APEK6211 A6211 High-Current LED Driver Evaluation Board The A6211 is a single IC switching regulator that provides constant-current output to drive high-power LEDs. It integrates a high-side N-channel DMOS switch for DC-to-DC step-down (buck) conversion. The A6211 EVB (evaluation board) accepts input voltage from 6 to 48 V to drive a single LED string. LED current can be from several hundred mA up to 3 A, selected by jumper combination on the EVB. Switching frequency is fixed at 1 MHz for the EVB, but it can be easily changed by changing a resistor (see A6211 datasheet for details). Allegro offers Gerber files for this evaluation board on the following website (click on the tab labeled “Technical Docs”): http://www.allegromicro.com/en/Products/ Regulators-And-Lighting/LED-Drivers-For-Lighting/ A6211.aspx Quick Startup Guide 1. Connect an LED string between LED+ (anode) and LED– (cathode). 2. Insert or remove jumpers from P1 to select the appropriate LED current (see Table 1). 3. Connect input power between VIN and GND. For LED current regulation, the minimum input voltage should be at least 20% higher than the LED string’s operating voltage. 4. Connect EN (enable) to a logic high signal, or connect it to VIN. This will turn on the LED string. 5. For LED dimming: connect EN to a suitable PWM signal (such as 0-3V, 200 Hz 50%). Vary the PWM duty cycle between 1% and 100% to control the brightness of LED string. A6213-DB Figure 1: A6211 Evaluation Board Table 1: Jumper Settings vs. LED Current Jumper 1-2 Jumper 3-4 Jumper 5-6 Jumper 7-8 Approximate LED Current (A) ON – – – 0.3 – ON – – 0.5 – – ON – 1.0 1.5 – – – ON – ON – ON 2.0 – – ON ON 2.5 – ON ON ON 3.0 Note that due to contact resistance introduced by connectors and jumpers, the above current settings are approximate. November 11, 2016 APEK6211 A6211 High-Current LED Driver Evaluation Board SCHEMATIC Figure 2: A6211 Evaluation Board Schematic Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 APEK6211 A6211 High-Current LED Driver Evaluation Board BILL OF MATERIALS Reference Description Footprint Part Number Notes 1 CAP 47 µF, 50 V, ELECT MZA SMD Cap Radial 8 mm surface mount 565-2568-1-ND VIN filter electrolytic cap (exactly value not critical) 0 CAP CER 10 µF, 50 V, X5R 1210 Capacitor_1210 587-2225-1-ND 1 CAP CER 4.7 µF, 50 V, X5R 1206 Capacitor_1206 587-1962-1-ND C3 0 0.1 µF, 10 V, X7R, ceramic Resistor_ Capacitor_0603 399-1095-1-ND Optional, use in case of nosily sense line C4 1 0.047 µF, 50 V, X7R 0603 Resistor_ Capacitor_0603 445-5095-1-ND BOOT cap C5 1 0.1 µF, 10 V, X7R ceramic Resistor_ Capacitor_0603 399-1095-1-ND VCC filter cap C6 0 10 nF, 50 V, X7R Resistor_ Capacitor_0603 490-1511-1-ND Optional input cap for EN (can be used for 10 kΩ pulldown resistor instead) C7 0 2.2 µF, 50 V, X5R Capacitor_1206 587-2402-1-ND Optional filter cap across LED string. Try 0.47 µF to 4.7 µF 0 B350A-13-F DIODE SCHOTTKY 3 A, 50 V SMA Diode_SMA B350A-FDICT-ND For LED current up to ~2 A 1 B560C-13-F DIODE SCHOTTKY 5 A, 60 V SMC Diode_SMC B560C-FDICT-ND For LED current up to 3 A 0 VLF12060T- 220M4R1 (22 µH, 4 A, 36 mΩ, 12 × 11.7 × 6 mm) 12 × 12 mm 445-3595-1-ND Use larger inductance for lower frequency and lower current 1 B82464G4103M (10 µH, 3.4 A, 10 × 10 × 5 mm) 10.4 × 10.4 mm 5-1796-1-ND Use smaller inductance for higher frequency and current 0 NR8040T100M (10 µH, 3.4 A, 20%, 44 mΩ, 8 × 8 × 4 mm) 8 × 8 mm 587-2001-1-ND 8 mm inductor is only good for up to ~2 A LED current P63.4KHDKR-ND RON = 63.4 kΩ gives fSW = 1 MHz C1 C2 Quantity D1 L1 P1 R1 1 Header, 4-Pin, Dual Row HDR2X4 1 63.4 kΩ, 0.1 W, 1% 603 VIN filter ceramic cap 0 27.4 kΩ, 0.1 W, 1% 603 P27.4KHCT-ND RON = 27.4 kΩ gives fSW = 2 MHz R2 1 0.13 Ω, 0.5 W, 1% Resistor_1206 RL16R.13FCT-ND ~1.35 A (due to jumper resistance) R3 1 0.20 Ω, 0.5 W, 1% Resistor_1206 RL16R.20FCT-ND ~0.9 A R4 1 0.39 Ω, 0.5 W, 1% Resistor_1206 RL16R.39FCT-ND ~0.45 A R5 1 0.75 Ω, 0.5 W, 1% Resistor_1206 RL16R.75FCT-ND ~0.24 A Resistor_ Capacitor_0603 P1.0KDBCT-ND Limits the input current in case VEN > VIN R7 1 1 kΩ, 0.1 W, 1% EN, LED– 2 Test Point, Yellow Test_Point 5014K-ND LED+, VIN 2 Test Point, Red Test_Point 5010K-ND GND, GND1 2 Test Point, Black Test_Point 5011K-ND U1 1 A6211/A6213 SOICN 8 Narrow SOIC-8 with exposed pad Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 APEK6211 A6211 High-Current LED Driver Evaluation Board Revision History Number Date – November 11, 2016 Description Initial release Copyright ©2016, Allegro MicroSystems, LLC Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4