ETC EUP3651

芯美电子
EUP3651
4-Channel, 1X/1.5X Charge Pump
White LED Driver
DESCRIPTION
FEATURES
The EUP3651 is a high efficiency charge pump white
LED driver. It supports 4 white LEDs with regulated
constant current for uniform intensity. The EUP3651
maintains the highest efficiency by utilizing a 1.5X
fractional charge pump and low dropout current
regulators. A low external parts count (two 1uF flying
capacitors and two small 1uF capacitors at VIN and
VOUT) makes the EUP3651 ideally suited for small
battery-powered applications.
The EN logic input is used to enable, disable, and set
current with a 16-step linear scale.The LED current can
be configured between 5mA and 25mA. If EN is kept
low for more than 1.5ms, the EUP3651 enters shutdown
mode.
The EUP3651 is available in a 12-pin 3mm x 3mm
TDFN package.
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1X/1.5X Mode for Ultra-High Efficiency
Up to 25mA Output Current for Each Channel
2.7V to 5.5V Input Voltage
1MHz Fixed Switching Frequency
Single-Wire Serial Pulse Interface to Set LED
Current with 16-step Linear scale
Soft Start Function
Built-In Short-Circuit Protection
Built-in Thermal Protection
IQ<1uA in Shutdown
TDFN-12 Package
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIONS
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Mobile phone
Small LCD Backlighting
Programmable Current Sinks
White Photo Flash for Digital Cameras
Typical Application Circuit
Figure 1.
DS3651
Ver1.0
Feb. 2008
1
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芯美电子
EUP3651
Block Diagram
Figure 2.
DS3651
Ver1.0
Feb. 2008
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芯美电子
EUP3651
Pin Configurations
Package Type
Pin Configurations
TDFN-12
Pin Description
PIN
NAME
1
LED4
2
EN
Device enable (active high) and 1 wire control input
3
C1P
Bucket capacitor 1, positive terminal
4
C1N
Bucket capacitor 1, negative terminal
5
VOUT
Charge pump output, connect to LED anodes
6
C2P
Bucket capacitor 2, positive terminal
7
C2N
Bucket capacitor 2, negative terminal
8
VIN
Charge pump input, connect to battery or supply
9
GND
Ground
10
LED1
LED1 cathode terminal
11
LED2
LED2 cathode terminal
12
LED3
LED3 cathode terminal
EP
TAB
Connect to GND on the PCB
DS3651
Ver1.0
Feb. 2008
DESCRIPTION
LED4 cathode terminal
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芯美电子
EUP3651
Ordering Information
Order Number
Package Type
Marking
Operating Temperature range
EUP3651JIR1
TDFN-12
xxxxx
P3651
-40 °C to 85°C
EUP3651 □ □ □ □
Lead Free Code
1: Lead Free 0: Lead
Packing
R: Tape & Reel
Operating temperature range
I: Industry Standard
Package Type
J: TDFN
DS3651
Ver1.0
Feb. 2008
4
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芯美电子
EUP3651
Absolute Maximum Ratings
„
„
„
„
„
Input Voltage (VIN)
----------------------------------------------------------- -0.3V to +6V
EN/SET to GND Voltage (VEN/SET)
---------------------------------- -0.3V to VIN +0.3V
Maximum DC Output Current (IOUT)
----------------------------------------------- 150mA
Operating Junction Temperature Range (TJ) ------------------------------- -40°C to +150°C
Maximum Soldering Temperature (at leads, 10 sec)
------------------------------300°C
Operating Ratings
„
„
Maximum Power Dissipation (PD) ------------------------------------------------------- 2W
Operating Temperature (θJA)
--------------------------------------------------------- 50°C/W
Electrical Characteristics
(Over recommended operating conditions unless specified otherwise) VIN = 3.6V, EN = High, TAMB = 25℃.
EUP3651
Symbol
Parameter
Conditions
Min
Typ
Max
VIN
Operating Voltage
3
5.5
1X mode, no load
IQ
Quiescent Current
ISD
Shutdown Current
VEN = 0V
LED Current Accuracy
EN Falling Edges = 1
ILED-ERR
1.5X mode, no load
ILED-LED-ERR LED Channel Matching
Any two channel mismatch
Output Resistance (open loop)
FOSC
Charge Pump Frequency
1.5X mode
Output short Circuit Current Limit
VOUT < 0.5V
1.5X mode, IOUT = 100mA
0.75
V
0.65
1
mA
2
2.5
mA
1
µA
27.5
mA
3
%
25
-3
1X mode, IOUT = 100mA
ROUT
ISC
22.5
Units
1.75
Ω
4
Ω
1
1.25
MHz
250
mA
VHYS
1.5X to 1X Transition Hysteresis
400
mV
TDLY
Transition Filter Delay
500
µs
TSD
Thermal Shutdown
160
℃
THYS
Thermal Hysteresis
20
℃
IEN
EN Input Leakage
-1
VHI
EN Logic High Level
1.6
VLO
EN Logic Low Level
TSETUP
1
µA
V
0.4
V
EN setup from shutdown
10
TLO
EN program low time
0.5
100
µs
THI
EN program high time
0.5
100
µs
TOFF
EN low time to shutdown
1.5
EN Delay to DATA
500
TDATADLY
DS3651
Ver1.0
Feb. 2008
µs
ms
1000
5
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µs
芯美电子
EUP3651
Typical Operating Characteristics
Shutdown Current vs. Temperature
2.40
0.5
2.20
0.4
Shutdown Current (uA)
Quiescent Current (mA)
Quiescent Current vs. Temperature
2.00
1.80
1.60
0.3
0.2
0.1
0.0
-40
-20
0
20
40
60
80
-40
-20
0
Temperature (℃ )
1200
1.10
1100
Frequency (kHz)
Normalized LED Current
1.20
1.00
0.90
60
80
1000
900
0.80
800
-40
-20
0
20
40
60
80
Temperature (℃ )
-40
0
20
40
Temperature (℃)
Quiescent Current vs. Input Voltage
Frequency vs. Input Voltage
2.50
-20
60
80
1200
-40℃
-40℃
25℃
2.00
25℃
85℃
1100
Frequency (kHz)
Quiescent Current (mA)
40
Frequency vs. Temperature
Normalized LED Current vs. Temperature
85℃
1.50
1.00
1000
900
800
700
0.50
2.7
3.2
3.7
4.2
4.7
2.7
5.2
Ver1.0
Feb. 2008
3
3.3
3.6
3.9
Input Voltage (V)
Input Voltage (V)
DS3651
20
Temperature (℃ )
6
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EUP3651
Efficiency vs. Load Current
Efficiency vs. Input Voltage
90
100
85
80
Efficiency (%)
Efficiency (%)
90
80
70
75
70
65
60
60
VIN=3.6V
55
VIN=4V
Load Currnet=40mA
50
50
20.00
30.00
40.00
50.00
60.00
70.00
3
80.00
3.2
Load Current (mA)
3.6
3.8
4
4.2
Efficiency vs. Input Voltage
90
90
85
85
80
80
Efficiency (%)
Efficiency (%)
Efficiency vs. Input Voltage
75
70
65
75
70
65
60
60
55
55
Load Currnet=60mA
Load Currnet=80mA
50
50
3
DS3651
3.4
Input Voltage (V)
3.2
3.4
3.6
3.8
4
3
4.2
3.2
3.4
3.6
3.8
Input Voltage (V)
Input Voltage (V)
Enable Transient Response
Shutdown Timeout
EN
EN
VOUT
VOUT
VLED
VLED
IIN
IIN
Ver1.0
Feb. 2008
4
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4.2
芯美电子
EUP3651
40mA Load at VIN=3V
80mA Load at VIN=3V
VIN
VIN
VOUT
VOUT
VLED
VLED
40mA Load at VIN=3.6V
DS3651
80mA Load at VIN=3.6V
VIN
VIN
VOUT
VOUT
VLED
VLED
Ver1.0
Feb. 2008
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芯美电子
EUP3651
The LED current vs. EN series pulses edges as the
Figure 4.
LED Current vs. Pulse Edges
Basic Operation
At power-up, the EUP3651 starts operating in 1X
mode where the output will be approximately equal to
the input supply voltage (less any internal voltage
losses). If the output voltage is sufficient to regulate
all LED currents, the device remains in 1X operating
mode.
If the input voltage is insufficient or falls to a level
where the regulated currents cannot be maintained, the
device automatically switches into 1.5X mode (after a
fixed delay time of about 500µs). In 1.5X mode, the
output voltage is approximately equal to 1.5 times the
input supply voltage (less any internal voltage losses).
If the device detects a sufficient input voltage is
present to drive all LED currents in 1X mode, it will
change automatically back to 1X mode.
25
LED Current (mA)
20
15
10
5
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
EN Pulse Falling Edges
Figure 4. LED Current vs. Single Wire Series Pulse
Falling Edges
Unused LED Channels
The EN Serial Pulses Interface
The current of the four LED channels can be
configured by the EN logic input. By pulsing this
signal with a specific protocol, the internal registers
can be written into and then configure LEDs with the
desired current.
The EN serial pulses timing diagram see Figure 3.
For applications with 3 LEDs or less, unused LEDs
can be disabled by connecting the LED pin directly to
VOUT, as shown on Figure 5. If LED pin voltage is
within 1V of VOUT, then the channel is switched off
and a 8µA test current is placed in the channel to sense
when the channel moves below VOUT – 1V.
Figure 3. EN Timing Diagram
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DS3651
The device requires a minimum 10us delay
TSETUP to ensure the initialization of the
internal logic at power-up.
TLO and THI must be between within 500ns to
100us.
Once the final rising edge of DATA1 pulses
transfer completed, the user must wait for
more than 500us before transferring another
DATA2 pulse falling edge.
To power-down the device, the EN input
should be kept low for a duration TOFF of
1.5ms or more.
To power-down the device, the EN input
should be kept low for a duration TOFF of
1.5ms or more. When power-down, all
registers data are lost and reset to default
value.
Ver1.0
Feb. 2008
Figure 5. 3 LEDs Application
Protection Mode
If an LED is disconnected, the output voltage VOUT
automatically limits at about 5.8V. This is to prevent
the output pin from exceeding its absolute maximum
rating.
If the die temperature exceeds 160°C the driver will
enter a thermal protection shutdown mode. When the
device temperature drops by about 20°C the device
will resume normal operation.
LED Selection
LEDs with forward voltages (VF) ranging from 1.3V
to 4V may be used with the EUP3651. Selecting LEDs
with lower VF is recommended in order to improve the
efficiency by keeping the driver in 1X mode longer as
the battery voltage decreases.
For example, if a white LED with a VF of 3.3V is
selected over one with VF of 3.5V, the EUP3651 will
stay in 1X mode for lower supply voltage of 0.2V.
This helps improve the efficiency and extends battery
life.
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芯美电子
EUP3651
Layout Consideration
Due to the switching frequency and high transient
current of EUP3651, careful consideration of PCB
layout is necessary. The CIN should be connected as
close to the IC as possible. The ground of CIN and
COUT should be placed as close as possible. To achieve
the best performance of EUP3651, minimize the
distance between every two components and also
minimize every connection length with a maximum
trace width. Make sure each device connects to
immediate ground plane. A copper area matching the
TDFN exposed pad (TAB) must be connected to the
ground plane underneath. The use of multiple via
improves the package heat dissipation.
External Component
The driver requires two external 1µF ceramic
capacitors for decoupling input, output, and for the
charge pump. Both capacitors type X5R and X7R are
recommended for the LED driver application. In
charge pump modes, the input current ripple is kept
very low by design and an input bypass capacitor of
1µF is sufficient.
In 1X mode, the device operates in linear mode and
does not introduce switching noise back onto the
supply.
Applications Examples
I. Use the EUP3651 to drive four LEDs for one panel backlighting.
II. Use the EUP3651 to drive 3 LEDs for one panel backlighting. The unused channel should be connected to VOUT.
DS3651
Ver1.0
Feb. 2008
10
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芯美电子
EUP3651
Packaging Information
TDFN-12
SYMBOLS
A
A1
b
E
D
D1
E1
e
L
DS3651
Ver1.0
Feb. 2008
MILLIMETERS
MIN.
MAX.
0.70
0.80
0.00
0.05
0.18
0.30
2.90
3.10
2.90
3.10
2.40
1.70
0.45
0.30
0.50
INCHES
MIN.
0.028
0.000
0.007
0.114
0.114
MAX.
0.031
0.002
0.012
0.122
0.122
0.094
0.067
0.018
0.012
0.020
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