Innoswitch CC mode doesnt works
Both devices INN3167C-H101 (output profile fixed CC), INN3168C-H101, and INN3670C-H606 perfectly works in CV mode, in different designs.
IS resistors 10mOhm (ie 3.5A protection/CC). Both design very similar to DS 12V power adapter.
Now, need a CC device (battery charger), so trying existing solutions - both made autorestart close to 3.5A of output current.
For test load, I use 2 and 3 Ohm resistors, CC/CV/CR active load, active load+resistors but result is same, PSU output switched off instead of reducing to limit the load current.
What can be wrong from my side?
Comments
Hi Nanoe,
Here is 2 cases, INN3670C-H606 with 5 and 10mOhm Ris.
Both have 12.2V out before AR. No other troubles while working, with wide voltage range (85-265), and wide load range (0..7 or 0..3.5A). May be, a bit low switching frequency (37 and 65kHz close to full load). Both works in clean DCM. AR happens even while output down from 12.2V to 12V.
Attached an osc screenshots and fragment of transparent board view, think You'll understand the connections, looking for the circuit simplicity and the total experience.
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| to_Power.pdf (415.56 KB) | 415.56 KB |
Hi Viktor,
From the waveform, it seems the SRFET is mis-triggering (turning on early). This waveform normally seen in a ZVS flyback but InnoSwitch3-EP do not have feature as ZVS. I would suggest checking the gate vs vds of the SRFET to verify. This switching may cause unstable behavior of the PSU. One possible reason is the SRFET (needs lower rds on) is not compatible with the design or layout itself.
For the layout, the IS resistor is too far from the IC pin. I would suggest following the layout found in the RDR-611.
RDR-611 - 10 W Dual Output Power Supply Using InnoSwitch3-EP (725 V Si Switch) | Power Integrations
Regards,
PI Nanoe
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| Waveform concern (80.42 KB) | 80.42 KB |
Hi Victor,
Could you please check the following item below. There is a possibility that it went to overload condition.
Also, since the IS pin of the Innoswitch is sensitive, proper implementation of layout is needed. If you can provide a copy/snapshot of the InnoSwitch layout, I can review it on my end.
Regards,
PI Nanoe