l6706 STMicroelectronics, l6706 Datasheet - Page 36

• Manufacturer Part Number: l6706
• Description: Vr11.1 Single Phase Controller With Integrated Driver
• Manufacturer: STMicroelectronics

Output voltage monitor and protections
Note:
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OCP during normal operation of the device. This value must take into consideration also the
extra current needed during the dynamic VID transition I
transitions
The device detects an over current when the I
programmable through OCSET pin.
where ΔIL is the inductor ripple current (peak-to-peak).
Since the device always senses the current across the inductor, the I
happen during the HS conduction time: as a consequence of OCP detection, the device will
turn OFF the HS MOSFET and turns ON the LSMOSFET until I
or until the next clock cycle. This implies that the device limits the peak of the inductor
current.
In any case, the inductor current won't overcome the I
maximum peak value to consider in the OC design.
The device works in constant-current, and the output voltage decreases as the load
increase, until the output voltage reaches the UVP threshold. When this threshold is
crossed, MOSFETs are turned off and the device stops working. Cycle the power supply or
the OUTEN pin to restart operation.
Figure 20. Overcurrent protection connection
In order to avoid the OCP intervention during the DVID, the device automatically increases
the OCP threshold to 150% of the selected OCP threshold during every VID transition
(adding an extra
Since the device reads the current information across inductor DCR, the process spread
and temperature variations of these sensing elements has to be considered. Also the
programmable threshold spread (I
spread, see
for details):
Table
15 µs
5) has to be considered for the R
R
OCSET
V
of delay).
OCSET
=
=1.260V (
I
INFO
-----------------------------------------------------------------------------------------------------------------------
Doc ID 15698 Rev 1
DCR MAX )
---------------------------------- -
IOUT
I
OCTH
OCP
OCTH
Rg
(
TYP)
OCP
=
=
current spread as a consequence of V
--------------------- -
R
DCR
------------ -
V
>
Rg
OCSET
OCSET
)
IOUT
R
⋅
V
OCSET
⎛
⎝
OCSET
I
INFO
⋅
OUT
⎛
⎝
I
MAX
OUT
=
(
OCP
overcome the threshold I
1.260 typ
----------------------------
(
OCSET
OCSET
+
OCP
MIN
R
I
OCP
OCSET
D VID
)
D-VID
–
+
)
(
+
ΔIL
-------- -
value and this will represent the
design:
ΔIL
-------- -
2
2
)
(see
⎞
⎠
⎞
⎠
INFO
+
77μA
Section 12: Dynamic VID
OCTH
re-cross the threshold
crossing will
OCTH
OCSET
externally
L6706