LM5161: VIN<Vout(setting) condition on diode emulation mode

Kuramochi Tadahiko

Guru 28715 points

Part Number: LM5161

Hi,

When VIN<Vout(setting) and light load condition, how does LM5161 behave on diode emulation mode?

Though I tried to simulate on Webench, it was not executed.

Best Regards,

Kuramochi

over 5 years ago

0 Iven Su over 5 years ago

TI__Expert 8245 points

Hi,

It's on dropout condition, the device will work with minimum off time with a frequency fold-back. You can refer to 8.2.1.2.3 on datasheet, also you can download its model and simulate it. Thanks.

0 Kuramochi Tadahiko over 5 years ago in reply to Iven Su

Guru 28715 points

Iven-san,

Thank you for your help.

Does it mean that diode emulation does't work on dropout condition?
I cannot execute Webench, could you show me waveforms?

Best Regards,

Kuramochi

0 Iven Su over 5 years ago in reply to Kuramochi Tadahiko

TI__Expert 8245 points

Hi,

Diode emulation is not disabled on dropout condition. You can easily use TI-TINA to do some simulations (find its model on below link), thanks.

www.ti.com/.../slvmay6

0 Kuramochi Tadahiko over 5 years ago in reply to Iven Su

Guru 28715 points

Iven-san,

I confirmed on WEBENCH, IL was achieved negative ampere as below.

Is this condition diode emulation mode?

webench_design_6122633_16.TSC

Best Regards,

Kuramochi

0 Iven Su over 5 years ago in reply to Kuramochi Tadahiko

TI__Expert 8245 points

Hi,

Cannot say it's diode emulation mode or not, because diode emulation mode allows 22.5mA negative current.

Power management

Power management forum

LM5161: VIN<Vout(setting) condition on diode emulation mode