Output voltage setting and protections

L6738A

18/32

Doc ID 18134 Rev 2

6.2

Overcurrent threshold setting

The L6738A detects OC when the difference between CSP and CSN is equal to 20 mV

(typ). By properly designing the current reading network, it is possible to program the OC

threshold as desired (See Figure 6).

Time constant matching is, in this case, designed considering:

This means that once inductor has been chosen, the two conditions above define the proper

values for R1 and R2.

Figure 6.

Current reading network

I

OCP

20mV

DCR

----------------

R1

R2

+

R2

----------------------

⋅

=

L

DCR

-------------

R1//R2

() C

⋅

=

L

C

R1

CSP

CSN

R2 (Opt)

DCR