BCT3140
1000mA Buck/Boost Charge Pump
LED Driver
BCT3140
1000mA Buck/Boost Charge Pump LED Driver
GENERAL DESCRIPTION
The BCT3140 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 BCT3140 automatically switches modes
between step-up and step-down ensuring that
LED current does not depend on the forward
voltage. It switches at 1.5MHz, allowing the use of
tiny components. The supply voltage ranges from
2.7V to 5.5V and is ideally suited for all
applications powered by a single LI-Ion battery
cell or three to four NiCd, NiMH, or Alkaline
battery cells.
The BCT3140 also features a very low shutdown
current, an automatic soft-start mode to limit
inrush current, as well as over current, over
voltage and over thermal shutdown control.
A low current sense reference voltage (47mV)
allows the use of small 0603 current sensing
resistors.
The BCT3140 is available in Green DFN3x3-10L
package and is specified over an ambient
temperature range of -40°C to +85°C.
FEATURES
Output Current up to 1000mA
Up to 90% Efficiency in Torch Mode
Adjustable FLASH Mode Current
1x and 2x Automatic Modes for High Efficiency
Input Voltage Range: 2.7V to 5.5V
Minimum External Components: No Inductors
High Frequency Operation: 1.5MHz
Low 47mV Reference For Low Loss Sensing
Built-In Soft Start Limits Inrush Current
Low Input and Output Ripple and Low EMI
Output Over Voltage Protection
Over-current and Over-temperature Protection
Available in Green DFN3x3-10L Package
APPLICATIONS
White LED Torch, Flash for Cell
Phones, DSCs and Camcorders
White LED Backlighting
Generic Lighting, Flash and Strobe Applications
General Purpose High Current Boost
ORDERING INFORMATION
Order Number
BCT3140EGG-TR
Package Type
DFN-10
Temperature
Range
-40°C to +85°C
Marking
3140
QTY/Reel
3000
REV1.4
www.broadchip.com
Copyright © BROADCHIP TECHNOLOGY CO., LTD
1
BCT3140
1000mA Buck/Boost Charge Pump
LED Driver
TYPICAL OPERATING CIRCUIT
BCT3140
ABSOLUTE MAXIMUM RATINGS
V
IN
, V
OUT
........................................................-0.3V to 6V
V
EN
……………...............................................0V to 5.5V
Output Current Pulse (Flash)......................................1A
Output Current Continuous (Torch)..........................0.4A
Package Thermal Resistance
DFN3x3-10L,θ
JA
....................................................57℃/W
Storage Temperature Range.................-40℃ to +150℃
Junction Temperature..............................................150℃
Operating Temperature Range.................-40℃ to +85℃
Lead Temperature (Soldering, 10 sec).....................260℃
ESD Susceptibility
HBM.....................................................................2000V
MM.........................................................................200V
CAUTION
This integrated circuit can be damaged by ESD if you don’t
pay attention to ESD protection. Broadchip recommends
that all integrated circuits be handled with appropriate
precautions. Failure to observe proper handling and
installation procedures can cause damage. ESD damage
can range from subtle performance degradation to
complete device failure. Precision integrated circuits may
be more susceptible to damage because very small
parametric changes could cause the device not to meet its
published specifications.
Broadchip reserves the right to make any change in circuit
design, specification or other related things if necessary
without notice at any time. Please contact Broadchip sales
NOTE:
Stresses beyond those listed under “Absolute Maximum Ratings”
may cause permanent damage to the device. These are stress
ratings only, and functional operation of the device at these or any
other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device
reliability.
office to get the latest datasheet.
REV1.4
www.broadchip.com
Copyright © BROADCHIP TECHNOLOGY CO., LTD
2
BCT3140
1000mA Buck/Boost Charge Pump
LED Driver
PIN CONFIGURATION
DFN3x3-10L
TOP VIEW
VIN
C1
C2
FLASH
EN
1
2
3
4
5
GND
10
9
8
7
6
VOUT
PGND
SGND
FB
RSET
PIN DESCRIPTION
PIN
NAME
FUNCTION
1
2
3
VIN
C1
C2
Input voltage for the charge pump. Decouple with 4.7μF or 10μF ceramic
capacitor close to the pins of the IC.
Positive input for the external flying capacitor. Connect a ceramic 1μF capacitor
close to the pins of the IC.
Negative input for the external flying capacitor. Connect a ceramic 1μF capacitor
close to the pins of the IC.
Logic input to toggle operation between FLASH and TORCH mode. In TORCH
mode FB is regulated to the internal 47mV 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 (R
SENSE
) based on desired
current in TORCH mode and FLASH mode.
Shutdown control input. Connect to VIN for normal operation, connect to ground
for shutdown.
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:
V
FB
=(1.26V/R
SET
) X 10.2 KΩ
Feedback input for the current control loop. Connect directly to the current sense
resistor.
Internal ground pin. Control circuitry returns current to this pin.
Power ground pin. Flying capacitor current returns through this pin.
Charge Pump Output Voltage. Decouple with an external capacitor. At least 1μF
is recommended. If Higher value capacitor is used, output ripple is smaller.
Exposed pad should be soldered to PCB board and connected to GND.
4
FLASH
5
EN
6
RSET
7
8
9
10
Exposed
Pad
REV1.4
www.broadchip.com
FB
SGND
PGND
VOUT
GND
Copyright © BROADCHIP TECHNOLOGY CO., LTD
3
BCT3140
1000mA Buck/Boost Charge Pump
LED Driver
ELECTRICAL CHARACTERISTICS
(VIN= 3.6V, C
IN
=4.7uF, C
OUT
=C
F
=1uF, V
SHDN
=V
IN
, T
A
= 25℃, unless otherwise specified.)
PARAMETER
SYM
CONDITIONS
MIN
TYP
Input Voltage Range
Quiescent Current
Shutdown Current
Oscillator Frequency
Charge Pump Equivalent Resistance
(2x mode)
Charge Pump Equivalent Resistance
(1x mode)
FB Reference Voltage
FB Pin Current
EN, FLASH Logic Low
EN, FLASH Logic High
EN, FLASH Pin Current
VOUT Turn-on Time
Thermal Shutdown Temperature
VIN=3.6V,
FB within 90% regulation
250
145
1.2
1
V
FB
I
FB
FLASH=VIN, RSET=56KΩ
FLASH=GND
V
FB
=0.3V
V
IN
I
Q
I
SHDN
V
IN
=2.7V to 5.5V, FLASH=0V,
I
LOAD
=100uA
FLASH=V
IN
, 2x Mode
V
EN
=0V, V
IN
=5.5V
2.7
0.3
2
1
1.5
5
0.6
229
47
1
0.4
uA
MHz
Ω
Ω
mV
uA
V
V
uA
us
℃
MAX UNITS
5.5
V
mA
REV1.4
www.broadchip.com
Copyright © BROADCHIP TECHNOLOGY CO., LTD
4
BCT3140
1000mA Buck/Boost Charge Pump
LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS
Ripple 1X Flash 1000mA
Ripple 1X Torch 200mA
Ripple 2X Flash 1000mA
Ripple 2X Torch 200mA
Start up 1000mA Flash
Start up 200mA Torch
REV1.4
www.broadchip.com
Copyright © BROADCHIP TECHNOLOGY CO., LTD
5
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