CAT3648 D

CAT3648
4-Channel Ultra High
Efficiency LED Driver with
32 Dimming Levels
Description
Applications
•
•
•
•
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
NC
NC
GND
LED1
1
LED2
C2−
LED3
C2+
LED4
C1−
RSET
C1+
VIN
High Efficiency 1.33x Charge Pump
Charge Pump: 1x, 1.33x, 1.5x, 2x
Drives up to 4 LEDs at 25 mA Each
1−wire EZDim 32 Linear Steps
Power Efficiency up to 92%
Low Noise Input Ripple in All Modes
“Zero” Current Shutdown Mode
Soft Start and Current Limiting
Short Circuit Protection
Thermal Shutdown Protection
3 mm x 3 mm, 16−pad TQFN Package
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
PIN CONNECTIONS
NC
•
•
•
•
•
•
•
•
•
•
•
•
TQFN−16
HV3 SUFFIX
CASE 510AD
VOUT
Features
http://onsemi.com
EN/DIM
The CAT3648 is a high efficiency fractional charge pump that can
drive up to four LEDs programmable by a one wire digital interface.
The inclusion of a 1.33x fractional charge pump mode increases
device efficiency by up to 10% over traditional 1.5x charge pumps
with no added external capacitors.
Low noise input ripple is achieved by operating at a constant
switching frequency which allows the use of small external ceramic
capacitors. The multi−fractional charge pump supports a wide range of
input voltages from 2.5 V to 5.5 V.
The EN/DIM logic input functions as a chip enable and a digital
dimming interface for setting the current in all LED channels. The
1−wire pulse−dimming interface supports 32 linear steps from
full−scale down to zero current.
The device is available in the tiny 16−pad TQFN 3 mm x 3 mm
package with a max height of 0.8 mm.
ON Semiconductor’s 1.33x, charge pump switching architecture is
patented.
(Top View)
MARKING DIAGRAM
JAAN
AXXX
YWW
JAAN = CAT3648HV3−GT2
A = Assembly Location
XXX = Last Three Digits of Assembly Lot Number
Y = Production Year (Last Digit)
WW = Production Week (Two Digits)
ORDERING INFORMATION
Device
Package
Shipping†
CAT3648HV3−GT2
(Note 1)
TQFN−16
(Pb−Free)
2000 /
Tape & Reel
1. NiPdAu Plated Finish (RoHS−compliant).
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
© Semiconductor Components Industries, LLC, 2014
August, 2014 − Rev. 3
1
Publication Order Number:
CAT3648/D
CAT3648
1 mF
C1+
VIN
2.4 V
to
5.5 V
C1− C2+
VIN
CIN
1 mF
C2−
VOUT
CAT3648
1 mF
1−Wire
EZDimt
Programming
COUT
1 mF
LED1
EN/DIM
LED2
LED3
RSET
3.74 kΩ
VOUT
20 mA
LED4
GND
Figure 1. Typical Application Circuit
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, LEDx, C1±, C2±, EN/DIM voltage
VOUT voltage
Rating
Unit
6
V
7
V
Storage Temperature Range
−65 to +160
°C
Junction Temperature Range
−40 to +150
°C
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
Table 2. RECOMMENDED OPERATING CONDITIONS
Rating
Unit
VIN
Parameter
2.5 to 5.5
V
Ambient Temperature Range
−40 to +85
°C
ILED per LED pin
up to 30
mA
LED Forward Voltage Range
1.3 to 4.3
V
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond
the Recommended Operating Ranges limits may affect device reliability.
NOTE: Typical application circuit with external components is shown above.
http://onsemi.com
2
CAT3648
Table 3. ELECTRICAL OPERATING CHARACTERISTICS
(over recommended operating conditions unless specified otherwise) VIN = 3.6 V, EN = High, TAMB = 25°C
Name
Symbol
Conditions
Min
Typ
IQ
Quiescent Current
1x mode, excluding load
1.33x mode, excluding load
1.5x mode, excluding load
2x mode, excluding load
IQSHDN
Shutdown Current
VEN = 0 V
LED Current Setting
RSET = 3.74 kW
20
RSET = 7.50 kW
10
±2
ILED−ACC
ILED−ACC
LED Current Accuracy
(ILEDAVG – INOMINAL) / INOMINAL
RSET = 4.99 kW
ILED−DEV
LED Channel Matching
(ILED − ILEDAVG) / ILEDAVG
Max
1.0
1.7
2.2
2.4
mA
1
%
%
VRSET
RSET Regulated Voltage
ROUT
Output Resistance (open loop)
1x mode
1.33x mode, VIN = 3 V
1.5x mode, VIN = 2.7 V
2x mode, VIN = 2.4 V
FOSC
Charge Pump Frequency
1.33x and 2x mode
1.5x mode
ISC_MAX
Output short circuit Current Limit
VOUT < 0.5 V
50
mA
IIN_MAX
Input Current Limit
VOUT > 1 V, 1x mode
250
mA
LEDTH
1x to 1.33x or 1.33x to 1.5x or 1.5x to 2x
Transition Thresholds at any LED pin
130
mV
1x Mode Transition Hysteresis
400
mV
Mode Transition Filter Delay
120
ms
100
kW
V
V
VHYS
TDF
REN/DIM
VHI
VLO
EN/DIM Pin
− Internal Pull−down Resistor
− Logic High Level
− Logic Low Level
TSD
Thermal Shutdown
THYS
Thermal Hysteresis
VUVLO
Undervoltage lockout (UVLO) threshold
0.6
mA
mA
±1.5
0.58
Units
0.62
0.8
5
5
10
0.8
1
1
1.3
W
1.3
1.6
1.3
0.4
150
1.8
MHz
°C
20
1.6
V
°C
2.0
V
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
http://onsemi.com
3
CAT3648
Table 4. RECOMMENDED EN/DIM TIMING
(For 2.4 V ≤ VIN ≤ 5.5 V, over full ambient temperature range −40°C to +85°C.)
Name
Symbol
Conditions
Min
TLO
EN/DIM program low time
0.2
THI
EN/DIM program high time
0.2
EN/DIM low time to shutdown
1.5
TPWRDWN
TLED
LED current settling time
Typ
Max
Units
100
ms
ms
ms
40
ms
THI
EN/DIM
TLO
TPWRDWN
TLED
100%
LED
Current
100%
97% 94%
32 Levels
Shutdown
3%
0%
Figure 2. EN/DIM Digital Dimming Timing Diagram
LED Current Setting
The full scale LED current is set by the external resistor
connected between the RSET pin and ground. Table 5 lists
standard resistor values for several LED current settings.
Table 5. RESISTOR RSET AND LED CURRENT
Full Scale LED Current [mA]
RSET [kW]
2
37.4
5
14.7
10
7.50
15
4.99
20
3.74
25
3.00
30
2.49
http://onsemi.com
4
Shutdown
CAT3648
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
100
100
VF = 3.3 V
VF = 3.3 V
1.33x
90
1.5x
90
1x
80
EFFICIENCY (%)
EFFICIENCY (%)
1x
2x
70
60
50
40
4.5
4.0
3.5
3.0
2.5
4.0
3.8
3.6
3.4
3.2
INPUT VOLTAGE (V)
Figure 3. Efficiency vs. Input Voltage
Figure 4. Efficiency vs. Li−Ion Voltage
3.0
4
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
4.2
INPUT VOLTAGE (V)
3
2
1
LEDs Off
5.5
5.0
4.5
4.0
3.5
3.0
2.5
3
2x
1.5x
1.33x
2
1x
1
0
−40
2.0
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 5. Quiescent Current vs. Input Voltage
Figure 6. Quiescent Current vs. Temperature
10
10
VF = 3.3 V
8
LED CURRENT VARIATION (%)
LED CURRENT VARIATION (%)
60
40
2.0
VF = 3.3 V
6
4
2
0
−2
−4
−6
−8
−10
70
50
4
0
1.33x
80
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
8
VF = 3.3 V
6
4
2
0
−2
−4
−6
−8
−10
−40
0
40
80
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 7. LED Current Change vs. Input
Voltage
Figure 8. LED Current Change vs.
Temperature
http://onsemi.com
5
120
CAT3648
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
12
1.2
OUTPUT RESISTANCE (W)
SWITCHING FREQUENCY (MHz)
1.3
1.5x Mode
1.1
1.0
0.9
1.33x, 2x Mode
0.8
0.7
−40
0
40
80
10
8
6
1.5x
1.33x
4
2
0
120
2x
1x
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
TEMPERATURE (°C)
INPUT VOLTAGE (V)
Figure 9. Switching Frequency vs.
Temperature
Figure 10. Output Resistance vs. Input Voltage
Figure 11. Power Up in 1x Mode
Figure 12. Power Up in 1.33x Mode
Figure 13. Power Up in 1.5x Mode
Figure 14. Power Up in 2x Mode
http://onsemi.com
6
CAT3648
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
Figure 15. Power Up Delay (1x Mode)
Figure 16. Power Down Delay (1x Mode)
Figure 17. Operating Waveforms in 1x Mode
Figure 18. Switching Waveforms in
1.33x Mode
Figure 19. Switching Waveforms in
1.5x Mode
Figure 20. Switching Waveforms in
2x Mode
http://onsemi.com
7
CAT3648
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
40
4.0
1x Mode
3.0
LED CURRENT (mA)
OUTPUT VOLTAGE (V)
3.5
2.5
2.0
1.5
1.0
30
20
10
0.5
0
0
100
200
300
0
400
0
50
100
150
200
250
OUTPUT CURRENT (mA)
LED PIN VOLTAGE (mV)
Figure 21. Foldback Current Limit
Figure 22. LED Current vs. LED Pin Voltage
Figure 23. Dimming Waveform
http://onsemi.com
8
300
CAT3648
Table 6. PIN DESCRIPTION
Pin #
Name
Function
1
LED2
LED2 cathode terminal.
2
LED3
LED3 cathode terminal.
3
LED4
LED4 cathode terminal.
4
RSET
Connect resistor RSET to set the LED current.
5
EN/DIM
6
VOUT
7
NC
Not connected inside the package.
8
VIN
Charge pump input, connect to battery or supply.
9
C1+
Bucket capacitor 1 Positive terminal
10
C1−
Bucket capacitor 1 Negative terminal
11
C2+
Bucket capacitor 2 Positive terminal
12
C2−
Bucket capacitor 2 Negative terminal
13
NC
Not connected inside the package.
14
NC
Not connected inside the package.
15
GND
Ground Reference
16
LED1
LED1 cathode terminal.
TAB
GND
Connect to GND on the PCB.
Device enable (active high) and Dimming Control.
Charge pump output connected to the LED anodes.
Pin Function
VIN is the supply pin for the charge pump. A small 1 mF
ceramic bypass capacitor is required between the VIN pin
and ground near the device. The operating input voltage
range is from 2.5 V to 5.5 V. Whenever the input supply falls
below the under−voltage threshold (1.8 V), all the LED
channels are disabled and the device enters shutdown mode.
EN/DIM is the enable and one wire dimming input for all
LED channels. Levels of logic high and logic low are set at
1.3 V and 0.4 V respectively. When EN/DIM is initially
taken high, the device becomes enabled and all LED
currents are set to the full scale according to the resistor
RSET. To place the device into “zero current” shutdown
mode, the EN/DIM pin must be held low for at least 1.5 ms.
VOUT is the charge pump output that is connected to the
LED anodes. A small 1 mF ceramic bypass capacitor is
required between the VOUT pin and ground near the device.
GND is the ground reference for the charge pump. The pin
must be connected to the ground plane on the PCB.
C1+, C1− are connected to each side of the ceramic bucket
capacitor C1.
C2+, C2− are connected to each side of the ceramic bucket
capacitor C2.
LED1 to LED4 provide the internal regulated current
source for each of the LED cathodes. These pins enter
high−impedance zero current state whenever the device is
placed in shutdown mode.
TAB is the exposed pad underneath the package. For best
thermal performance, the tab should be soldered to the PCB
and connected to the ground plane.
RSET is connected to the resistor (RSET) to set the full scale
current for the LEDs. The voltage at this pin regulated to
0.6 V. The ground side of the external resistor should be star
connected back to the GND of the PCB. In shutdown mode,
RSET becomes high impedance.
http://onsemi.com
9
CAT3648
Block Diagram
C1+
VIN
C1−
C2−
C2+
VOUT
1x mode (LDO)
4/3x, 3/2x, 2x Charge Pump
1, 1.3 MHz
Oscillator
EN/DIM
Mode Control
LED1
LED2
LED3
100 kΩ
Serial
Interface
Reference
Voltage
Registers
Current
Setting DAC
LED4
LED Channel
Current Regulators
RSET
GND
Figure 24. CAT3648 Functional Block Diagram
Basic Operation
At power−up, the CAT3648 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 1.33x mode (after a fixed delay
time of about 120 ms). In 1.33x mode, the output voltage is
approximately equal to 1.33 times the input supply voltage
(less any internal voltage losses).
This sequence repeats in the 1.33x and 1.5x mode until the
driver enters the 2x mode. In 1.5x mode, the output voltage
is approximately equal to 1.5 times the input supply voltage.
While in 2x mode, the output is approximately equal to 2
times the input supply voltage.
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. This only applies for
changing back to the 1x mode. The difference between the
input voltage when exiting 1x mode and returning to 1x
mode is called the 1x mode transition hysteresis (VHYS) and
is about 400 mV.
http://onsemi.com
10
CAT3648
LED Current Selection
Table 7. DIMMING LEVELS
After power−up, the LED current is set by the external
resistor (RSET) value and the number of pulses (n) on the
EN/DIM input as follows:
LED current + 125
0.6 V
R SET
Full Scale Current in %
Dimming Pulses [n]
100
0
97
1
94
2
90
3
87
4
84
5
81
6
77
7
74
8
71
9
68
10
ǒ3131* nǓ
The full scale current is calculated from the above formula
with n equal to zero.
The EN/DIM pin has two primary functions. One function
enables and disables the device. The other function is LED
current dimming with 32 different levels by pulsing the input
signal, as shown on Figure 25. On each consecutive pulse
rising edge, the LED current is decreased by about 3.2%
(1/31th of the full scale value). After 30 pulses, the LED
current is 3.2% of the full scale current. On the 31st pulse, the
current drops to zero, and then goes back to full scale on the
following pulse.
Each pulse width should be between 200 ns and 100 ms.
Pulses faster than the minimum TLO may be ignored and
filtered by the device. Pulses longer than the maximum TLO
may shutdown the device. By pulsing the EN/DIM signal at
high frequency, the LED current can quickly be set to zero.
The LED driver enters a “zero current” shutdown mode if
EN/DIM is held low for 1.5 ms or more.
The dimming level is set by the number of pulses on the
EN/DIM after the power−up, as shown in Table 7.
65
11
61
12
58
13
55
14
52
15
48
16
45
17
42
18
39
19
35
20
32
21
29
22
26
23
23
24
19
25
16
26
13
27
10
28
6
29
3
30
0
31
100
32
THI
EN/DIM
TLO
TPWRDWN
TLED
100%
LED
Current
Shutdown
100%
97% 94%
32 Levels
3%
0%
Figure 25. EN/DIM Digital Dimming Timing Diagram
http://onsemi.com
11
Shutdown
CAT3648
Unused LED Channels
LED Selection
For applications not requiring all the channels, it is
recommended the unused LED pins be tied directly to
VOUT (see Figure 26).
LEDs with forward voltages (VF) ranging from 1.3 V to
4.3 V may be used. 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 3.3 V is selected
over one with VF of 3.5 V, the driver will stay in 1x mode for
lower supply voltage of 0.2 V. This helps improve the
efficiency and extends battery life.
1 mF
C1+
VIN
VIN
CIN
C1− C2+
1 mF
C2−
VOUT
COUT
CAT3648
1 mF
LED1
ENABLE
DIMMING
EN/DIM
LED2
RSET
LED3
LED4
GND
External Components
The driver requires four external 1 mF 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 all charge pump modes, the input
current ripple is kept very low by design and an input bypass
capacitor of 1 mF is sufficient.
In 1x mode, the device operates in linear mode and does
not introduce switching noise back onto the supply.
1 mF
RSET
Figure 26. Application with 3 LEDs
Recommended Layout
In charge pump mode, the driver switches internally at a
high frequency. It is recommended to minimize trace length
to all four capacitors. A ground plane should cover the area
under the driver IC as well as the bypass capacitors. Short
connection to ground on capacitors CIN and COUT can be
implemented with the use of multiple via. A copper area
matching the TQFN exposed pad (TAB) must be connected
to the ground plane underneath. The use of multiple via
improves the package heat dissipation.
Protection Mode
If an LED is disconnected, the driver senses that and
automatically ignores that channel. When all LEDs are
disconnected, the driver goes to 1x mode where the output
is equal to the input voltage.
As soon as the output exceeds about 6 V, the driver resets
itself and re−evaluates the mode.
If the die temperature exceeds +150°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.
GND
Pin1
C2
EN/DIM
C1
RSE T
VIN
GND
CIN
COUT
GND
Figure 27. Recommended Layout
http://onsemi.com
12
CAT3648
PACKAGE DIMENSIONS
TQFN16, 3x3
CASE 510AD
ISSUE A
A
D
e
b
L
E2
E
PIN#1 ID
PIN#1 INDEX AREA
A1
TOP VIEW
SYMBOL
MIN
SIDE VIEW
NOM
A
0.70
0.75
0.80
0.00
0.02
0.05
0.20 REF
b
0.18
0.25
0.30
D
2.90
3.00
3.10
D2
1.40
−−−
1.80
E
2.90
3.00
3.10
E2
1.40
−−−
1.80
e
L
BOTTOM VIEW
MAX
A1
A3
D2
A
A3
A1
FRONT VIEW
0.50 BSC
0.30
0.40
0.50
Notes:
(1) All dimensions are in millimeters.
(2) Complies with JEDEC MO-220.
2. All packages are RoHS−compliant (Lead−free, Halogen−free).
3. The standard lead finish is NiPdAu.
4. For additional package and temperature options, please contact your nearest ON Semiconductor Sales office.
ON Semiconductor and the
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.
SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed
at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation
or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets
and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each
customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended,
or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which
the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or
unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim
alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable
copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
Literature Distribution Center for ON Semiconductor
P.O. Box 5163, Denver, Colorado 80217 USA
Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada
Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada
Email: [email protected]
N. American Technical Support: 800−282−9855 Toll Free
USA/Canada
Europe, Middle East and Africa Technical Support:
Phone: 421 33 790 2910
Japan Customer Focus Center
Phone: 81−3−5817−1050
http://onsemi.com
13
ON Semiconductor Website: www.onsemi.com
Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
CAT3648/D
Similar pages