ST EVAL-RHRICL1AFV1, User Manual, Page: 19 / 27

Figure 19. Testing environment
5.1.1.2 Current limit and foldback current programming
The V-I characteristic of a foldback current limiter developed with the EVAL-RHRICL1FV1A evaluation board is
shown below (two curves are depicted, showing the foldback characteristics for two different values of I
F
):
Figure 20. Foldback current limiter characteristic
This behavior is obtained by adding two sensing resistors RS3+ and RS3- between the R
SENSE
terminals and
ISNS+ and ISNS- pins of the RHRPMICL1A device. In addition, the foldback resistor R
FLB
is connected between
the power MOSFET drain and ISNS- pin.
Thanks to this sensing network, the output current in foldback mode, referring to
Figure 20. Foldback current
limiter characteristic , is given by:
I =
VCC − VF − R + RFLB *IFLB − R + RSENSE *IRS
RSENSE
(10)
UM2605
Getting started
UM2605 - Rev 1
page 19/27