IR3094PBF 데이터 시트보기 (PDF) - International Rectifier
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IR3094PBF Datasheet PDF : 29 Pages
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IR3094PBF
PWM Operation
The IR3094 is a fully integrated 3 phase interleaved PWM control IC which uses voltage mode control with trailing
edge modulation. A high-gain wide-bandwidth voltage type Error Amplifier in the Control IC is used for the voltage
control loop. The PWM block diagram of the IR3094 is shown in Figure 2.
C D AC
R D AC
VR EF
U30
IROSC
CLK1
CLK2 CLK2
CLK3 CLK3
OSC BLOC K
OVP SET
OVP LATCH
S
Q
OVP RESET
QB
R
VOSN S-
VDAC
ERROR AMPLIFIER
PWM COMPARATOR
-
+
RSFF
S
Q
QB
R
RESET DOMINANT
I R OSC / 2
9p
0. 6V
FB
CCOMP
RCOMP
EAOU T
I R OSC
RDRP VDRP
VDRP BUFFER
RFB
SC OMP2
0.575V
0% DUTY CYCLE
C LK2
PWM COMPARATOR
R SF F
S
Q
-
QB
R
+
RESET DOMINANT
IROSC
Share Adjust Error Amp
+
9p
-
0 TO IROSC*3/4
0.6V
CSC2
RSC2
RSFF
C LK3
S
PWM COMPARATOR
Q
EAOUT
-
QB
R
+
RESET DOMINANT
IROSC
SC OMP3
CSC3
RSC3
Share Adjust Error Amp
+
9p
-
0 TO IROSC*3/4
0.6V
VDAC
VDAC
VDAC
X23.5
-
+
X23.5
-
+
X23.5
-
+
VI N
GATEH 1
GATEL1
1
2
RCS1 CCS1
GATEH 2
GATEL2
VI N
1
2
RCS2 CCS2
GATEH 3
GATEL3
VI N
1
2
RCS3 CCS3
C SI N M3
C SI N P3
C SI N M2
C SI N P2
C SI N M1
C SI N P1
VOUT SENSE+
VOUT+
COUT
VOUT-
VOUT SENSE-
Figure 2 – PWM Block Diagram
Refer to Figure 3. Upon receiving a clock pulse, the RSFF is set, the internal PWM ramp voltage begins to
increase, the low side driver is turned off, and the high side driver is then turned on. For phase 1, an internal 9pf
capacitor is charged by a current source that proportional to the switching frequency resulting in a ramp rate of
50mV per percent duty cycle. For example, if the steady-state operating switch node duty cycle is 10%, then the
internal ramp amplitude is typically 500mV from the starting point (or floor) to the crossing of the EAOUT control
voltage. When the PWM ramp voltage exceeds the Error Amplifier’s output voltage, the RSFF is reset. This turns
off the high side driver, turns on the low side driver, and discharges the PWM ramp to 0.6V until the next clock
pulse.
Page 11 of 29
09/26/05
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