LM74720-Q1: Switching frequency of LM74720 boost converter

Kento Adachi

Expert 7065 points

Part Number: LM74720-Q1

Hi team,

I understand switching frequecny of LM74720 boost converter is not fixed and it will be affected external compoenents.

Is there any general switching frequency range the boost converter will have based on typical use-case?
When we want to measure the switching frequency by oscilloscope, does probing LX pin work?
Regards,
Kento

5 months ago

0 Shiven Dhir 5 months ago

TI__Guru 62240 points

Hi Kento,

LX switching frequency is not fixed. Probing LX current will not help.

Regards,

Shiven Dhir

0 Kento Adachi 5 months ago in reply to Shiven Dhir

TI__Expert 7065 points

Hi Shiven,

what I meant is not current but voltage of LX.

Can customer see the switching waveform by proving LX voltage?

Or, if there other pins customer can prove to evaluate the switching frequency in their system?

0 Shiven Dhir 5 months ago in reply to Kento Adachi

TI__Guru 62240 points

Hi Kento,

LM74720 does not have a fixed switching frequency and measuring voltage or current will not help.

Regards,

Shiven Dhir

0 Kento Adachi 5 months ago in reply to Shiven Dhir

TI__Expert 7065 points

Hi Shiven,

Shiven Dhir said:
LM74720 does not have a fixed switching frequency and measuring voltage or current will not help.

Customer understands this. However, they should be able to estimate the expected switching frequency range if there is a pin which represents a SW node of the boost converter.

Thus, please kindly answer the questions below.

1. Can customer see the switching waveform by proving LX voltage?

2. Or, if there other pins customer can prove to evaluate the switching frequency in their system?

Regards,

Kento

+1 Shiven Dhir 5 months ago in reply to Kento Adachi

TI__Guru 62240 points

Hi Kento,

In the datasheet if you see, during first startup, VLX has varying switch frequency. You can probe it and see.

Regards,

Shiven Dhir

0 Kento Adachi 5 months ago in reply to Shiven Dhir

TI__Expert 7065 points

Thank you Shiven!

Regards,

Kento

Power management

Power management forum

LM74720-Q1: Switching frequency of LM74720 boost converter