ir3084a International Rectifier Corp., ir3084a Datasheet - Page 36

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

Soft Start Capacitor C
Calculate the soft start capacitor from the required soft start time using Equation (9) with Boot Mode;
The soft start delay time can be calculated using Equation (10) with Boot Mode;
The VID sample time can be found using Equation (11);
The power good delay time can be found using Equation (12);
Finally, use Equation (13) to calculate the over-current fault latch delay time;
TD1
Select RFB = 324 ohms and then calculate the droop resistor,
Choose the next standard value higher than this with 1% tolerance or RDRP = 787ohms.
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TD
TD
T
C
RDRP
OCDEL
SS
3
5
/
DEL
=
=
=
=
C
C
C
=
=
. 2
I
=
SS/DEL
CHG
SS
SS
C
RFB
31
VDAC
/
/
SS
DEL
DEL
ms
I
I
/
CHG
40
CHG
DEL
SS/DEL
∗
⋅
*
∗
VSETPT
D



*
. 0
0
1.3V
70
*
∗
10
7 .
−
75
100



and Startup Times
V
VSETPT
*
1
−
V
6
10
−
mV
+
=
−
RFB
−
VDAC
6
0
+
TD
1 .
*
C
=
70
TD
*
RFB
4
+
. 0
10
=
=
*
RDRP
2
* 1
∗
324
10
−
. 0
6
RFB
10
∗
−
* 1
40
6
⋅
0
−
70
. 0
10
7 .
6
. 0
RFB



*
+
*
00494
*
10
015
=
−
=
100
RDRP
6
10
1
. 1
*
−
1 .
6
70
. 0
−
00
−
*
V
6
75
10
+
. 0
*
mS
*
10



. 0
00494
V



−
=
3
1
0195
−
−
−
6
=
0
70
73
1 *
1 .
324
250
*
*
us
1 .
=
10
324
10
us
*
+
787
=
10
−
−
787
6
6
. 0
−
*
1 .
998
3



ohms



1
3 .
=
ms
V
. 0
+
0988
1
1 .
V
uF
*
324
or
0.1uF
IR3084A
324
10/30/2006
+
787


