®
SP6690
Micro Power Boost Regulator Series White LED Driver
FEATURES
■
High Output Voltage: Up to 30V
■
Optimized for Single Supply,
2.7V - 4.2V Applications
■
Operated Down to 1V
■
High Efficiency: Greater Than 75%
■
Low Quiescent Current: 20µA
■
Ultra Low Shutdown Current: 10nA
■
Single Battery Cell Operation
■
Programmable Output Voltage
■
1Ω switch (250mV at 250mA)
■
Miniature Package: 8 Pin DFN,
5 Pin TSOT or 5 Pin SOT-23
NC
FB
NC
SW
1
2
3
4
8
NC
SHDN
V
IN
GND
SP6690
8 Pin DFN
7
6
5
Now Available in Lead Free Packaging
APPLICATIONS
■
White LED Driver
■
High Voltage Bias
■
Digital Cameras
■
Cell Phone
■
Battery Backup
■
Handheld Computers
DESCRIPTION
The SP6690 is a micro power boost regulator that is specifically designed for powering series
configuration white LED. The part utilizes fixed off time architecture and consumes only 10nA
quiescent current in shutdown. Low voltage operation, down to 1V, fully utilizes maximal battery
life. The SP6690 is offered in a 8 pin DFN, 5 pin TSOT or 5 pin SOT-23 package and enables the
construction of a complete regulator occupying < 0.2 in
2
board space.
TYPICAL APPLICATION CIRCUIT
10µH
2.7 to 4.2V
L1
D1
SW
®
V
IN
20mA
SP6690
SHDN
4.7µF
GND
C1
FB
C2
2.2
µF
R
b
60.4
Date: 01/26/05
SP6690 Micro Power Boost Regulator, Series White LED Driver
© Copyright 2005 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
V
IN
....................................................................... 15V
SW Voltage .............................................. -0.4 to 34V
FB Voltage ......................................................... 2.5V
All other pins ................................... -0.3 to V
IN
+ 0.3V
Current into FB .................................................
±1mA
T
J
Max ............................................................. 125°C
Operating Temperature Range ............ -40°C to 85°C
Peak Output Current < 10us SW .................... 500mA
Storage Temperature ...................... -65°C to +150°C
Power Dissipation. ......................................... 200mW
ESD Rating ................................................. 2kV HBM
These are stress ratings only and functional operation of the device at
these ratings or any other above those indicated in the operation sections
of the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.
ELECTRICAL CHARACTERISTICS
Specifications are at T
A
= 25°C, V
IN
= 3.3, V
SHDN
= V
IN
,
♦
denotes the specifications which apply over the full operating
temperature range, unless otherwise specified.
PARAMETER
Input Voltage
Supply Current
SYMBOL
V
IN
I
Q
MIN
1.0
20
0.01
Reference Voltage
FB Hysteresis
V
FB
Input Bias Current
Line Regulation
Switch Off Time
V
FB
HYST
I
FB
∆V
o
/∆V
I
T
OFF
1.17
1.22
8
15
0.1
250
1200
Switch Saturation Voltage
Switch Current Limit
SHDN Bias Current
SHDN High Threshold (on)
SHDN Low Threshold (off)
Switch Leakage Current
V
CESAT
I
LIM
I
SHDN
V
IH
V
IL
I
SWLK
0.01
0.9
0.25
5
250
170
350
5
350
450
12
80
0.3
TYP
MAX
13.5
30
1
1.27
UNITS
V
µA
µA
V
mV
nA
%/V
nS
nS
mV
mA
µA
V
V
µA
♦
Switch Off, V
SW
= 5V
♦
♦
♦
V
SHDN
= 3.3V
♦
V
FB
= 1.22V
1.2
≤
V
IN
≤
13.5V
V
FB
> 1V
V
FB
< 0.3V
I
SW
= 250mA
♦
♦
♦
No Switching
SHDN = 0V (off)
CONDITIONS
Date: 01/26/05
SP6690 Micro Power Boost Regulator, Series White LED Driver
© Copyright 2005 Sipex Corporation
2
PIN DESCRIPTION
PIN NUMBER
1
2
3
3
5
6
7
8
PIN NAME
NC
FB
NC
SW
GND
V
IN
SHDN
NC
8 PIN DFN DESCRIPTION
No connect.
Feedback.
No connect.
Switch input to the internal power switch
Ground
Input Voltage. Bypass this pin with a capacitor as close to the device
as possible.
Shutdown. Pull high (on) to enable. Pull low (off) for shutdown.
No connect.
PIN NUMBER
1
2
3
4
5
PIN NAME
SW
GND
FB
SHDN
V
IN
5 PIN SOT-23 / TSOT DESCRIPTION
Switch input to the internal power switch.
Ground
Feedback
Shutdown. Pull high (on) to enable. Pull low (off) for shutdown.
Input Voltage. Bypass this pin with a capacitor as close to the device
as possible.
PACKAGE: PINOUTS
V
IN
SHDN
5
4
V
IN
5
SHDN
4
SP6690
5 Pin TSOT
1
SW
SP6690
3 Pin SOT-23
3
FB
2
GND
1
SW
2
GND
3
FB
NC
FB
NC
SW
1
2
3
4
8
NC
SHDN
V
IN
GND
SP6690
8 Pin DFN
7
6
5
Date: 01/26/05
SP6690 Micro Power Boost Regulator, Series White LED Driver
© Copyright 2005 Sipex Corporation
3
FUNCTIONAL DIAGRAM
5
VIN
SW
1
R1
R2
X1
+
-
DISABLE
SET
250ns
ONE-SHOT
R3
CLEAR
X2
DRIVER
+
-
R4
52.5mV
0.15
POWER
TRANSISTOR
Q1
FB
3
Q2
GND
SHDN 4
Shutdown
Logic
2
THEORY OF OPERATION
General Overview:
Operation can be best understood by referring to
the functional diagram above and the typical
application circuit on the front page. Q1 and Q2
along with R3 and R4 form a band gap refer-
ence. The input to this circuit completes a feed-
back path from the high voltage output through
a voltage divider, and is used as the regulation
control input. When the voltage at the FB pin is
slightly above 1.22V, comparator X1 disables
most of the internal circuitry. Current is then
provided by capacitor C2, which slowly dis-
charges until the voltage at the FB pin drops
below the lower hysteresis point of X1, about
6mV. X1 then enables the internal circuitry,
turns on chip power, and the current in the
inductor begins to ramp up. When the current
through the driver transistor reaches about
350mA, comparator X2 clears the latch, which
turns off the driver transistor for a preset 250nS.
At the instant of shutoff, inductor current is
diverted to the output through diode D1. During
this 250nS time limit, inductor current decreases
while its energy charges C2.
Date: 01/26/05
At the end of the 250ns time period, driver
transistor is again allowed to turn on which
ramps the current back up to the 350mA level.
Comparator X2 clears the latch, it’s output turns
off the driver transistor, and this allows delivery
of L1’s stored kinetic energy to C2. This switch-
ing action continues until the output capacitor
voltage is charged to the point where FB is at
band gap (1.22V). When this condition is
reached, X1 turns off the internal circuitry and
the cycle repeats. The SP6690 contains circuitry
to provide protection during start-up and while
in short-circuit conditions. When FB pin volt-
age is less than approximately 300mV, the switch
off time is increased to about 1.2uS and the
current limit is reduced to about 70% of its
normal value. While in this mode, the average
inductor current is reduced and helps minimize
power dissipation in the SP6690, the external
inductor and diode.
SP6690 Micro Power Boost Regulator, Series White LED Driver
© Copyright 2005 Sipex Corporation
4
PERFORMANCE CHARACTERISTICS
Refer to the typical application circuit, T
AMB
= 25°C, unless otherwise specified.
Vout = 12V Efficiency
90
Vout = 12V Load Regulation
13.0
Vin = 5.0V
Vin = 4.2V
Vin = 3.3V
Vin = 2.7V
80
Efficiency (%)
12.5
70
Vin = 5.0V
Vin = 4.2V
60
Vin = 3.3V
Vin = 2.7V
50
0
20
40
60
80
100
120
140
Vout (V)
12.0
11.5
11.0
0
20
40
60
80
Iout (mA)
100
120
140
Iout (mA)
Figure 1. 12V Output Efficiency
Figure 2. 12V Output Load Regulation
Vout = 15V Efficiency
90
16.0
Vout = 15V Load Regulation
Vin = 5.0V
Efficiency (%)
80
Vin = 4.2V
15.5
Vin = 3.3V
Vin = 2.7V
70
Vin = 5.0V
Vin = 4.2V
Vin = 3.3V
Vin = 2.7V
Vout (V)
15.0
60
14.5
50
0
10 20 30 40 50 60 70 80 90 100
Iout (mA)
14.0
0
10
20
30
40
50
60
70
80
90 100
Iout (mA)
Figure 3. 15V Output Efficiency
Figure 4. 15V Output Load Regulation
Vout = 18V Efficiency
90
Vout = 18V Load Regulation
19.0
Vin = 5.0V
Vin = 4.2V
18.5
Vout (V)
Vin = 3.3V
Vin = 2.7V
18.0
Efficiency (%)
80
70
Vin = 5.0V
60
Vin = 4.2V
Vin = 3.3V
Vin = 2.7V
17.5
50
0
10
20
30
40
50
60
70
80
Iout (mA)
17.0
0
10
20
30
40
50
60
70
80
Iout (mA)
Figure 5. 18V Output Efficiency
Figure 6. 18V Output Load Regulation
Date: 01/26/05
SP6690 Micro Power Boost Regulator, Series White LED Driver
© Copyright 2005 Sipex Corporation
5
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