pfs729 900w pfc
hello
i,ve builded a 900 w pfs boost based on datasheet of pi but output inductor is been heated very much in power more than 100w i think it is because of my ferrite core pls guide?
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I changed ferrite with powder iron and I got 400 w by overheated but tolerable temperature in datasheet is said you should use sendust core but in our city I couldn't find sendust pls guide about replaceable solution.
before I thank.
I changed ferrite with powder iron and I got 400 w by overheated but tolerable temperature in datasheet is said you should use sendust core but in our city I couldn't find sendust pls guide about replaceable solution.
before I thank.
Pls. post inductor current waveforms.
hello
this is my drain voltage waveform instead of rectangular waveform.
pls guide
image
My spreadsheet is exactly right like der 274 of pi.i have very large dissipation and heat on drain gate.
First, can you check the bandwidth setting on the scope, and the bandwidth of your probe?
2nd, can you borrow a DSO?
hello
I have problem of overheating yet.
my current waveform is triangular and is good but my heatsink overheat.
I thought maybe heatsink is problem and added a large heatsink as you see in picture.
but still ic turn on 1 min and turn off 15 sec.
I thing temp of heatsink should be 60 c.
What is the efficiency?
Can you put a thermocouple on the front face of the device, halfway up the package, between pins 5 and 7?
Are you using a heat spreader?
i have offerded a heat sink with specifications like der274.may my problem be solved?
What was your heatsink temperature right before shutdown?
i changed my heat sink as you see and my pcb.and changed mpp core with sendust 60 u and followed every thing in pixi.and increased voltage with a variac.but my heatsink temp was 65 c and ic shut downs.even while reducing variac voltage in 185 v ic burned.
i think about possiblity of warming drain.
ive spent 6 month on this project
pls guide
i changed my heat sink as you see and my pcb.and changed mpp core with sendust 60 u and followed every thing in pixi.and increased voltage with a variac.but my heatsink temp was 65 c and ic shut downs.even while reducing variac voltage in 185 v ic burned.
i think about possiblity of warming drain.
ive spent 6 month on this project
pls guide
i changed my heat sink as you see and my pcb.and changed mpp core with sendust 60 u and followed every thing in pixi.and increased voltage with a variac.but my heatsink temp was 65 c and ic shut downs.even while reducing variac voltage in 185 v ic burned.
i think about possiblity of warming drain.
ive spent 6 month on this project
pls guide
i changed my heat sink as you see and my pcb.and changed mpp core with sendust 60 u and followed every thing in pixi.and increased voltage with a variac.but my heatsink temp was 65 c and ic shut downs.even while reducing variac voltage in 185 v ic burned.
i think about possiblity of warming drain.
ive spent 6 month on this project
pls guide
hello
What are you using to measure heatsink temperature?
Are you using a heat spreader between the PFS and the heatsink?
Can you post a photo of the mechanical mounting of the PFS to the heatsink?
Thnaks for your support.
The problem that is strange for me is overheating heatsink because if even my heat spreader has problem its not a reason for overheating heatsink while in datasheet ambient is 24 c and heatsink is 29 c
this is my previous pcb that i attached had less emi problems but overheating problem too.ofcource i removed 100nf decoupling vcc pin cap.
before everything thanks for your guidance.
may this problem is caused by lacking snubber on output diode in attention to spike in inductor current as shown?
may this problem is caused by lacking snubber on output diode in attention to spike in inductor current as shown?
What are you using to measure the current?
Do you have access to a DSO?
hello
i improved components in the circuit and i take efficiency of 96 percent for loads below 700w.but more than it efficiency starts from 96 and decrease to 60 until shuting down of ic because of overheating.
best regards.
Pls. log the temperature of the IC and the choke at 650W load, and at 750W load.
Also capture the choke current at full power and post it.
Pls. post your spreadsheet, inductor design details, and inductor current waveform.