Some questions about using ISO5451

user4267931

Other Parts Discussed in Thread: ISO5451

Hello, I have some questions about designning with ISO5451,would you please help me?

I am just using ISO5451 to driving my IGBT. the collector voltage of IGBT is about 320V and bipolar output supply(+15V and -9V).

and the schematic is the same as figure 20 in the ISO 5451 datasheet.

I have 3 questions about the usage:

1, what is the right boot sequence, the Vcc1,Vcc2 and Vee2 boot first or the collector voltage first?why?

2, shall I pull the /RST low through the boot process? The /RST pin has a internal pull high resistor,but I found that I must pull low the /RST unless the IGBT collector voltage had raised,or if /RST has been high before the IGBT collector voltage raised,there will be about 100V pulse on Vcc2(+15v),when the collector voltage rising.

3,when use the bipolar output supply,how to deal with the CLAMP pin,left it open,or connect to GND1,GND2?

over 8 years ago

0 High Hopes over 8 years ago

Prodigy 110 points

the default state of the MOSFET/IGBT must be OFF while powering up. the chip's undervoltage detection should hold the drive OFF while powering up,. so look at the datasheet and see if you can discover how the undervoltage works and you might know which power rail needs to energize last.

0 High Hopes over 8 years ago

Prodigy 110 points

now i have a question for you. the peak source current is 2.5A max. makes sense. but i also see in the datasheet a minimum current of 1A. does this mean i can not use this chip to drive a single small mosfet because such a mosfet would not pull 1Amp? or what if i have a large IGBT that would pull large current but i have for some reason lots of gate resistance that limits current <1A peak. can't use this chip? i don't understand why there is a minimum source current.