AT1380A [AIMTRON]
Switching Regulator Controller for LCD Bias; 开关稳压器控制器的LCD偏置
| 型号： | AT1380A |
| 厂家： | 
AIMTRON TECHNOLOGY |
| 描述： | Switching Regulator Controller for LCD Bias |
| 文件： | 总12页 (文件大小：332K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Features
General Description
• 2.5 to 15 V supply voltage operating range.
• Low current consumption: 6 mA in operation,
1 µA or less in stand-by.
The AT1380A is a single-channel PWM control IC
for DC/DC conversion with soft start function and
short circuit detection. Adjustable soft start is
programmed with an external capacitor on SCP
pin. The AT1380A is ideal for up, down and fly-
back conversion.
• 20 kHz to 1 MHz operation frequency range.
• Provides a fixed output current with minimal
supply voltage fluctuations by using an external
resistor to set the output current.
• Totem-pole output.
• Built-in soft start circuit.
• Built-in timer-latch short circuit detection and
protection circuit (SCP).
Applications
• LCD Displays
• PDAs
• Digital Still Cameras
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
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
1
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Pin Configuration
Ordering Information
Part number
Package
Marking
AT1380AS
AT1380AS
SOP8
_
SOP8, Pb-Free
SOP8, Green
AT1380AS, Date Code with one bottom line
AT1380AS PBF
_
AT1380AS, Date Code with two bottom line
AT1380AS GRE
AT1380AP
TSSOP8
AT1380AP
_
TSSOP8, Pb-Free
AT1380AP, Date Code with one bottom line
AT1380AP PBF
_
TSSOP8, Green
AT1380AP, Date Code with two bottom line
AT1380AP GRE
Pin Description
Pin No. Symbol
I/O
Description
1
2
3
4
5
6
7
IN-
I
Error amplifier inverting input
SCP
—
—
I
Soft start and SCP setting capacitor connection
VCC
Power supply
BR/CTL
OUT
Output current setting
O
—
—
Totem-pole type output
GND
OSC
Ground
Capacitor and resistor connection pin for setting the oscillation
frequency
8
FB
O
Error amplifier output
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
2
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Absolute Maximum Ratings
(Ta=+250C)
Parameter
Symbol
Condition
Rated Value
Unit
Min.
Max.
Power supply voltage
Output source current
Output sink current
Allowable dissipation
VCC
—
—
—
—
—
—
-30
-55
15
-50
50
V
+
IO-
—
mA
mA
mW
IO
—
PD
570
SOP-8, Ta ≦+25°C
PD
430
+85
+125
mW
TSSOP-8, Ta ≦+25°C
Operating temperature
Storage temperature
ESD Classification
TOP
—
—
0C
Tstg
0C
MIL-STD-883
Class 2
* : When mounted on a 10 cm square double-sided epoxy board
WARNING: Do not exceed these ratings. IC devices can be permanently damaged by stress (voltage,
current, temperature, etc.) in excess of absolute maximum ratings.
Recommended Operating Conditions
(Ta=+250C)
Parameter
Symbol
Values
Typ.
Unit
Min.
Max.
Power supply voltage
VCC
VI
2.5
-0.2
-0.2
-20
--
--
13.5
Ｖ
Ｖ
Error amplifier input voltage
BR/CTL pin input voltage
Output source current
Output sink current
--
1.0
VBR
--
VCC
--
40
--
--
5000
10.0
10000
1000
+85
Ｖ
+
IO
--
ｍＡ
ｍＡ
μＦ
μＦ
Ω
ｋΩ
pF
kHz
°C
-
IO
--
SCP pin capacitance
CPE
CP
--
0.1
0.1
390
3.0
270
500
+25
Phase compensation capacitance
Output current setting resistance
Timing resistance
--
RB
150
1.0
100
10
RT
Timing capacitance
CT
Oscillation frequency
fOSC
TOP
Operating temperature
-30
WARNING: Recommended operating conditions are normal operating ranges for the IC device. All the
device’s electrical characteristics are warranted for operation within these ranges. Use IC devices only
within the recommended operating conditions. Operation outside these ranges may adversely affect the
reliability and can result in device failure.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
3
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Electrical Characteristics
(VCC=+3.0V, Ta=+250C)
Parameter
Symbol
Condition
Values
Unit
Min. Typ. Max.
VCC Under voltage Reset voltage for
VR
--
1.8 1.9
V
Lockout
falling Vcc. OUT
remains off if Vcc is
below this level.
Startup voltage for
rising Vcc.
(U.V.L.O.)
--
VTH
2.4 2.5 2.6
V
Charging current
ICS
Vts
VSCP=0V
-1.5 -1.0 -0.7
0.7 0.8 0.9
μA
V
Soft start
Voltage at soft start
--
--
completion
Short circuit
Charging current
ICPC
VtPC
fOSC
f∆V
f∆T
VT
VSCP=0V
-1.5 -1.0 -0.7
0.7 0.8 0.9
μA
V
detection (S.C.P.)
Threshold voltage
Oscillation frequency
400 500 600 kHz
RT=3kΩ, CT=270pF
VCC=2.5V to 13.5V
Sawtooth waveform
oscillator (OSC)
Frequency input
--
2
10
%
Stability
Frequency variation
with temperature
Input threshold
Voltage
Ta =-300C to 850C
VFB = 450mV
--
5
--
%
480 500 520 mV
VT input stability
VT variation with
Temperature
VT∆V VCC=2V to 13.5V
VT∆T Ta = -300C to 850C
--
--
5
1
20 mV
--
%
Input bias current
IB
VIN = 0V
-1.0 -0.2 1.0
70 100 145 V/V
μA
Error amplifier
Voltage gain
AV
--
--
Frequency bandwidth
Maximum output
voltage range
BW
AV = 0 dB
--
6
-- MHz
+
VOM
VOM
0.78 0.87 --
-- 0.05 0.2
V
V
μA
μA
%
_
+
Output source current
Output sink current
Maximum duty cycle
IOM
IOM
VFB = 450mV
--
24
75
-40 -24
40
--
_
--
85
Idle period
TDUTY
RT=3.3kΩ, CT=270pF
fOSC = 500KHz
adjustment section
VOH1
VOH2
1.0 1.2
0.8 1.0
--
--
V
V
RB= 390Ω, IO= -15 mA
RB= 750Ω, VCC = 3.0V
IO= -10 mA
Output voltage
Output section
VOL1
VOL2
--
--
0.1 0.2
0.1 0.2
V
V
RB= 390Ω, IO= -15 mA
RB= 750Ω, VCC = 3.0V
IO= -10 mA
+
Output source current
Output sink current
Pull down resistance
IO
--
40
20
-40 -30 mA
70
30
RB= 390Ω, VO = 0.9V
-
IO
--
40
mA
ｋΩ
RB= 390Ω, VO = 0.3V
RO
--
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
4
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Pin voltage
VBR
IOFF
ION
IBR
ICCS
0.10 0.19 0.25
V
RB= 390Ω
Output current
Setting section/
Control section
Input off condition
Input on condition
Pin current range
Stand-by current
--
-20
--
-1.8
--
--
--
--
0
-45
-0.1
1
μA
μA
ｍＡ
μA
BR/CTL pin open or --
Entire device
VCC
Average supply current
ICC
RB= 390,
--
6
10.0
ｍＡ
VCC =2.5~13.5V
Timing Chart
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
5
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Typical Application Schematic
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
6
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
7
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Functional Description
Soft Start SCP
Figure 1. Soft-Start SCP circuit
At power-on, the AT1380A enters the soft-start mode to prevent current spike and overshoot. The
capacitor CS is charged from 0V at a constant current of 1µA.
The soft-start time for the duty cycle
tS = 0.8×CS(µF)
When VSCP reaches 0.8V, the AT1380A leaves the soft-start mode to enter the normal mode and enable
the SCP function. If the output load conditions change rapidly causing the output to drop suddenly, the
external capacitor CS will start to charge because the error amplifier output (FB pin) is fixed at VOM
.
+
When the external capacitor is charged above 0.8V, the output pin is set low. Once the latch circuit has
set, the capacitor CS will be discharged to low state and the latch circuit will not reset until power is
turned off or the power supply is restarted.
Short-circuit detection time (or full soft-start time) :
tPE = 0.8×CS(µF)
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
8
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Setting Oscillating Frequency
The oscillator circuit generates a triangular sawtooth wave with a peak of 0.8V and a trough of 0.1V
using the timing capacitor (CT) and the timing resistor (RT) that are connected to the OSC pin. This
oscillator can provide oscillating frequency in the range from 20KHz to 1MHz. The waveform of the
OSC pin is shown as Figure 2.
Figure 2 Oscillator Waveform
The cycle (T) can be determined as follows:
t
VX
VH
VX = VHe−CT×RT
t = −CT × RT × loge (
)
T = −CT × RT × loge (0.1/ 0.8) = 2.1×CT × RT s
[ ]
Switching Regulator Function
(1) Reference voltage circuit
A temperature-compensated reference voltage (~1.25V) is generated by the reference voltage
circuit from the voltage supplied by the power supply pin (pin 3). The circuit also sets the idle
period besides providing the reference voltage for the switching regulator.
(2) Error amplifier
The error amplifier detects the output voltage of the switching regulator and sets the PWM
control signal. The voltage gain is fixed. The system is made stable by connecting a phase
compensation capacitor to the FB pin (pin 8).
(3) PWM comparator
The voltage comparator includes one inverting and three non-inverting inputs. The comparator is
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
9
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
a voltage to pulse width converter that controls the ON time of the output pulse depending on the
level of input voltage. The output level remains high when the sawtooth wave is lower than the
error amplifier output voltage, the soft start setting voltage, and the idle period setting voltage.
(4) Output circuit
The output circuit can drive an external NPN transistor directly and has a totem pole
configuration. The value of the ON/OFF current can be set by a resistor connected to the
BR/CTL pin (pin 4). Stand-by mode (supply current 1µA or less) can be set by connecting the
BR/CTL pin (pin4) to VCC or by making the pin open.
(5) Under-Voltage Lockout (UVLO)
Transients during powering on or instantaneous glitches in the supply voltage can cause the
control IC to malfunction and damage the system. To prevent malfunction at low input voltage,
the circuit compares the supply voltage to the internal reference voltage to detect a low input
voltage. Once detected, the circuit sets the output pin low.
To cancel the status, set VCC below the reset voltage VR (0.9V) and then set VCC up to the
recommended operation range and the latch will be restored to operate normally.
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
10
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Small Outline 8-pin Plastic SOL
INCHES
MILLIMETERS
SYMBOL
NOTES
MIN
MAX
MIN
MAX
A
B
C
D
E
0.188
0.149
0.228
0.197
0.158
0.244
4.80
3.80
5.80
5.00
4.00
6.20
-
-
-
-
-
-
-
0.050 BSC
1.27 BSC
0.013
0.020
0.010
0.069
0.019
0.010
0.050
0.33
0.10
1.35
0.28
0.19
0.40
0.51
0.25
1.75
0.48
0.25
1.27
F
0.004
0.053
0.011
0.007
0.016
H
J
K
M
L
-
0.150 REF
3.81 REF
-
-
-
e1
α
450
450
00
80
00
80
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
11
AT1380A
Preliminary Product Information
Switching Regulator Controller for LCD Bias
Small Outline 8-pin TSSOP
INCHES
MILLIMETERS
SYMBOL
MIN
NOTES
MAX
MIN
MAX
A
0.114
0.169
0.244
0.122
0.177
0.260
2.90
4.30
6.20
3.10
4.50
6.60
-
-
-
-
-
-
-
-
B
C
D
E
0.026 BSC
0.65 BSC
0.010
0.002
0.041
0.012
0.006
0.047
0.25
0.05
1.05
0.30
0.15
1.20
F
H
K
M
α
0.005 BSC
0.127 BSC
0.020
0.028
0.50
0.70
00
80
00
80
-
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: 886-3-563-0878
Fax: 886-3-563-0879
WWW: http://www.aimtron.com.tw
Email: service@aimtron.com.tw
12
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