AAT3193 - Skyworks Solutions, Inc.

DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
General Description
Features
The AAT3193 is a charge-pump based, current-sink
white LED driver capable of driving one to three LEDs up
to 30mA, each. It automatically switches between 1x
mode and 2x mode to maintain the highest efficiency
and optimal LED current accuracy and matching.
•
•
•
•
The AAT3193 charge pump’s 1x mode (bypass mode)
has very low resistance allowing LED current regulation
to be maintained with input supply voltage approaching
the LED forward voltage.
The AAT3193 is available in a 2×2.2mm, 10-lead
SC70JW-10 package.
•
•
•
•
•
•
Drives up to 3 LEDs at up to 30mA, each
Automatic Switching Between 1x and 2x Modes
0.9MHz Switching Frequency
Linear LED Output Current Control
▪ Single-wire, S2Cwire Interface
• AAT3193-1: 16-step
• AAT3193-2: 8-step
• AAT3193-3: 4-step
ON/OFF
or PWM Interface
▪
• AAT3193-4
±10% LED Output Current Accuracy
±3% LED Output Current Matching
Low-Current Shutdown Mode
Built-in Thermal Protection
Automatic Soft-Start
Available in 2×2.2mm SC70JW-10 Package
Applications
•
•
•
•
Entry
Entry
Entry
Entry
Level
Level
Level
Level
Cordless Phone Handsets
Digital Cameras
Mobile Phone Handsets
MP3 and PMP Players
Typical Application
Input Voltage
2.7V to 5.5V
IN
C+
C IN
1µF
CP
1µF
OUT
AAT3193-1
C-
EN/SET
S 2Cwire
Interface
EN/SET
COUT
1µF
WLEDs
OSRAM LW M 678
or equivalent
D1
D2
RSET
R SET
14.3kΩ
D3
GND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
1
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Pin Descriptions
Pin
Symbol
1
D1
2
OUT
3
4
CC+
5
IN
EN/SET
(AAT3193-1/-2/-3)
6
EN/PWM
(AAT3193-4)
7
RSET
8
GND
9
D3
10
D2
Description
LED1 current sink input. D1 is the input of LED1 current sink. Connect LED1’s anode to OUT and its
cathode to D1.
Charge pump output. OUT is the output of the charge pump. Bypass OUT to GND with a 1μF or larger
ceramic capacitor.
Charge pump capacitor negative node.
Charge pump capacitor positive node. Connect a 1μF ceramic capacitor between C+ and C-.
Power source input. Connect IN to the power source, typically the battery. Bypass IN to GND with a
1μF or larger ceramic capacitor.
LED enable and serial control input. EN/SET is the ON/OFF control for the LED and the S2Cwire digital
input for the AAT3193-1/-2/-3 to control serially the LED brightness according to the maximum current set by RSET.
LED ON/OFF and PWM control input. This logic input controls the LED outputs for the AAT3193-4.
Alternatively, a PWM signal from a GPIO or an equivalent signal from a separate controller can be
used to control LED output current linearly. A PWM signal, ranging from 10% to 100% duty cycle,
controls the LED current linearly between ZS and FS.
A 1% tolerance resistor from this pin to GND sets the maximum LED current level. For optimal LED
output current accuracy and matching in the AAT3193-1/-2/-4, a 14.3kΩ resistor sets each full-scale
output current to 20mA, maximum. For the AAT3193-3, a 11.5kΩ resistor is recommended.
Ground. Connect this pin to the system’s ground plane.
LED3 Current Sink Input. D3 is the input of LED3 current sink. Connect LED3’s anode to OUT and its
cathode to D3.
LED2 Current Sink Input. D2 is the input of LED2 current sink. Connect LED2’s anode to OUT and its
cathode to D2.
Pin Configuration
SC70JW-10
(Top View)
D1
OUT
CC+
IN
2
1
10
2
9
3
8
4
7
5
6
D2
D3
GND
RSET
EN/SET
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Part Number Descriptions
Part Number
Interface
Current Control, Inverting
AAT3193IJQ-1
AAT3193IJQ-2
AAT3193IJQ-3
AAT3193IJQ-4
S2Cwire
S2Cwire
S2Cwire
PWM
16-step
8-step
4-step
Linear
Absolute Maximum Ratings1
Symbol
Description
IN, C+, C-, OUT, D1, D2, D3, and RSET Pin Voltages to GND
EN/SET or EN/PWM Pin Voltage to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
-0.3 to 6.0
-0.3 to VIN + 0.3
-40 to 150
300
V
V
°C
°C
Value
Units
625
160
mW
°C/W
Thermal Information
Symbol
PD
qJA
Description
Maximum Power Dissipation2, 3
Maximum Thermal Resistance2
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 circuit board.
3. Derate 6.25mW/°C above 40°C ambient temperature.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
3
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Electrical Characteristics1
IN = EN = 3.6V; CIN = 1µF; COUT = 1µF; CCP = 1µF; RSET = 14.3kΩ; TA =-40°C to 85°C unless otherwise noted. Typical
values are at TA = 25°C.
Symbol
Description
Conditions
Input Power Supply
IN
Input Voltage Range
IIN
Input Operating Current
IIN(SHDN)
Input Shutdown Current
Charge Pump Section
IOUT
OUT Maximum Output Current
fOSC
Charge Pump Oscillator Frequency
VIN_(TH)
Charge Pump Mode Hysteresis
tOUT
Output Start-Up Time
AAT3193-1/-2/-4: LED Current Sink Outputs
ID_(MAX)
D1 - D3 Current Accuracy
ΔID_(MAX)
D1 - D3 Current Matching
D1 - D3 Current Accuracy (AAT3193-1
ID_(DATA15)
only)
D1 - D3 Current Accuracy (AAT3193-2
ID_(DATA8)
only)
D1 - D3 Current Accuracy (AAT3193-4
ID_(10%)
only)
D1- D3 Charge Pump Mode Transition
VD_(TH)
Threshold
Min
Typ
2.7
EN/SET or EN/PWM = IN; VD1 = VD2 = VD3 =
IN, excluding ID1-ID3
EN/SET or EN/PWM = IN; ID1 = ID2 = ID3 =
FS, excluding ID1-ID3; VIN – VF = 1.5V
Operating, ID1 = ID2 = ID3 = FS; D1, D2 and
D3 = OPEN
IN = 5.5V; EN/SET or EN/PWM = GND
Max
Units
5.5
V
0.6
1.5
mA
4.5
0.65
ID1 = ID2 = ID3= 20mA; Excluding AAT3193-4,
PWM Option
EN/SET or EN/PWM = IN
1
μA
100
0.9
1.15
mA
MHz
115
250
mV
150
μs
DATA = 1; VIN - VF = 1.5V
DATA = 1; VIN - VF = 1.5V
18
20
±3
22
mA
%
DATA = 15; VIN - VF = 1.5V
1.0
1.3
1.56
mA
DATA = 8; VIN - VF = 1.5V
1.0
1.3
1.56
mA
DC = 10%; fPWM = 10kHz; VIN - VF = 1.5V
2.4
mA
ID1 = ID2 = ID3 = 20mA
125
mV
1. The AAT3193 is guaranteed to meet performance specification over the -40°C to 85°C operating temperature range and is assured by design, characterization and correlation
with statistical process controls.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Electrical Characteristics1
IN = EN = 3.6V; CIN = 1µF; COUT = 1µF; CCP = 1µF; RSET = 14.3kΩ; TA =-40°C to 85°C unless otherwise noted. Typical
values are at TA = 25°C.
Symbol
Description
AAT3193-3: LED Current Sink Outputs
ID_(MAX)
D1 - D3 Current Accuracy
ΔID_(MAX)
D1 - D3 Current Matching
ID_(DATA4)
D1 - D3 Current Accuracy
D1- D3 Charge Pump Mode Transition
VD_(TH)
Threshold
AAT3193-1/-2/-3: EN/SET and S2Cwire Control
VENH
EN Input High Threshold Voltage
VENL
EN Input Low Threshold Voltage
IEN(LKG)
EN Input Leakage Current
tEN/SET(OFF)
EN/SET Input OFF Timeout
tEN/SET(LAT)
EN/SET Input Latch Timeout
tEN/SET(LOW)
EN/SET Input LOW Time
tENSET(H-MIN)
EN/SET Minimum High Time
tENSET(H-MAX)
EN/SET Maximum High Time
AAT3193-4: EN/PWM Current Control
VENH
EN/PWM Input High Threshold Voltage
VENL
EN/PWM Input Low Threshold Voltage
IEN(LKG)
EN/PWM Input Leakage Current
tPWM(ON)
PWM Control Turn-on Delay
tEN/PWM
EN/PWM Input OFF Timeout
fPWM
PWM Control Frequency
Conditions
RSET = 11.5kΩ; DATA = 1; VIN - VF = 1.5V
RSET = 11.5kΩ; DATA = 1; VIN - VF = 1.5V
RSET = 11.5kΩ; DATA = 4; VIN - VF = 1.5V
Min
Typ
Max
Units
18
20
±3
0.9
22
mA
%
mA
0.72
RSET = 11.5kΩ; ID1 = ID2 = ID3 = 20mA
1.1
125
mV
1.4
EN/SET = IN = 5V
0.4
1
500
500
75
-1
0.3
50
75
1.4
EN/PWM = IN = 5V
0.4
1
-1
2
0.15
Duty Cycle = 80%
1
50
V
V
μA
µs
µs
µs
ns
µs
V
V
μA
µs
ms
kHz
1. The AAT3193 is guaranteed to meet performance specification over the -40°C to 85°C operating temperature range and is assured by design, characterization and correlation
with statistical process controls.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
5
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Typical Characteristics
Operating Current (No Load)
vs. Input Voltage
Shutdown Current vs. Temperature
3.60
0.010
3.50
IQ (mA)
IIN(SHDN) (µA)
0.008
3.40
85°C
3.30
25°C
3.20
3.10
3.00
2.7
3.1
3.5
3.9
4.3
4.7
5.1
10
35
60
85
Temperature (°C)
Current Matching vs. Temperature
21.0
100%
90%
20.5
80%
60%
Current (mA)
70%
30mA
VF = 3.8V
50%
40%
30%
10mA
VF = 3.2V
20%
10%
3.1
3.5
3.9
20mA
VF = 3.5V
4.3
4.7
5.1
19.5
19.0
18.0
-40
5.5
D3
D1
-15
10
35
60
Temperature (°C)
Turn On to 2X Mode
Turn Off from 2X Mode
(20mA/ch)
(20mA/ch)
EN/SET
(2V/div)
EN/SET
(2V/div)
VOUT
(2V/div)
VSINK
(2V/div)
VOUT
(1V/div)
IIN
(200mA/div)
IIN
(200mA/div)
Time (200µs/div)
D2
20.0
18.5
Input Voltage (V)
6
-15
Efficiency vs. Input Voltage
Efficiency (%)
2.7V
0.000
-40
5.5
VIN (V)
0%
2.7
5.5V
0.004
0.002
0°C
-40°C
0.006
Time (200µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
85
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Typical Characteristics
Turn On to 1X Mode
Maximum LED Current vs RSET
(VIN = 4.2V; 20mA/ch)
32
EN/SET
(2V/div)
28
24
ILED (mA)
VF
(2V/div)
VSINK
(2V/div)
20
16
12
8
IIN
(200mA/div)
4
0
8
13
18
1.2
1.2
1.0
1.0
0.8
0.8
85°C
0.4
0.2
2.7
3.1
3.5
3.9
-40°C
0.6
-40°C
0.4
4.3
4.7
5.1
0.2
5.5
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
EN/SET Input Latch Timeout vs. Input Voltage
EN/SET Input OFF Timeout vs. Input Voltage
350
350
85°C
300
TEN/SET(OFF) (µs)
TEN/SET(LAT) (µs)
25°C
85°C
Input Voltage (V)
250
25°C
200
-40°C
150
100
2.7
33
EN Input Low ThresholdVINVoltage
= 4.2V
3.6V
VIN =Voltage
vs. Input
VIN = 2.7V
VENL (V)
VENH (V)
EN Input High Threshold Voltage
vs. Input Voltage
25°C
28
RSET (kΩ)
Time (200µs/div)
0.6
23
3.1
3.5
3.9
4.3
Input Voltage (V)
4.7
5.1
5.5
85°C
300
250
25°C
200
-40°C
150
100
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
7
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Typical Characteristics
Transition of LED Current
Transition of LED Current
(20mA to 1.3mA)
(1.3mA to 20mA)
EN
(2V/div)
EN
(2V/div)
VOUT
(1V/div)
4.0V
VOUT
(1V/div)
VSINK
(1V/div)
0.5V
VSINK
(1V/div)
IIN
(50mA/div)
4.2V
1.5V
IIN
(50mA/div)
Time (100µs/div)
Time (100µs/div)
Input Current vs. Input Voltage
Output Ripple Waveform
(Excluding AAT3193-4, PWM Option)
(2X Mode; 20mA Load)
200
VIN
(AC Coupled)
(20mV/div)
Input Current (mA)
180
VOUT
(AC Coupled)
(20mV/div)
VSINK
(AC Coupled)
(50mV/div)
160
VIN Falling
ILED = 30mA
VIN Rising
140
120
100
ILED = 20mA
80
60
40
ILED = 10mA
20
0
Time (1µs/div)
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
Input Voltage (V)
8
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Functional Block Diagram
C+
IN
C–
OUT
Two-Mode
CP Control
D1
D2
VF Monitoring
3
D3
GND
IREF
EN/SET
(EN/PWM)
S2Cwire Control
(PWM Control)
Functional Description
The AAT3193 is a low-cost charge-pump solution
designed to drive up to three white LEDs. The charge
pump operates from a 2.7V to 5.5V power source and
converts it to voltage levels necessary to drive the LEDs.
LED current is individually controlled through integrated
current sinks powered from the output of the charge
pump. Low 1x charge-pump output resistance and lowdrop voltage current sinks allow the charge pump to stay
in 1x mode with an input voltage as low as 3.75V and
LED forward voltages as high as 3.5V. Once in 2x mode,
the AAT3193-1/-2/-3 continuously monitor the input
supply voltage and automatically switch back to 1x mode
when there is sufficient input voltage. To support fast
PWM response, the 2x mode is latched in the AAT3193-4
and the device, once there, stays in that mode. To reset
the AAT3193-4 to the 1x mode, strobe EN/PWM low for
1ms or longer.
The AAT3193 requires only four external components:
one 1µF ceramic capacitor for the charge pump flying
capacitors (CP), one 1µF ceramic input capacitor (CIN),
DAC
RSET
one 1µF ceramic output capacitor (COUT) and a resistor
(RSET) to set the maximum LED current. The three constant current outputs of the AAT3193 (D1 to D3) can
drive three individual LEDs with a maximum current of
30mA each. Skyworks' S2Cwire serial Interface enables
the AAT3193-1/-2/-3 and changes the current sink magnitudes through the EN/SET pin. The AAT3193-4 uses an
external PWM signal to enable the IC and control the
brightness of the LEDs.
Constant Current Control using RSET
The maximum current is programmed by an external
resistor at the RSET pin. Using a 14.3kΩ external resistor at the RSET pin, the AAT3193-1/-2/-4 includes an
integrated serial LED current control that sets the fullscale LED current between 20mA and 0.63mA. For the
AAT3193-3, a 11.5kΩ external resistor at the RSET pin
sets the full-scale LED current between 20mA and
1.3mA. The full-scale LED current can set higher or lower
than 20mA; see Table 5. For maximum accuracy, a 1%
tolerance resistor is recommended.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
9
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
S2Cwire Serial Interface
(AAT3193-1/-2/-3 only)
grammed current is then seen at the current sink outputs. When EN/SET is held low for an amount of time
longer than tOFF (500µs), the AAT3193 enters into shutdown mode and draws less than 1µA from the input and
the internal data register is reset to zero.
The LED output current of the AAT3193 is controlled by
Skyworks' S2Cwire serial interface. Since the LED current
is programmable, no PWM or additional control circuitry
is needed to control LED brightness. This feature greatly
reduces the burden on a microcontroller or system IC to
manage LED or display brightness, allowing the user to
“set it and forget it.” With its high-speed serial interface
(1MHz data rate), the LED current can be changed quickly and easily. Also the non-pulsating LED current reduces
system noise and improves LED reliability. The S2Cwire
interface relies on the number of rising edges to the EN/
SET pin to set the register. A typical write protocol is a
burst of EN/SET rising edges, followed by a pause with
EN/SET held high for at least tLAT (500µs). The pro-
The AAT3193-1/2/3’s serial interface reduces the LED
current on each rising pulse of the enable input. If the
AAT3193 is in shutdown, the first rising edge of the EN/
SET input turns on the LED driver to the maximum current. Successive rising edges decrease the LED current
as shown in Table 1 and Figure 2 for the AAT3193-1.
For the AAT3193-2, Table 2 and Figure 3 illustrate an
8-step LED current control profile. For the AAT3193-3,
Table 3 and Figure 4 illustrate a 4-step LED current control profile.
THI
TLO
TOFF
TLAT
EN/SET
1
2
n-1
Data Reg
n ≤ 16
0
n
0
Figure 1: S2C Serial Interface Timing.
AAT3192/93-1 Current Control Profile
EN Rising Edges
D1-D3 Current (mA)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
20
18.7
17.3
16
14.7
13.3
12
10.7
9.3
8
6.7
5.3
4
2.7
1.3
0.63
20.00
Dx Output Current (mA)
Data
15.00
10.00
5.00
0.00
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
S2Cwire Interface Data Code
Figure 2: AAT3193-1 Current Control Profile.
Table 1: AAT3193-1 LED Current Settings.
10
14
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Data
EN Rising Edges
D1-D3 Current (mA)
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
20
17.3
14.7
12
9.3
6.7
4
1.3
PWM (Pulse Width Modulation) is an industry standard
technique of controlling LED brightness by modulating
the conduction duty cycle of the LED current. LED
brightness is determined by the average value of the
PWM signal multiplied by the LED’s intensity where
intensity is proportional to the LED drive current. A PWM
control signal can be applied into the EN/PWM pin of the
AAT3193-4. By changing the duty cycle of the PWM signal from 100% (logic high) to 10%, LEDs sink current
can be programmed from 20mA to 2.4mA. To save
power when not used, AAT3193-4 can be shutdown by
holding the EN/PWM pin low for 1ms.
ControlSettings.
Profile
Table AAT3192/93-2
2: AAT3193-2Current
LED Current
Dx Output Current (mA)
20.00
Lastly, Table 4 and Figure 5 illustrate the AAT3193-4’s
LED current control profile as a function of a PWM control signal.
15.00
10.00
5.00
0.00
PWM Control (AAT3193-4 only)
1
2
3
4
5
6
7
EN/PWM Duty Cycle
D1-D3 Current (mA)
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
20
17.9
15.9
14
12.1
10.1
8.2
6.3
4.3
2.4
8
S2Cwire Interface Data Code
Figure 3: AAT3193-2 Current Control Profile.
Data
EN Rising Edges
D1-D3 Current (mA)
1
2
3
4
1
2
3
4
20
13.3
6.7
0.87
Table 4: AAT3193-4 LED Current Settings
AAT3192/93-4
Current
Control
Profile
(R
fPWM =
50kHz).
SET = 14.3kW,
20.00
Dx Output Current (mA)
ControlSettings.
Profile
Table AAT3192/93-3
3: AAT3193-3Current
LED Current
Dx Output Current (mA)
20.00
15.00
10.00
15.00
10.00
5.00
0.00
5.00
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
EN/PWM Input Pin Duty Cycle (%)
0.00
1
2
3
4
S2Cwire Interface Data Code
Figure 5: AAT3193-4 Current Control Profile
(RSET = 14.3kW, fPWM = 50kHz).
Figure 4: AAT3193-3 Current Control Profile.
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11
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Applications Information
LED Selection
The AAT3193 is specifically intended for driving white
LEDs. However, the device design will allow the AAT3193
to drive most types of LEDs with forward voltage specifications ranging from 2.2V to 4.7V. LED applications
may include mixed arrangements for display backlighting, keypad display, and any other application needing a
constant current sink generated from a varying input
voltage. Since the D1 to D3 constant current sinks are
matched with negligible supply voltage dependence, the
constant current channels will be matched regardless of
the specific LED forward voltage (VF) levels.
The low dropout current sinks in the AAT3193 maximize
performance and make it capable of driving LEDs with
high forward voltages. Multiple channels can be combined to obtain a higher LED drive current without complication.
Constant Current Setting
The LED current is controlled by the RSET resistor. For
maximum accuracy, a 1% tolerance resistor is recommended. Table 5 shows RSET resistor values for AAT31931/2/4 and Table 6 shows RSET resistor values for
AAT3193-3 for various LED full-scale current levels.
ILED (mA)
RSET (KΩ)
30
20
15
10
9.53
14.3
19.1
28.7
Table 5: Maximum LED Current and RSET Resistor
Values (1% Resistor Tolerance)
for the AAT3193-1/2/4.
ILED (mA)
RSET (KΩ)
30
20
15
10
7.68
11.5
15.4
23.2
Table 6: Maximum LED Current and RSET Resistor
Values (1% Resistor Tolerance)
for the AAT3193-3.
12
Device Switching Noise Performance
The AAT3193 operates at a fixed frequency of approximately 1MHz to control noise and limit harmonics that
can interfere with the RF operation of mobile communication devices. Back-injected noise appearing on the
input pin of the charge pump is 20mV peak-to peak,
typically ten times less than inductor-based DC/DC boost
converter white LED backlight solutions. The AAT3193
soft-start feature prevents noise transient effects associated with inrush currents during start-up of the charge
pump circuit.
Shutdown
Since the current switches are the only power returns for
all loads, there is no leakage current when all sink
switches are disabled. To activate the shutdown operation, the EN/SET input for the AAT3193-1/2/3 should be
strobed low for longer than tOFF (500μs). For the 3193-4
PWM options, shutdown operation is enabled when the
EN/PWM input is strobed low longer than 1ms.In this
state, the AAT3193 typically draws less than 1μA from
the input. Registers are reset to 0 in shutdown.
Power Efficiency and Device Evaluation
The charge pump efficiency discussion in the following
sections accounts only for efficiency of the charge pump
section itself. Due to the unique circuit architecture and
design of the AAT3193, it is very difficult to measure
efficiency in terms of a percent value comparing input
power over output power.
Since the AAT3193 outputs are pure constant current
sinks and typically drive individual loads, it is difficult
to measure the output voltage for a given output to
derive an overall output power measurement. For any
given application, white LED forward voltage levels can
differ, yet the output drive current will be maintained as
a constant.
This makes quantifying output power a difficult task
when taken in the context of comparing to other white
LED driver circuit topologies. A better way to quantify
total device efficiency is to observe the total input power
to the device for a given LED current drive level. The
best white LED driver for a given application should be
based on trade-offs of size, external component count,
reliability, operating range, and total energy usage...not
just % efficiency.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
The AAT3193 efficiency may be quantified under very
specific conditions and is dependent upon the input voltage versus the output voltage across the loads applied
to outputs D1 through D3 for a given constant current
setting. Depending on the combination of VIN and voltages sensed at the current sinks, the device will operate
in load switch mode. When any one of the voltages
sensed at the current sinks nears dropout, the device
will operate in 2X charge pump mode. Each of these
modes will yield different efficiency values. Refer to the
following two sections for explanations for each operational mode.
In addition, with an ideal 2X charge pump, the output
current may be expressed as 1/3 of the input current.
The expression to define the ideal efficiency (h) can be
rewritten as:
1X Mode Efficiency
For a charge pump with an output of 5V and a nominal
input of 3.5V, the theoretical efficiency is 71%. Due to
internal switching losses and IC quiescent current consumption, the actual efficiency can be measured at
51%. Efficiency will decrease substantially as load current drops below 1mA or when the voltage level at VIN
approaches the voltage level at VOUT.
The AAT3193 1X mode is operational at all times and
functions alone to enhance device power conversion efficiency when VIN is higher than the voltage across the
load. When in 1X mode, voltage conversion efficiency is
defined as output power divided by input power.
An expression for the ideal efficiency (h) in 1X chargepump mode can be expressed as:
η=
POUT
V ·I
VF
= F LED ≅
PIN
VIN · IOUT
VIN
-or-
η=
-or-
POUT
V ·I
VF
= F LED =
PIN
VIN · 2IOUT 2VIN
 VF 
η (%) = 100 · 2V
 IN
Additional Applications
The current sinks of the AAT3193 can be combined to
drive higher current levels through a single LED. As an
example, a single LED can be driven at 90mA total by
combining together the D1-D3 outputs.
 VF 
η (%) = 100 · V
 IN
2X Charge Pump Mode Efficiency
The AAT3193 contains a charge pump which will boost
the input supply voltage in the event where VIN is less
than the voltage required to supply the output. The efficiency (h) can be simply defined as a linear voltage
regulator with an effective output voltage that is equal
to one and two times the input voltage. Efficiency (h) for
an ideal 2X charge pump can typically be expressed as
the output power divided by the input power.
η=
PF
PIN
C2
1µF
VIN
C1
1µF
1
2
3
4
5
C3
1µF
D1
D1
D2
OUT
D3
CGND
C+ RSET
IN EN/SET
10
9
8
7
6
AAT3193
R1
14.3k
EN/SET
Figure 6: Higher Current, Single LED Application.
For lower-cost applications, the flying capacitor can be
removed. This will force the AAT3193 to operate in 1X
mode. To maintain regulated LED current, the input supply voltage has to be higher than the charge-pump’s
dropout voltage in 1X mode.
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13
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
C2
1µF
D1
D2
D3
U1
1
2
3
4
5
VIN
C3
1µF
D2
D1
D3
OUT
GND
CC+ RSET
IN EN/SET
AAT3193
10
9
8
7
6
lowest cost, has a smaller PCB footprint, and is nonpolarized. Low ESR ceramic capacitors help maximizing
charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect
connection damage.
Equivalent Series Resistance
R1
14.3k
EN/SET
Figure 7: Lower Cost 1X Mode Application.
Capacitor Selection
ESR is an important characteristic to consider when
selecting a capacitor. ESR is a resistance internal to a
capacitor that is caused by the leads, internal connections, size or area, material composition, and ambient
temperature. Capacitor ESR is typically measured in milliohms for ceramic capacitors and can range to more
than several ohms for tantalum or aluminum electrolytic
capacitors.
Careful selection of the three external capacitors CIN, CP,
and COUT is important because they will affect turn-on
time, output ripple, and transient performance. Optimum
performance will be obtained when low equivalent series
resistance (ESR) ceramic capacitors are used; in general, low ESR may be defined as less than 100mΩ. A value
of 1μF for all four capacitors is a good starting point
when choosing capacitors. If the constant current sinks
are only programmed for light current levels, then the
capacitor size may be decreased.
Ceramic Capacitor Materials
Capacitor Characteristics
Capacitor area is another contributor to ESR. Capacitors
that are physically large will have a lower ESR when
compared to an equivalent material smaller capacitor.
These larger devices can improve circuit transient
response when compared to an equal value capacitor in
a smaller package size.
Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the
AAT3193. Ceramic capacitors offer many advantages
over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically has very low ESR, is
14
Ceramic capacitors less than 0.1μF are typically made
from NPO or C0G materials. NPO and C0G materials generally have tight tolerance and are very stable over temperature. Larger capacitor values are usually composed
of X7R, X5R, Z5U, or Y5V dielectric materials. Large
ceramic capacitors (i.e., larger than 2.2μF) are often
available in low cost Y5V and Z5U dielectrics, but capacitors larger than 1μF are not typically required for
AAT3193 applications.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Evaluation Board Schematic
DC-
DC+
1
2
3
C2 JP5
1µF
VIN
J1
JP4
D1
D2
D3
JP1
JP2
JP3
GND
C1
1µF
1
2
3
4
5
C3
1µF
10
9
D1
D2
OUT
D3
CAGND
C+
RSET
IN EN/SET
8
7
6
U1 AAT3193
R1
14.3k
GND
GND
J2
R7
100K
VIN
GND
R4 R3 R2
1K 1K 1K
CYCLE
SW3
4
UP
SW2
DOWN
SW1
C5
1µF
U2
1
2
3
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
8
7
6
VR4
POT10K
5
PIC12F675
R6
330
GND
R5
330
LED2
RED
GND
LED1
GRN
GND
GND
Figure 8: AAT3193 Evaluation Board Schematic.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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15
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Evaluation Board Layout
16
Figure 9: AAT3193 Evaluation Board Component Side Layout.
Figure 10: AAT3193 Evaluation Board Solder Side Layout.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Ordering Information
Package
Interface
Current Control, Inverting
Marking1
Part Number (Tape and Reel)2
SC70JW-10
SC70JW-10
SC70JW-10
SC70JW-10
S2Cwire
S2Cwire
S2Cwire
PWM
16-step
8-step
4-step
Linear
XGXYY
AAT3193IJQ-1-T1
AAT3193IJQ-2-T1
AAT3193IJQ-3-T1
AAT3193IJQ-4-T1
ZHXYY
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information
SC70JW-10
2.20 ± 0.20
1.75 ± 0.10
0.40 BSC
0.225 ± 0.075
Top View
0.100
7° ± 3°
0.45 ± 0.10
4° ± 4°
0.05 ± 0.05
0.15 ± 0.05
1.10 MAX
0.85 ± 0.15
2.00 ± 0.20
2.10 ± 0.30
Side View
End View
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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17
DATA SHEET
AAT3193
Three-Channel Charge Pump LED Driver
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
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service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no
responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes.
No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.
THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR
PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES
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THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product
design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
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18
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
202162A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012