95220 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Description Features • Constant current LED driver: • 20mA to 2A programmable • Step-up or step-down operation • >90 efficiency • 2.5V to 450V • Up to 2MHz switching frequency The PA5910 is a high efficiency LED driver control Integrated Circuit. It is a universal control LED driver that can be configured to operate as a step-up or step-down LED driver. The input and output voltage can be extended beyond 450V. Applications • • • • • The PA5910 uses a fixed off time and 2MHz switching frequency can be achieved. DC/DC LED Drivers AC/DC LED Drivers RGB Backlighting Flat Panel Backlighting Signs and Decorative LED Lighting The minimum off time can be set by an external capacitor and resistor. ROFF and COFF The LED current is programmable from 20mA to 2.0A and is set by an external resistor. Pin Designation 1 8 2 7 3 6 4 5 Description Symbol 1：Ground VSS 8：Power supply (2V-6.5V) VDD 2：Chip Enable EN 7：Off time selection TOFF 3：No connection NC 6：LED Current sensing 4：Voltage feedback GND Description Symbol 5：Driver CS DRV Absolute Maximum Ratings Type Symbol VMAX Description Maximum voltage on VDD pins Value Unit 8 V Voltage VMIN-MAX Voltage range on EN, CS and FB pins -0.3-VDD+0.3 V TMIN-MAX Operation temperature range -20-85 o C TSTORAGE Storage temperature range -40-165 o C Thermal ESD VESD ESD voltage for human body model 2000 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS V 1 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Block Diagram VIN L VDD TOFF Zener Diode 2.5V – 5.5V PA5910 BANDGAP OFF TIME S R Q DRV EN 250mV RTC CS GND (Optional) RCS Fig.1 Electrical Characteristics. Parameter Symbol Test Condition Min Max Unit 6.5 V 250 260 mV IDD 0.5 1 mA Off time (without ROFF and COFF) TOFF 620 Standby current IDDQ EN pin high level voltage VENH EN pin low level voltage VENL DRV Rising Time TRISE DRV Falling Time TFALL Power supply VDD 2.5 CS pin feedback voltage VCS 240 Operation current Typ nS 1 2.0 V 0.8 V 500pF cap on DRV pin 50 nS 500pF cap on DRV pin 50 nS 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS μA 2 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Typical Applications Step-Up LED Driver without Schottky Diode VIN L VDD TOFF PA5910 BANDGAP OFF TIME S R Q DRV EN 250mV CS GND RCS Fig.2 Step-Up LED Driver with Schottky Diode VIN L VDD TOFF PA5910 BANDGAP OFF TIME S R Q EN Zener Diode 2.5V – 5.5V DRV 250mV CS GND RCS Fig.3 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 3 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION 220VACIN Drive 45series 6 parallel white LED’s ILED = 120mA AC~ L1 10mH R1 510K LED+ 220vAC In BD1 300V 0.5A AC~ C1 22μF 400V D1 SF36 D2 12V C2 4.7μF LEDQ1 5N60 D4 1N5819 R2 330Ω C2 4.7μF D3 5.1V PA5910 1 VSS VCC 8 2 EN TOFF 7 3 NC CS 6 4 GND C4 470pF Q2 AP2306 DRV 5 R3 100K R4 2.5Ω Fig.4 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 4 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION 220VACIN Drive 12 series connected 1WATT white LED’s AC~ L1 10mH R1 510K LED1 1Watt 220vAC In BD1 300V 0.5A AC~ C1 22μF 400V D1 SF36 D2 12V C2 4.7μF LED2 1Watt LED3 1Watt Q1 5N60 LED4 1Watt D4 1N5819 R2 330Ω C2 4.7μF D3 5.1V PA5910 1 VSS VCC 8 2 EN TOFF 7 3 NC CS 6 4 GND C4 470pF LED11 1Watt Q2 AP2306 DRV 5 LED12 1Watt R3 100K R4 2.5Ω Fig.5. 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 5 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Detail Description LED lighting applications The PA5910 is suitable for 110 V/220VAC lighting applications as shown in Fig.5. AC 220V through bridge rectifier, will be about 310VDC. The VDD supply of 5.1V is provided through a resistor and a Zener network. When MOSFET control is high, the MOSFET conducts and the inductor L is charged until it reaches the peak current 250mV/R CS . When MOSFET control is low, the MOSFET is off, the inductor releases energy through Schottky diode circuit, thereby lighting the LED string. Circuit parameters LED average current When the circuit in Fig. 1 operates in continuous mode, the LED average current is IL ILMAX is the maximum current flowing through LED’s as shown in Fig.6 T TON TOFF ILMAX ∆IL IL(t) IL Fig.6. Programming Operation Frequency The switching duty ratio can be determined by D= VOUT / VIN TON is on time of MOSFET TOFF is the off time of the MOSFET. The TOFF can be calculated by the formula TOFF = 0.51 × 100 KΩ × ROFF × (COFF + 10 pF ) ROFF + 100 KΩ If TOFF pin is left open the typical value is TOFF = 0.51 × 100 KΩ × 10 pF = 510nS 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 6 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION VDD PA5910 BANDGAP ROFF TOFF COFF OFF TIME S R Q EN DRV 250mV CS GND TOFF can be reduced by adding ROFF and increased by adding COFF Operation Frequency can be calculated by the following formula F = 1 1− D = T TOFF When TOFF is connected to a 1000pF capacitor, TOFF =51μS, D=0.1 the resultant frequency will be 20 KHz. Inductor Design. Inductor selection criteria are to ensure that current flow through inductor is less than the maximum value specified. Referring to the typical application in Fig.5 the value can be calculated from the desired peak-to-peak LED ripple current in the Inductor. Typically the ripple current is selected to be 30% of the nominal LED current. In this example the ILED is 350mA For example, when the string consists of 12 High Brightness LED’s and each diode has a forward drop of 3.3V at nominal current, the total LED voltage VLEDS is 39.6V Knowing the rectified input voltage VIN = 220V x 1.414 = 310V, the duty ratio can be determined as: D= VLED 39.6 = = 0.128 310 VIN Given the switching frequency (20KHz) the required on time of the MOSFET can be calculated by: TON = D f OSC = 6.4µS The required value of the inductor is given by: L = (VIN − VLED ) × TON = 16mH 0.3 × I LED 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 7 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Setting LED Output When the buck converter topology is used, the peak current sense (CS) is a good representation of the average current of the LED. There is a certain error associated with this CS method that needs to be accounted for. The error is introduced by the difference between the the peak and average current in the inductor: RCS = 250mV I L + 0.5ΔI L e.g. If the peak-to-peak ripple current in the inductor is 10.5mA, to maintain a 350mA LED current, the sense resistor should be 0.7Ω LED Brightness. There are two methods of adjusting the brightness of the LED’s. 1. Changing the resistance of RCS the lower the resistance the higher the brightness. 2. PWM dimming. The brightness of the LED’s is controlled by varying the duty ratio of the output current. This is achieved by applying a PWM signal at the EN (pin 2). 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 8 PA5910 Switching Type LED Driver. ANALOG PRODUCTS DIVISION Package Outlines and Dimensions PACKAGE OUTLINE SO-8 -A- 8 5 -B- 0.010” (0.25 MM) P M B M 4 PL 1 PACKAGE DIMENSIONS 4 DIM D G C R X 45º 0º - 10º -T- K 0.010” (0.25 MM) M T B S J F A S 8 PL MOUNTING PAD 0.050” ± 0.005” 0.030” ± 0.005” MILLIMETERS MIN MAX INCHES MIN MAX A 4.80 5.00 0.189 0.196 B 3.80 4.00 0.150 0.157 C 1.35 1.75 0.054 0.068 D 0.35 0.49 0.014 0.019 F 0.40 1.250 0.016 0.049 G 1.27 BSC 1.27 BSC 0.05 BSC 0.05 BSC J 0.18 0.25 0.007 0.009 K 0.10 0.25 0.004 0.008 P 5.80 6.20 0.229 0.244 R 0.25 0.50 0.010 0.019 NOTES 1. - T - = Seating Plane and Datum Surface. 2. Dimensions “A” and “B” are Datum. 3. Dimensions “A” and “B” do not include mold protrusion. 4. Maximum mold protrusion is 0.015” (0.380 mm) per side. 5. Dimensioning and tolerances per ANSI Y14.5M, 1982. 6. Dimensions are exclusive of mold flash and metal burrs. TAPE & REEL/BULK ORDERING NOMENCLATURE 0.160” ± 0.005” 0.245” MIN 1. Surface mount product is taped and reeled in accordance with EIA-481. 2. Suffix-T7 = 7 Inch Reel - 1,000 pieces per 12mm tape. 3. Suffix-T13 = 13 Inch Reel - 2,500 pieces per 12mm tape. 4. No Suffix = Product Shipped in Tubes of 98 pcs per Tube. 0.045” ± 0.005” Life Support Policy PROTEK ANALOG'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 PROTEK DEVICES. 561 E. Elliot Road #175 Chandler, AZ 85225 Tel: (480) 539-2900. Fax: (480) 632-1715 www.protekanalog.com 95220 Rev.0. 04/09 NOT FOR USE IN LIFE SUPPORT SYSTEMS 9