TLV62569: At what load does it enter Power Save Mode?

Louie

Part Number: TLV62569

Hello,

I am currently using this device to go from 3.3V to 1.8V, and i noticed some ripples/oscillations at around 500mA.

I was wondering when this device goes into power save mode as in my scope captures, the current capture appears to go discontinuous at this load.

Thank you,

Louie

over 7 years ago

0 Emmanuel Granatello over 7 years ago

TI__Expert 3465 points

Hello Louie,

it's a pleasure to support you.

The scope you posted shows a transition between PFM and PWM behaviour, and it is normal on this device. Indeed you can observe that in few switching cycles the device is in PWM (higher current) and then it gets PFM detection (current oscillating around 0A).

0 Louie over 7 years ago in reply to Emmanuel Granatello

TI__Expert 3180 points

Hello,

So at what load point does the device switch from PWM to PFM mode for this device?

Thank you,
Louie

0 Louie over 7 years ago in reply to Louie

TI__Expert 3180 points

Hello,

Just to provide some more information for the first scope capture:
Yellow is the Vout ripple while AC coupled
Blue is the Switch node
Green is the Inductor current measured with current sense proble

Thanks for the help,
Louie

0 Emmanuel Granatello over 7 years ago in reply to Louie

TI__Expert 3465 points

Hi Louie,

this cannot be determined with absolute precision since it depends on the passives (L,Cout) and their tolerances/deratings. Therefore, this value is also not specified by the datasheet.

Though, you can rely on Figure 12 and 13 of the DS, which show the typical Fsw behaviour: when the Fsw starts to drop, that's where the transition starts.

0 Louie over 7 years ago in reply to Emmanuel Granatello

TI__Expert 3180 points

Hello,

Thank you for clarifying this issue up.

Louie

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TLV62569: At what load does it enter Power Save Mode?