KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
FEATURES
DESCRIPTION
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The KB3386 is a current regulated charge pump ideal for
powering high brightness LEDs for camera flash applications.
The charge pump can be set to regulate two current levels for
FLASH and TORCH modes. The KB3386 automatically switches
modes between step-up and step-down ensuring that
LED current does not depend on the forward voltage. A low
current sense reference voltage (50mV) allows the use
of small 0603 current sensing resistors. The KB3386 is .
offered in 10-pin DFN package.
Output Current up to 400mA
Up to 94% Efficiency in Torch Mode
Automatic Softstart Limits Inrush Current
Adjustable FLASH Mode
x1 and x2 Automatic Modes for High Efficiency
Minimum External Components: No Inductors
High Frequency Operation: 2.4 MHz
Low 50mV Reference for low Loss Sensing
1+A Shutdown Current
PWM Dimming Control
Automatic Switchover Between Buck/Boost
Overvoltage Protection on Output
Overcurrent/Temerature Protection
Low Ripple and EMI
Space Saving 10-pin 3mm x 3mm DFN
Package
APPLICATIONS
■ White LED Torch/Flash for Cell
Phones, DSCs, and Camcorders
■ Generic Lighting/Flash/Strobe
Applications
■ White LED Backlighting
VIN
1
10
VOUT
C1
2
9
PGND
C2
3
8
SGND
FLASH
4
7
IFB
EN
5
6
ISET
KB3386
10 Pin DFN
Now Available in Lead Free Packaging
APPLICATION CIRCUIT
VIN
(2.7 - 5.5V)
CIN
2.2+F
VIN
CFC
0.47+F
2
C1
KB3386 PGND
9
3
C2
SGND
8
TORCH/FLASH
4
FLASH
5
ENABLE
EN
VOUT
400mA FLASH
10
1
FB
7
RSET
6
COUT
1+F
WLED
FB=150mV
RSET
106K 1
RSENSE
0.331
1
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
PIN CONFIGURATION
VOUT
PGND
SGND
IFB
ISET
10
9
8
7
6
TOP VIEW
TOP Marking
XXXX
1
2
3
4
5
VIN
C1
C2
FLASH
EN
86ER
yyyy
XXXX: LOT number
yyyy: Data code
ORDER INFORMATION
Part number
KB3386ER
: Pin 1
Package
DFN-10,GREEN
Marking
86ER
PIN DESCRIPTION
PIN NUMBER
PIN NAME
DESCRIPTION
1
VIN
Input Voltage for the charge pump. Decouple with 2.2+F ceramic
capacitor close to the pins of the IC.
2
C1
Positive input for the external fly capacitor. Connect a ceramic 0.47+F
capacitor close to the pins of the IC.
3
C2
Negative input for the external fly capacitor. Connect a ceramic
0.47+F capacitor close to the pins of the IC.
4
FLASH
Logic input to toggle operation between FLASH and TORCH mode.
In TORCH mode FB is regulated to the internal 50mV reference. In
FLASH mode FB reference voltage can be adjusted by changing the
resistor from RSET pin to ground. Choose the external current sense
resistor (RSENSE) based on desired current in TORCH mode.
5
EN
Shutdown control input. Connect to VIN for normal operation, connect
to ground for shutdown.
6
RSET
Connect a resistor from this pin to ground. When in FLASH mode
(FLASH = High) this resistor sets the current regulation point
according to the following: VFB = (1.26V/ RSET)*11.2K1.
7
FB
Feedback input for the current control loop. Connect directly to the
current sense resistor.
8
SGND
Internal ground pin. Control circuitry returns current to this pin.
9
PGND
Power ground pin. Fly capacitor current returns through this pin.
10
VOUT
Charge Pump Output Voltage. Decouple with an external capacitor.
At least 1uF is recommended. Higher capacitor values reduce output
ripple.
2
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
0
400mA Buck/Boost Charge Pump LED Driver
ABSOLUTE MAXIMUM RATINGS
(Ta=+250C)
VIN , VOUT ...................................................................... -0.3V to 6V
Output Current Pulse (Flash) .......................... 500mA
Output Current Continuous (Torch) ................. 200mA
Storage Temperature ...................... -65°C to +150°C
Operating Temperature ..................... -40°C to +85°C
VEN ......................................................... ZeroV to 7V
3x3 10 DFN .........................................OJA = 57.1°C/W
ESD Rating. ................................................ 2kV HBM
ELECTRICAL CHARACTERISTICS
0
(Ta=+25 C)
TA = -40°C to +85°C, VIN = 3.6, CIN = 2.2+F, CFC = 0.47+F, COUT = 1.0+F. VSHDN = VIN, typical values at 25°C. The
z denotes the specifications which apply over the full operating range unless otherwise noted.
PARAMETER
Operating Input Voltage
MIN.
TYP.
2.7
Quiescent Current
0.5
MAX.
UNITS
CONDITIONS
5.5
V
z
3
mA
z
2
Shutdown Current
FLASH = VIN, 2x mode
1
Oscillator Frequency
V IN = 2.7 - 5.5V FLASH = 0Volts,
Iload = 100µA
2.4
µA
V IN = 5.5V, VEN = 0Volts
MHz
Charge Pump Equivalent
Resistance (x2 mode)
5
V FB = 0Volts, VIN = 3.6V
Charge Pump Equivalent
Resistance (x1 mode)
0.6
0.8
V IN= 3.6V
FB Reference Voltage
138
150
162
mV
z
FLASH = VIN R SET = 106K
FB Reference Voltage
45
50
55
mV
z
FLASH = GND
FB Pin Current
0.5
µA
EN, FLASH Logic Low
0.4
V
z
V
z
0.5
µA
z
500
µs
z
EN, FLASH Logic High
1.3
EN, FLASH Pin Current
V OUT Turn-on Time
250
Thermal Shutdown
Temperature
145
V FB = 0.3V
V IN = 3.6V, FB within 90% of
regulation
ºC
3
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 3.6, Typical Application, TA = 25°C unless otherwise noted.
Torch Mode 150mA Iout
250
D1 = AOT 2015HPW-1915B LED.
Flash Mode 400mA Iout
600
500
200
IOUT (mA)
(mA)
400
150
Iout
Vf = 3.5V
100
Vf = 3.3V
Vf = 4.1V
200
Vf = 3.8V
Vf = 3.5V
Vf = 3.1V
50
300
100
Vf = 3.2V
Vf = 3.0V
0
3.0
3.2
3.4
3.6
Vin (V)
3.8
4.0
0
3.0
4.2
Figure 1. Output Current vs. Supply Voltage (CIN =
2.2+F, CFC = 0.47+F, COUT = 1.0+F
Torch Mode 150mA Efficie
3.2
3.6
VIN (V)
3.8
4.0
4.2
Figure 2. Output Current vs. Supply Voltage (CIN =
2.2+F, CFC = 0.47+F, COUT = 1.0+F
Flash Mode 400mA Efficie
100
100
3.4
90
Efficiency (%)
Efficiency (%)
Vf = 4.1V
80
Vf = 3.5V
70
Vf = 3.3V
Vf = 3.1V
60
Vf = 3.8V
Vf = 3.5V
80
Vf = 3.2V
70
60
Vf = 3.0V
50
40
3.0
90
50
3.2
3.4
3.6
Vin (V
3.8
4.0
4.2
Figure 3. Efficiency vs. Supply Voltage (CIN = 2.2+F,
CFC = 0.47+F, COUT = 1.0+F)
40
3.0
3.2
3.4
3.6
Vin (V
3.8
4.0
4.2
Figure 4. Efficiency vs. Supply Voltage (CIN = 2.2+F,
CFC = 0.47+F, COUT = 1.0+F)
Recommended PCB Layout
4
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
FUNCTIONAL DIAGRAM
CLK
RSET BLOCK
RSET 6
+
RSET
{ }
1.26V
V= RSET
RSET REF
BG REF
+
- 1.26V
RESISTOR
TAPS
COUNTER
32 COUNT
FB REF
1
MUX
2x1
50mV 0 s
+
-
FB 7
FB COMP
FB
COM P
SGN 8
ONE
SHOT
x11.2kohms
FLASH 4
FLASH=1, S=1, RSET REF
FLASH=0, S=0, 50mV
SET
DOMINANT
S
0
CLR
R
EN 5
VIN 1
MODE SWITCH
0 =1X
1=2X
135C ON
THERMAL FAULT
OVER TEMP COMP
145C OFF
2.4MHZ
CLK
CHARGE
PUMP
SWITCHES
C1
C2
VOUT
CLK
PGND
THEORY OF OPERATION
The KB3386 is a charge pump regulator
designed for converting a Li-Ion battery
voltage of 2.7V to 4.2V to drive a white LED
used in digital still camera Flash and Torch
applications. The KB3386 has two modes
of operation which are pin selectable for
either Flash or Torch. Flash mode is usually
used with a pulse of about 200 to 300
milliseconds to generate a high intensity
Flash. Torch can be used continuously at a
lower output current than Flash and is often
used for several seconds in a digital still
camera “movie” mode.
The KB3386 also has two modes of operation to control the output current, the 1X
mode and 2X mode. Operation begins after
the enable pin EN receives a logic high, the
bandgap reference wakes up after 200+sec,
and then KB3386 goes through a soft-start
mode designed to reduce inrush current.
The KB3386 starts in the 1X mode, which
acts like a linear regulator to control the
output current by continuously monitoring
the feedback pin FB. In 1X mode, if the
KB3386 auto detects a dropout condition,
which is when the FB pin is below the
5
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
APPLICATION INFORMATION
regulation point for more than 32 cycles of
the internal clock, the KB3386 automatically switches to the 2X mode. The KB3386
remains in the 2X mode until one of four
things happens: 1) the enable pin EN has
been toggled, 2) the Flash pin has changed
from high to low, 3) VIN is cycled or 4) a
thermal fault occurs. The 2X mode is the
charge pump mode where the output can be
pumped as high as two times the input
voltage, provided the output does not exceed the maximum voltage for the KB3386,
which is internally limited to about 5.5V. In
the 2X mode, as in the 1X mode, the output
current is regulated by the voltage at the FB
pin.
In the Torch mode, (Flash = GND) the Flash
pin is set to logic low and the KB3386 FB pin
regulates to 50mV output:
VFB = 50mV (Torch Mode)
When in Flash mode, (Flash = VIN), the FB
regulation voltage is set by the resistor RSET
connected between the RSET pin and SGND
and the equation:
VFB = (1.26V/ RSET)*11.2K1 (Flash Mode)
Where 1.26V is the internal bandgap reference voltage and 11.2K1 is an internal
resistance used to scale the RSET current.
Typical values of RSET are 40K1 to 180K1
for a range of VFB = 300mV to 75mV in Flash
mode.
The output current is then set in either Flash
or Torch mode by the equation:
IOUT = VFB / RSENSE
Manufacturers/ Website
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
Murata/www.murata.com
Murata/www.murata.com
Murata/www.murata.com
Murata/www.murata.com
Part Number
C1005X5R0J474K
C1005X5R0J105K
C1608X5R0J225K
C1608X5R0J475K
GRM155R60J474KE19D
GRM155R60J105KE19D
GRM188R60J225KE19D
GRM188R60J475KE19D
_______________OVERTEMPERATURE
PROTECTION
When the temperature of the KB3386 rises
above 145 degrees Celsius, the over temperature protection circuitry turns off the
output switches to prevent damage to the
device. If the temperature drops back down
below 135 degrees Celsius, the part automatically recovers and executes a soft start
cycle.
____________________OVERVOLTAGE
PROTECTION
The KB3386 has over voltage protection. If
the output voltage rises above the 5.5V
threshold, the over voltage protection shuts
off all of the output switches to prevent the
output voltage from rising further. When the
output decreases below 5.5V, the device
resumes normal operation
____________________OVERCURRENT
PROTECTION
The over current protection circuitry monitors the average current out of the VOUT =
50mV (Torch Mode) pin. If the average
output current exceeds approximately
1Amp, then the over current protection circuitry shuts off the output switches to protect the chip.
Capacitance/
Voltage
0.47uF/6.3V
1uF/6.3V
2.2uF/6.3V
4.7uF/6.3V
0.47uF/6.3V
1uF/6.3V
2.2uF/6.3V
4.7uF/6.3V
Capacitor
ESR at
Size/Type/Thickness 100KHz
0402/X5R/0.55mm
0402/X5R/0.55mm
0603/X5R/0.9mm
0603/X5R/0.9mm
0402/X5R/0.55mm
0402/X5R/0.55mm
0603/X5R/0.8mm
0603/X5R/0.8mm
0.03
0.03
0.03
0.02
0.03
0.03
0.03
0.02
Table 1: Recommended Capacitors
6
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
APPLICATION INFORMATION
The KB3386 charge pump circuit requires 3
capacitors: 4.7+F input, 1+F output and
0.47+F fly capacitor are typically recommended. For the input capacitor, a larger
value of 10+F will help reduce input voltage
ripple for applications sensitive to ripple on
the battery voltage.
All the capacitors
should be ceramic to obtain low ESR, which
improves bypassing on the input and output
and improves output voltage drive by reducing output resistance. X5R or X7R Ceramic
capacitors are recommended for most applications. A selection of recommended capacitors is included in Table 1. The input
and output capacitors should be located as
close to the VIN and VOUTpins as possible to
obtain best bypassing, and the returns
should be connected directly to the PGND pin
or to the thermal pad ground located under
the KB3386. The fly capacitor should be
located as close to the C1 and C2 pins as
possible.
The sense resistor Rsense is determined by
the value needed in the Torch mode for the
desired output current by the equation:
RSENSE = VFB / IOUT where VFB = 50mV (Torch
Mode)
Part Reference
RSET
RSET
RSET
RSET
RSET
RSET
RSET
RSET
RSET
RSET
RSENSE
RSENSE
RSENSE
RSENSE
RSENSE
Value
68k
75k
82k
91k
100k
110k
120k
130k
140k
150k
0.22
0.27
0.33
0.39
0.47
Once the RSENSE resistor has been selected
for Torch mode, the VFB voltage can be
selected for Flash mode using the following
equation:
VFB = IOUT *RSENSE (Flash Mode) where IOUT is
for Flash Mode
Next, the RSET resistor can be selected for
Flash mode using the following equation:
RSET = (1.26V/ VFB)*11.2K1 (Flash Mode)
For an example of 150mA Torch mode and
400mA Flash mode, the values RSENSE =
0.331, VFB = 135mV (Flash Mode), and RSET
= 106K1 are calculated. The power obtained in the Flash mode would be:
PFLASH = VFB *IOUT = 133mV*400mA = 53mW.
The typical 0603 surface mount resistor is
rated at 1/10 Watt continuous power and
1/5 Watt pulsed power, more than enough
for this application. For other applications,
the PFLASH can be calculated from the resistor size selected. The RSENSE resistor is
recommended to be size 0603 for most
applications.
Tolerance
5%
Size
0402
5%
5%
5%
5%
5%
5%
5%
5%
5%
5%
5%
5%
5%
5%
0402
0402
0402
0402
0402
0402
0402
0402
0402
0603
0603
0603
0603
0603
Manufacturers
any
any
any
any
any
any
any
any
any
any
Panasonic or
Panasonic or
Panasonic or
Panasonic or
Panasonic or
Vishay
Vishay
Vishay
Vishay
Vishay
Table 2: Resistor values and sizes
7
KB3386
Kingbor Technology Co.,Ltd
TEL:(86)0755-26508846 FAX:(86)0755-26509052
400mA Buck/Boost Charge Pump LED Driver
PACAGE DESCRIPTION
PACKAGE: 10 PIN DFN
D
D/2
ø
E/2
A
(A3)
E
A1
Seating Plane
SIDE VIEW
Pin1 Designator
to be within this
INDEX AREA
(D/2 x E/2)
TOP VIEW
D2
D2/2
1
2
3
4
5
INDEX AREA
(D/2 x E/2)
E2/2
E2
K
L
10
9
e
8
7
6
b
BOTTOM VIEW
3x3 10 Pin DFN
SYMBOL
Dimensions in Millimeters:
Controlling Dimension
MIN
0.80
0.00
A
A1
A3
K
ø
b
D
D2
E
E2
e
L
0.20
0º
0.18
2.20
1.40
0.30
NOM
0.90
0.02
0.20 REF
0.25
3.00 BSC
3.00 BSC
0.50 BSC
0.40
Kingbor Technology
TEL:(86) 0755-83095458 FAX: (86) 0755-88364052 www.kingbor.com
MAX
1.00
0.05
14º
0.30
2.70
1.75
0.50
Dimensions in Inches
Conversion Factor:
1 Inch = 25.40 mm
MIN
NOM
MAX
0.032
0.036
0.039
0.000
0.001
0.002
0.008 REF
0.008
0º
14º
0.008
0.010
0.012
0.119 BSC
0.087
0.106
0.119 BSC
0.056
0.069
0.020 BSC
0.012
0.016
0.020
8