PRELIMINARY
CM9321
Asymmetrical High Efficiency Three Channel Boost LED/OLED Driver
Features
•
•
•
Integrated WLED and OLED driver
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
(35 mA per channel)
OLED channel with up to 18V/30 mA capability
Independent current/voltage setting using external
low power resistors for each channel (no ballast resis-
tors)
No external frequency compensation needed
Low (<1%) LED output ripple voltage and current
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 0.3
Ω
internal power switch
Disconnects LEDs during shutdown
Low profile TQFN-16 package
Optional RoHS compliant lead free packaing
Product Description
The CM9321 is a high frequency, three-channel inductor-
based PWM boost regulator specifically designed for con-
stant current white LED and constant voltage OLED drive
applications. With a maximum 19V/140mA output capabil-
ity, the circuit can drive up to 10 WLEDs (5 series x 2 par-
allel) and one OLED, allowing up to 35 mA per channel.
With an input voltage range from 2.7V to 6.0V, it can oper-
ate from a single cell Li-Ion battery.
The proprietary
FlexBoost™
architecture (patent pending)
provides high efficiency (typical 85%) for a wide input volt-
age range, even for asymmetrical channel loads in term of
LED number, LED current and LED type. A standard (non-
interleave) version is also available using a MODE selec-
tion pin (not availalbe fo mass production). The maximum
LED current and OLED voltage for each channel is inde-
pendently 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 which per-
mits designers to avoid sensitive IF bands in RF applica-
tions. The output over-voltage protection circuit prevents
damage in the 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.
The CM9321 is available in a compact TQFN-16 package.
It can operate over the industrial temperature range of -
40°C to 85°C.
•
•
•
•
•
•
•
•
•
•
•
•
Applications
•
•
•
•
•
Drives white LED backlighting and OLED
Cell phones
Digital Cameras
PDA, GPS, MP3 players
Handheld devices
Typical Application
V
IN
2.7V to 6.0V
C
IN
10 uF/10V
off
on (by default)
L1
4.7 uH
D1
1A/20V
V
OUT
C
OUT
1 uF/16V
Enable
16
R
SET 1
22K
2
3
R
SET 21
20K
4
R
SET 22
91K
R
SET 3
22K
C
OLED
10 uF/16V
LED2
NC
15
NC
14
NC
13
VOUT
12
CH1
Channel
CH2 CH3
EN
1
ISET1
LED1
PhotonIC
TM
CM9321
SW
GND
11
10
OLED
VREF
ISET3
VSET2
MODE
LED3
VIN
9
interlv (by default)
no-interlv
5
6
7
8
C
REF
1 uF/6.3V
©
2006 California Micro Devices Corp. All rights reserved.
04/26/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
1
PRELIMINARY
CM9321
Package Pinout
PACKAGE / PINOUT DIAGRAM
Bottom View
6 ISET3
5 LED2
7 LED3
8 VIN
VSET2
VREF
LED1
ISET1
4
3
2
1
16
15
14
13
9 MODE
TQFN16
4 X4
10 GND
11 SW
12 VOUT
NC
NC
Note: This drawing is not to scale.
16-Lead TQFN Package
(4mm x 4mm)
Ordering Information
PART NUMBERING INFORMATION
Lead-free Finish
Pins
16
Package
TQFN
Ordering Part Number
1
CM9321-01DE
Part Marking
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
Specifications
ABSOLUTE MAXIMUM RATINGS
PARAMETER
ESD Protection (HBM)
VIN to GND
Pin Voltages
V
OUT
, SW to GND
LED1, LED2, LED3 to GND
ISET1, VSET2, ISET3, VREF, EN to GND
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10s)
RATING
±
2
[GND - 0.3] to +6.0
20
20
[GND - 0.3] to +5.0
-65 to +150
-40 to +85
300
UNITS
kV
V
V
V
V
°C
°C
°C
©
2006 California Micro Devices Corp. All rights reserved.
2
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
NC
EN
l
Fax: 408.263.7846
l
www.cmd.com
04/26/06
PRELIMINARY
CM9321
Specifications (cont’d)
ELECTRICAL OPERATING CHARACTERISTICS
(SEE NOTE 1)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
V
IN
= 3.6V; C
IN
= 10μF, C
OUT
= 1μF, C
OLED
= 1μF, L
1
= 4.7μH,
interleave mode,
T
A
= 25°C (unless otherwise specified)
V
IN
I
Q
V
UVLO
V
OVP
I
SD
V
EN
Input Voltage Range
Quiescent Current
Undervoltage Lockout
I
LED
< 0.6mA (each channel), non-
switching
V
IN
Rising
2.7
1.2
2.0
19.0
2.2
19.5
10
1.0
0.2
2
1
0.80
8
2
5
3
1.180
10
2
1
0.80
1
140
V
IN
50
5
300
95
500
20
1.220
20
450
---------------
R
SET1
1.260
50
30
5
V
%/V
mA
V
mVpp
%
mΩ
20
×
V
VSET2
18
30
450
---------------
R
SET1
35
5
V
V
mA
%
%
V
μA
mA
6.0
2.0
2.4
20.0
15
V
mA
V
V
μA
V
V
mA
Output Overvoltage Protec- V
OUT
Rising
tion
Shutdown Current
V
EN
= 0V
Device Enable Threshold
Device ON (by default)
Device OFF
V
IN
= 3.0V to 6.0V, R
SET1
(kΩ)
4 WLED
Channel 1 (WLED)
LED Current (Note 1)
I
LED1
Number of WLEDs (Note 2) V
IN
= 2.7V to 6.0V
V
LED1
Voltage on LED1 Pin
Standard load (Note 3)
V
IN
= 3.0V to 6.0V
V
IN
= 2.7V to 6.0V
V
IN
= 3.0V to 6.0V,
I
OLED
= 5mA to 20mA
1% divider resistors
T
A
= 25°C to 85°C
(Recommended)
V
IN
= 3.0V to 6.0V, R
SET1
(kΩ)
4 WLED
Channel 2 (OLED)
V
OLED
OLED Voltage (Note 4)
I
OLED
OLED Current Range
Δ
V
OLED
/ V
OLED
V
OLED
Regulation
V
OLEDacc
V
REF
I
REF
O
LED
Voltage Accuracy
Reference Voltage
V
REF
Divider Current
Channel 3 (WLED)
I
LED3
LED Current (Note 1)
Number of WLEDs (Note 2) V
IN
= 2.7V to 6.0V
V
LED3
Voltage on LED3 Pin
Standard load (Note 3)
V
IN
= 3.0V to 6.0V Each Channel
V
IN
= 3.0V to 6.0V
Standard Load (Note 3)
Standard Load (Note 3)
V
IN
= 2.7V to 6.0V,
I
LED
= 2mA to I
LED MAX
I
SW
= 0.8A, V
GS
= 15V
Boost Circuit
(Note 3)
ΔI
LED
/ I
LED
⋅ ΔV
IN
Line Regulation
I
OUT
V
OUT
V
OUTR
D
R
DSON
Boost Output Current
Boost Output Voltage
Output Voltage Ripple
Duty Cycle Range
MOSFET ON Resistance
©
2006 California Micro Devices Corp. All rights reserved.
04/26/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
l
Tel: 408.263.3214
l
Fax: 408.263.7846
l
www.cmd.com
3
PRELIMINARY
CM9321
Specifications (cont’d)
ELECTRICAL OPERATING CHARACTERISTICS
(SEE NOTE 1)
SYMBOL
Eff
I
SW
P
IN
Control
I
LED acc
I
LEDR
I
LEDNL
fs
PARAMETER
Efficiency
Switch Peak Current
Input Power
CONDITIONS
Standard Load (Note 3)
Standard Load (Note 3)
I
LED 1,2
= 20mA,
4WLED+OLED+2W
1% R
SET
Accuracy, Each Channel
Standard Load (Note 3)
All Channels
V
IN
= 2.7V to 6.0V
0
0.8
1.0
MIN
TYP
85
0.65
950
MAX
UNITS
%
A
mW
Channel Current Matching
(Note 5)
LED Current Ripple
No-Load Mode (Note 5)
Switching Frequency
3
0.2
0.6
1.2
%
mApp
mA
MHz
V
IN
= 3.6V; C
IN
= 10μF, C
OUT
= 1μF, C
OLED
= 1μF, L
1
= 4.7μH,
non-interleave mode
(Note 7), T
A
= 25°C (unless otherwise
specified)
LED Current
V
IN
= 3.0V to 6.0V, R
SET
(kΩ)
2
I
MAX
mA
I
LED
730-
------------
R
SET
P
IN
Input Power
I
LED 1,2,3
= 20mA,
4WLED+OLED+2W
I LED
(
mA
)
450
= ---------------------
-
990
mW
Note 1: I
LED
is the average PWM current through the LED string with internal 2/3 duty cycle and a 6 ms period. The following for-
mula must be used to calculate the LED current:
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 WLEDS configured for I
setLED
= 20 mA each channel (R
SET1
= R
SET3
= 22 kΩ) and
one OLED channel (CH2) which drives V
OLED
=12V and I
OLED
=20mA.
Note 4: V
VSET2
, the voltage on VSET2 pin should be maintained in the 0.4V - 1.0V range. The following formulae are related to
OLED channel settings:
R
SET22
V
OLED
= V
OUT
– V
LED
,
V
OLED
= 20
×
V
SET2
,
V
VSET2
= ------------------------------------------
×
V
REF
R
SET21
+ R
SET22
Note 5: [ILED(set) - ILED(effective)]/ILED(set) for each channel.
Note 6: A ILED value below 0.6 mA for each channel set the circuit in no-load mode; all channels and MOSFET switch are in shut-
down and DC circuit current consumption is limited to 1 mA (see quiescent current).
Note 7: 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
l
Fax: 408.263.7846
l
www.cmd.com
04/26/06
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