noise in this method is to connect a converter to the primary GND and secondary GND with a capacity of 1000pF to 10000pF, if done correctly the common mode currents main part will not go towards to the load side but come back to the primary circuit traveling through the capacitor, therefore reducing the noise. Farthermore, by connecting a common mode filter to the load line will help reduce noise as well.
For the current noise that flows through the GND in ⑤, static shields or by-pass capacitors which connect to the GND and are noise countermeasures flow through them before going to the GND. If the current pattern is too long, magnetic flux will form around the area, thusinducting to other parts. The GND voltage will also differ from the different places and makinga circuit for the common impedance. If these are not treated well, the noise countermeasures may actually make way for the noise to travel. When dropping the converter’s case to the GND, the distance short as possible is recommended for the input to GND, however better solutions may occur if not dropped at at all.
For noise countermeasures, the final step should be to include all the steps ①～⑤, however each noise countermeausre set up will need another countermeasure to block out the since some noise reductions may cause a chanel for noise to trabel through. When noise travels through the current, the other circuits induct the noise, so it is hard to reduce the noise by a whole lot, and only reducing the noise about 1/10 is probably the limit for normal usage range.
Our company’s BR-LB has 3mVp-p while the BY-L has about 10 mVp-p (the power is the same as the BR-LB and about 3mVp-p), by connecting a low impedance capacitor to the output side about 1mV can be reduced, however taking all the other steps may reduce the noise about 0.1mVp-p in reality. (This also depends on the countermeasures taken, however for ① and ④ reducing the noise about 1/100 will be a hard task).
- 《Q121》 Right now I am using your company’s BY05-15S10L and BR05-1516LB. As stated in your catalog specs, the noise is very low, however I was wondering if there was anything else I could do to lower the noise even more. If you know any ways, please inform me.
- ①Inserting a capacitor on the output side.
The smaller the impedance on the output capacitor the smaller the noise will get, connect a capacitor to lower your impedance to the required frequency. Electrolysis will work with lower frequencies, but not so well with higher frequencies, so with a higher frequency use a lower impedance OS capacitor or multi layered ceramic capacitor. Combining the above capacitorz should lower the impedance and lower your noise as well.
②Inserting an LC filter on the output
By inserting an LC filter the noise will greatly decrease when compared to just using a capacitor. Above are the ways to decrease noise.
If more measures need to be taken then rather than the noise conducted through the power supply line, the noise from electromagnetic induction or radiation noise, common mode noise are some other issues which may have increased your noise, therefore lowering the output noise from the converter would not have helped. Noise from electromagnetic indution or radiation noise is hard to cancel, but an easy step would be to move the converter away from the parts which are sensitive or using a shield may also be helpful.
- 《Q120》 Can the data line be pulled from under the module? Also is a shield required?
- The BSV-H series and BSV-M series does not have a secured isolation for the base module and PCB sides that are touching, so please avoid putting a pattern on the PCB and DC-DC converter which have the sides that touch. Adding a lower level and wiring has no problem, however please aaboid patterns which are weak to noise. Also by using the lower level pattern and building a shield, the wiring pattern is less influenced by noise.
- 《Q119》 It states the input is 9V to 36V, however when the input is 12V does it have twice the current compared to running in 24V? At 9V can the rated be pulled?(BSA)
- The input voltage when set at 12V will have about twice the current compared to 24V input Therefore, when using a converter releasing the minimal input voltage and input current is important.
The BSA series will have the rated current released as long as the input voltage range written in the catalog and datasheet are followed.
- 《Q118》 On the data sheet it states that a over current protection circuit is in place, it states “auto restart type”, what needs to happen to the output load before restarting?
- To be in over current mode, the output load must be in over load state (The output resistance is minimal and current higher than the set value is running). This will lock the output voltage, and the output voltage should decrease. Auto restart means the main load has changed from over load to normal mode (the output current is below the rated value) and the when the voltage is normal, it will restart.
- 《Q117》 Is the P-Good pulled up?(BSV) Also please inform about the voltage range.
- The P-Good pin on BSV-3.3S6R0DA is an open drain, and not pulled up interenally. When the P‐GOOD pin has a voltage of H, ｜Output Voltage－Set Voltage｜≦0.4V（typ）. However when the input output voltage difference is Vin－Vo≦0.5V, even though the requirements for output voltage｜Output Voltage－Set Voltage｜≦0.4V（typ） have been satisifed, it may show LOW sometimes. Also when the input voltage is below 3V, the internal FET is turned OFF.
- 《Q116》 There is an NC(NO CONNECTION) pin, what should I do with that pin?
- Do not connect the NC pin anywhere, and keep open.