LM5022: PMP7764 TI reference design input impedance

Hi Liqi,

You will not find measured input impedance because 1) the characteristic is well understood and 2) trying to measure it directly is difficult.

For any converter with a regulated output, the dc input impedance is simply -Vin/Iin. The worst case occurs at minimum input and maximum load. In the frequency domain, this negative input impedance is flat up until the crossover frequency on the control loop. For stability the input filter is designed such that |Zout(filter)| << |Zin(converter)|.

Best Regards,

Bob Sheehan

Power Design Services