PAM2846 EVB User Guide PAM2846 EV Board User Guide AE Department 1. Revision Information Date 2008/3/26 Revision V2.0 Description Initial Release Comment 2. EV Board Schematic VIN 1 C1 10uF L1 2 22uH C6 1uF 1 D1 2 C5 10uF R2 1M ENA ENA PWM VIN U1 SW SW SW PWMD FSEL FSEL FB R3 30.9K PAM2846 VDD VC Vdd_driv er C4 100nF C3 1uF C2 1uF R1 10K GND GND GND ISET LED1 LED2 LED3 LED4 LED5 LED6 PGND PGND PGND Vdd_5V R10 0 R11 200k This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide 3. EVB PAM2846 EB7BDA Description PAM2846 EVB7BDA is an evaluation board for the PAM2846, a six strings LED current sink. The board is targeted to be used in providing a simple and convenient evaluation environment for the PAM2846. Analog dimming, PWM dimming, single wire dimming, current matching and efficiency etc, on the board make it easy to be evaluated. Use single power supply (8V-24V), LED: 6-12 serials*6 parallel, the output voltage is auto-adaptive to LED numbers. PAM2846 EVB7BDA is working in boost and sink mode, so make sure the power supply voltage not exceed the LED voltage too much. 4. EV Board View Vout Vi LED1 LED2 LED3 LED4 LED5 LED6 R11 ENA PWMD FSEL EV Board Operational Sequence: (1) Potentiometer for LED Dimming. a) Connect ENA to high (Vin, left side). b) Connect PWMD to high (right side). c) Setting operating frequency. Connect FSEL to high (left side), f=1.6MHz; connect FSEL to low (right side), f=500kHz; FSEL NC (no connect), f=800kHz. d) Connect Vout to anode of all the six String’s LED, their cathode connect to LED1, LED2, LED3, LED4, LED5, LED6 separately. e) Connect Vin to power supply. Vin=8V-24V. f) Adjust R11’s value to adjust the LED’s brightness. This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide (2) PWM Signal Dimming Dunction. a) Connect ENA to high (Vin, left side). b) Connect PWMD to an external PWM signal (the center pin). c) Setting operating frequency. Connect FSEL to high (left side), f=1.6MHz; connect FSEL to low (right side), f=500kHz; FSEL NC (no connect); f=800kHz. d) Connect Vout to anode of all the six String’s LED, their cathode connect to LED1, LED2, LED3, LED4, LED5, LED6 separately. e) Connect Vin to power supply. Vin=8V-24V. f) Adjust external PWM signal duty cycle to adjust the LED’s brightness. (3) Single Wire Dimming Function. a) Connect ENA to external PWM signal (the center pin). b) Connect PWMD to high (right side). c) Setting operating frequency. Connect FSEL to high (left side), f=1.6MHz; connect FSEL to low (right side), f=500kHz; FSEL NC (no connect); f=800kHz. d) Connect Vout to anode of all the six String’s LED, their cathode connect to LED1, LED2, LED3, LED4, LED5, LED6 separately. e) Connect Vin to power supply. Vin=8V-24V. f) Adjust external PWM signal to adjust the LED’s brightness (see Figure-1). Figure 1 ENA Timing Diagram This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide 5. EV Board BOM List Item C1, C5 C6 C2,C 3 C4 L1 D1 R1 R11 R2 R3 R10 White LED Value Type 10µF X5R/X7R, Ceramic/1210 1.0µF X5R/X7R, Ceramic/0805 1.0µF X5R/X7R, Ceramic/0805 100nF X5R/X7R, Ceramic/0805 22µH 1210 Nihon EC31QS06 10k 0603 200k potentiometer 1Meg 0805 30.9K 0603 0Ω 0603 3.2V(typ) 3.5V(max) at 20mA Rating Description Vender and Part No. Input coupling CAP Torch 50V Output CAP UDK325BJ106MM-T 25V Vin coupling CAP Murata GRM21BR71E105K VDD_dr and VDD_5V 25V Murata GRM21BR71E105K coupling CAP 50V comp CAP Murata GRM219C0G1H104K 2A Inductor Sumida CDRH5D16-22R 3A/60V Schottky Diode Nihon EC31QS06 1% Iset Resistor Iset Resistor 1% Feedback Resistor 1% Feedback Resistor 5% Comp Resistor This BOM is for 12 series * 6 parallel LED output. To optimize different numbers LED applications please see Append 1 and 2. 6. External Components Selection Input Capacitors (C1) and Output Capacitors (C5) (1) C1 Low ESR needed, 10µF, X5R/X7R ceramic recommended. (2) C5 Low ESR needed, 10µF, X5R/X7R (rating 50V) ceramic recommended. Coupling Capacitors (C2, C3, C6) (1) 1µF, X5R/X7R ceramic recommended. Iset Resistors (R1, R11) (1) R set all the string’s LED current, Iled=228*Viset/R, R=R1+R11. (2) R1, 10K±1% recommend; R11, adjustable, 0-200k. Feedback Resistors (R2, R3) (1) Vout=VFB*R3/(R3+R2). (2) R2, 1Meg±1% recommend. (3) Vout_limit is set in 40V, so R3 is 30.9K minimum. Comp Resistor (R10) and Comp Capacitor (C4) (1) R10, shorted. (2) C4, 100nF, X5R/X7R ceramic recommended. Inductor (L1) (1) Low DCR needed, 22µH (rating 2A) recommended Schottky Diode (D1) (1) Nihon EC31QS06(3A, 60V) recommended. (2) B360A (3A, 60V) recommended. This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide 7. PCB Layout Guidelines Decoupling Capacitors (1) The capacitors (C6, C2, C3) need to place very close to the PAM2846’s pins. The capacitor C1 need place close to the power supply. Grounding (1) The decupling capacitors C2, C3, C4, C6 and R1, R3 should each to be grounded to analog ground (AGND). (2) The capacitors C1, C5 should each be grounded to power ground (PGND). (3) Connect the AGND and PGND islands by connecting the GND pins directly to the exposed backside pad. Make no other connections between these separate ground planes. Others (1) Connect L1, SW, D1, C5 with short and wide connections. (2) Place the Output voltage setting-divider resistors ( R2, R3) as close to the OV pin as possible. The divider’s center trace should be kept short. (3) Minimize the size of the SW node while keeping it wide and short. Keep the SW node away from the feedback node and ground. (4) Place the Iset resistors (R1, R11) as close to the Iset pin as possible. 8. PCB Layout Example Top Layer Bottom Layer This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide 9. Append 1, External Component Selection table: Circuit Switching Frequency White LED Number of White LEDs Figure 3 Figure 2 Figure 2 Figure 2 Figure 3 1.6MHz 500KHz 500KHz 500KHz 800KHz 3.2V(typ), 3.5V(max) 3.2V(typ), 3.5V(max) 3.2V(typ), 3.5V(max) 3.2V(typ), 3.5V(max) 3.2V(typ), 3.5V(max) at 20mA at 20mA at 20mA at 20mA at 20mA 6 series*6 parallel 25mA(max) 4.8V to 6V, Vdd_dr=Vdd_5V=Vin or 5V (Vdd) 2.2uH, 2.5A power Inductor L1 inductor Sumida CDRH5D16-2R2 Input Voltage 8 series*6 parallel 25mA(max) 10 series*6 parallel 25mA(max) 12 series*6 parallel 25mA(max) 4.8V to 24V 8V to 28V 8V to 28V 6 series*6 parallel 25mA(max) 4.8V to 6V Vdd_dr=Vdd_5V=5V (Vdd) 4.7uH, 2.5A power inductor Sumida CDRH5D16-4R7 22uH, 2A power 22uH, 2A power 22uH, 2A power inductor Sumida inductor Sumida inductor Sumida CDRH5D16-220 CDRH5D16-220 CDRH5D16-220 10uF±20%, 50V X7R 10uF±20%, 50V X7R 10uF±20%, 50V X7R 10uF±10%, 10V X5R 10uF±10%, 10V X5R ceramic ceramic ceramic Ceramic capacitor Input Ceramic capacitor capacitor(1210) capacitor(1210) capacitor(1210) (1206) Murata Capacitor (1206) Murata Torch Torch Torch GRM31MR61A106K GRM31MR61A106K UDK325BJ106MM-T UDK325BJ106MM-T UDK325BJ106MM-T 10uF±20%, 50V X7R 10uF±20%, 50V X7R 10uF±20%, 50V X7R 10uF±20%, 50V X7R 10uF±20%, 50V X7R Output ceramic ceramic ceramic ceramic ceramic Capacitor capacitor(1210) capacitor(1210) capacitor(1210) capacitor(1210) capacitor(1210) UDK325BJ106MM-T UDK325BJ106MM-T UDK325BJ106MM-T UDK325BJ106MM-T UDK325BJ106MM-T 2A, 30V Schottky 2A, 40V Schottky 3A, 40V Schottky 3A, 60V Schottky 3A, 30V Schottky Diode diode Nihon diode Nihon diode Nihon diode Nihon diode Nihon Rectifier EC21QS03L EC21QS04L EC31QS04L EC31QS06L EC31QS03L Feedback 1M±1%, 0603 1M±1%, 0603 1M±1%,0603 1M±1%, 0603 1M±1%, 0603 Resistors 60K±1%, 0603 45K±1%, 0603 36K±1%,0603 30.9K±1%, 0603 60K±1%,0603 100nF±10%,50V 100nF±10%,50V 100nF±10%,50V 100nF±10%,50V 100nF±10%,50V Comp X7R Ceramic X7R Ceramic capacitor X7R Ceramic X7R Ceramic X7R Ceramic capacitor capacitor capacitor Murata Murata capacitor Murata capacitor Murata Murata GRM188R71H104K GRM188R71H104K GRM188R71H104K GRM188R71H104K GRM188R71H104K This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2846 EVB User Guide Append 2, Application Circuit: 1 VIN C10 L1 2 1 C6 D1 2 C5 R2 VIN U? ENA PWM SW SW SW PWMD FSEL R3 FB PAM2846 VC Vdd_5V R10 LED1 LED2 LED3 LED4 LED5 LED6 Vdd_driv er GND GND GND C2 C4 PGND PGND PGND ISET R1 C3 Figure 2 L1 1 VIN C10 2 C6 1 D1 2 C5 R2 ENA PWM VIN U? SW SW SW PWMD FSEL FSEL FB R3 PAM2846 VDD VC Vdd_driv er C2 C4 R1 GND GND GND ISET LED1 LED2 LED3 LED4 LED5 LED6 PGND PGND PGND Vdd_5V R10 C3 Figure 3 This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.