MP6922—DUAL FAST TURN-OFF INTELLIGENT CONTROLLER
BLOCK DIAGRAM
LL
RCP
VDD
PGND
EN
VD1
VS1
VG1
VS2
VD2
VG2
Figure 1—Functional Block Diagram
OPERATION
The MP6922 supports operation in DCM, CCM
and CrCM condition. Operating in either a DCM
or CrCM condition, the control circuitry controls
the gate in forward mode and will turn the gate
off when the MOSFET current is fairly low. In
CCM operation, the control circuitry turns off the
gate when very fast transients occur.
CCM condition in LLC converter, otherwise shoot
through may occur)
VD Clamp
Because VD1,2 can go as high as 180V, a High-
Voltage JFET is used at the input. To avoid
excessive currents when Vg goes below -0.7V, a
small resistor is recommended between VD1,2 pin
and the drain of the external MOSFET.
Blanking
The control circuitry contains blanking function.
When it pulls the MOSFET on/off, it makes sure
that the on/off state at least lasts for some time.
The turn on blanking time is ~1us, which
determines the minimum on-time. During the turn
on blanking period, the turn off threshold is not
totally blanked, but changed to ~+50mV (instead
of 0mV). This assures that the part can always
be turned off even during the turn on blanking
period. (Albeit slower, so it is not recommended
to set the synchronous period less than 1μs at
Under-Voltage Lockout (UVLO)
When VDD is below UVLO threshold, the part falls
into sleep mode and Vg is pulled down by a
10kΩ resistor.
Enable pin
If EN is pulled low, the part is in sleep mode.
Thermal shutdown
If the junction temperature of the IC exceeds
150oC, Vg will be pulled low and the part
MP6922 Rev. 1.23
9/19/2012
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