www.fairchildsemi.com
KA7552A/KA7553A
SMPS Controller
Features
鈥?Built-in drive circuits for direct connection power
MOSFET (l
O
=
鹵1.5A)
鈥?Wide operating frequency range (5kHz ~ 600kHz)
鈥?Pulse by pulse over current limiting
鈥?Over load protection
鈥?On/off control by external trigger
鈥?Internal UVLO
鈥?Low standby current (typ. 90uA)
鈥?Soft start circuit
Description
The KA7552A/KA7553A are switching power control IC
for wide operating frequency range. The internal circuits
include pulse by pulse current limiting, protection, on/off
control by external trigger, low standby current, soft start,
and high current totempole output for driving a POWER
MOSFET. Maximum duty of the KA7552A is 70% and the
KA7553A is 46%. When duty is maximum, the input
threshold voltage of pin2 & pin8 are not same in KA7552A
and KA7553A.
8-DIP
1
Internal Block Diagram
CS
+
_
+
-
0.56 ~ 0.42V
C
T
7
R
T
1
10uA
V
CC
6
8
OSC
7V
UVLO
BIAS
(4V)
OFF
3.6V
2.8V
4.3K
+
-
2.4V
1.9V
+
-
-
-
5
PWM
OUTPUT
0.24V
R
_
+
O.C.P
Q
S
2
FB
3
IS(+)
4
GND
Rev. 1.0.2
漏2004 Fairchild Semiconductor Corporation