INN3696C
I am designing a 20 W,24 V , for single phase input. I want my Vin to be around 440nV, but if i am selecting it, i am getting a warning at overvoltage .
Files
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InnoSwitch3-EP900V Flyback Design13.pdf | 534.05 KB |
Comments
Hi, akanksha,
A value of 440V in the field specified as "Maximum AC input voltage" leads to peak mains value of 622V.
Please reconsider your input conditions.
I have designed a power supply using INN3696C, of specification 24V and 830mA ,i did not wanted the overvoltage monitoring system so i connected the only one 3.9M resistor to the voltage pin and also connected the voltage pin to source pin of IC . But i am facing a problem , output is not as required and it keeps on fluctuating form 0.234 to 2.2 V . What can be the possible fault.
Hi akanksha
It is look like your unit is trying to start but some protection loop kicks in and prevents is from starting.
Without detailed information about the schematics and transformer design is not possible to estimate propelry the actual operating conditions.
Regards,
I probably think its due to FET , what is the role of sense FET ,i observed it in the block diagram of IC .The voltage across drain to source pin of this FET (SQSA12CENW-T1_GE3) is fluctuating around 0..23 V to 6.1 V . Can i not use this Fet and go for other alternative ? I am attaching the Schematic diagram.
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PS-24V830M1P.pdf | 60.16 KB |
Without a transformer design I cannot be more specific, but your synchronous FET selection - 100V rating for 24V output seems too low.
However, I do not think that that is the reason for the restarting of your circuit. It is most likely to be a result.
The most likely reason for the restarting is the 5.1 Zener in the auxiliary OVP.
Please, use the online design tools PIexpert and/or PIXls to design your unit and check components ratings and transformer design!
The tools will protect you from the most common errors during the design process.
Regards,
Actually i have disabled the OVP feature of it. Can i disable the SRFET application what effect will it have?
Actually i have disabled that feature of OVP, i.e. i have removed the ZENER diode and left the path open and also i have removed the High value resistance of 3.9M and 442K . can i disable the SRFET feature. What pros and cons it will have?
Transformer specification is as under
core - EE19
Primary turns - 82
Secondary turns- 35
Nbias turns- 19
Hi akanksha
please create your design on PIExpert and send me a link, or the file to piexpert@power.com with the comment 'for PIYODA'
Best Regards
In order to get input till 410V i have removed the over voltage protection feature (i.e. i have open the loop by removing 5.1V zener diode).Also i have attached two schottky diode (B2100AE ) in series in the place of SRFET and connected the SR pin of ic to its GND pin. also I have removed D4 ,R9 and R8. at the V pin.
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InnoSwitch3-EP900VGANDA.pdf | 29.65 KB |
If your unit is still not starting please do the following
1. Recover the original datasheet (DER) schematics. (no zeners in the aux loop)
2. Set the input voltage to 150Vdc
3. Set the load to 0.5A (assuming nominal output)
4. Apply the input voltage to the input terminals
5. If the unit is still flickering some of your transformer windings leads maybe not connected correctly.
If you still struggling to get the unit running capture the transformer windings pulses and send it to me. (please mark on which terminal the Ground of the probe is)
Ones you get the unit running at the above conditions than try to do the changes you required.
In this no. 7 pin of the transformer was connected to Positive probe and no. 9 pin was connected to ground probe.
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ad0a0e80-fc29-4128-9c25-d65b9bc281f3-converted.pdf | 262.98 KB |
Second picture is showing the starting signal.
Please try to zoom the amplitude so I can see the whole signal.
And do the same for the auxiliary (GND lead on pin5, sense probe on pin4)
Regards,
secondary side output of transformer
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0f34f072-7626-4f59-94c7-e4ccb7c1c6bf-converted.pdf | 224.41 KB |
Transformer auxiliary output main probe at pin number 4 and gnd probe at pin 5
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dae99202-dc90-45b0-8142-531c44f4aa9e-converted.pdf | 167.99 KB |
Can you swap pins 7 and 9 on the transformer.
Pin 7 to go to the FET, and pin 9 to go to + of C12.
yes i did that and IC got burnt after 30 sec probably.
Please recover the circuit and make the output loop looks like the one on the picture below. Keep the transformer pins how they were on your original circuit.
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Capture_14.JPG | 15.04 KB |
Hello,
Sorry but image is not clear.
Hi akanksha
To see what the output circuit of the controller just create PIExpert Inno3CE 24V 0.85mA. The sense circuit, output capacitors will be the same even your are using 900V device.
I have created the link for same design. You cannot connect the sense circuit to 0V. Just copy the output sense circuit from there.
How can i reduce the ripple in the output? Output expected is 24 V but i am getting V p-p about 10V.
Hi akanksha
The ripples in the output voltage a due to the secondary current flowing in the output capacitors and are with the switching frequency.
If you have the correct capacitors (value and ESR) 10 V ripples are extremely unlikely.
Are those ripple at low frequency? Than.. maybe your unit is restarting because of reaching some protection level?
Please copy the actual schematics and design file (PIExpert/PIXLS). Plots with the ripples zoomed to one period will also help.
Regards,
And also can i design it for 3 Phase input using INN3696C.