www.fairchildsemi.com FAN5609 LED Driver with Adaptive Charge Pump DC/DC Converter Features Applications • • • • • • • • • • • • • • • • • • • • • • • • Parallel LED Driver Supports All Forward Voltages Adaptive VOUT Adjustment to the Highest Diode Voltage Internally Matched LED Current Sources No External Components Needed to Set LED Current Built-in Charge Pump has Three Modes of Operation: – Linear Regulation VIN > 4.2V – 3/2 DC-DC Converter and Regulation 3.6V<VIN<4.2V – 2/1 DC-DC Converter and Regulation 2.7V<VIN<3.6V Up to 86% Efficiency Low EMI, Low Ripple Up to 80mA Output Current (4 × 20mA) Built-in DAC for Digital or PWM Brightness Control Can be Duty Cycle Modulated between 0 to 18mA 2.7V to 5.5V Input Voltage Range ICC < 2µA in Shutdown Mode 1MHz Operating Frequency Shutdown Isolates Output from Input Soft-Start Limits Inrush Current Short Circuit Protection Minimal External Components Needed Available in a 14-lead TSSOP Package Available in a 16-lead MLP Package Cell Phones Handheld Computers PDA, DSC, MP3 Players Keyboard Backlight LED Displays Description The FAN5609 generates regulated output current from a battery with input voltage varying between 2.7V to 5.5V. Switch reconfiguration and fractional switching techniques are utilized to achieve high efficiency over the entire input voltage range. A proprietary internal circuitry continuously monitors each LED current loop and automatically adjusts the generated output DC voltage to the lowest minimum value required by the LED having the highest forward voltage. This adaptive nature of the FAN5609 eliminates the need for LED pre-selection (matching) and ensures operation at high efficiency. When the input voltage is sufficiently high to sustain the programmed current level in the LEDs, the FAN5609 re-configures itself to operate as a linear regulator, and the DC-DC converter is turned off. An internal two-bit digital to analog converter provides programmability of the output currents. Only two 0.1µF bucket capacitors and two 4.7µF input/output capacitors are needed for proper operation. Soft-start circuitry prevents excessive current draw during power on. The device has built-in short circuit protection. Typical Application VOUT COUT VOUT VIN CIN D A C LED- LED- VIN IN A LED- LEDCAP- FAN5609 CAP2 CAP+ CAP+ CAP1 IN B GND CAP- REV. 1.0.2 5/30/03 FAN5609 PRODUCT SPECIFICATION Pin Assignments NC CAP2- CAP2+ 15 14 13 12 CAP1+ 2 11 CAP1- GND 3 10 NC B 4 9 LED- LED- FAN5609 14-Lead TSSOP 5 6 7 8 LED- LED- 16 1 LED- FAN5609 A LED- VIN VOUT A GND B CAP2CAP2+ CAP1+ CAP1NC LED- LED- VIN VOUT NC Top-View FAN5609 4x4mm 16-Lead MLP Pin Descriptions FAN5609 Pin No. 14L-TSSOP 4mmX4mm 16L-MLP Pin Function Description 1 VIN VIN 2 VOUT VOUT Output to LEDs Anode 3 GND GND Ground 4 B B DAC B 5 A A DAC A 6 LED - LED - 4th LED Cathode 7 LED - LED - 3rd LED Cathode 8 LED - LED - 2nd LED Cathode Input 9 LED - LED - 10 NC NC 1st LED Cathode 11 CAP1- CAP1- Bucket capacitor negative terminal 12 CAP1+ CAP1+ Bucket capacitor positive connection 13 CAP2+ CAP2+ Bucket capacitor positive terminal 14 CAP2- CAP2- No Connection Bucket capacitor negative connection 15 NC No Connection 16 NC No Connection Test Circuit CAP2 0.1µF NC NC VIN = 2.7V to 5.5V 1 CIN 16 CAP1 0.1µF VOUT COUT 13 12 4.7µF FAN5609 4.7µF NC VL 4 VH 5 8 9 VH VL 4 White LEDs Fairchild QTLP670C-IW Super Bright LED All capacitors are Ceramic chip capacitor 2 REV. 1.0.2 5/30/03 PRODUCT SPECIFICATION FAN5609 Absolute Maximum Ratings Parameter Min Max Unit VIN, VOUT, A, B Voltage to GND -0.3 6.0 V CAP+, CAP-, to GND -0.3 VIN + 0.3 V VOUT Short Circuit Duration INDEFINITE Lead Soldering Temperature (10 seconds) 300 °C Operating Junction Temperature Range 150 °C Storage Temperature -55 Electrostatic Discharge Protection Level (Note 1) HBM 4 CDM 2 150 °C kV Recommended Operating Conditions Parameter Min Input Voltage Range, VIN 2.7 Operating Ambient Temperature Range -40 Typ 25 Max Unit 5.5 V 85 °C DC Electrical Characteristics Unless otherwise noted, VIN =3V to 5.5V, TA = 25°C. Refer to “Test Circuit”. Boldface values indicate specifications over the ambient operating temperature range. Parameter Quiescent Current Output Current Accuracy INOM = 20mA LED to LED Current Matching Efficiency Conditions Min. VOUT = 5.5V, No Load A = High B = High 17 VIN = 5.5V A = B = High -5 VIN = 4.5V VIN at Configuration Change Oscillator Frequency Supply Current, "OFF Mode" Max. Units 1.5 4 mA 20 23 mA +5 % 85 to75 VIN = 3V Input A, B Threshold Typ. % 65 to 55 Low 0 0.3 × VIN High 0.6 × VIN VIN From 1:1 to 3:2 4.2 From 3:2 to 2:1 3.6 0.80 1 V V 1.2 MHz 2 µA Note: 1. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model) REV. 1.0.2 5/30/03 3 FAN5609 PRODUCT SPECIFICATION Block Diagram 1µF VOUT Linear Regulator VIN Voltage Selector A DAC B D R I V E R S Oscillator On Off And Current Range Bandgap Reference Power Good P U M P Reference 5µF Analog Detector I. LIM. Regulator I. LIM. Ref2 Ref1 I. LIM. Low Battery Ref. I. LIM. Range Selection Ref3 Mode Change VIN Ref4 (BG) GND 1µF Circuit Description The FAN5609’s switched capacitor DC/DC converter automatically configures its internal switches to achieve high efficiency and to provide tightly regulated output currents for the LEDs. An analog detector determines which diode requires the highest voltage in order to sustain the pre-set current levels, and adjusts the pump regulator accordingly. Every diode has its own linear current regulator. In addition, a voltage regulator controls the output voltage when the battery voltage is within a range where linear regulation can provide maximum possible efficiency. If the battery voltage is too low to sustain the diode current in the linear mode, a fractional 3:2 charge pump is enabled. When the battery voltage drops further and this mode is no longer sufficient to sustain proper operation, the pump is automatically reconfigured to operate in 2:1 mode. As the battery discharges and 4 the voltage decays, the FAN5609 switches between modes to maintain a constant current through LED throughout the battery life. The transition has hysteresis to prevent toggling. Supply Voltage The internal supply voltage for the device is automatically selected from VIN or VOUT pins, whichever is higher. Soft Start The soft-start circuit limits inrush current when the device is initially powered up and enabled. The reference voltage controls the rate of the output voltage ramp-up to its final value. Typical start-up time is 1ms. The rate of the output voltage ramp-up is controlled by an internally generated slow ramp, and an internal variable resistor limits the input current. REV. 1.0.2 5/30/03 PRODUCT SPECIFICATION FAN5609 Switch Configuration VIN VIN VOUT + CAP1 VOUT = 2 X VIN + CAP2 GND - COUT Figure 1 Step-up, 2:1 configuration. Switch positions shown in charge phase. Reverse all switches for pump phase. GND Figure 2 Step-up 3:2 configuration Switch positions shown in charge phase. Reverse all switches for pump phase. Shutdown and Short Circuit Current Limit Set both DAC inputs low to shut down the device. Built-in short circuit protection limits the supply current to a maximum of 50mA. Digital Control A digital-to-analog converter (DAC) allows selection of the following modes: OFF, 7mA, 14mA, 20mA, per diode. By turning the IN B pin ON and OFF, the current can be modulated between 7 to 20mA to achieve any IAverage value (PWM). In PWM mode, the modulating frequency has to be set sufficiently high in order to avoid a flickering effect (100Hz to 1kHz). A 0 1 0 Any input can be modulated by a pulse train of variable duty cycle (δ). By turning ON and OFF DAC inputs A or B, the current can be continuously modulated to any average value between 1 to 19mA. For a maximum range of LED current, both A&B can be modulated at the same time. 1 B 0 0 1 1 ILED OFF 7mA 14mA 20mA REV. 1.0.2 5/30/03 Digital Control with PWM 5 FAN5609 PRODUCT SPECIFICATION Digital Control with PWM A is PWM and B is Low. ILED (Average) = δ x 7mA, where δ is Duty Cycle. (Note 2) A Input (PWM) ss 30% Duty Cycle 70% Duty Cycle 1KHz B Input (0) 1KHz ILED (Average) = 0.7 x 7mA = 4.9mA ILED (Average) = 0.3 x 7mA = 2.1mA ILED ss 0mA OFF A is High and B is PWM. ILED (Average) = 6mA + δ x 12mA, where δ is Duty Cycle. (Note 3, 4) A Input B Input (PWM) ss 30% Duty Cycle 70% Duty Cycle 1KHz 1KHz ILED (Average) = 7mA + 0.7 x 14mA = 16.8mA ILED (Average) = 7mA + 0.3 x 14mA = 11.2mA ILED 0mA ss OFF Notes: 2. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 6mA. 3. If either input A or B is continuously high, the other input can be modulated at a maximum rate of 30kHz. Otherwise the maximum rate of modulation should be limited to 1kHz. 4. Proportionally select the duty cycle to achieve a typical LED current between 8mA to 19mA. 6 REV. 1.0.2 5/30/03 PRODUCT SPECIFICATION FAN5609 Digital Control with PWM (Continued) A and B are PWM. ILED (Average) = δ x 20mA, where δ is Duty Cycle. (Note 3, 5) A Input (PWM) ss 30% Duty Cycle 70% Duty Cycle 1KHz 1KHz B Input (PWM) ss 70% Duty Cycle 30% Duty Cycle ILED (Average) = 0.7 x 20mA = 14mA ILED (Average) = 0.3 x 20mA = 6mA ILED ss 0mA OFF Notes: 5. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 19mA. Application Information It is important to select the appropriate capacitor types and the values for use with the FAN5609. These capacitors determine parameters such as power efficiency, maximum sustainable load current by the charge pump, input and output ripple and start-up time. CAP1 and CAP2 control the current capability of the charge pump and affect the overall efficiency of the system. A lower value will improve efficiency, but it may limit the LED’s currents at low input voltage. A capacitor of 100nF is optimal for 4 × 20 mA load over the entire input voltage range of 2.7V to 4.2V. To save space and cost, and to increase efficiency, this value may be reduced to 10nF for loads less than 4 x 7mA. In order to reduce ripple, both CIN and COUT should be low ESR capacitor. Increasing the COUT capacitor reduces the output ripple voltage. However this will increase the power-on time. The CIN value controls input ripple. If necessary, this ripple can be further reduced by powering the FAN5609 through a very small series inductor filter, as shown in Figure 3. Pulse-Width-Modulated (PWM) Mode Conversion errors are minimized and the best LED to LED matching is achieved over the entire range of average current settings, when PWM brightness control is used to modulate the LED current between zero and the maximum value (A=1, B=1). Selecting Capacitors PC Board Layout Input Power Supply 100nH 0.1µF 4.7µF VIN FAN5609 GND For best performance, a solid ground plane is recommended on the back side of the PCB. The ground tails of CIN and COUT should be connected together close to the GND pin of IC. Figure 3. REV. 1.0.2 5/30/03 7 FAN5609 PRODUCT SPECIFICATION Typical Performance Characteristics TA = 25°C, CIN =COUT = 4.7µF, CAP1 = CAP2 = 0.1µF, using Fairchild’s QTLP670C-IW Super Bright LED. DAC Threshold Voltage vs Input Voltage DAC Inputs Threshold Votlage (V) Regulated LED Current (mA) Regulated LED Current vs LED Forward Voltage 20.4 20.2 20.0 19.8 19.6 3.0 3.2 3.4 3.6 3.8 2.2 2.0 1.8 1.6 1.4 1.2 1.0 2.5 3.0 LED Forward Voltage (V) 3.5 4.0 Supply Current vs Input Voltage (4 LEDs) 5.5 25 160 A = 1, B = 1 20 140 LED Current (mA) Supply Current (mA) 5.0 Regulated LED Current vs Input Voltage 180 A = 1, B = 1 120 100 80 A = 0, B = 1 60 40 15 A = 0, B = 1 10 5 A = 1, B = 0 A = 1, B = 0 20 0 2.5 4.5 LED Forward Voltage (V) 3.0 3.5 4.0 4.5 5.0 0 5.5 2.5 3.0 Input Voltage (V) 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) Efficiency vs Input Voltage (4 LEDs x 20mA) Shutdown Current vs Input Voltage 1.6 0.9 Shutdown Current (µA) A = 0, B = 0 Efficiency 0.8 0.7 0.6 0.5 0.4 2.5 3.0 3.5 4.0 VIN(V) 8 4.5 5.0 5.5 1.4 1.2 1.0 0.8 0.6 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) REV. 1.0.2 5/30/03 PRODUCT SPECIFICATION FAN5609 Mechanical Dimensions 14-Lead TSSOP Package 14 8 4.16 TYP 7.72 TYP 4.4±0.1 -B- 6.4 3.2 D 1.78 TYP 1 7 0.2 C 0.65 TYP B A ALL LEAD TIPS PIN #1 IDENT. 0.42 TYP LAND PATTERN RECOMMENDATION 0.1 C ALL LEAD TIPS 0.25 0.09-0.20 0 -8 0.6±0.1 SEATING PLANE 1.1 MAX TYP 0.9 0.10 ±0.05 TYP -C0.19 - 0.30 TYP 0.65 TYP 0.19-0.30 M A B S C S REV. 1.0.2 5/30/03 9 FAN5609 PRODUCT SPECIFICATION Mechanical Dimensions 4mmX4mm 16-Lead MLP Package 2.64 4.0 0.15 C 16 A 13 B 2X 1 12 3.04 2.64 4.50 4.0 4 9 (0.73) 5 0.15 C 8 0.42 TYP 2X TOP VIEW 1.00 MAX 0.65 TYP RECOMMENDED LAND PATTERN 0.10 C (0.20) 0.05 0.00 C SEATING PLANE SIDE VIEW 5 2.80 2.50 8 4 9 2.80 2.50 0.65 1 PIN #1 IDENT 12 16 13 0.25~0.35 0.65 0.10 M C A B 0.10 M C BOTTOM VIEW NOTES: A. B. C. 10 CONFORMS TO JEDEC REGISTRATION MO-220, VARIATION VGGC-3, DATED AUG/2002 DIMENSIONS ARE IN MILLIMETERS. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 REV. 1.0.2 5/30/03 FAN5609 PRODUCT SPECIFICATION Ordering Information Product Number FAN5609 Package Type Order Code 14-Lead TSSOP FAN5609MTCX 4mmx4mm 16-Lead MLP FAN5609MPX DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 5/30/03 0.0m 005 Stock#DS30005609 2003 Fairchild Semiconductor Corporation