FT886A-RT

Preliminary FT886xx Fremont Micro Devices High Performance Non-isolated Buck LED Driver DESCRIPTION FEATURES No Auxiliary winding for sensing and FT886x is optimized for low cost non-isolated Buck supplying switching mode LED driver applications. It operates Inductor current boundary conduction mode in inductor current boundary conduction mode. With BCM source driving architecture, special demagnetization Constant current control without secondary sensing technology and the ultra low operating sense and feedback circuit current, FT886xx doesn’t need the auxiliary winding Built-in 500V Power MOSFET for output current sensing and chip power supplying. ±3% LED current accuracy FT886x also integrates a 500V power MOSFET that Ultra low operating current to improve further improves the system reliability and lowers efficiency the system cost and complexity. Built-in line compensation Cycle-by-Cycle current limiting Its highly integrated functions such as Leading Edge Precision OVP voltage for best LED open Blanking (LEB) and built-in line compensation offer circuit protection users a high efficiency and low cost solution for LED short circuit protection constant current LED driver applications. Over temperature compensation CS resistor short circuit protection. Furthermore, FT886x offers fruitful protections like Inductor short circuit protection. LED open and short circuit protection, over VCC under-voltage lockout temperature Available in SOP8 and DIP8 packages inductor short circuit protection. compensation, CS resistor and The industry leading OVP voltage accuracy ensures the best LED open circuit protection APPLICATIONS DC/DC or AC/DC LED Driver Applications Back Lighting of Flat Panel Displays © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886xx-A0-page1 Preliminary FT886xx Fremont Micro Devices TYPICAL APPLICATION CIRCUIT Figure 1: Typical Application Circuit ABSOLUTE MAXIMUM RATINGS CS to GND…………………………………………...……………………………………….……..-0.3V to +7V VCC to GND…………………………………..………….………………………………………-0.3V to +20V DRAIN to GND…………………………………...…………………………….……….………-0.3V to +500V TP to GND………………………………...…………………………………….………….….…………. -0.3V to +20V Operating Temperature Range…………………………………………………………………..-40 to +125 Junction Temperature………………………………..……………………………………….. -40 to +150 Storage Temperature Range ……………………………..……………………………….….-60 to +150 ESD Protection HBM………………………………………………………………………………………………2000V ESD Protection MM………………..……………………………….……………………………………………….200V * Stresses exceed those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. Functional operation of the device at conditions beyond those listed in the specification is not guaranteed. Prolonged exposure to extreme conditions may affect device reliability or functionality. © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page2 Preliminary FT886xx Fremont Micro Devices PIN CONFIGURATION T o p V ie w GND 1 8 CS NC 2 7 CS VCC 3 6 D TP 4 5 D Figure 2: Pin Assignments TERMINAL DESCRIPTION No. PIN FUNCTION 1 GND 2 NC No connection 3 VCC Power supply Ground 4 TP Test Point 5,6 D Internal high voltage MOSFET Drain 7,8 CS Current sense. This pin connects a current sense resistor to GND Table1 © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page3 Preliminary FT886xx Fremont Micro Devices ORDERING INFORMATION FT886 xx – x x x HSF and Packaging Circuit Type RB: RoHS and Tube Internal MOS Type RT: RoHS and T&R GB: Green and Tube GT: Green and T&R Package Blank: SOP8 D: DIP8 Internal MOS Max Package Type Output Current Max Output Voltage/Power 90V-264V HSF Packaging Ordering Code 176V-264V Tube FT886A-RB RoHS A SOP8 180mA 60V/10W T&R 150V/18W Tube FT886A-RT FT886A-GB Green T&R Tube FT886A-GT FT886C-RB RoHS C SOP8 280mA 60V/15W T&R 150V/27W Tube FT886C-RT FT886C-GB Green T&R CD DIP8 380mA © 2013 Fremont Micro Devices Inc. 60V/22W FT886C-GT RoHS Tube FT886CD-DRB Green Tube FT886CD-DGB 150V/40W Confidential Rev0.8 DS886x-A0-page4 Preliminary FT886xx Fremont Micro Devices MARKING RULE Figure 3 marking rule for internal reference BLOCK DIAGRAM DRAIN VCC 3 + 15V VOLTAGE REGULATOR UVLO - 5,6 Internal reference & bias VCC 12.8V/ 9V OVP OCP OTP 4 Constant Current & Logic Control TP LEB GND 1 + Current Sense 7,8 CS 0.5V Figure 4 Block Diagram © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page5 Preliminary FT886xx Fremont Micro Devices ELECTRICAL CHARACTERISTICS (Tj = 25°C, VCC = 14V, unless otherwise specified) Symbol Parameter Test Condition Min Typ Max Unit SUPPLY VOLTAGE VCCon Turn-on threshold 12.8 V VCCoff Turn-off threshold 9 V VCC clamp voltage 15.4 V 100 uA 150 uA VCCclamp SUPPLY CURRENT Istart-up Start-up current Before turn-on, VCC= VCCon -1V Iq Quiescent Current CURRENT SENSE VCS_TH Threshold voltage for peak 485 current limit TLEB Leading edge blanking time for current sense TDELAY Switch off delay time 500 515 mV 350 ns 200 ns SWITCH FREQUENCY FMIN TDIS Minimum working 5 frequency Minimum inductor current KHz 8.2 discharge time us MOSFET (FT886A) RDS_ON BVDSS IDSS IDMAX Static drain-source on-resistance Drain-source breakdown voltage Drain-source leakage current Maximum Drain Current VGS=10V,IDS=0.5A VGS=0V,IDS=250uA 10.8 500 V VGS=0V,VDS=500V 10 Vd=6V 0.50 VGS=10V,IDS=0.5A 4.6 uA A MOSFET (FT886C) RDS_ON BVDSS IDSS IDMAX Static drain-source on-resistance Drain-source breakdown voltage Drain-source leakage current Maximum Drain Current VGS=0V,IDS=250uA 500 V VGS=0V,VDS=500V Vd=6V 10 1.0 uA A Over Temperature Compensation © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page6 Preliminary FT886xx Fremont Micro Devices TSD TSD_HYS Thermal compensation 150 threshold Thermal compensation 25 hysteresis Table2 © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page7 Preliminary FT886xx Fremont Micro Devices FUNCTIONAL DESCRIPTION Operating Description FT886x is a cost effective and high-performance non-isolated Buck LED driver. It operates in inductor current boundary conduction mode. The constant current (CC) control is achieved accurately without the secondary feedback circuit and auxiliary winding. Startup Control The start-up current in FT886x is designed to be 100uA. The VCC capacitor will be charged through a start-up resistor when the system is powered on. Once the VCC voltage reaches the start-up threshold, FT886x will start to switch. The VCC voltage of FT886x is clamped at 15V. Due to the ultra-low operating current, the auxiliary winding is not needed to supply the IC, good efficiency is achieved. Constant Current Control Cycle-by-Cycle current sense is adopted in FT886x, and the voltage on CS will be compared with the internal 500mV reference voltage through the current sense comparator, the MOSFET will be switched off when the voltage on CS reaches the threshold. The primary peak current is given by: I P _ PK 500 (mA) Rcs The current in LED can be calculated by the equation: I OUT I P _ PK 2 Where, IP_PK is the peak current in MOSFET, Leading Edge Blanking (LEB) Each time the power transistor is switched on, a turn-on spike occurs at the sense resistor. To avoid premature termination of the switching pulse, a 350ns leading edge blanking time is built in. Conventional RC filtering can therefore be omitted. During this blanking period, the current limit comparator is disabled and can not switch off the gate driver. Over Voltage Protection (OVP) FT886x features the industry leading output OVP accuracy. Output LED open circuit will trigger the over-voltage protection logic and latch, the system stops switching immediately. VCC will be pulled down and charged up again, the system works in a hiccup mode. LED Short Circuit Protection When LED short circuit is detected, the system works at minimum frequency (Fop=5KHz), so the power consumption is low. CS Resistor Short or Inductor Saturation If these catastrophic fault conditions happen, the internal fast fault detection circuit will trigger and latch, the system stops switching immediately, the system VCC will be pulled down and charged up again, system working in a hiccup mode. Over Temperature Compensation © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page8 Preliminary FT886xx Fremont Micro Devices FT886x senses the die temperature after start up, and the thermal compensation threshold is set to 150 with a 25 hysteresis. When FT886x temperature rises and reaches the 150 threshold, the switching frequency will be reduced to approximately 18kHz, so the output current will decrease proportionally, until the IC temperature falls 25 below the thermal compensation trigger point, at which point the output current will recover to 100% of its designed target. © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page9 Preliminary FT886xx Fremont Micro Devices SOP8 PACKAGE OUTLINE DIMENSIONS Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.100 0.250 0.004 0.010 A2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.006 0.010 D 4.700 5.100 0.185 0.200 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 e L 1.270 (BSC) 0.050 (BSC) 0.400 1.270 0.016 0.050 0° 8° 0° 8° © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page10 Preliminary FT886xx Fremont Micro Devices DIP8 PACKAGE OUTLINE DIMENSIONS Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 3.710 4.310 0.146 0.170 A1 0.510 A2 3.200 3.600 0.126 0.142 B 0.380 0.570 0.015 0.022 B1 0.020 1.524 BSC 0.060 BSC C 0.204 0.360 0.008 0.014 D 9.000 9.400 0.354 0.370 E 6.200 6.600 0.244 0.260 E1 7.320 7.920 0.288 0.312 e 2.540 (BSC) 0.100 BSC L 3.000 3.600 0.118 0.142 E2 8.400 9.000 0.331 0.354 © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page11 Preliminary FT886xx Fremont Micro Devices Fremont Micro Devices (SZ) Limited #5-8, 10/F, Changhong Building, Ke-Ji Nan 12 Road, Nanshan District, Shenzhen Tel: (86 755) 86117811 Fax: (86 755) 86117810 Fremont Micro Devices (Hong Kong) Limited #16, 16/F, Blk B, Veristrong Industrial Centre, 34-36 Au Pui Wan Street, Fotan, Shatin, Hong Kong Tel: (852) 27811186 Fax: (852) 27811144 Fremont Micro Devices (USA), Inc. 42982 Osgood Road Fremont, CA 94539 Tel: (1-510) 668-1321 Fax: (1-510) 226-9918 Web Site: http://www.fremontmicro.com/ * Information furnished is believed to be accurate and reliable. However, Fremont Micro Devices, Incorporated (BVI) assumes no responsibility for the consequences of use of such information or for any infringement of patents of other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Fremont Micro Devices, Incorporated (BVI). Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. Fremont Micro Devices, Incorporated (BVI) products are not authorized for use as critical components in life support devices or systems without express written approval of Fremont Micro Devices, Incorporated (BVI). The FMD logo is a registered trademark of Fremont Micro Devices, Incorporated (BVI). All other names are the property of their respective owners. © 2013 Fremont Micro Devices Inc. Confidential Rev0.8 DS886x-A0-page12