Description
The SE3901 is a green-mode Pulse Width Modulation
(PWM) controller. It is specifically designed for low
power applications such as 5W-20W Adaptors and
Off-line
battery
Chargers.
In
these
typical
applications, the low standby power, space saving,
and low cost are all required. SE3901 is a perfect
solutions to meet these challenges. The typical
standby power is only 0.13Watt.
In normal operation, the SE3901 switches on and off
at a fixed switching frequency of 60 kHz. With a
current limit capability of about 420mA, the SE3901
can directly drive the emitter of a high voltage NPN
transistor. When the output power falls below a given
level, the IC enters skip cycle mode to reduce power
consumption.
The SE3901 also features Under-Voltage Lockout ,
Over-Temperature
Protection,
Over-Current
and
Short Circuit Protections.
The SE3901 is available in TO-94 Packages.
Features
Internal Zener Diode
Low Cost Emitter Drive PWM Solution
0.13W Standby Power
Current Mode Operation
Short Circuit Protection
Over-Current Protection
Over-Temperature Protection
Under-Voltage Lockout with Auto-restart
Available in TO-94 Packages
RoHS Compliant and 100% Lead (Pb)-Free
Application
Battery Chargers
Universal Off-line Power Supplies
Power Adaptors
LED 3W-9W Lighting Solutions with SE1051
Pin Configuration
TO-94
TOP VIEW
ZENER
OUT
GND
Vcc
Pin Description
Name
VCC
GND
OUT
ZENER
Pin#
1
2
3
4
Function
The power supply of the IC, and is generally connected to opto-coupler's emitter
Supply ground
The output pin, connected to the emitter of NPN transistor.
The output pin, connected to Internal ZENER
Revision 1/20/2009
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc., 2008. • www.seawardinc.com • Page 1
Absolute Maximum Rating
Symbol
VCC
OUT
θ
JA
T
J
T
STG
T
LEAD
DC Supply Voltage
Voltage at OUT
Thermal Resistance Junction to Ambient (TO92)
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering 10 Sec)
Parameter
Maximum
-0.3 ~ 6
-0.3~ 18
220
0 to 125
-40 to 150
260
Units
V
V
°C/W
°C
°C
°C
Electrical Characteristics
(Vcc=4V,
T
J
=25℃,unless
otherwise specified)
Parameter
UVLO SECTION
Start-up Voltage
Minimal Operating
Voltage
THERMAL PROTECT
Thermal Shutdown
Thermal Hysteresis
Symbol
Conditions
Min
Typ
Max
Unit
V
TH
(ST)
V
OPR
(Min)
5.00
3.4
5.25
3.65
5.5
3.9
V
V
T
SD
T
Hy
I
ST
I
CC(OPR)
Vz
Vcc=4V
150
20
℃
℃
0.4
0.7
mA
mA
V
KΩ
STANDBY CURRENT SECTION
Start-up Current
Operating Current
VCC Zener Voltage
Dynamic Impedance
INTERNAL OSCILLATOR
Switching Frequency
DRIVE OUTPUT SECTION
OUT Start-up Voltage
Short Circuit
Threashold Voltage
Maximum Duty Cycle
Minimum Duty Cycle
Driver OUT
On-Resistance
Switch Off Current
Effective Current Limit
OUT Current
Coefficient
Revision 1/20/2009
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc., 2008. • www.seawardinc.com • Page 2
f
50
60
75
KHz
0.22
0.45
I
CC
=10mA
Vcc=3.8 to 4.8V
6
6.3
9
R
VCC
V
ST
V
SC
D
max
V
OPR
(Min)+0.2
Vcc=Vth(st)-0.2
8.5
6
75
3
3
20
420
-0.3
11
V
V
%
%
Ω
R
OUT
I
OUT
=0.06A
Driver off, Vout=10V
40
uA
mA
A/V
I
LIM
G
A
Vcc=
V
OPR
+0.1V
1
220V
R1 10/1W
1N4007
2
Brid g e D1-D4
4
3
220V
R2
100K 1/2W
1.5M 1/4W
R3
C12
2.2uF
D5
1N4007
C8
D7
1N4148
C9
D8 SB240
C10
220uF/15V
R18
1K
8.4V/2A
222M 400V
R12
22K
C12
224
C13
104
BAT1
C10
4.7uF/15V
R5
4.7
U2
Q1
D6
1N4818
R4
400
R6
200
R10
0.8K
R13
470K
R17
60K
BAT2
R11
100
13003
R8
2K
LED-R
LED-G
SE3901
OUT
Z
C4
10uF
Red Green
Vcc
Vctrl
R15
10K
R14
1K
Vcc
3.3n
C5
C6
10uF
Vout Vsense
Ictrl
GND
GND
U1
0.05ohm
R16
Fig.3 8.4V/1A 2 Cell Batteries Charger, using SE3901(TO94) and SE1052.
Note:
SE1052 integrates Voltage reference, Voltage setting and Current setting and LED drivers all in the
same IC. When the charging is on-going, the Red LED is On and the Green LED is Off. When the
Charging is completed, the Green LED is On and the Red LED is Off. The charging current can be
programmed by setting the R16 to the proper value. Please refer to SE1052 datasheet for details.
Revision 1/20/2009
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc., 2008. • www.seawardinc.com • Page 5
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