InnoSwitch4-QR losses estimate
Posted by: alberto.mari.m…
on
Hi there.
Is there a way to estimate the total losses in a device like the INN4276?
The only thing you find in the family datasheet is the Figure 22, which links power to drain voltage without specifiying at what frequency if was obtained.
Thanks.
Files
Figure 22
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Thank you for replying so quickly.
Hi Alberto,
Thank you for reaching out to Power Integrations and for your trust in our devices.
To estimate the total power loss of the InnoSwitch device itself can be computed by totaling the switching loss and conduction loss.
The switching loss of the device can be computed by the formula -> (Switching Frequency/100kHz)*Drain Capacitance Power at Vin. For more accurate result of losses, you can manually check the switching frequency of the device on whatever input voltage you want to estimate the device losses. The Drain Capacitance Power is what you saw at Figure 22 of the datasheet. The drain voltage is just the (input voltage (VAC) * 1.414) + VOR.
The conduction loss of the device can be computed using the formula -> (Ipri_rms^2)*Rds(on_max). The first variable can be found using your PI-XLs and the second variable can be found on the datasheet of your device.
We do actually have an example of such computation using InnoSwitch, you can refer to page 22-23 of the link below:
an-106_innoswitch3-aq_design_guide.pdf (power.com)
You can find in the document above the computation for power losses of the device.
Kindly reply to this thread if you have further questions.
Thank you.