o/p inductor in lnk306
hi
i have designed constant current power supply with constant current of 240mA 40v max using lnk306
the problem is i have used 6 inductors in parallel and series combination ....
when i replace these inductors with its equivalent value which is coming as 3.4mh the circuit does not work..........
im not understanding the problem ........
is the max current rating of the inductor creating problem
im using the inductor of current rating of 300ma
please help as soon as possible
Comments
i have attached the schematic and inductor details.
i/p- 165v-265v ac
o/p 40 v 240mA constant current.
pf=1 (so used valley fill circuit)
PIEXPERT was not used as it does not have constant current using lnk306
i have connected leds as load . the leds go on and off with time interval of approx. 1-2 secs. which i think is due to shut down and auto restart ,im not sure
Regards
madhura
Hi,
I have sent the details .If any of the details are missing please let me know.
please reply soon.
waiting for your reply..
Regards,
madhura
Hi,
From your schematic, I could not read the value of R-SENSE and C-SENSE. Please refer to page no.11 of our application note AN-37 for guidance on selecting these components:
http://www.powerint.com/sites/default/files/product-docs/an37.pdf
From the description of the problem it appears that the power supply is entering auto-restart mode which suggests that there is inadequate feedback.
Please try a larger value of R-sense resistor for debug to verify if the circuit is working correctly.
I also noticed that you are not using the output voltage feedback. In case the LED load is accidentally disconnected during your testing, that would lead to a high voltage at output which could be destructive.
It was difficult to read the values of components in the scanned image that you sent. If you need additional support, I suggest you send us another copy with a higher resolution image.
In order to expedite your development, you could also contact our office in India. Our office in India is staffed with field applications engineers who will be happy to help as well.
# 1, 14th Main Road
Vasanthanagar
Bangalore 560052 India
+91-80-4113-8020
+91-80-4113-8028
FAX: +91-80-4113-8023
E-mail: indiasales@powerint.com
Regards
PI-Sarek
Hi,
I have again attached the file. R-sense-8.2 ohms and c-sense-47uF
With R-sense greater i.e. 15 ohms I get o/p 45v 120mA. But I want current as 240mA.
waiting for reply
hello,
I tried using 4mH 1A instead of 3.4mH 300mA but im getting the same response
I have attached the new details .
regards,
madhura
Hi,
Please verify the input voltage to the link switch converter. You will need verify the voltage across the valley fill circuit.
Please attach a copy of the voltage waveform across the valleyfill when your load is connected and nominal input voltage is applied.
Regards
PI-Sarek
hello,
o/p vol of valley fill circuit comes out to be 220v . Now I have added a 1uF 450V capacitor across valley fill circuit.But the problem remains. According to application note AN-37 o/p inductor value should be between 680uH to 1.5 X Ltyp could you tell me what is the effect if I put L greater than 1.5Ltyp .
regards,
madhura sugandhi
Hi,
In order to help you further, we will need a copy of the schematic and details of the single inductor in terms of construction.
Please also provide us a detailed input, output spec that your circuit needs to meet and any PIExpert files if PIExpert was used to design this circuit.
Please aslo elabore on the problem. What exactly is the problem? Is it with starting up? Or ability to deliver rated power? or maintaining regulation?
Regards
PI-Sarek