AL1794EV1 DIODES | Alldatasheet
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Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 1 of 13 July 2015 www.diodes.com General Description These four key elements, AC -to-DC Power Stage, LED Driver, LED Emitter Module and Wireless Connectivity block (enabled by embedded MCU and RF), form a typical system configuration for Smart Connected Lighting (SCL) bulbs. AL1794, a four -channel Constant Current Regulator (CCR) LED driver with analog and PWM dimming control, is targeted for Tunable White/Color SCL applications. Powered by Constant Voltage (CV) power source(s) provided by an AC -DC Power Conversion Block, AL1794 generates Constant Currents (CC) driving attached LED emitter strings. The channel currents are further modulated by analog or digital PWM signals generated by the associated external MCU. Key Merits Cost-Effectiveness Dimming Performance Ease of System Implementation Key Features Input voltage range: 6.5VDC to 30VDC 4-Channel LED drivers: Independent Analog or PWM dimming control for each channel Reference Current: Adjustable RSET Low Standby Power with Enable pin E-flicker free High PWM Frequency dimming: 0.1%@1KHz, 0.4%@4KHz, 1.0%@10KHz UVLO, OTP, Open, and Short protection Operating Temperature Range: -40° C to +125° C Low system BOM cost U-DFN4030-14 “Green” Moulding Compound package
Applications
1-Channel Dimmable SCL Bulbs 2-Channel Tunable White SCL Bulbs 3-Channel Tunable White SCL Bulbs 4-Channel Tunable White+Color SCL Bulbs Smart Connected LED Tubes, Panel Lights, Troffers, and Ceiling Lights AL1794 EV1 Specifications Parameter Value VLED1 Input Voltage 6.5VDC to 24VDC (Note 1), connect to Anode of LEDs strings VLED2 Input Voltage Connect to Anode of LEDs strings if a separate voltage for LEDs stings is required Input Voltages for LED1, 2, 3, and 4 0.25V (Minimum) 3.3V LDO 150mA (Maximum) LED_Bar Connectors (Top, Male) 6pins, Power and LED Inputs MCU1 Connectors (Bottom, Male) 10pins, PWM Signals Input IC Pin Test points 16 test points (J3 and J4) XYZ Dimension 1.9 ” x 2.0” x 0.6” Note 1: Vin(max) for AL1794 is capable of up to 30V, but Vin(max) for AP2204K (3.3V @ 150mA for MCU Power) limits the Vin(max) of AL1794EV1 Board to 24V only. If higher than 24V is required for testing, users can drive Vin up to 30V as long as 3.3V power output from the AP2204K is NOT used.
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 2 of 13 July 2015 www.diodes.com AL1794 IC Pin Assignment EN PWM4/GND PWM3/GND PWM2/GND PWM1 LED1 LED2/GND VIN REF FAULTB LEDPG LED4/GND LED3/GND GND 7 8 Pin Part Number Descriptions Name U-DFN4030-14 EN 1 Active-high to Enable, Internally Pulled Down PWM4/GND 2 PWM Signal Input for channel 4, Internally Pulled Down for AL1794. GND for AL1791, AL1792, and AL1793. PWM3/GND 3 PWM Signal Input for channel 3, Internally Pulled Down for AL1793 and AL1794. GND for AL1791 and AL1792. PWM2/GND 4 PWM Signal Input for channel 2, Internally Pulled Down for AL1792, AL1793, and AL1794. GND for AL1791. PWM1 5 PWM Signal Input for channel 1, Internally Pulled Down (Tied to GND when this channel is NOT used). LED1 6 Channel 1 LED Cathode LED2/GND 7 Channel 2 LED Cathode for AL1792, AL1793, and AL1794. GND for AL1791. GND 8 Ground LED3/GND 9 Channel 3 LED Cathode for AL1793 and AL1794. GND for AL1791 and AL1792. LED4/GND 10 Channel 4 LED Cathode for AL1794. GND for AL1791, AL1792, and AL1793. LEDPG 11 LED Power Good Indication. Asserted Low to report insufficient headroom. Needs an external pull- up resistor. FAULTB 12 Fault Report. Asserted Low to report faulty conditions. Needs an external pull-up resistor. REF 13 Reference Current Setting through External Resistor (RSET) VIN 14 Voltage Input Exposed PAD Exposed PAD Exposed pad. Internally connected to GND. It should be externally connected to GND and thermal mass for enhanced thermal impedance. It should not be used as electrical conduction path.
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 4 of 13 July 2015 www.diodes.com 3. MCU1 Connectors (10 pins) - (Left to Right Pin Sequence) 1) GND - Ground - Leftmost pin (Top View) 2) 3.3V (OUT) - 3.3V (output for MCU Power); Generated by AP2204K -3.3 (WIDE INPUT VOLTAGE RANGE, 150mA ULDO REGULATOR, http://diodes.com/datasheets/AP2204.pdf) with Vin(max) at 24V. 3) LEDPG (OUT) - LED Power Good signal 4) FAULTB (OUT) - FaultB, active low, indication of fault occurrence 5) EN (IN) - Enable AL1794 to turn ON 6) PWM4 (IN) - PWM signal for Channel #4 7) PWM3 (IN) - PWM signal for Channel #3 8) PWM2 (IN) - PWM signal for Channel #2 9) PWM1 (IN) - PWM signal for Channel #1 10) GND 4. Test Points 1) VLED1 Connected to VLED1 2) VLED2 Connected to VLED2 3) GND_1, GND_2, GND_3, GND_4 Connected to GND 4) EN Connected to AL179x Pin#1 5) PWM4 Connected to AL179x Pin#2 6) PWM3 Connected to AL179x Pin#3 7) PWM2 Connected to AL179x Pin#4 8) PWM1 Connected to AL179x Pin#5 9) LED1 Connected to AL179x Pin#6 10) LED2 Connected to AL179x Pin#7 11) LED3 Connected to AL179x Pin#9 12) LED4 Connected to AL179x Pin#10 13) LEDPG Connected to AL179x Pin#11 14) FAULTB Connected to AL179x Pin#12
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 5 of 13 July 2015 www.diodes.com Board Setup Procedure The channel current ratio for Channel 1, 2, 3 and 4 are fixed at 1:1:0.75:0.25. The default Channel Current of LED1, LED2, LED3 and LED4, are preset at 250mA, 250mA, 187.5mA and 62.5mA, respectively with Rset (R601) of 12KΩ. Users can change the current setting by replacing Rset to obtain desired current value as follows: 1. Ensure that the DC source is switched OFF or disconnected. 2. Connect the DC line wires of power supply to VIN and GND terminals on the board. 3. Connect the anode wire of external LED string to VLED1 of the board. 4. Connect t he cathode wire of the external LED emitter strings to relevant LED channels inputs (LED1, LED2, LED3, LED4) of the board. 5. Make sure the length of both anode/cathode wires connected between AL1794EV1 and LEDs strings is minimized (less than 1 inch) to redu ce wire inductance and improve ringing performance. 6. Ensure that the area around the board is clear and safe, and preferably that the board and LEDs are enclosed in a transparent safety cover. 7. Turn on the main DC Power switch. 8. Send proper PWM Signal patte rn and then turn ON the EN pin (High) to enable the AL1794 IC. 9. LED strings should light up according to the Dimming pattern driven by PWM signals. CAUTION: 1. Make sure the maximum DC input voltage is not higher than 30V DC (if 3.3V Power Output is NOT used), or 24VDC (if 3.3V Power Output is used).
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 6 of 13 July 2015 www.diodes.com 2. If different current is required, please modify the Rset (R601) to proper value before start the Turn-On procedure. 3. The maximum recommended channel current is at 500mA (for channel 1 and 2) with Rset (R601) at 6KΩ. 4. Channel PWM Dimming patterns are recommended to be spread out to avoid sharp turn - on and turn-off rush currents. 5. Though there are various protection mechanism built in AL1794, it is good practice to check maximum dimming pattern to avoid Thermal Shutdow n (when Case Ambient Temperature exceeds 160ºC). Thermal resistivity θja (Junction -to-Ambient) of AL1794 is 55 ºC/Watt. AL1794 will have to absorb any additional voltage headroom provided by the VLED power input to the Anodes of Emitter Strings. Theref ore, thermal management of AL1794 must follow the following guidelines: PDmax (Maximum Power Dissipation) = (160ºC Junction Shutdown Temperature - Ambient Temperature, e.g. 85ºC) / 55ºC/W = 1.364Watts PAmax (Power to be Absorbed by AL179x) = Σ(VLEDx * Cu rrent through the emitter string * Associated PWM Dimming Duty Cycle) Thermal Management Guideline PAmax < PDmax
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 7 of 13 July 2015 www.diodes.com PWM Dimming Linearity Tests Using PWM Dimming signals to create desired dimming effects had the advantages of reducing current to desired ra tio without changing either CCT (Correlated Color Temperate) of White emitters or causing Color shifts of Color emitters. To avoid eFlicker ("Dark Stripes on Images" when taking photos or videos with Smartphones under PWM dimmed Lighting situation), users can use higher PWM frequency (e.g. 4KHz and above ). The dimming linearity performance at Deep Dimming (less than 1% light output) is very important as human eyes are very sensitive to low light situations. For example, 10% of measured light is 30% of perceived light 5% of measured light is 22% of perceived light 1% of measured light is 10% of perceived light 0.1% of measured light is 3% of perceived light Source: IESNA Lighting Handbook, 9th Edition, (New York; IESNA, 2000), 27-4.
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 11 of 13 July 2015 www.diodes.com Evaluation Board Schematic LED1 C681 1.0uF/50V 3.3V GND_1 VLED1' U681 AP2204K 3 4 5VIN GNDEN ADJ/NC VOUT 3.3V JP_EN 3.3V VLED1 C682 4.7uF/10V C602 100uF/50V LED3 VIN REF FAULTB LEDPG LED4 LED3 GND GND' R601 / LED1 / LED2 / LED3 /LED4 GND 12K / 250mA/250mA /187mA /62mA PWM2 PWM4 LEDPG 10K / 300mA/300mA /225mA /75mA MCU1 LEDPG FAULTB EN PWM4 PWM3 PWM2 PWM1 GND1 GND2 3.3Vcc R608 10K FAULTB 9K / 333mA/333mA /250mA /83mA VLED2 R607 10K GND_3 AL179x Test Fixture Rev_2.0 2.0 AP1794 Test Fixture 1 1Tuesday , February 17, 2015 Title Size Document Number Rev Date: Sheet of C621 1uF 6K / 500mA/500mA /375mA /125mA EN PWM4 PWM3 PWM2 PWM1 LED1 LED2 GND PWM3 LED2 R602 10K PWM1 GND_4 C601 100uF/50V C603 0.1uF U601 AL1794 GD 5 10 EN PWM3 PWM2 FAULTB VIN PWM4 LED1 LED2 LED3 GND REF LEDPG PGND PWM1 LED4 VLED2' LED4 CON3 LED Board LED1 LED2 LED3 LED4 VLED1 VLED2 R601 RES EN GND_2 Figure 9: Evaluation Board Schematic
Quad-Channel Current-Ratio-Optimized LED Driver with Analog and PWM Dimming AL1794EV1 REV1 Page 12 of 13 July 2015 www.diodes.com Bill of Material # Name QTY Part number Manufacturer Description
1 U601 1 AL1794AFE-13 Diodes Inc 4-Channel LED Driver
2 U681 1 AP2204K-3.3VTRG1 Diodes Inc Wide-Input (2.5V-24V) 150mA ULDO 3 C601 1 ECA-1HM101 Panasonic E-CAP 100uF 50V (8x11.5mm) 4 C602 1 ECA-1HM101 Panasonic E-CAP 100uF 50V (8x11.5mm) 5 C603 1 CC0603KRX7R9BB104 Yageo CAP CER 0.1uF 50V X7R 0603 6 C621 1 CC0805KRX7R9BB104 Yageo CAP CER 1.0uF 50V X7R 0805 7 C681 1 CC0805KRX7R9BB104 Yageo CAP CER 1.0uF 50V X7R 0805 8 C682 1 CC0805ZRY5V6BB475 Yageo CAP CER 4.7uF 10V X7R 0805
9 R601 (Rset) 1 RC0603JR-0712KL Yageo RES 12KΩ 1/10W 5% 0603 SMD
10 R602 1 RC0603JR-0710KL Yageo RES 10KΩ 1/10W 5% 0603 SMD
11 R607 1 RC0603JR-0710KL Yageo RES 10KΩ 1/10W 5% 0603 SMD
12 R608 1 RC0603JR-0710KL Yageo RES 10KΩ 1/10W 5% 0603 SMD
13 JP_EN 1 800-10-002-10-001000 Mill-Max Enable 2 pin SIP header w/Jumper
14 LED_BAR 1 800-10-006-10-001000 Mill-Max LED Emitter Output I/O 6pin SIP header
15 MCU1 1 800-10-010-10-001000 Mill-Max MCU I/O 10pin SIP header
16 VLED1 1 534-1598-2 Mouser VLED1 Anode Input, Term 0.094”x1/16” 17 VLED2 1 534-1598-2 Mouser VLED2 Anode Input, Term 0.094”x1/16” 18 GND 1 534-1598-2 Mouser Ground Input, Term 0.094”x1/16”
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