SRK2000 STMicroelectronics, SRK2000 Datasheet - Page 9

• Manufacturer Part Number: SRK2000
• Description: SYNCHRONOUS RECTIFIER SMART DRIVER FOR LLC RESONANT CONVERTER
• Manufacturer: STMicroelectronics

SRK2000
5.1.2
1.8 V: if this threshold is exceeded the gate drivers GD1 and GD2 are enabled and the SR
MOSFET is operated; otherwise, the device stays in an idle condition and the SR MOSFET
in the off state.
Using the pull-up resistor R
to Vcc, therefore exceeding V
Essentially, this results in enabling the gate-driving as Vcc exceeds V
as Vcc falls below V
are logic-level types.
Resistor divider configuration
To enable gate-driving with a Vcc voltage higher than a predefined value V
drive a standard SR MOSFET, the EN pin is biased by a resistor divider (R1 upper resistor,
R2 lower resistor) whose value is chosen so as to exceed V
also to set the desired V
at a Vcc level about 2.5% lower than V
comparator.
The equations that describe the circuit in the two crucial conditions Vcc = V
decision of the V
enabled) are respectively:
Figure 6.
Equation 1
Solving these equations for R
EN pin biased with a resistor divider to program the gate-drive UVLO
threshold V
DVS1,2_Off
CCOn
DVS1,2_Off
. This configuration is thereby recommended when SR MOSFETs
CC_G
P
level is made) and Vcc = V
, the voltage on the EN pin rises as I
EN_On
1
Doc ID 17811 Rev 2
and R
⎧
⎪
⎨
⎪
⎩
V
V
level. Note that, with a falling Vcc, gate-driving is disabled
CC
CCOn
and enabling the operation of both SR MOSFETs.
_
2
R
G
CC_G
we get:
1
−
R
1
V
R
+
EN
2
, because of the 45 mV hysteresis of the
R
2
=
I
=
EN
V
+
EN
V
R
_
CC_G
EN
On
2
(when gate-driving is to be
EN_On
EN
Application information
when Vcc = V
is switched off and tends
CCOn
CC_G
and disabling it
CCOn
, to properly
CC_G
(when the
and
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