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FAN5609
LED Driver with Adaptive Charge Pump DC/DC Converter
Features
•••••
Parallel LED Driver Supports All Forward Voltages
Adaptive VOUT Adjustment to the Highest Diode VoltageInternally Matched LED Current Sources
No External Components Needed to Set LED CurrentBuilt-in Charge Pump has Three Modes of Operation:–Linear Regulation VIN > 4.2V
–3/2 DC-DC Converter and Regulation 3.6V Built-in DAC for Digital or PWM Brightness ControlCan be Duty Cycle Modulated between 0 to 18mA 2.7V to 5.5V Input Voltage RangeICC < 2µA in Shutdown Mode1MHz Operating Frequency Shutdown Isolates Output from InputSoft-Start Limits Inrush CurrentShort Circuit Protection Minimal External Components NeededAvailable in a 14-lead TSSOP PackageAvailable in a 16-lead MLP Package Applications ••••• Cell Phones Handheld ComputersPDA, DSC, MP3 PlayersKeyboard BacklightLED 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 opera-tion 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 VOUTCOUTVINCINVOUTVININ ALED-LED-LED-LED-CAP-CAP2DACFAN5609GNDCAP+CAP+CAP1IN BCAP-REV. 1.0.2 5/30/03 元器件交易网www.cecb2b.com FAN5609 PRODUCT SPECIFICATION Pin AssignmentsNCCAP2+1312111095678Top-ViewVINVOUTGNDBALED-LED-CAP2-CAP2+CAP1+CAP1-NCLED-LED-CAP2-1416FAN5609VINVOUTGNDBNC151234CAP1+CAP1-NCLED-LED-LED-FAN560914-Lead TSSOPFAN56094x4mm 16-Lead MLPPin DescriptionsFAN5609 Pin No.123456 14L-TSSOP VINVOUTGNDBALED - LED - LED - LED - NCCAP1-CAP1+CAP2+CAP2-4mmX4mm 16L-MLP VINVOUTGNDBALED - LED - LED - LED - NCCAP1-CAP1+CAP2+CAP2-NCNC Input Output to LEDs AnodeGroundDAC BDAC A 4th LED Cathode3rd LED Cathode2nd LED Cathode1st LED CathodeNo Connection Bucket capacitor negative terminalBucket capacitor positive connectionBucket capacitor positive terminalBucket capacitor negative connectionNo ConnectionNo Connection Pin Function Description 78910111213141516 Test Circuit CAP2NCNCVIN = 2.7V to 5.5VCINVOUTCOUT4.7µFVL4VH5894.7µFFAN5609NC1160.1µF1312CAP10.1µFVHVL4 White LEDs Fairchild QTLP670C-IWSuper Bright LEDAll capacitors are Ceramic chip capacitor2 LED-AREV. 1.0.2 5/30/03 元器件交易网www.cecb2b.com PRODUCT SPECIFICATION FAN5609 Absolute Maximum Ratings Parameter VIN, VOUT, A, B Voltage to GNDCAP+, CAP-, to GNDVOUT Short Circuit Duration Lead Soldering Temperature (10 seconds)Operating Junction Temperature RangeStorage Temperature Electrostatic Discharge Protection Level (Note 1) HBMCDM -5542Min-0.3-0.3 Max6.0VIN + 0.3INDEFINITE 300150150 °C°C°CkVUnitVV Recommended Operating Conditions Parameter Operating Ambient Temperature Range Min-40 Typ25 Max5.585 UnitV°C Input Voltage Range, VIN 2.7DC 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 Conditions Min. Typ. Max. Units Quiescent CurrentOutput Current Accuracy INOM = 20mA LED to LED Current MatchingEfficiency Input A, B Threshold VIN at Configuration Change Oscillator FrequencySupply Current, \"OFF Mode\" VOUT = 5.5V,No LoadA = HighB = HighVIN = 5.5VA = B = HighVIN = 4.5VVIN = 3VLowHighFrom 1:1 to 3:2From 3:2 to 2:1 0.8000.6 × VIN 17-5 1.520 423+5 mAmA%% 85 to7565 to 55 0.3 × VIN VIN 4.23.61 1.22 VVMHzµA Note: 1. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model) REV. 1.0.2 5/30/033 元器件交易网www.cecb2b.com FAN5609 PRODUCT SPECIFICATION Block Diagram 1µFVIN LinearRegulatorVoltageSelectorVOUT ADACBDRIVERSPowerGoodPUMP On OffAndCurrent RangeOscillatorBandgapReferenceRange SelectionReferenceAnalogDetector5µFI. LIM.I. LIM.Ref2Ref1RegulatorRef3Mode Change VIN Ref4 (BG)GND 1µFCircuit Description The FAN5609’s switched capacitor DC/DC converter auto-matically configures its internal switches to achieve high effi-ciency 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 bat-tery 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 reconfig-ured to operate in 2:1 mode. As the battery discharges and the voltage decays, the FAN5609 switches between modes to maintain a constant current through LED throughout the bat-tery 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 con-trols 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. 4REV. 1.0.2 5/30/03 I. LIM.I. LIM.Low Battery Ref.元器件交易网www.cecb2b.com PRODUCT SPECIFICATION FAN5609 Switch ConfigurationVIN VINVOUT CAP1 +-VOUT = 2 X VIN+CAP2GND-COUTFigure 1Step-up, 2:1 configuration.Switch positions shown in charge phase.Reverse all switches for pump phase. GNDFigure 2Step-up 3:2 configurationSwitch positions shown in charge phase.Reverse all switches for pump phase. Shutdown and Short Circuit Current LimitSet both DAC inputs low to shut down the device. Built-in short circuit protection limits the supply current to a maxi-mum of 50mA.Digital ControlA 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).ABILED00OFF107mA0114mA1120mADigital Control with PWMAny 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.REV. 1.0.2 5/30/035 元器件交易网www.cecb2b.com 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) 30%Duty Cycless 70%Duty Cycle1KHz1KHzB Input (0)ILED (Average) = 0.7 x 7mA = 4.9mAILED (Average) = 0.3 x 7mA = 2.1mAILED 0mAssOFFA 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) 30%Duty Cycless 70%Duty Cycle1KHz1KHz ILED (Average) = 7mA + 0.7 x 14mA = 16.8mAILED ILED (Average) = 7mA + 0.3 x 14mA = 11.2mA0mAssOFFNotes: 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. 6REV. 1.0.2 5/30/03 元器件交易网www.cecb2b.com 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) 30%Duty Cycle1KHzss 70%Duty Cycle1KHzB Input (PWM) 30%Duty Cycless 70%Duty CycleILED (Average) = 0.7 x 20mA = 14mAILED (Average) = 0.3 x 20mA = 6mAILED 0mAssOFFNotes:5. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 19mA. Application InformationSelecting CapacitorsIt 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.In order to reduce ripple, both CIN and COUT should be low ESR capacitor. Increasing the COUT capacitor reduces the out-put 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.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 opti-mal 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 effi-ciency, this value may be reduced to 10nF for loads less than 4 x 7mA.Pulse-Width-Modulated (PWM) ModeConversion 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).PC Board Layout InputPowerSupply100nH0.1µF4.7µFVINFAN5609GNDFor 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 5/30/037 元器件交易网www.cecb2b.com 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. Regulated LED Current vsLED Forward VoltageRegulated LED Current (mA)20.4DAC Threshold Voltage vsInput VoltageDAC Inputs Threshold Votlage (V)2.22.01.81.61.41.21.02.520.220.019.819.63.03.23.43.63.83.03.54.04.55.05.5LED Forward Voltage (V)LED Forward Voltage (V)Supply Current vs Input Voltage(4 LEDs)18016025Regulated LED Current vs Input VoltageA = 1, B = 120Supply Current (mA)1401201008060402002.53.03.54.0LED Current (mA)A = 1, B = 11510A = 0, B = 1 A = 0, B = 1A = 1, B = 05A = 1, B = 04.55.05.502.53.03.54.04.55.05.5Input Voltage (V)Input Voltage (V)Efficiency vs Input Voltage(4 LEDs x 20mA)0.9Shutdown Current vs Input Voltage1.6A = 0, B = 0Shutdown Current (µA)0.81.4Efficiency0.71.20.61.00.50.80.42.53.03.54.04.55.05.50.62.53.03.54.04.55.05.5VIN(V)Input Voltage (V)8REV. 1.0.2 5/30/03 元器件交易网www.cecb2b.com PRODUCT SPECIFICATION FAN5609 Mechanical Dimensions 14-Lead TSSOP Package1486.44.4±0.1-B-4.16 TYP7.72 TYP3.21.78 TYP0.2CBA0.65TYPDPIN #1 IDENT.17ALL LEAD TIPS0.42TYPLAND PATTERN RECOMMENDATION0.1CALL LEAD TIPS0.250.09-0.200.6±0.1SEATING PLANE0-81.1 MAXTYP-C-0.19 - 0.30 TYP0.65 TYP0.90.10±0.05TYP 0.19-0.30MABSCSREV. 1.0.2 5/30/039 元器件交易网www.cecb2b.com FAN5609 PRODUCT SPECIFICATION Mechanical Dimensions 4mmX4mm 16-Lead MLP Package 2.644.0AB16130.15C2X1123.044.5092.644.04(0.73)50.15C1.00 MAX0.10C(0.20)0.050.00SEATINGPLANE0.65 TYP80.42 TYPTOP VIEW2XRECOMMENDED LAND PATTERNCSIDE VIEW2.80 2.50 58492.80 2.500.65112PIN #1 IDENT160.65130.25~0.350.10MCAB0.10MCBOTTOM VIEWNOTES:A.B.C.CONFORMS TO JEDEC REGISTRATION MO-220,VARIATION VGGC-3, DATED AUG/2002DIMENSIONS ARE IN MILLIMETERS.DIMENSIONS AND TOLERANCES PERASME Y14.5M, 199410REV. 1.0.2 5/30/03 元器件交易网www.cecb2b.com FAN5609 PRODUCT SPECIFICATION Ordering InformationProduct NumberFAN5609Package Type14-Lead TSSOP4mmx4mm 16-Lead MLP Order CodeFAN5609MTCXFAN5609MPX 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. www.fairchildsemi.com 5/30/03 0.0m 005Stock#DS30005609 2003 Fairchild Semiconductor Corporation 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. 因篇幅问题不能全部显示，请点此查看更多更全内容