BW7386 Accuracy Constant Current LED Driver Description The BW7386 is a highly-integrated, low startup current, current mode, and fixed switching frequency PWM controller. These functions enable the LED driver to easily meet the accuracy average LED current requirements. The integrated functions also include the LED open protection, and internal over temperature protection. The COMP pin controls the duty by Packing & Order Information connected an RC compensation network to ground and 3,000/Reel forming the closed loop feedback control. To protect the external power MOSFET from being damaged by supply Pin Configurations (Top View) over voltage, the BW7386 OU T pin voltage is clamped to about 17V. The BW7386 improves the performance and reduces the cost of the LED driver. It is a 6-pin SOT-26 package. Features • Accuracy Constant Current • Low BOM Cost • Current Mode/Fixed Frequency Control • Gate Output Voltage Clamp Applications • LED Open Protection(OVP) • E26/27, T5/T8 LED Lamp • Over Current Protection (OCP) • Others LED Lighting Applications • 300mA Driving Capability for OUT Pin • RoHS compliant package PIN DESCRIPTIONS Pin Name Pin Description VCC Power supply pin GND Ground pin OUT The output driver for driving the external MOSFET DIM Dimming Control Pin by Input a DC Voltage COMP Feedback compensation network CS Current sense pin, connect to sense the MOSFET current Publication Order Number: [BW7386] © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver TYPICAL APPLICATION CIRCUITS ABSOLUTE MAXIMUM RATINGS (Note 1) Parameter Symbol Range Unit Power supply pin VDD 30 V DIM voltage to GND VDIM -0.3 to 7 V CS voltage to GND VCS -0.3 to 7 V OUT voltage to GND VOUT 15 V TJ 150 °C Storage temperature rang TSTG -65 to +150 °C Lead temperature (Soldering 5 sec) TLEAD 260 °C Power dissipation @TA=25°C PD 300 Mw Thermal resistance junction to ambient (Note 2) θJA 333 °C/W Thermal Resistance θJC 106.6 °C/W ESD rating, Human body mode (Note 3) VESD 2 kV ESD rating, machine mode (Note 3) VESD 200 V Maximum junction temperature Publication Order Number: [BW7386] © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver RECOMMENDED OPERATING CONDITIONS (Note 4) Parameter Symbol Operation Conditions Unit Supply voltage VDD 26 V Operating junction temperature range TJ 150 °C Operating ambient temperature range TOPA -20 to +85 °C Note 1: Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2: Thermal Resistance is specified with the component mounted on a low effective thermal conductivity test board in free air at TA=25°C. Note 3: Devices are ESD sensitive. Handing precaution recommended. Note 4: The device is not guaranteed to function outside its operating conditions. BLOCK DIAGRAM Publication Order Number: [BW7386] © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver ELECTRICAL CHARACTERISTICS VCC=15V, TA= 25°C, unless otherwise specified. SUPPLY VOLTAGE Parameter Symbol Conditions Startup Current VDD(ST) VCC=UVLO on -1V Operating Current VCOMP With 1nF load on OUT pin Min Typ. Max. 8 Units uA 1.5 2.5 mA 1.2 1.8 mA With 1nF load on OUT pin Operating Current IOPA Protection Tripped (OCP, OVP,SCP,OTP) UVLO(off) 7 8 8 V UVLO(on) 17 18 19 V 26 28 30 V Min Typ. Max. Units 0.194 0.2 0.206 V OVP Level on VCC Pin OVP VOLTAGE FEEDBACK Parameter Symbol Feedback Reference Voltage VFB Conditions Tran-Conductance 120 uS Output Sink Current Io-sink 12 uA Output Source Current Io-source 12 uA CURRENT SENSING Parameter Symbol Input Over Voltage Protection FOSC Conditions Min Typ. Max. Units 0.8 V 5 V Leading-Edge Blanking Time 410 nS Delay to Output 100 nS Open Loop Voltage, CS Pin Open SWITCHING FREQUENCY Parameter Symbol Conditions Min Typ. Max. KHz Switching Frequency 42 45 48 % Maximum Duty 90 % +/-6 Frequency Jitter Range % Temp. Stability -40°C ~125°C 6 % Voltage Stability VCC=11V~25V 1 % Max. Units GATE DRIVER OUTPUT Parameter Symbol Conditions Min Typ. Rising Time Load Capacitance = 1000pF 160 nS Falling Time Load Capacitance = 1000pF 80 nS VGATE-Clamp VCC=25V 17 19 V 17 Publication Order Number: [BW7386] 19 V © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver DIM INPUT SECTION Parameter Symbol Conditions Min Saturation Threshold Voltage 3.0 Linear Dimming Range 0.6 Current Source 270 Min Thermal Section Parameter Symbol Thermal Shutdown TSD Publication Order Number: [BW7386] Conditions Typ. Max. Units V 3.0 V 300 330 uA Typ. Max. Units 150 °C © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver APPLICATION INFORMATION OCP(Over Current Protection) Start-up Current The BW7386 has an over current protection function on CS pin. The typical start-up current is around 8uA. Very low start-up An internal circuit detects the current level, when the current is current allows the PWM controller to increase the value of larger than a threshold level, the gate output will keep on low start-up resistor and then reduce the power dissipation on it. level. Then VCC decreases below UVLO off level, the controller resets again. UVLO(Under Voltage Lockout) A hysteresis UVLO comparator is implemented in BW7386 then OVP (Over Voltage Protection) on VCC the turn-on an turn-off thresholds level are fixed at 18V and 8V The prevent the LED driver from being damaged, the BW7386 respectively. This hysteresis shown in Fig.1 ensures that the is implemented an OVP function on VCC. When the VCC start-up capacitor will be adequate to supply the chip during voltage is higher than the OVP threshold voltage 28V, the output start-up. For quickly startup the LED driver, the start-up resistor gate driver circuit will be shut down immediately to stop the should be matched with the startup capacitor. Due to the low switching of power MOSFET. The VCC pin OVP function is an UVLO on level, so the turn-on delay time will also never greater auto recovery type protection (latch off type optional). If the OVP than the general PWM IC. condition happens, the pulses will be stopped and never recovery unless the VCC pin voltage is down to the UVLO off level. The BW7386 is working in an auto-recovery mode as shown in Fig. 2. Oscillator The maximum duty-cycle of internal oscillator is up to 90% for driving high LED voltage string. The frequency of the oscillator is fixed to 45KHZ by internal setting. Gate Clamp/Soft Driving LEB(Leading-Edge Blanking) Driver is clamped to 17V by an internal clamping circuit. Those Each time the power MOSFET is switched on, a turn-on spike damages usually come from undesired over-voltage gate will inevitably occur at the sense resistor. To avoid fault trigger, a signals. Under the conditions listed below, the gate output will 410ns leading-edge blanking time is built in. Conventional RC turn off immediately to protect the power circuit. The BW7386 filtering can therefore be omitted. During this blanking period, the also has soft driving function to minimize EMI. current-limit comparator is disabled and can not switch off the gate driver. Publication Order Number: [BW7386] © Bruckewell Technology Corporation Rev. A -2014 BW7386 Accuracy Constant Current LED Driver Disclaimer ALL PRODUCT, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE TO IMPROVE RELIABILITY, FUNCTION OR DESIGN OR OTHERWISE. Bruckewell Technology Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, “Bruckewell”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained in any datasheet or in any other disclosure relating to any product. Bruckewell makes no warranty, representation or guarantee regarding the suitability of the products for any particular purpose or the continuing production of any product. To the maximum extent permitted by applicable law, Bruckewell disclaims (i) Any and all liability arising out of the application or use of any product. (ii) Any and all liability, including without limitation special, consequential or incidental damages. (iii) Any and all implied warranties, including warranties of fitness for particular purpose, non-infringement and merchantability. Statements regarding the suitability of products for certain types of applications are based on Bruckewell’s knowledge of typical requirements that are often placed on Bruckewell products in generic applications. Such statements are not binding statements about the suitability of products for a particular application. It is the customer’s responsibility to validate that a particular product with the properties described in the product specification is suitable for use in a particular application. Parameters provided in datasheets and/or specifications may vary in different applications and performance may vary over time. Product specifications do not expand or otherwise modify Bruckewell’s terms and conditions of purchase, including but not limited to the warranty expressed therei Publication Order Number: [BW7386] © Bruckewell Technology Corporation Rev. A -2014