PRELIMINARY CM9330 Asymmetrical High Efficiency Three Channel Boost LED Driver Features Product Description • • The CM9330 is a high frequency, three-channel inductor-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) 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 3 parallel WLED drive capability Up to 140 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-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 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. A standard (non-interleave) version is also available 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 permitting designers to avoid sensitive IF bands in RF applications. 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 CM9330 is available in a compact TQFN-16 packages. It can operate over the industrial temperature range of -40°C to 85°C. Typical Application VIN 2.7V to 6.0V CIN on (by default) 10 uF/10V off 1 ISET1 Enable D1 4.7 uH 1A, 20V VOUT COUT 1 uF/16V 13 EN 14 NC RSET1 15 NC NC 16 L1 VOUT CH1 12 Channel CH2 CH3 22K ISET2 MODE VIN 4 22K GND LED3 RSET2 CM9330 NC SW ISET3 3 PhotonICTM LED1 LED2 2 5 6 7 8 RSET3 11 10 9 interlv ( by default) no-interlv 22K © 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 CM9330 Package Pinout PACKAGE / PINOUT DIAGRAM 7 LED3 8 VIN 11 SW 14 13 12 VOUT EN 1 NC 2 ISET1 10 GND 15 LED1 9 NC TQFN16 4 X4 16 3 NC 4 NC ISET2 MODE 6 ISET3 5 LED2 Bottom View 16-Lead TQFN Package (4mm x 4mm) Note: This drawing is not to scale. Ordering Information PART NUMBERING INFORMATION Lead Free Finish Pins Package Ordering Part Number1 16 TQFN CM9330-01QE 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, LED3 to GND ISET1, ISET2, ISET3 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 l Tel: 408.263.3214 l Fax: 408.263.7846 l www.cmd.com 04/26/06 PRELIMINARY CM9330 Specifications (cont’d) ELECTRICAL OPERATING CHARACTERISTICS (SEE NOTE 1) VIN = 3.6V; CIN = 10μF, COUT = 1μF, L1 = 4.7μH, interleave mode, TA = 25°C (unless otherwise specified) SYMBOL PARAMETER VIN Input Voltage Range IQ Quiescent Current CONDITIONS MIN VUVLO Undervoltage Lockout VOVP Output Overvoltage Protection VOUT Rising ISD Shutdown Current VEN = 0V VEN Device Enable Threshold Device ON (by default) Device OFF mA 2.2 2.4 V 19.5 20.0 V 15 μA 0.2 V V 35 mA 1.2 2.0 19.0 10 VIN = 3.0V to 6.0V, RSET1(kΩ) 4 WLED 2 Number of LEDs (Note 2) VIN = 2.7V to 6.0V 1 VLED1 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 VLED2 Voltage on LED2 Pin Standard load (Note 3) Channel 3 ILED3 LED Current (Note 1) VIN = 3.0V to 6.0V, RSET3(kΩ) 4 WLED 2 Number of LEDs (Note 2) VIN = 2.7V to 6.0V 1 Voltage on LED3 Pin Standard load (Note 3) Boost Circuit (Note 3) ΔILED / ILED ⋅ ΔVIN Line Regulation MAX 1.0 LED Current (Note 1) VLED3 2.0 2.7 ILED < 0.6mA (each channel), nonswitching VIN Rising Channel 1 ILED1 6.0 UNIT S V TYP 450 --------------R SET1 5 0.80 450 --------------R SET2 V 30 mA 5 0.80 450 --------------R SET3 V 30 mA 5 VIN = 3.0V to 6.0V Each Channel 0.80 V 1 %/V IOUT Boost Output Current VIN = 3.0V to 6.0V 100 VOUT Boost Output Voltage ILED 1,2,3 = 2mA to ILED MAX VIN 20 V Duty Cycle Range VIN = 2.7V to 6.0V, ILED 1,2,3 = 2mA to ILED MAX 5 95 % VOUTR Output Voltage Ripple Standard Load (Note 3) 50 RDSON MOSFET ON Resistance ISW = 0.8A, VGS = 15V 300 Eff Efficiency Standard Load (Note 3) 85 ISW Switch Peak Current Standard Load (Note 3) 0.65 A PIN Input Power ILED 1,2,3 = 20mA, 4WLED+1W+1W 835 mW Channel Current Matching (Note 4) 1% RSET Accuracy, Each Channel 3 % D Control ILED acc mA mVpp 500 mΩ % © 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 CM9330 Specifications (cont’d) ELECTRICAL OPERATING CHARACTERISTICS (SEE NOTE 1) VIN = 3.6V; CIN = 10μF, COUT = 1μF, L1 = 4.7μH, interleave mode, TA = 25°C (unless otherwise specified) SYMBOL PARAMETER CONDITIONS ILEDR LED Current Ripple Standard Load (Note 3) ILEDNL No-Load Mode (Note 5) All Channels Switching Frequency VIN = 2.7V to 6.0V fs MIN TYP MAX 0.2 0 0.8 1.0 UNIT S mApp 0.6 mA 1.2 MHz VIN = 3.6V; CIN = 10μF, COUT = 1μF, L1 = 4.7μH, non-interleave mode (Note 6), TA = 25°C (unless otherwise specified) SYMBOL ILED ΔILED / ΔVIN PIN PARAMETER CONDITIONS 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+4W, 40mA+40mA+40mA L = 10μH, VIN = 3.0V to 5.5V 4W+4W+4W, 60mA+40mA+40mA\ ILED 1,2,3 = 20mA, 4WLED+1W+1W Input Power MIN TYP MAX 2 730-----------R SET IMAX UNIT S mA 1 %/V 3 %/V 975 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 3 parallel configuration set for IsetLED = 20 mA each channel (RSET1,2,3 = 22 kΩ). Generally, a "4W+1W+1W" like formula denotes the WLED number of each channel, i.e. CH1+CH2+CH3 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 l Fax: 408.263.7846 l www.cmd.com 04/26/06 PRELIMINARY CM9330 Typical Performance Curves ILED vs. VIN (high current) ILED vs. VIN 21.2 160 21.0 ILED1+IED2+ILED3 (mA ILED2 20.6 ILED (mA) 150 ILED1 20.8 20.4 20.2 20.0 19.8 ILED3 19.6 Interleave L = 4.7uH 4 WLED/ch TA = 25 ºC 19.4 19.2 19.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 L=10uH, 3W+4W+4W, 60mA+40mA+40mA 140 L=10uH, 4W+4W+4W, 60mA+40mA+40mA 130 L=10uH, 4W+4W+4W, 40mA+40mA+40mA 120 L=4.7uH, 4W+4W+4W, 40mA+40mA+40mA 110 100 L=4.7uH, 4W+4W+4W, 35mA+30mA+30mA 90 80 No-Interleave TA = 25 ºC 70 6.0 2.0 2.5 3.0 3.5 V IN (V) 4.0 4.5 5.0 5.5 6.0 V IN (V) EFFICIENCY v.s VIN EFFICIENCY vs. ILED 90 90 Vin=5.6V 85 Efficiency (% Efficiency (% 85 80 Interleave ILED1,2,3 = 20mA L = 4.7uH 4 WLED/ch 2.5 3.0 3.5 4.0 4.5 5.0 5.5 80 75 70 65 L = 4.7uH 4 WLED/ch TA = 25 ºC 60 75 2.0 4.2V 3.6V 3.0V 2.7V 0 6.0 5 10 15 V IN (V ) 20 25 30 35 ILED (m A) EFFICIENCY vs. INDUCTOR EFFICIENCY vs. STRING CONFIGURATION 90 90 L=4.7uH 88 L=3.3uH L=2.7uH 80 75 ILED=20mA+20mA+20mA 86 L=1.5uH Efficiency (% Efficiency (% 85 L=10uH L=15uH 84 ILED=5mA+10mA+20mA 82 ILED=20mA+10mA+5mA 80 78 Interleave L = 4.7uH CH1,2,3 = 4W+3W+2W TA = 25 ºC 70 ILED1,2,3 = 20 mA 4 WLED/ch 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 V IN (V ) 3.0 3.5 4.0 4.5 5.0 5.5 6.0 V IN (V ) © 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 5 PRELIMINARY CM9330 Functional Block Diagram VIN VOUT UVLO BIAS OSC BG EN OVP PMW LOGIC D4 ENABLE R ISET1 LED1 D1 ISET2 SW Q4 Q1 LED2 D2 CONTROL Q2 LED3 ISET3 D3 Q3 MODE CM9330 GND 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 ) where ILED1 is the DC LED current in channel 1. 2 LED1 3 NC 4 ISET2 Pin to cathode of channel 1 LED string. 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 Pin to cathode of channel 2 LED string. © 2006 California Micro Devices Corp. All rights reserved. 6 490 N. McCarthy Blvd., Milpitas, CA 95035-5112 l Tel: 408.263.3214 l Fax: 408.263.7846 l www.cmd.com 04/26/06 PRELIMINARY CM9330 Pin Descriptions (cont’d) PIN DESCRIPTIONS 6 ISET3 Channel 3 LED current set pin. Between this pin and GND connect the RSET3 resistor, calculated as follows: 450 R SET3 ( kΩ ) = ---------------------------I LED3 ( mA ) where ILED3 is the DC LED current in channel 3. 7 LED3 Pin to cathode of channel 3 LED string. 8 VIN 9 MODE Input supply voltage pin. Bypass with a 10 µF or larger ceramic capacitor to ground. 10 GND 11 SW 12 VOUT Output voltage pin, which connects to the anodes of all LEDs. Bypass with a 1.0 µF or greater ceramic capacitor to ground for low output ripple voltage. 13 EN 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. 14 NC Not internally connected. For better heat flow, connect to GND. 15 NC Not internally connected. For better heat flow, connect to GND. 16 NC Not internally connected. For better heat flow, connect to GND. EPad GND When MODE is HIGH (default), the circuit uses interleave mode. When MODE is LOW (GND), the circuit uses non-interleave mode. Ground terminal pin. Switching node. Internally connected to the drain of the integrated switch. Ground; backside exposed pad. Application Information The CM9330 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 CM9330 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 140mA/19V output capability, the circuit can drive up to 15 WLEDs (5 series x 3 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 CM9330 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 ballast resistors. An 1MHz constant frequency PWM scheme saves board space using of small, low cost external components , allowing designers to avoid sensitive IF bands in RF applications. The circuit operates with low value inductor and low value output ceramic capacitor keeping voltage and current ripple in 1% range. 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 limit 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. CM9330 Operation When a voltage that exceeds the undervoltage lockout threshold (UVLO) is applied to the VIN pin, the CM9330 initiates a softstart which limits the inrush current while the output capacitors are charged. Following © 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 7 PRELIMINARY CM9330 Application Information (cont’d) softstart, the CM9330's internal NMOS drives an external inductor and Schottky diode 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: 450 R SET ( kΩ ) = ------------------------I LED ( mA ) (a) Interleave 730 R SET ( kΩ ) = -------------------------I LED ( mA ) (b) Non-interleave 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 switch transistor for positive slope. See Figure 1 for different brightness control methods and results. 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 minimal core losses. An inductance of 4.7-µH is optimum 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 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 × 0.95 × --------------1MHz I PEAK ≅ --------------------------------------- ≅ ----------------------------------------------- ≅ 0.7A L 4.7μH RSET1 PWM signal Inductor Selection ISET1 22k RSET2 ISET2 Diode Selection 36k RSET3 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. ISET3 91k CM9330 (a) Schematic 25 ILED1 negative slope 20 ILED2 ILED (mA) Capacitor Selection 15 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. 10 ILED3 positive slope 5 0 0 10 20 30 40 50 60 70 80 90 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. 100 DUTY (%) (b) Brightness Curves Figure 1. Brightness Control Using Different Methods © 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 l www.cmd.com 04/26/06 PRELIMINARY CM9330 Application Information (cont’d) For such applications, when low ripple is needed, a 22μF input capacitor and/or 2.2 μF output capacitor are recommended. REF DES CIN COUT L1 D1 DESCRIPTION Capacitor, 10μF, 10V, Ceramic, 1206 Capacitor, 1μF, 16V, Ceramic, 0805 Inductor, 4.7μH, 1A, Low DCR Schottky Diode, 1A, 20V, SMD 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 CM9330 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). In this case, because of small input ripple, the efficiency is about 2% higher. Layout Guide Components should be placed ase 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 has 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. 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(1,2,3) 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. to VIN 7 GND MODE VIN LED3 CM9330 10 9 RF 100 8 CF 0.1 uF/10V Figure 2. Input Filter Solution Mode Selection Two working modes are available for CM9330: interleave mode (output voltage is periodically adjusted depending on each channel load) and non-interleave mode (same output voltage level for all channels). For interleave option, keep MODE pin floating (HIGH by default) and for non-interleave option, connect MODE pin to GND. Figure 3. Example CM9330 PC Layout and Component Placement for Standard Application © 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 9 PRELIMINARY CM9330 Mechanical Details TQFN-16 Mechanical Specifications Mechanical Package Diagrams The CM9330 is supplied in a 16-lead, 4.0mm x 4.0mm TQFN package. Dimensions are presented below. For complete information on the TQFN16, see the California Micro Devices TQFN Package Information document. D Package TQFN-16 (4x4) Leads 16 Millimeters Min A A1 A3 b Nom Max 0.80 0.84 0.00 0.04 Min Nom Max 0.031 0.033 0.15 C 0.002 0.15 C 0.00 0.20 REF 0.25 .008 0.33 0.010 D 4.0 BSC 0.157 1.95 REF 0.077 E 0.08 C 0.077 2.15 0.081 0.65 TYP. 0.55 0.085 0.157 1.95 REF 2.05 e L 0.081 4.0 BSC E1 E2 2.15 0.10 C A3 A1 SIDE VIEW 0.085 A 0.026 0.65 0.022 # per tube xx pieces* # per tape and reel xxxx pieces D1 0.026 E1 2.05 TOP VIEW 0.013 D1 D2 Pin 1 Marking Inches E2 Dim. E PACKAGE DIMENSIONS Controlling dimension: millimeters D2 * This is an approximate number which may vary. L DAP SIZE 1.8 X 1.8 b e 16X 0.10 M CAB BOTTOM VIEW Package Dimensions for 16-Lead TQFN © 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 04/26/06