ZSPM2000 Datasheet

© 2016 Integrated Device Technology, Inc.

36

January 27, 2016

5.2.

DCR Current Sensing Components

Figure 5.2

Inductor Current Sensing Using the DCR Method

The ZSPM2000 supports the loss-less DCR current sense method. The equivalent DC resistance (DCR) of the

inductor is used to measure the inductor current without adding any additional components into the power path.

The technique is based on matching the time constants of the inductor and the parallel low-pass filter. Therefore

the components R6, R7, and C8 must be selected depending on the selected inductor. The following procedure is

recommended:

1.) Set R7’ = 1k

Ω

2.) Calculate C8’ = L / (DCR * R7’).

3.) Pick capacitor C8 from the appropriate E-series close to C8.

4.) Recalculate R6=R7= L / (DCR * C8) based on the capacitor selected for C8.

ZSPM2000

+Vout

R7

R6

ISNSP

ISNSN

C8

L

DCR