AN8353UB [PANASONIC]
High Efficiency Car Dashboard Dimmer IC; 高效率的汽车仪表板调光IC
| 型号： | AN8353UB |
| 厂家： | 
PANASONIC |
| 描述： | High Efficiency Car Dashboard Dimmer IC |
| 文件： | 总4页 (文件大小：52K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AN8353UB
High Efficiency Car Dashboard Dimmer IC
■ Overview
Unit : mm
The AN8353UB is a dimmer IC to control illumination of the
car dashboard at high efficiency and high performance by pulse
width control. It outputs pulses at a duty proprotional to an
input voltage.
2.4±0.25
3.3±0.25
6.0±0.3
9
8
7
6
5
4
3
2
1
■ Features
•
•
•
•
•
•
Low power consumption by pulse control
External ON/OFF control by the standby pin
Pulse frequency range : 50Hz to 10kHz
Built-in overvoltage protective circuit approx. 20V
Wide operating ambient temperature range : –40˚C to+100˚C
All products temperature cycle, high reliability by normal
and high temperature checks reliability equivalent to the air
bags requested in U.S.
+ 0.1
– 0.05
0.3
3.0±0.3
9-pin SIL Plastic Package (SIP009-P-0000C)
■ Block Diagram
4
9
1
VCC
Over
Voltage
Protector
Control
Voltage
3
Conversion
PWM
Comparator
Triangular
Wave Gen.
GND
2
6
5
7
8
■ Pin Descriptions
Pin No.
Pin name
Description
1
2
3
4
Output pin
GND
Outputs an intermittent source current at a duty proportional to an input voltage
GND
Input pin
Applies a control voltage.
Noise eliminating capacity connection pin 1 Connect a capacitor to eliminator a noise.
Output a triangular wave, which serves as a reference for the PWM signal,
to the Pin6 by connecting the resistor RT between the Pins5 and6, and
capacity CT between the Pin6 and GND.
5
6
Square wave output pin
Output a triangular wave, which serves as a reference for the PWM signal,
to this pin by connecting the resistor RT between the Pins6 and 5, and
capasity CT between the Pin6 and GND.
Triangular wave output pin
7
8
9
Noise eliminating capacity connection pin 2 Connect a capacitor to eliminator a noise.
Forces to shut off an output current if a voltage higher than a threshold
Standby pin
VCC
voltage of 1.1V is applied to the Pin8.
Supply Voltage
■ Absolute Maximum Ratings (Ta=25˚C)
Parameter
Supply voltage
Symbol
VCC
PD
Rating
22
Unit
V
Power dissipation
550
mW
˚C
Storage temperature
Topr
–40 to +100
–50 to +150
Operating ambient temperature
Tstg
˚C
■ Recommended Operating Range (Ta=25˚C)
Parameter
Symbol
VCC
Range
Operating supply voltage range
8 to 18V
■ Electrical Characteristics (Ta=25˚C)
Parameter
Supply current
Symbol
Condition
Eliminate CT and RT
CT=0.027µF
CT=0.027µF
CT=0.027µF
CT=0.027µF
CT=0.027µF
CT=0.027µF
CT=0.027µF
CT=2100pF
min
4
typ
7.5
max
11
Unit
ICC
fosc
mA
Hz
V
Oscillation frequency
0% duty input voltage
100% duty input voltage
Center duty (VCC=12V)
Center duty (VCC=8V)
Center duty (VCC=18V)
Output duty gain
90
2
115
2.5
10
45
0
140
3
VIN– 0
VIN–100
D12V
DD8V
DD18V
DG
9.5
35
–1
–1
45
0.6
10.5
55
1
V
%
%
%
%
V
0
1
50
0.9
0
55
1.2
4
Output voltage at ON
Leakage current at OFF
Over voltage detection voltage
Standby threshold voltage
VON
IL
CT=2100pF
µA
V
VOV
CT=2100pF
18
20
1.1
22
1.65
VSTH
CT=2100pF
0.55
V
■ Application Circuit
• Bipolar Transister Output
• MOS FET Output
AN8353UB
AN8353UB
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
RT
CT
RT
CT
180Ω (3W)
0.056µF
0.1µF
0.1µF
0.1µF
0.1µF
0.056µF
10kΩ
+
+
180kΩ VR
20kΩ
180kΩ VR
20kΩ
33µF
33µF
22V
22V
±
±
2kΩ
10kΩ
1/fOSC=1.705RTCT
1/fOSC=1.705RTCT
■ Supplementary Description
• System Operational Principle
to generate pulses and input them to one end (Pin6) of the
PWM comparator. The triangular wave frequency fOSC can be
freely set from 50Hz to 10kHz, depending on the resistance
value RT connected between the square wave output Pin5 and
triangular wave output Pin6, and capacity value CT connected
between the triangular wave output Pin6 and ground Pin2.
The approximating expression for the then PWM frequency
fOSC is ;
The following describes the operational principle of the
system using the AN8353UB.
As shown in the block diagram in Fig. 1, a battery voltage
is divided by the VR and input to the input Pin3 in accord-
ance with rotation amount. The voltage at the output Pin1 is
controlled by the AN8353UB so that the duty of the ON/OFF
period of the external output transistor will be proportional to
the input voltage, thus controlling a current flowing to the
lamps of the dashboard, etc. to adjust their brightness. Since
the output transistors are saturated at ON time and no current
flows at OFF time, power consumption is low.
1/fOSC=1.705CTRT ······················································(1)
For your refence, Fig. 3 shows the relations among CT, RT,
and oscillation frequency fOSC. The voltage V4, whose voltage
level is made matching the amplitude of the triangular wave
by the control voltage converter, is given to the other input
(Pin4) of the PWM comparator. That is, in Fig. 2 (II), the
input voltage V3 is linearly converted into V4 by the control
voltage converter so that the amplitude of the triangular wave
will be about 20% to 80% of the input voltage input range
(axis of abscissas in Fig. 2 (II)).
The PWM method is used to control the output transistors.
This method, as shown in Fig. 2 I/O Characteristic Chart
(III), generates the triangular wave V6 as a reference signal
0.1µF
Then, a current is supplied from the output Pin1 to turn on
the output transistors during the period (TON) when the
inverted input voltage is larger than the triangular wave. (Fig.
2 (II), (IV)) To the contrary, while the converted input
voltage is smaller than the triangular wave, no current is
supplied from the output Pin1and the output transistors are
turned off. The output pulse duty is expressed as follows.
Duty=TON · fOSC ······················································(2)
For the duty control characteristic of the output pulses to the
input voltage V3, the duty of the output pulses is controlled
from 0% to 100% at high-precision linearity while the “input
voltage V3/supply voltage V9” is between about
C1
4
9
Control
voltage
converting
circuit
Battery
±
Over
voltage
protection
3
PWM
compa-
rator
10kΩ
1
2
+
–
Tranguian
waveform
generator
6
5
7
8
RT
0.1µF
C2
CT
STB
Fig. 1 AN8353UB Block Diagram
1M
100k
10k
1k
■ Supplementary Description (cont.)
• System Operational Principle (cont.)
VCC=12V
VIN=6V
0.2 (B-point) and 0.8 (C-point). The A-point in the figure
shows the I/O characteristics when the “input voltage V3/sup-
ply voltage V9” is 0.7. And, when V3/V9 is from 0.05V to
about 0.2V (B-point), the duty is controlled to 0%, and when
V3/V9 is from 0.8V (C-point) to t.0V, the duty is controlled to
100%.
The standby Pin8 can forcibly turn off the output transistors
by applying a voltage of about 1.1V or more to this pin.
When it is not necessary to forcibly turn off the output tran-
sistors, Leave the standby Pin8 open.
CT=0.001µF
CT=0.01µF
CT=0.1µF
100
10
100%
Duty
C
Turn-up Line
(I)
A
CT=1µF
50%
1k
10k
100k
1M
10M
Resistance RT (Ω)
0.5
1
0%
1
Fig. 3 Relations between Oscillation Frequency and CT and RT
B
V3/V9
(III)
(II)
V4/V9
max V6/V9
• Duty D1 vs. Input Voltage VIN
C´
V4/V9
V6/V9
(VCC=12V)
A´
0.5
0
D1
100%
B´
max V6/V9
t
0.5
1
(IV)
V3/V9
V1
DG
D12V
TON
1/fOSC
Duty=TON · fOSC
t
Fig. 2 I/O Characteristic Chart
0%
VIN–0
4V
6V
8V VIN–100
VIN
· Output voltage at ON VON · Leakage current at OFF
V 1–2
VON=VCC –V1–2
IL=
IMΩ
• Over voltage Detecting Voltage vs. Output
• Standby Threshold Voltage vs. Output
D1
D1
50%
0%
50%
0%
0
VSTH
VOV
V8–2
V9–2
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