LM61460-Q1: LM61460-Q1 PFM Mode

Fery Feng

Intellectual 2270 points

Part Number: LM61460-Q1

Hi team,

What are the requirement for LM61460-Q1 to enter PFM mode? and when will run at PWM mode?

Thanks.

over 4 years ago

0 Frank De Stasi over 4 years ago

TI__Guru 58885 points

Hello

I will direct you question to the application engineer for this device and

we will get back to you as soon as possible.

Thanks

0 Marshall_Beck over 4 years ago in reply to Frank De Stasi

TI__Mastermind 30430 points

PFM is engaged at light load and controlled by peak inductor current value.

Specifications ipeak_min_0 and ipeak_min_100 designate the boundary on peak inductor current value at transition.

Ipeak_min is modulated with duty cycle, hence, the min and max of ipeak_min is given.

If modulated frequency is undesirable and constant frequency operation is needed, factory programmable LM61460AFS opn is available.

0 Fery Feng over 4 years ago in reply to Marshall_Beck

TI__Intellectual 2270 points

Hi Marshall,

What is the meaning of Ipk_min_0 and I_pk_min_100? Also the pulse duration?

0 Marshall_Beck over 4 years ago in reply to Fery Feng

TI__Mastermind 30430 points

Ipeak min varies with duty cycle, as ton time varies.

Ipeak min percentage is based on duty cycle, or on time. As in PFM mode, switched waveform is no longer a true pulse width modulated waveform (ringing when FETs tristates), we describe the on time as pulse duration.A pulse duration of < 100nS would describe the on time for a duty cycle approaching 0% and a pulse duration of >1uS would describe the on time for a duty cycle approaching 100%.

Inductor value will dictate on time.

Power management

Power management forum

LM61460-Q1: LM61460-Q1 PFM Mode