ir3084a International Rectifier Corp., ir3084a Datasheet - Page 39

• Manufacturer Part Number: ir3084a
• Description: Xphase Tm Vr 10/11 Control Ic
• Manufacturer: International Rectifier Corp.

Phase Delay Timing Resistors RPHASEx1 to RPHASEx2 (x=1,2,…,7)
The phase delay resistor ratios for phases 1 to 7 at 400kHz are (from the X Phase Excel based design
spreadsheet); RAPHASE1=0.580, RAPHASE2=0.397, RAPHASE3=0.215, RAPHASE4=0.206,
RAPHASE5=0.353 RAPHASE6=0.5 and RAPHASE7=0.647.
Pre select RPHASE11=RPHASE21=RPHASE31=RPHASE41=RPHASE51=RPHASE61=RPHASE71=20k
Calculating the other resistors from the same formula results in; R
R
Phase ICs 1
they will trigger on the negative slope of the RMPOUT waveform. Phase ICs 4
voltage from the 3084A controller connected to their RMPIN+ pin so they will trigger on the positive slope of the
RMPOUT waveform.
Bootstrap Capacitor C
Choose C
Decoupling Capacitors for Phase IC and Power Stage
Choose C
VOLTAGE LOOP COMPENSATION
AL Polymer output capacitors are used in the design, for instructional purposes Type III compensation as shown
in Figure 18(b) will be demonstrated here. First, choose the desired crossover frequency as 1/10 of the switching
frequency, f
PHASE42
Choose C
C
C
R
R
CP
CP
FB
FB
Page 39 of 45
1
R
=
=
=
=
BST
VCC
PHASE
2 (
10
C
4
=
1
2
π
π
=40 kHz, and determine Rcp and C
=0.1uF.
=0.1uF, C
CP1
. 2
*
*
12
*
*
R
49
R
f
f
=100pF to reduce high frequency noise.
=
FB
L
C
C
1
K
CP
PHASE52
E
1
)
*
Ω
=
2
−
*
RA
R
*
C
1
2
RA
VCCL
BST
FB
L
PHASE
E
*
E
1
PHASE
324
*
=
=
V
=0.1uF
C
1
10
o
4
E
π
=
1
*
*
∗
162
*
R
R
40
FB
(
PHASE
220
Ω
*
*
PHASE62
1
10
V
11
*
PWMRMP
3
10
*
=
. 2
162
−
1
9
49
−
. 0
CP
/
Choose R
=
) 7
. 0
58
*
=
2 (
using Equations (30) and (31):
58
10
( *
12
π
3
560
∗
3 .
*
PHASE72
20
nF
40
FB1
3084A controller connected to their RMPIN
*
*
*
10
=162
10
10
−
3
3
6
PHASE22
)
*
=
2
10
( *
27
. 1
)
30
220
6 .
=
Choose C
k
−
Ω
53
*
. 0
10
nF
015
−
9
,
/
−
) 7
FB
130
PHASE32
( *
=10nF
560
1 *
Choose C
*
*
10
10
IR3084A
−
10/30/2006
3
−
6
*
CP
10
=56nF
* )
324
*
0
8 .