l6706 STMicroelectronics, l6706 Datasheet - Page 33

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

L6706
Note:
14.1
Connecting SSOSC pin to SGND through only the R
Figure
In this case use the following relationship to select F
start time:
Figure 16. Soft-start time (T
Low-side-less startup
In order to avoid any kind of negative undershoot on the load side during startup, L6706
performs a special sequence in enabling LS driver to switch: during the soft-start phase, the
LS driver results disabled (LS = OFF) until the HS starts to switch. This avoid the dangerous
negative spike on the output voltage that can happen if starting over a pre-biased output
(see
This particular feature of the device masks the LS turn-on only from the control loop point of
view: protections are still allowed to turn-ON the LS MOSFET in case of over voltage if
needed.
Figure 17. Low-side-less startup comparison.WITH LS-Less startup
V
Figure
OUT
14), the soft-start time depends on the F
WITHOUT LS-Less startup
17).
LGATE
Doc ID 15698 Rev 1
SS
R
FLIM SS
) vs F
T
D2
–
[
μs
LIMIT
[
]
kΩ
=
]
when using R
-------------------------------- -
F
5.275 10
=
LIMIT
LIMIT
V
-------------------------------- -
F
OUT
2.11 10
LIMIT
[
⋅
kHz
LIMIT
FLIM_SS
selected.
⋅
[
5
kHz
]
WITH LS-Less startup
and as a consequence the soft-
4
]
FLIM_SS
resistor (blue one network in
LGATE
resistor versus SGND
Soft-start
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