ir3502b International Rectifier Corp., ir3502b Datasheet - Page 32
ir3502b
Manufacturer Part Number
ir3502b
Description
Xphase3 Control Ic
Manufacturer
International Rectifier Corp.
Datasheet
1.IR3502B.pdf
(38 pages)
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Droop Resistor
Based on the above calculation R
Pre-select R
find out R
Over Current Threshold
The OCP is fixed at 1.17 V above the VDAC voltage. Therefore, it can be determined as follows
VCCL Drive Resistor R
example, it’s assumed that IR6622 and IRF6628 are used as the control and sync FET respectively.
The minimum input voltage is assumed to be 10.5 V and VCCL is fixed at 6.5V for this design.
Choose a transistor with β(min) of 50. The maximum input voltage is assumed 13.5 V,
Thermistor R
Choose NTC thermistor R
resistance at the allowed maximum temperature T
Select R
range. Then calculate R
R
R
The maximum drive current for the linear regulator is dependent on the type of MosFET used. For this
TMAX
HOTSET
1
HOTSET2
R
Page 32 of 38
DRP
HOTSET
(
R
FB
.
TMAX
HOTSET3
=1 kΩ and using R
3
*
= 931Ω to linearize the NTC, which has non-linear characteristics in the operational temperature
EXP
R
HOTSET
and Over Temperature Setting Resistors R
[
HOTSET1
B
VCCLDRV
I
1
HOTSET
drive
I
6 .
2
HOTSET3
OCP
)
_
( *
R
avg
3
VCCL
DRP
( *
corresponding to the allowed maximum temperature TMAX.
o
DRP
1
3
=0.8 mΩ, G
T
=2.2kΩ, which has a constant of B
L
(
R
can be selected to obtain specific output impedance.
30
. 0
_
1
3
VCCLDRV
1
MAX
35
. 1
3 .
0
) 6
m
n
5
1
8 .
13
k
33
m
T
11
5 .
cs
_
5 .
(
10
V
142
=33.5 along with the converter parameters can be plugged into (24) to
ROOM
n
1
700
)
5 .
MAX
0
V
195
7 .
33
1
700
)]
931
5 .
. 1
0
mA
. 8 (
is,
6
1
k
7 .
5 .
17
2
* )
6 .
5
457
V
. 0
2 .
/
30
10
7 (
35
*
9
k
mA
6
10
m
)
mA
5 .
II
. 1
V
3
. 8 (
1
*
) 6
10
k
EXP
837
5
1
mA
700
HOTSET1
. 3
k
195
[
. 5
63
3520
HOTSET3
618
1
10
k
k
mA
k
k
)
( *
and R
, choose R
273
=3520, and the NTC thermistor
7
182
5 .
HOTSET2
1
k
115
A
HOTSET1
273
IR3502B
1
=3.65kΩ.
25
)]
V3.2
142