IR3623MPBF_1 IRF [International Rectifier], IR3623MPBF_1 Datasheet - Page 10

• Manufacturer Part Number: IR3623MPBF_1
• Description: HIGH FREQUENCY 2-PHASE, SINGLE OR DUAL OUTPUT SYNCHRONOUS STEP DOWN CONTROLLER WITH OUTPUT TRACKING AND SEQUENCING
• Manufacturer: IRF [International Rectifier]

Internal Regulator
IR3623 features an on-board regulator capable of
sourcing current up to 200mA. This integrated
regulator can be used to generate bias voltage
an example of how this can be used to power the
iP2005A is shown in figure 22.
The output of regulator is protected for short
circuit and thermal shutdown.
Out-of-Phase Operation
The IR3623 drives its two output stages 180
of-phase. In current share mode single output,
the two inductor ripple currents cancel each other
and result in a reduction of the output current
ripple and yield a smaller output capacitor for the
same ripple voltage requirement. Figure 4 shows
two channels inductor current and the resulting
voltage ripple at output.
www.irf.com
HDRV2
Ic
HDRV1
Fig. 4: Current ripple cancellation for output
IL1
0
IL2
DT
T
o
out-
Io
In addition, the 180
input current cancellation. This result in much
smaller input capacitor’s RMS current and
reduces the input capacitor quantity. Figure 5
shows the equivalent RMS current.
Mode Selection
The IR3623 can operate as a dual output
independently regulated buck converter, or as a
2 phase single output buck converter (current
share mode). The SS2 pin is used for mode
selection. In current share mode this pin should
be floating and in dual output mode a soft start
capacitor must be connected from this pin to
ground to program the start time for the second
output.
Independent Mode
In this mode the IR3623 provides control to two
independent output power supplies with either
common or different input voltages. The output
voltage of each individual channel is set and
controlled by the output of the error amplifier,
which is the amplified error signal from the
sensed output voltage and the reference voltage.
The error amplifier output voltage is compared to
the ramp signal thus generating fixed frequency
pulses of variable duty-cycle, (PWM) which are
applied to the external MOSEFT drivers. Figure
23
application.
shows
Fig. 5: Input RMS value vs. Duty Cycle
a
Duty Cycle (Vo/Vin)
typical
o
out of phase contributes to
2 Phase
Single Phase
IR3623MPbF
schematic
for
such
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