DW8501 High Power LED Driver

Transcription

1 Descriptions The is an instant On/Off LED driver for high power LED applications. At output stage, one regulated current port is designed to provide a uniform and constant current sink for driving LEDs within a large range of V F variations. easily provides users a consistent current source. User may adjust the output current from up to 1.5A through an external resistor,r S, which gives users flexibility in controlling the light intensity of LEDs. In addition, users can precisely adjust LED brightness from 0% to 100% via output enable (EN) with Pulse Width Modulation. also guarantees that LEDs can be cascaded to maximum 40V at the output port. Ordering Information Device Marking Package Operating Temp XXXXXXXX YWW XXXXXXXX YWW TO-252 SOT O C ~ +85 O C Features Package Information Constant output current invariant to supply and load voltage change 5V to 40V supply voltage Up to1.5a adjustable regulated output current Built-in thermal derating circuit Available PWM dimming control Output current adjusted through an external resistor TO-252, SOT-223 Package Applications LED light bulbs Signage and decorative LED lighting General lighting of flat panel displays RGB backlighting LED driver Current stabilizer with DC/DC or AC/DC Automotive lighting General purpose constant current source Package TO-252-5L SOT-223-5L Size 6.5x5.5x2.3(mm) 6.5x3.5x1.8(mm) Typical Application Circuit - 1 -

2 Pin Connection Pin Description Pin Name Description 1 VDD Supply voltage input 2 RS Output current set input. Connect a resistor from RS to GND to set the LED bias current 3 GND Ground 4 EN Output stage enable control pin. High enable the OUT pin. It can be left floating for normally on. 5 OUT Output pin. Sink current is decided by the current on R SET connected to RS 6 HS Heat sink, normally connected GND - 2 -

3 Absolute Maximum Ratings Characteristics Symbol Value Unit Supply voltage V DD 41 V Output voltage V OUT 23 V Enable voltage V EN 41 V Package thermal resistance TO-252-5L θ JA 90 /W SOT-223-5L θ JA 100 /W Operating temperature T OPR -35~+85 Storage Temperature T STG -55~+150 Note 1. θja is measured in the convection at Ta=25 on a high effective thermal conductivity test board(4 Layers, 2S2P) of JEDEC 51-7 thermal measurement standard. Recommended Operation Conditions Characteristics Symbol Min. Typ. Max. Unit Supply voltage V DD 5-40 V Enable voltage V EN V Output sink current I OUT A - 3 -

4 Electrical Characteristics V DD = 24V, EN= 0~24V, Ta = -35 ~+85, unless otherwise specified. Typical values are at T A =+25 Characteristics Symbol Conditions Min. Typ. Max. Unit Input supply voltage V DD 5-40 V Output linearity voltage V OUT_LINE V DD =24V, I SET = 300mA, V Output current I OUT A Quiescent Current I Q_ON EN = 24V ma I Q_OFF EN = 0V ua EN input leakage current I EN_LIK ua Input high voltage V IH V Input low voltage V IL V LED output drop-out voltage V DROP V DD =40V, I SET =1A V Thermal derating T D Thermal derating hysteresis T DHYS Rset Voltage V SET V 2KΩ 300 ma 1KΩ 600 ma R SET 600Ω 1000 ma 400Ω 1500 ma Note2 : Output dropout voltage : 90% x I OUT - 4 -

5 Block Diagram Circuit Description Setting Output Current Iout [ma] = (610(mV)/Rset ( ))X 1000 The output current of each channel (I OUT ) is set by an external resistor, R S. The output current can be calculated from the equation : V R-EXT =0.62V; R EXT =(V R-EXT /I OUT )X1000=(0.61V/I OUT )X1000, I OUT =(V R-EXT /R EXT )X1000=(0.61V/R EXT )X1000 within ±5% chip skew where R EXT is the resistance of the external resistor connected to R-EXT terminal and V R-EXT is the voltage of R-EXT terminal

6 Typical Applications LED VF = 3.3V, 1W Power LED VDD=5V C1=2.2uF VDD EN OUT RS RSET GND Figure 1. VDD=5V Figure 2. VDD=12V Figure 3. VDD=24V Figure 4. VDD=12V, 9 LED Figure 5. PWM Typical Application Figure 6. R VALLAST Application - 6 -

7 Package Dimension (TO-252-5L 6.5 x 5.5 x 2.3) - 7 -

8 Package Dimension (SOT-223-5L 6.5 x 3.5 x 1.8) - 8 -