AT1741
Preliminary Product Information
2-Channel PWM Controller for CCFL Backlight
Features
• High-accuracy reference voltage circuit (±2%).
• Built-in short-circuit protection circuit.
• Built-in Undervoltage Lockout protection.
• Internal 2.5V Reference supply.
• Variable Dead time provides control over total
Range.
General Description
The AT1741 is 2-channel PWM switching
regulator controllers that contains an on-chip 2.5V
reference, two error amplifier, an adjustable
oscillator, two dead-time comparators, under-
voltage lockout circuitry and 2 common-emitter
output. It is idea for step-up, step-down, and
inverting converter.
Applications
• LCD CCFL Backlight
• Portable equipment
Block Diagram
Aimtron reserves the right without notice to change this circuitry and specifications.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
WWW:
http://www.aimtron.com.tw
Fax: 886-3-563-0879
Email:
service@aimtron.com.tw
1
AT1741
Preliminary Product Information
2-Channel PWM Controller for CCFL Backlight
Pin Configuration
Ordering Information
Part number
AT1741S
AT1741S_GRE
AT1741D
Package
SOP16
SOP16,Green
DIP16
Marking
AT1741S
AT1741S, date code with one bottom line
AT1741D
Pin Description
Pin No.
Symbol
I/O
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
CT
RT
NON1
INV1
FB1
DT1
OUT1
GND
Vcc
OUT2
DT2
FB2
INV2
NON2
SCP
REF
--
--
I
I
O
I
O
--
--
O
I
O
I
I
--
O
External timing capacitor
External timing resistor
Positive input for error amplifier 1
Negative input for error amplifier 1
Error amplifier 1 output
Output 1 dead time / soft start setting
Output 1
Ground
Power supply
Output 2
Output 2 dead time / soft start setting
Error amplifier 2 output
Negative input for error amplifier 2
Positive input for error amplifier 2
Time latch setting
Reference voltage output（2.5V）
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
WWW:
http://www.aimtron.com.tw
Fax: 886-3-563-0879
Email:
service@aimtron.com.tw
2
AT1741
Preliminary Product Information
2-Channel PWM Controller for CCFL Backlight
Absolute Maximum Ratings
(Ta=+25
0
C)
Parameter
Power supply voltage
Power dissipation
Operating temperture
Storage temperture
Output current
Output voltage
＊2
Should not exceed Pd and values.
Symbol
Vcc
Pd
Topr
Tstg
Io
Vo
Limits
28
500*
1
-30~+85
-55~+125
120*
2
30
Unit
V
mW
℃
℃
mA
V
＊1
When mounted on 70mm×70mm×1.6mm glass epoxy board. Reduced by 6.5mw for each increase in Ta of 1℃ over 25℃.
Recommended Operating Conditions
(Ta=+25
0
C)
Parameter
Power supply voltage
Output current
Output voltage
Error amplifier input voltage
Timing capacitor
Timing resistor
Oscillator frequency
Symbol
V
CC
Io
Vo
V
OM
C
CT
R
RT
F
OSC
Min.
3.6
--
--
0.3
100
5.1
10
Values
Typ.
6.0
--
--
--
--
--
--
Max.
25
100
25
1.6
15000
50
800
Unit
Ｖ
mA
V
V
pF
kΩ
kHz
Timing chart
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
WWW:
http://www.aimtron.com.tw
Fax: 886-3-563-0879
Email:
service@aimtron.com.tw
3
AT1741
Preliminary Product Information
2-Channel PWM Controller for CCFL Backlight
Electrical Characteristics
Parameter
Output voltage
Input stability
Load stability
Oscillation frequency
Frequency deviation
Threshold voltage
Standby voltage
Latch voltage
Source current
Comparator threshold
voltage
Input threshold voltage
（fosc=10kHz）
On duty cycle
Input bias current
Latch mode source
current
Latch input voltage
Threshold voltage
Input offset voltage
Input offset current
Input bias current
Open circuit gain
Common-mode input
voltage range
Common-mode
rejection ratio
Maximum output
voltage
Minimum input voltage
Output sink current
Output source current
Input threshold voltage
（fosc=10kHz）
Saturation voltage
Leak current
Standby current
Average current
consumption
Symbol
Vref
V
DL1
V
DLO
Fosc
F
DV
V
IT
V
STB
V
LT
I
SCP
V
CT
V
t0
V
t100
D
ON
I
BDT
I
DT
V
DT
V
UT
V
IO
I
IO
I
IB
AV
V
OM
CMRR
V
OH
V
OL
I
OI
I
OO
V
t0
V
t100
V
SAT
I
REAK
I
CCS
I
CCA
(unless otherwise noted, Ta=25℃, and Vcc=6V )
Condition
Values
Min. Typ. Max.
Unit
Reference voltage
block
Triangular wave
oscillator
Protection circuit
Iref=1mA
2.45 2.5 2.55 V
Vcc=3.6~25V
--
1
10 mV
Iref=0~5mA
--
1
10 mV
R
RT
=10kΩ, C
CT
=220pF 320 400 480 kHz
Vcc=3.6~25V
--
1
--
%
--
1.48 1.64 1.80 V
No pull up
--
50 100 mV
No pull up
--
30 100 mV
--
-1.5 -2.5 -3.5
μA
Pin 5, Pin 12
Duty cycle=0%
Duty cycle=100%
Divide Vref using 13
kΩ and 27 kΩ
DT1, DT2=2.0V
DT1, DT2=0V
I
DT
=40μA
--
--
--
--
--
Vcc=3.6~25V
--
--
--
FB=1.25V
FB=1.25V
Duty cycle=0%
Duty cycle=100%
Io=75mA
Vo=25V
When output is off
R
RT
=10 kΩ
0.9
1.05
1.2
V
V
V
%
μA
μA
V
V
mV
nA
nA
dB
V
dB
V
1.79 1.97 2.15
1.32 1.48 1.64
60
--
70
-0.1
80
-1
--
--
--
6
30
100
--
1.6
--
--
Rest period
adjustment circuit
-200 -560
2.28 2.48
--
--
--
--
70
0.3
60
2.3
2.53
--
--
15
85
--
80
2.5
Low-voltage input
miss-operation
prevention circuit
Error amplifier
PWM comparator
Output block
Total device
--
0.7 0.9
V
3
20
--
mA
-45 -75
--
μA
1.79 1.97 2.15 V
1.32 1.48 1.64 V
--
0.8 1.2
V
μA
--
0
5
--
1.3 1.8 mA
--
1.6
2.3
mA
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
WWW:
http://www.aimtron.com.tw
Fax: 886-3-563-0879
Email:
service@aimtron.com.tw
4
AT1741
Preliminary Product Information
2-Channel PWM Controller for CCFL Backlight
Timing Curve
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
WWW:
http://www.aimtron.com.tw
Fax: 886-3-563-0879
Email:
service@aimtron.com.tw
5
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