Pin settings
Table 2. Pin description
(continued)
N°
11
Name
GND
Description
L6911E
All the internal references are referred to this pin. Connect it to the PCB signal
ground.
This pin is an open collector output and is pulled low if the output voltage is not
within the above specified threshlds.
If not used may be left floating.
This pin is connected to the source of the upper mosfet and provides the return
path for the high side driver. This pin monitors the drop across the upper mosfet
for the current limit.
High side gate driver output.
Bootstrap capacitor pin. Through this pin is supplied the high side driver and
the upper mosfet. Connect through a capacitor to the PHASE pin and through
a diode to Vcc (catode vs boot).
Power ground pin. This pin has to be connected closely to the low side mosfet
source in order to reduce the noise injection into the device
This pin is the lower mosfet gate driver output
Device supply voltage. The operative supply voltage range is from 4.5 to 12V.
DO NOT CONNECT V
IN
to 12V if V
CC
IS 5V.
Over voltage protection. If the output voltage reach the 15% above the
programmed voltage this pin is driven high and can be used to drive an
external SCR that crowbar the supply voltage.
If not used, it may be left floating.
Oscillator switching frequency pin. Connecting an external resistor from this pin
to GND, the external frequency is increased according to the equation:
5
⋅
10
-
f
S
=
200kHz
+ -------------------
R
T
(
kΩ
)
6
12
PGOOD
13
14
15
PHASE
UGATE
BOOT
16
17
18
PGND
LGATE
VCC
19
OVP
20
RT
Connecting a resistor from this pin to Vcc (12V), the switching frequency is
reduced according to the equation:
4
⋅
10
-
f
S
=
200kHz
– -------------------
R
T
(
kΩ
)
If the pin is not connected, the switching frequency is 200KHz.
The voltage at this pin is fixed at 1.23V. Forcing a 50µA current into this pin, the
built in oscillator stops to switch.
7
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