I am pulling my hair out since I keep destroying the Murata NMC1215SC DC/DC converters in my CPU controlled H-Bridge design. There is no obvious signs of damage such as heat or smell, they simply stop outputting +/- 15V. Testing out of circuit against a reference device shows they truly are dead.
The H-bridge design uses the 4x Murata device to provide an 4x isolated power rails for the 4x Fairchild IGBTs and the Vishay VO3120 opto-isolated MOSFET drivers.
I have attached a pictures that shows the general idea of the schematic, as well as a detailed schematic with every component.
The design is for switching a 150V / 40A high-voltage power source, but so far I've only been bench testing with 12V into a 27 Ohm resistor.
I suppose I must be damaging the Murata's though inadequate protection, although so far I haven't been able to catch any suspicious spikes on the oscilloscope. At $20 a pop though from Farnell, these parts aint cheap and it's proving to be an expensive detective project.
My only other thought is that I'm over-loading the output of the Muratas which are only rated to 1W.
I'm beginning to run out of ideas - can anyone suggest something to try?
View attachment 40944
View attachment 40945
The H-bridge design uses the 4x Murata device to provide an 4x isolated power rails for the 4x Fairchild IGBTs and the Vishay VO3120 opto-isolated MOSFET drivers.
I have attached a pictures that shows the general idea of the schematic, as well as a detailed schematic with every component.
The design is for switching a 150V / 40A high-voltage power source, but so far I've only been bench testing with 12V into a 27 Ohm resistor.
I suppose I must be damaging the Murata's though inadequate protection, although so far I haven't been able to catch any suspicious spikes on the oscilloscope. At $20 a pop though from Farnell, these parts aint cheap and it's proving to be an expensive detective project.
My only other thought is that I'm over-loading the output of the Muratas which are only rated to 1W.
I'm beginning to run out of ideas - can anyone suggest something to try?
View attachment 40944
View attachment 40945
