NCV7683GEVB ON Semiconductor

NCV7683GEVB NCV7683GEVB Evaluation Board User s Manual Eight (8) Channel Enhanced 100 mA Linear Current Regulator and Controller www.onsemi.com for Automotive LED Lighting in Daisy Chain Sequencing Application EVAL BOARD USERS MANUAL Evaluation Board Users Manual Description Features Automotive Rear Combination LED Lighting systems Sequencing Functionality often require the electronics to execute a sequence lighting One Out, All Out (Latch Off) Optional Functionality event for a blinker function to indicate directional change in STOP, TAIL, TURN (100% Duty Cycle, PWM, movement. This evaluation board will demonstrate to the Sequencing) Modes user this functionality using NCV7683 devices in a daisy Flexibility for chain fashion along with the typical DC current drive and External LED Connections PWM demonstration. LED Current Programmability (RSTOP) The three typical control inputs into the system are LED PWM Programmability (RTAIL) available through onboard switches or through the pin Sequence Time Programmability connections to external controls. The three system control Sequence Interval Programmability inputs are the STOP, TAIL, and TURN functions. The STOP STOP, TAIL, TURN External Connections function displays a 100% duty cycle current through the External DIAG Pin Connection LEDs. The TAIL function displays a programmable PWM current through the LEDs. The TURN function displays the sequence event through the 8 onchip channels and through a serial connection through a second series of 8 channels on a second device. Figure 1. Evaluation Board Picture Semiconductor Components Industries, LLC, 2016 1 Publication Order Number: July, 2016 Rev. 2 EVBUM2297/DNCV7683GEVB Sequencing (TURN) outputs increase the current capabilities of each string. The major focus of this evaluation board and the Combining 2 outputs increase the current capability from NCV7683 is the ability of the device to perform an LED 100 mA to 200 mA. Internal timing circuitry to the output of drive sequencing function whereby each string of LEDs is SEQOUT insures String4 is fully illuminated before the illuminated in a predictive increasing succession. Figure 2 turnon signal is transferred out to IC2. shows the main component connections which are utilized Programming features of the NCV7683 allow for the for this function. The combined pair of paralleled outputs of programmed pairs to turnon at the same time. Additional the IC1 are first turned on, and the signal is carried through combinations of combined outputs are also designed into the to IC2 from the output of IC1 (SEQOUT) in a daisy chain part. Consult the datasheet for further details. fashion to the input of IC2 (EN). Parallel combinations of Ballast Transistor Ballast Transistor LED Loads LED Loads String 1 String 2 String 3 String 4 String 5 String 6 String 7 String 8 OUT1/2 OUT1/2 VP VP OUT3/4 OUT3/4 SEQON SEQON OUT5/6 OUT5/6 OUT7/8 OUT7/8 EN SEQOUT EN SEQOUT GND Daisy Chain Connectrion Vbat GND IC1 IC2 NCV7683 NCV7683 LED Sequence 1...2...3...4...5...6...7...8 Figure 2. Focus Demonstration 100 STOP The STOP function displays the highest system output 90 current at 100% duty cycle. Using the STOP switch activates 80 this function. An alternative connection The current is 70 programmable with a resistor on the RSTOP pin to ground. 60 Jumpers J12 and J15 provide isolation of pin 5 of the 50 NCV7683 allowing access to the pin for alterative selection of output current. The range of programmability is from 40 15 mA to 100 mA using the equation: 30 150 20 Iout RSTOP 10 T = 25C where RSTOP is the resistor value. 0 0 1 2 3485 6 7 910 RSTOP (k ) Figure 3. Iout vs. RSTOP www.onsemi.com 2 Iout OUTPUT CURRENT (mA)