CM9330 Datasheet, PDF (1/10 Pages) California Micro Devices Corp – Asymmetrical High Efficiency Three Channel Boost LED Driver

PRELIMINARY
CM9330
Asymmetrical High Efficiency Three Channel Boost LED Driver
Features
• 2.7V to 6V input voltage range
• Up to 85% typical efficiency even for asymmetrical
channel loads in terms of LED number, LED cur-
rent and LED dropout
• Excellent 5 series x 3 parallel WLED drive capabil-
ity
• Up to 140 mA/19V output current/voltage
• Independent current setting using an external low
power resistor for each channel (no ballast resis-
tors)
• 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-Channel
MOSFET switch
• Disconnects LEDs during shutdown
• Low profile TQFN-16 package
• Optional RoHS compliant lead-free packaging
Applications
• Drives white LEDs for backlighting color LCD
• Cell phones
• MP3 players
• PDA, GPS
• Digital Still Cameras
• LED flashlights
• Handheld devices
Product Description
The CM9330 is a high frequency, three-channel induc-
tor-based PWM boost regulator specifically designed
for constant current white LED drive applications. With
a maximum 140mA/19V output capability, the circuit
can drive up to 15 WLEDs (5 series x 3 parallel) allow-
ing up to 35 mA per channel. With a typical input volt-
age range from 2.7V to 6.0V, it can be operated from a
single cell Li-Ion battery.
The proprietary FlexBoost™ architecture (patent pend-
ing) 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. A standard (non-interleave) version is also avail-
able using a MODE selection pin (not available for
mass production). 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, and per-
mitting designers to avoid sensitive IF bands in RF
applications. The output over-voltage protection circuit
prevents damage in the case of a high impedance out-
put (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 CM9330 is available in a compact TQFN-16 pack-
ages. It can operate over the industrial temperature
range of -40°C to 85°C.
Typical Application
VIN ^{2.7V to 6.0V}
CIN
10 uF/10V
16 15
on (by default)
off ^Enable
14 13
RSET1
22K
1 _ISET1
2
LED1
3 _NC
12
VOUT
PhotonIC^{TM SW 11}
CM9330 _{GND 10}
RSET2
22K
4 _ISET2
MODE
9 ^{interlv ( by default)}
no-interlv
L1
4.7 uH
D1
1A, 20V
Channel
CH1 CH2 CH3
RSET3
22K
5
6
7
8
VOUT
COUT
1 uF/16V
© 2006 California Micro Devices Corp. All rights reserved.
04/26/06 490 N. McCarthy Blvd., Milpitas, CA 95035-5112 l Tel: [phone] l Fax: [phone] l www.cmd.com
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