TLV62568: PFM knee

Hi Kazuto, 

Can you please elaborate more on this:

"although IL reaches 0A when 0.14A at VOUT=1.2V, 0.2A at VOUT=2.5V respectively. I think it is opposite because delta_IL at VOUT2.5V should be larger than VOUT1.2V "

Please let me know what do you mean by the above statement. It would help me to answer you better. Thank you!

Best regards

Sneha

Hi Sneha,

I mean the IL waveform below. Input the same condition to Power Stage Designer then I got the point when IL_min reaches to 0A.

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Regards,
Kazuto

Hello Kazuto,

The area marked in red below shows an approximate threshold load current value when the PWM to PFM transition occurs. 

The IL should be continuous in PWM mode and discontinuous in PFM mode. In PFM mode, IL (min) should reach zero. So, are you trying to simulate this transition using the power stage designer? 

Best regards

Sneha

Hi Sneha,

Please see my previous post. The load current when IL(min) reaches to zero is different for each output voltage. With VOUT=1.2V, Load=0.14A is the point. With VOUT=2.5V, Load=0.2A, according to the power stage designer. However on Figure 12, the plot for VOUT=1.2V enters PFM from larger current than VOUT=2.5V. I wanted to ask why it is opposite result compare to the calculation.

Regards,
Kazuto

Hi Kazuto,

I will give you a feedback on Monday.

Best regards

Sneha

Hi Sneha, I understood. Thanks for your support!