Automotive 24V power supply problems

Hi,

I'm working on an automotive device, 24V. I'm using IPS6011 from International Rectifier. It works ok, but when I try to charge battery IPS burn. I noticed that charger raises up voltage to 29V and in datasheet 28V is maximum continuous voltage for this device while 36V is maximum supply voltage. how can i protect my device?
do you think IPS has too low power supply to work on 24V automotive application??

The IPS6011's voltage rating is just to low ..
I wouldn't use it close to, or above, it's maximum ratings ..
Keep in mind, that car's power supply is very 'dirty' and spikes of all kinds are pretty common ..

Regards,
IanP

could you suggest me any similar device to use in that application??

And if I use 2 or more diodes in series with power supply in order to make it lower of about 2V?

Using diodes to drop the input voltage may cause headroom problems when the battery is not charging.

Does the IPS6011 get hot if the battery is charging, but the load is turned off? How about if the load is on by a very light load, like a 1K resistor? If it gets hot due when off or only lightly loaded, the it would suggest that noise spikes from the alternator are causing internal junctions within the part to zener conduct and consume lots of current. You can try adding additional filtering on the input like an inductor and a capacitor. This should limit the noise spikes.
I would also suggest contacting International Recitifer. They are pretty good at answering apps questions with regard to their devices. For example, the datasheet lists two values for VCC max, 36V and then 28V continuous. Under what conditions do these two apply?

What about if device is openload?
In my circuit this device has usually an Inductive load. but some of them could have load disconnected if not used. and it could happen it is activated accidentally by user.
Do you think this couls cause this kind of fault at higher voltage?

now i'm going to try if it burns in these conditions.

What if you use a DC-DC converter and match 30V as an output? I guess then there will be no problem with your charger - maybe you should iplement some extra protection. An you will end up with a dual output device!
D.

It's not a good solution for me a 30 V dc converter. it will raise its cost a lot. I think i'm going to change device. Using Profet Infineon. Always a smart high side power switch . certified for 12 and 24V automotive use.


Whata do you think about it??

fuzzzy, could you tell more details in your circuit and purpose, hope we can find out the reasonable solution.

nguyennam

nguyennam, my circuit is intended to power up some hydaulic valves.
instead of using relays as old circuit i decided to use a solid state device. I choose IPS series. My device is powered by 12V or 24V battery. With 12V non problems.
Bevice has got 1 IPS6011(security) to power up 12 different IPS6031(working maximum 2 at time with 2Ampere).
When testing 24V Iconnected an Automotive battery charger to battery and after some minutes(while circuit wasn't working:all outputs closed) I heard a whisper on the device and IPS6011 become hot. and i noticed there was a short circuit to GND and IPS6011 was in protection while 1 or more IPS6031 shorted VCC to GND(broke up). Voltage on battery from charger was 29V.
I don't know now if the IPS6031 that failed was connected to valve or it was left open. so i can't say if it was a open load problem.
I made some tests with only one IPS6031 connected or not to Valve and voltage up to 35V but it worked correctly without fault. I don't know what to think.
Datasheet says IPS accept only 28V Continuous voltage and up to 36V DC.

What do you think about this problem??

Let me ask you this question:
Instead of playing with high-side switch at its's voltage limit(s) why not to use simple low-side switch .. see attached picture ..
These N-channel power MOSFETs can easily cope with 12 or 24 volt instalations and will withstand amps of current ..

Just a few thoughts to get you going ..

Regards,
IanP