KAC3305DN [KEC]
Analog CMOS Integrated Circuits; 模拟CMOS集成电路
| 型号： | KAC3305DN |
| 厂家： | 
KEC(KOREA ELECTRONICS) |
| 描述： | Analog CMOS Integrated Circuits |
| 文件： | 总6页 (文件大小：485K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SEMICONDUCTOR
KAC3305DN
Analog CMOS Integrated Circuits
TECHNICAL DATA
700mA White LED Regulating Charge Pump for
Camera Flashes and Movie Lights
D
G
5
8
The KAC3305DN is charge pumps drive white LEDs, including camera
strobes, with regulated current up to 700mA. The very low open-loop
output resistance allows high flash brightness, even from a low battery
input voltage. The adaptive 1 /2 regulating charge pump operation
provides high efficiency while in movie mode or backlighting. Fast
switching allows the use of tiny external components. The KAC3305DN
use an external resistor to set the full-scale LED current.
4
1
E
A
B
Top View
Bottom View
DIM
A
B
MILLIMETERS
_
3.0 0.1
+
_
+
2.3 0.05
_
C
1.6 0.05
+
D
E
1.950 Ref
_
+
0.3 0.05
Features
_
+
0.4
0.05
F
Up to 700mA Output Drive Capability
Current Regulation for Flash
2.7V to 5.5V Supply voltage Range
PWM Dimming Control
Side View
G
H
I
0.65
_
+
0.75 0.05
_
0.203 0.008
0.0 ~ 0.05
+
J
Soft-Start Limits Inrush current
Over Voltage Protection on Output
Low Shutdown Current
TDFN-8
Thermal Shutdown Protection
Applications
White LED Flashes Strobes, and Movie Lights LCD Backlighting
Camera Phones, Cell Phones, and Smart Phones, PDAs, Digital Cameras, and camcorders
Generic Lighting Flash, and Strobo applications
Typical operating Circuit
Pin Configuration
1µF
CN
V
CP
VOUT
EN1
1
Rs
8
5
2.7V to 5.5V
V
OUT
IN
FB
CP
TDFN-8
TOP VIEW
10µF
4.7µF
VIN
CN
GND
KAC3305DN
EN2
GND
4
FB
EN
OFF ON
2007. 8. 22
Revision No : 1
1/6
KAC3305DN
Block Diagram
CP
2
CN
3
V
V
OUT
8
Charge Pump ( 1, 2)
IN
6
OVP
OSC
(1MHz)
Soft Start TSD
+
REFERENCE
EN1
1
FB
7
CONTROL
EN2 4
GND
5
Pin Descriptions
Pin
1
Name
EN1
CP
Function
Current and Shutdown Control Input
Positive terminal of switched capacitor
Negative terminal of switched capacitor
Current and Shutdown Control Input
Ground.
2
3
CN
4
EN2
GND
VIN
5
6
Power supply voltage Input
7
FB
Feedback Input for the Current Control
Output of the charge pump
VOUT
8
2007. 8. 22
Revision No : 1
2/6
KAC3305DN
Absolute Maximum Ratings
Characteristics
Symbol
VIN
Rating
-0.3 to +6.0
-0.3 to (VIN +0.2)
1.6
Units
V
Input supply voltage
Input pin
EN1, EN2
PD
V
W
Maximum Power Dissipation, ( Ta=25
Thermal Resistance
)
62.43
/W
JA
Operating Ambient
Ta
-40 to +85
150
Tj
Junction Temperature Range
Storage Temperature Range
Lead Temperature
Tstg
-65 to +150
300
TLEAD
Electrical Characteristics
(VIN = 3.6V, CIN=10 F, C=1 F, COUT=4.7 F, Ta= 25 , unless otherwise noted.)
Parameter
Input Supply voltage
Symbol
VIN
Conditions
Min
Typ
Max
Units
V
2.7
-
1
5.5
IIN
Supply Current
no load
-
2
mA
ISHUT
tsoft
Shutdown Supply Current
Soft Start time
EN1=EN2=GND
-
-
1
A
ms
V
-
0.3
5.3
300
700
1
-
VOVP
VReg(FB)
IOUT
OUT Overvoltage Protection
FB Regulation Voltage (VOUT-VFB
Maximum OUT Current
-
-
)
EN1=EN2=VIN
VLED=3.8V
270
330
mV
mA
500
-
-
-
-
1 mode
2 mode
ROUT
Open Loop OUT Resistance
4.5
5
-
OUT Internal Pulldown in Shutdown
Switching Frequency
EN1=EN2=GND
-
-
k
FOSC
VEN_IH
VEN_IL
IEN
-
1
-
MHz
V
VIN=2.7V to 5.5V
VIN=2.7V to 5.5V
VEN=0V to 5.5V
EN Logic High Voltage
EN Logic Low Voltage
1.4
-
-
-
-
0.4
1
-
V
Logic Input Current
-
-
A
TSD
Thermal Shutdown Threshold
-
150
2007. 8. 22
Revision No : 1
3/6
KAC3305DN
Application Information
temperature drops back down below 110 , the part
automatically recovers.
Output Current
The KAC3305DN is designed to deliver 200mA of continuos
current and up to 700mA of pulsed current(about 500ms).
The charge pump switching frequency is approximately
1MHz, enabilng the use of small external flying capacitor.
Setting the Output Current
The output regulation current is set by Rs by the equation :
Rs=(VOUT-VFB)/IOUT
Where IOUT is the output current and (VOUT-VFB) is the
reference voltage.
Mode Switching
The resistor power obtained in the full current would be :
The KAC3305DN has two modes of operation to control the
output current : the 1 mode and 2 mode. When VIN is
greater than VOUT, the KAC3305DN regulate the current
through Rs. As VIN decreases and detects a dropout condition,
P=(VOUT-VFB
)
IOUT 300
V 700 A=210 W
For this application, the over 210mW resistor is recom-
mended.
the 2
charge pump starts boosting the output to maintain
Capacitor Selection
the regulation current.
To reduce noise and ripple, it is recommended that low
equivalent series resistance(ESR) ceramic capacitors be used
for both CIN and COUT. Tantalum and aluminum capacitors
are not recommended because of their high ESR. The flying
capacitors control the strength of the charge pump. In order to
achieve the rated output current it is necessary to have at least
1 F of actual capacitance.
Shutdown (EN1=EN2=Low)
When voltage of the ENABLE pin goes under 0.4V, the
KAC3305DN enter the shutdown mode. In shutdown mode,
input current of IC go to zero and there are no current
between output capacitors and transfer capacitor.
Ceramic capacitors with X5R or X7R temperature grade are
recommended for most applications.
Soft-Start
To limit excessive inrush current at turn-on, the KAC3305DN
employs built-in soft-start circuitry. When starting up with an
output voltage that is not near the input voltage, the output
capacitor and flying capacitor are charged directly from the
input until the output voltage approaches the input voltage.
Soft-start is achieved a period of approximately 300 s. If
detects a dropout condition, the KAC3305DN automatically
switches to the 2 mode soft-start.
Power Efficiency
To calculate the power efficiency of a white LED driver chip,
the LED power should be compared to the input power. The
difference between these two numbers represents lost power
whether it is in the charge pump or the current sources. The
power efficiency is given by
= PLED/PIN=(VLED ILED)/(VIN
2
ILED) VLED/2 VIN
Short protection
Layout Considerations
If output is shorted to ground, output current is limited until
VOUT exceeds 2.3V.
Due to its high switching frequency and the transient currents
produced the KAC3305DN, careful board layout is necessary.
The input and output capacitors should be located as close to
the VIN and VOUT as possible to obtain best bypassing. The
flying capacitor should be located as close to the CP and CN
as possible. Connect the exposed pad to GND directly under
the IC and allow sufficient copper area for cooling
Overvoltage Protection
The KAC3305DN has over voltage protection. If the output
voltage rises above the 5.3V threshold, the over voltage
protection shuts off all of the output switches to prevent the
output voltage from rising further.
Thermal Protection
When the temperature of the KAC3305DN rises above 150
, the over temperature protection circuitry turns off the
output switches to prevent damage to the device. If the
2007. 8. 22
Revision No : 1
4/6
KAC3305DN
Start Up
=700mV]
Input and Output Ripples in 1 Mode
[I
OUT
EN
VOUT : 2V/div
VIN : 100mV/div
VOUT : 100mV/div
IOUT : 200mA/div
40µS/div
1µS/div, AC Coupled
Input and Output Ripples in 2 Mode
[I =200mA]
Input and Output Ripples in 2 Mode
[I
=700mA]
OUT
OUT
VIN : 100mV/div
VIN : 100mV/div
VOUT : 100mV/div
VOUT : 100mV/div
1µS/div, AC Coupled
1µS/div, AC Coupled
LED Current vs. Temperature
Efficiency vs. Supply Voltage
[I
=200mA]
OUT
[I
= 700mA]
OUT
210
208
206
204
202
200
198
196
194
192
190
90
80
70
60
50
40
30
20
10
0
VLED = 4.3V
VLED = 3.5V
2.7
3.1
3.5
3.9
V
4.3
4.7
5.1
5.5
-40
-15
10
35
60
85
(V)
TEMPERATURE
(
)
C
IN
2007. 8. 22
Revision No : 1
5/6
KAC3305DN
LED Current vs. Supply Voltage
[I =700mA]
Reference Voltage vs. Temperature
OUT
800
700
600
500
400
300
200
100
0
305
303
301
299
297
295
VLED=3.5V
VLED=4.3V
-40
-15
10
35
60
85
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
VIN (V)
TEMPERATURE
(
)
C
Battery Current vs. Supply Voltage
[I =700mA]
LED Current vs. R
S
OUT
1600
1400
1200
1000
800
600
400
200
0
800
700
600
500
400
300
200
100
0
VLED=3.5V
VLED=4.3V
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
RS (Ω)
V
IN (V)
2007. 8. 22
Revision No : 1
6/6
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