CALMIRCO CM9320-01DE

PRELIMINARY
CM9320
Asymmetrical High Efficiency Two Channel Boost LED Driver
Features
Product Description
•
•
The CM9320 is a high frequency, two-channel inductorbased PWM boost regulator specifically designed for constant current white LED drive applications. With a maximum 100 mA/19V output capability, the circuit can drive
up to 10 WLEDs (5 series x 2 parallel) allowing up to 35
mA per channel. With a typical input voltage range from
2.7V to 6.0V, it can be operated from a single cell Li-Ion
battery.
•
•
•
•
•
•
•
•
•
•
•
•
2.7V to 6V input voltage range
Up to 85% typical efficiency even for asymmetrical
channel loads in terms of LED number, LED current
and LED dropout
Excellent 5 series x 2 parallel WLED drive capability
Up to 100 mA/19V output current/voltage
Independent current setting using an external low
power resistor for each channel (no ballast resistors)
No external frequency compensation needed
Low (<1%) LED output voltage and current ripple
Input undervoltage lockout and output over-voltage
protection
1 MHz fixed switching frequency (0.5 MHz option
available)
Uses small inductor and ceramic capacitors
Integrated low ON-Resistance (0.3 Ω) N-Chann el
MOSFET switch
Disconnects LEDs during shutdown
Low profile TDFN-10 package
Optional RoHS compliant lead free packaging
The proprietary FlexBoost™ architecture (patent pending)
provides high efficiency (typical 85%) for a wide input voltage range, even for asymmetrical channel loads in terms
of LED number, LED current and LED type. The maximum
LED current for each channel is independently programmed with external low-power resistors (no ballast
resistors needed).
A 1 MHz constant frequency PWM saves board space,
allowing small, low-cost external components, permitting
designers to avoid sensitive IF bands in RF applications.
The output over-voltage protection circuit prevents damage in case of a high impedance output (e.g. faulty LED).
The controlled current limit circuit prevents large inductor
current spikes, even at start-up. To avoid possible leakage
currents, the EN control pin disconnects the LEDs from
ground during shutdown.
Applications
•
•
•
•
•
•
Drives white LEDs for backlighting color LCD
Cell phones
MP3 players, PDA, GPS
Digital Still Cameras
LED flashlights
Handheld devices
The CM9320 is available in a compact TDFN-10 package.
It can operate over the industrial temperature range of 40°C to 85°C.
Typical Application
VIN
L1
2.7V to 6.0V
CIN
on (by default)
10 uF/10V
Enable
D1
4.7 uH
VOUT
1A, 20V
COUT
1 uF/16V
off
RSET1
1
22K
2
3
RSET2
EN
ISET1
VOUT
LED1
PhotonICTM
NC
CM9320
SW
4
ISET2
GND
5
LED2
VIN
10
Channel
CH1
9
CH2
8
7
22K
6
© 2006 California Micro Devices Corp. All rights reserved.
05/08/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
1
PRELIMINARY
CM9320
Package Pinout
PACKAGE / PINOUT DIAGRAM
Pin 1
Marking
TOP VIEW
BOTTOM VIEW
(Pins Down View)
(Pins Up View)
10 9 8 7 6
1 2 3 4 5
CMxxx
xxxxxx
GND
PAD
10 9 8 7 6
1 2 3 4 5
CM9320-01DE
10 Lead TDFN Package
Note: This drawing is not to scale.
Ordering Information
PART NUMBERING INFORMATION
Lead Free Finish
Pins
Package
Ordering Part Number1
10
TDFN
CM9320-01DE
Part Marking
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
Specifications
ABSOLUTE MAXIMUM RATINGS
PARAMETER
RATING
UNITS
±2
kV
VIN to GND
[GND - 0.3] to +6.0
V
Pin Voltages
VOUT, SW to GND
LED1, LED2 to GND
ISET1, ISET2 to GND
20
20
[GND - 0.3] to +5.0
V
V
V
Storage Temperature Range
-65 to +150
°C
Operating Temperature Range
-40 to +85
°C
300
°C
ESD Protection (HBM)
Lead Temperature (Soldering, 10s)
© 2006 California Micro Devices Corp. All rights reserved.
2
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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05/08/06
PRELIMINARY
CM9320
Specifications (cont’d)
ELECTRICAL OPERATING CHARACTERISTICS (SEE NOTE 1)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
VIN = 3.6V; CIN = 10μF, COUT = 1μF, L1 = 4.7μH, interleave mode, TA = 25°C (unless otherwise specified)
VIN
Input Voltage Range
IQ
Quiescent Current
VUVLO
Undervoltage Lockout
VOVP
Output Overvoltage Protection
VOUT Rising
ISD
Shutdown Current
VEN = 0V
VEN
Device Enable Threshold
Device ON (by default)
Device OFF
V
1.2
2.0
mA
V
LED Current (Note 1)
2.2
2.4
19.0
19.5
20.0
V
10
15
μA
0.2
V
V
35
mA
1.0
VIN = 3.0V to 6.0V, RSET1(kΩ)
4 WLED
2
1
Number of LEDs (Note 2)
VIN = 2.7V to 6.0V
Voltage on LED1 Pin
Standard load (Note 3)
Channel 2
ILED2
LED Current (Note 1)
VIN = 3.0V to 6.0V, RSET2(kΩ)
4 WLED
2
Number of LEDs (Note 2)
VIN = 2.7V to 6.0V
1
Voltage on LED2 Pin
Standard load (Note 3)
Boost Circuit (Note 3)
ΔILED / ILED ⋅ ΔVIN Line Regulation
IOUT
6.0
2.0
VLED1
VLED2
UNITS
2.7
ILED < 0.6mA (each channel), nonswitching
VIN Rising
Channel 1
ILED1
MAX
450
--------------R SET1
5
0.80
450
--------------R SET2
VIN = 3.0V to 6.0V
80
30
mA
5
VIN = 3.0V to 6.0V Each Channel
Boost Output Current
V
0.80
V
1
%/V
mA
Boost Output Voltage
ILED 1,2 = 2mA to ILED MAX
VIN
20
V
Duty Cycle Range
VIN = 2.7V to 6.0V,
ILED 1,2 = 2mA to ILED MAX
5
95
%
VOUTR
Output Voltage Ripple
Standard Load (Note 3)
50
RDSON
VOUT
D
mVpp
MOSFET ON Resistance
ISW = 0.8A, VGS = 15V
300
Eff
ISW
Efficiency
Switch Peak Current
Standard Load (Note 3)
Standard Load (Note 3)
85
0.5
%
A
PIN
Input Power
ILED 1,2 = 20mA, 4WLED+1W
835
mW
Channel Current Matching
(Note 4)
LED Current Ripple
1% RSET Accuracy, Each Channel
3
%
0.2
mApp
No-Load Mode (Note 5)
All Channels
Switching Frequency
VIN = 2.7V to 6.0V
Control
ILED acc
ILEDR
ILEDNL
fs
Standard Load (Note 3)
0
0.8
1.0
500
mΩ
0.6
mA
1.2
MHz
© 2006 California Micro Devices Corp. All rights reserved.
05/08/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
3
PRELIMINARY
CM9320
Specifications (cont’d)
ELECTRICAL OPERATING CHARACTERISTICS (SEE NOTE 1)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
VIN = 3.6V; CIN = 10μF, COUT = 1μF, L1 = 4.7μH, non-interleave mode (Note 6), TA = 25°C (unless otherwise specified)
ILED
ΔILED / ΔVIN
PIN
LED Current
VIN = 3.0V to 6.0V, RSET(kΩ)
Line Regulation @ High Load
L = 4.7μH, VIN = 3.0V to 5.5V
4W+4W, 40mA+40mA
L = 10μH, VIN = 3.0V to 5.5V
4W+4W, 50mA+40mA
L = 10μH, VIN = 2.8V to 5.5V
3W+4W, 60mA+40mA
ILED 1,2 = 20mA, 4WLED+1W
Input Power
2
730-----------R SET
IMAX
mA
1
%/V
3
%/V
1
%/V
730
mW
Note 1: ILED is the average PWM current through the LED string with internal 2/3 duty cycle and a 6 ms period. The following formula must be used to calculate the LED current:
I LED ( mA )
450
= --------------------R
SET ( kΩ )
Note 2: For lower LED forward voltage the number of LEDs can be increased up to the maximum output voltage limit.
Note 3: Standard Load is a 4 series x 2 parallel configuration set for IsetLED = 20 mA each channel (RSET1,2 = 22 kΩ).
Generally, a "4W+1W" like formula denotes the WLED number of each channel, i.e. CH1+CH2 configurations.
Note 4: [ILED(set) - ILED(effective)] / ILED(set) for each channel.
Note 5: A LED current value below 0.6 mA for each channel set the circuit in No-load mode; all channels and MOSFET switch are in
shutdown and DC circuit current consumption is limited to 1 mA (see quiescent current).
Note 6: For non-interleave mode, all parameters have the same min/typ/max interleave mode values, unless otherwise specified.
© 2006 California Micro Devices Corp. All rights reserved.
4
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
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Fax: 408.263.7846
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www.cmd.com
05/08/06
PRELIMINARY
CM9320
Typical Performance Curves
ILED vs. VIN
ILED vs. VIN (high currents)
21.2
120
21.0
ILED1
20.8
110
L=10uH, 3W+4W, 60mA+40mA
ILED1+ILED2 (mA)
ILED (mA)
20.6
20.4
20.2
20.0
ILED2
19.8
19.6
19.4
100
L = 4.7uH
4 WLED/ch
TA = 25 ºC
19.2
L=10uH, 4W+4W, 50mA+40mA
90
80
L=4.7uH, 4W+4W, 40mA+40mA
70
60
No-Interleave
TA = 25 ºC
50
19.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.0
6.0
2.5
3.0
3.5
VIN (V)
4.0
4.5
5.0
5.5
6.0
VIN (V)
EFFICIENCY vs. ILED
EFFICIENCY v.s VIN
90
90
Vin=5.6V
85
Efficiency (%)
Efficiency (%)
85
80
ILED1,2 = 20mA
L = 4.7uH
4 WLED/ch
4.2V
3.6V
80
3.0V
2.7V
75
70
L = 4.7uH
4 WLED/ch
TA = 25 ºC
65
60
75
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
6.0
5
10
15
VIN (V)
86
Efficiency (%)
Efficiency (%)
35
ILED=20mA+20mA
88
L=3.3uH
L=2.7uH
L=1.5uH
80
75
30
90
L=4.7uH
85
25
EFFICIENCY vs. STRING CONFIGURATION
EFFICIENCY vs. INDUCTOR
90
20
ILED (m A)
L=10uH
L=15uH
84
ILED=5mA+20mA
82
ILED=20mA+5mA
80
78
70
ILED1,2 = 20 mA
4 WLED/ch
TA = 25 ºC
L = 4.7uH
CH1,2 = 4W+3W
TA = 25 ºC
76
74
65
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
2.0
2.5
VIN (V)
3.0
3.5
4.0
4.5
5.0
5.5
6.0
VIN (V)
© 2006 California Micro Devices Corp. All rights reserved.
05/08/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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5
PRELIMINARY
CM9320
Functional Block Diagram
V IN
UVLO
BIAS
BG
EN
V OU T
OVP
OSC
PMW
LOGIC
D4
ENABLE
SW
Q4
R
D1
ISET1
CONTROL
L E D1
Q1
L E D2
D2
ISET2
Q2
CM9320
G ND
Pin Descriptions
PIN DESCRIPTIONS
LEAD(s)
NAME
DESCRIPTION
1
ISET1
Channel 1 LED current set pin. Between this pin and GND connect the RSET1 resistor, calculated as follows:
450
R SET1 ( kΩ ) = ----------------------------I LED1 ( mA )
2
LED1
Pin to cathode of channel 1 LED string.
where ILED1 is the DC LED current in channel 1.
3
NC
4
ISET2
Not internally connected. For better heat flow, connect to GND.
Channel 2 LED current set pin. Between this pin and GND connect the RSET2 resistor, calculated as follows:
450
R SET2 ( kΩ ) = ----------------------------I LED2 ( mA )
where ILED2 is the DC LED current in channel 2.
5
LED2
6
VIN
Input supply voltage pin. Bypass with a 10µF or larger ceramic capacitor to ground.
7
GND
Ground terminal pin.
8
SW
9
VOUT
Pin to cathode of channel 2 LED string.
Switching node. Internally connected to the drain of the integrated switch.
Output voltage pin, which connects to the anodes of all LEDs. Bypass with a 1.0µF or greater
ceramic capacitor to ground for low output ripple voltage.
© 2006 California Micro Devices Corp. All rights reserved.
6
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
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Fax: 408.263.7846
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www.cmd.com
05/08/06
PRELIMINARY
CM9320
Pin Descriptions (cont’d)
PIN DESCRIPTIONS
10
EN
EPad
GND
Enable pin. The circuit is ON when VEN is above 1.0V. The circuit is OFF when VEN is below
0.2V. Active High (ON) by default.
Ground (backside exposed pad).
Application Information
The CM9320 is a high efficiency, constant frequency
current regulating boost driver ideally suited for driving
white LEDs to backlight LCD color displays and a camera flash in Li-ion powered portable devices. The
CM9320 is the perfect driver for portable applications
such as cellular phones, digital still cameras, PDAs and
any application where small space, compact overall
size and low system cost are critical.
With a maximum 100 mA/19V output capability, the circuit can drive up to 10 WLEDs (5 series x 2 parallel),
allowing up to 35 mA per channel. It includes a switch
and an internally compensated loop for regulating the
current into the LEDs. The CM9320 delivers a constant
current to series-connected LEDs, ensuring uniform
brightness and color purity regardless of any LED forward voltage variations.
The proprietary design architecture allows asymmetrical loading on each channel and maintains high efficiency (typ 85%) at low VIN resulting in longer battery
life, and cool, reliable operation when an adapter is
supplying high VIN. The maximum LED current for
each channel is independently programmed with external low power resistors avoiding the need for ballast
resistors.
An 1MHz constant frequency PWM scheme saves
board space with the use of small, low cost external
components, allowing designers to avoid sensitive IF
bands in RF applications. The circuit operates with low
value inductors and low value output ceramic capacitors, keeping voltage and current ripple in the 1%
range.
possible leakage currents, the EN control pin disconnects the LEDs from ground during shutdown.
CM9320 Operation
When a voltage that exceeds the undervoltage lockout
threshold (UVLO) is applied to the VIN pin, the
CM9320 initiates a softstart which limits the inrush current while the output capacitors are charged. Following
softstart, the CM9320's internal NMOS drives an external inductor and Schottky diode that delivers the inductor's stored energy to the load.
Setting the LED Current
The output current is set by the value of the RSET connected between the ISET pin and GND, according to
the equations:
(a) Interleave
450 R SET ( kΩ ) = ------------------------I LED ( mA )
(b) Non-interleave
730 R SET ( kΩ ) = ------------------------I LED ( mA )
PWM Brightness Control
The brightness WLEDs level can be continuously controlled for each channel using a PWM signal in 1-50
KHz range (recommended value is 10 kHz). As an
example, the PWM signal can be applied directly
through RSET resistor for negative slope or by using a
The output over-voltage protection circuit prevents
damage in case of a high impedance output (e.g. faulty
LED). The controlled current limit circuit limit prevents
large inductor current spikes, even at start-up. To avoid
© 2006 California Micro Devices Corp. All rights reserved.
05/08/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
7
PRELIMINARY
CM9320
Application Information (cont’d)
switch transistor for positive slope. See Figure 1 for different brightness control methods and results.
RSET1
PWM
signal
ISET1
22k
selected based on the required load power and the
minimum input voltage. The saturation current rating
should be chosen well above the steady state peak
inductor current. At minimum VIN and full duty cycle
(worse case), this is approximately:
1 V IN ( MIN ) × t ON 3V × 0.8 × --------------1MHz
I PEAK ≅ --------------------------------------- ≅ -------------------------------------------- ≅ 0.5A
L
4.7μH
RSET2
ISET2
91k
CM9320
Diode Selection
(a) Schematic
The low forward voltage and fast switching time make
Schottky diodes the choice for high efficiency operation. Make sure the diode has a reverse voltage rating
greater than the maximum output voltage. The diode
conducts only when the power switch is on, so a peak
current rating above 1A should be sufficient for a typical design.
25
ILED1
negative slope
ILED (mA)
20
15
10
Capacitor Selection
ILED2
positive slope
For proper performance, use surface-mount, low ESR
ceramic capacitors for CIN and COUT. X7R or X5R
ceramic dielectric provides good stability over the operating temperature and voltage range.
5
0
0
10
20
30
40
50
60
70
80
90
100
DUTY (%)
In most LED applications, high frequency output ripple
is not a concern because it will not cause intensity variations that are visible to the human eye.
(b) Brightness curves
Figure 1. Brightness Control Using
Different Methods
For such applications, when low ripple is needed, a
22μF input capacitor and/or 2.2 μF output capacitor are
recommended.
Inductor Selection
The inductor is used to store energy in a boost converter. The amount of energy stored in the inductor and
transferred to the load is controlled by the PWM. The
inductor is operated in the discontinuous conduction
mode, and to assume proper operation, the inductor
value must be limited to a maximum value.
An inductor with low series resistance (DCR)
decreases power losses and increases efficiency. The
core material should be capable of operating at I MHz
with minimum core losses. An inductance of 4.7µH is
optimal for most applications, but low DCR inductor values in 1.5-15uH range are also recommended for high
efficiency applications.
To ensure proper operation of the current regulator
over a wide range of conditions, the inductor should be
REF
DES
CIN
COUT
L1
DESCRIPTION
Capacitor, 10μF,
10V, Ceramic, 1206
Capacitor, 1μF, 16V,
Ceramic, 0805
Inductor, 4.7μH, 1A,
Low DCR
Schottky Diode, 1A,
20V, SMD
D1
SOURCE
Murata, GRM319R61A106KE19D
Vishay, VJ1206G106KXQ
Murata, GRM188R61C105KA93D
TDK, C2012X5R1C105K
Coilcraft, LP06013-472ML
TMP Electronics Co., SPC-03802-4R7
CHILISIN, SCD03015-4R7
SUMIDA, CDH3D13/S4R7
IR, MBRS120
CHENMKO, SSM5817S
Input Filter
If CM9320 is more than 4" from main power supply
point, use an input RC filter to avoid high ripple and
input transients to the circuit input pin (see Figure 2).
© 2006 California Micro Devices Corp. All rights reserved.
8
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
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www.cmd.com
05/08/06
PRELIMINARY
CM9320
Application Information (cont’d)
In this case, because of small input ripple, the efficiency is about 2% higher.
to VIN
CM9320
GND
VIN
7
RF
100
6
CF
0.1 uF/10V
Figure 2. Input Filter Solution
Layout Guide
Components should be placed as close as practical to
the IC to assure good performance. The input and output capacitors should be close, with minimum trace
resistance and inductance. Reflected input ripple
depends on the impedance of the VIN source, such as
the PCB traces and the Li-ion battery, which have elevated impedance at higher frequencies. The input
capacitor located near the converter input reduces this
source impedance and ripple. Any ESR from the
capacitor will result in steps and spikes in the ripple
waveform, and possibly produce EMI.
Figure 3. Example CM9320 PC Layout and
Component Placement for Standard Application
Route any noise sensitive traces away from the switching power components. Place the inductor and diode
as close as possible to the SW pin to prevent noise
emissions.
The ground connections for RSET(1,2) resistors
should be kept separate from the high power grounds
and connect directly to the ground pin to assure accurate current and voltage settings. For better heat flow,
connect all NC pins to GND plane. Also connect the
thermal landing to the bottom ground plane with thermal vias.
© 2006 California Micro Devices Corp. All rights reserved.
05/08/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
9
PRELIMINARY
CM9320
Mechanical Details
TDFN-10 Mechanical Specifications
Dimensions for the CM9320 packaged in a 10-lead
TDFN package are presented below.
Mechanical Package Diagrams
For complete information on the TDFN-10, see the California Micro Devices TDFN Package Information document.
D
10 9 8 7 6
PACKAGE DIMENSIONS
TDFN
JEDEC
No.
MO-229 (Var. WEED-3)=
Leads
10
E
Package
Dim.
Millimeters
Pin 1
Marking
Inches
Min
Nom
Max
Min
Nom
Max
A
0.70
0.75
0.80
0.028
0.030
0.031
1 2 3 4 5
A1
0.00
0.02
0.05
0.000
0.001
0.002
TOP VIEW
A2
0.45
0.55
0.65
0.018
0.022
0.026
b
0.20
0.18
D
D2
0.30
0.007
3.00
2.20
E
E2
0.25
0.008
2.30
e
1.50
0.012
0.118
2.40
0.087
3.00
1.40
0.010
0.10 C
0.091
0.08 C
0.094
A1
0.118
1.60
0.055
0.50
0.060
A
SIDE VIEW
A3 A2
0.063
0.020
K
1.30
1.50
1.70
0.051
0.060
0.067
L
0.20
0.30
0.40
0.008
0.012
0.016
# per
tube
NA
# per
tape and
reel
3000 pieces
1
2
3
4
5
Pin 1 ID
C0.35
E2
A3
GND PAD
L
D2
Controlling dimension: millimeters
=This package is compliant with JEDEC standard MO-229, variation
WEED-3 with exception of the "D2" and "E2" dimensions as called
out in the table above.
10
K
9
8
7
6
b
e
8X
BOTTOM VIEW
0.10
M
CAB
Package Dimensions for 10-Lead TDFN
© 2006 California Micro Devices Corp. All rights reserved.
10 490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
05/08/06