L6722

9 Output voltage monitor and protections

23/34

Figure 12. output voltage protections and typical principle connections

9.4

Feedback disconnection

Output voltage i monitored by the device in two different points:

●

Remotely, through the remote buffer, across VSEN

●

Locally across the CS- pin (negligibly offset by

).

By comparing the voltage present at these two different locations, L6722 is able to understand

if the output voltage feedback is connected. When CS- is more than 1.375V higher than VSEN,

(See Figure 13) the device stops switching with the low side mosfets permanently ON and

drives high the FAULT pin. The condition is latched until VCC or INH cycled.

Figure 13. Feedback disconnection

VCC

+12V

+5V

SB

Vcc

UVLO

OVP

UVLO

VCC

Preliminary OVP Enabled

FBR Monitored

No Protection

Provided

(INH = Free)

OVP Protection

VSEN Monitored

(INH = 0)

Preliminary OVP

FBR Monitor

R

D

I

CS

⋅

L2

L1

L3

DCR1

DCR2

DCR3

PHASE3

PHASE2

PHASE1

CS_DROOP+

CS_DROOP-

FB

x 3

COMP

VSEN

FBR

FBG

VID

FB_DISCONNECTED

1V