SY7701FHC

Ap pplicatiions Noote: SY Y7701 H High Effi ficiency 500kHz, 5 25V PW WM Contrroller For WLED backligh ht application Generral Descrription Feeatures SY7701 is a current moode boost conntroller targetedd for d has a wide WLED backlight appliication. The device input volltage range of o 3V to 255V. The external compensaation provides flexible adjuustment of coontrol loop for different appllications. The internal low side driver is capable of sourcing s 1.5A A and sinkingg 3A current. Orderring Infoormation n SY7701 □(□□)□ Temperature Coode T P Package Code O Optional Spec Code C Orderingg Number SY7701DBC SY77701FHC Package type DFN3x3-10 SOP10 • • • • Input I voltage range r 3V to 255V 500kHz fixed switching freqquency d frequuency 100Hz~1kHz dimming 10%~100% dimming duty cyycle @200Hz dimming frequency f • External E comppensation • Integrated I low w side driver: 1.5A sourcing and a 3A sinking • OVP, O OTP funnctions • RoHS R Compliant and Halogeen Free • Compact C packkage: DFN3x3--10,SOP10 Ap pplicatioons Note ---- • Monitor M LCD Panel Backligght • TV T LCD Paneel Backlight • LED L Lighting Typiccal Applications SY7701 Figure 1. Schematic Diagram SY77011 Rev. 0.2A Silergyy Corp. Connfidential- Prrepared for Internal I Usee Only 1 SY7 7701 Pinou ut (top vieew) (DF FN3x3-10) (SOP10) Top p Mark: GOxyyz for SY7701DBC (Device code:GO, x=yyear code, y=w week code, z= loot number cod de) AEYxxyz for SY7701FHC (Devicee code:AEY, x=year x code, y= =week code, z= = lot number code) c Pin Nam me Pinn Number Pin Desccription IN 10 Input pin. Decouple D this pin p to GND pinn with at least 1uF ceramic capacitor 5V Internall LDO output from f VIN. Connnect a 4.7 uF ccapacitor from m this pin VCC C 9 to GND GATE E 8 Driver pin. Connect to thee gate of power MOSFET Current sennse pin. Connecct an external current c sensingg resistor RS frrom this pin to GND D. The voltage on this pin is used u to providee mosfet curren nt CS 7 feedback inn the control loop and cycle by b cycle peak ccurrent limit. Peak P current limiit is triggered when w the senseed voltage pluss the slope compensation exceed 340 0mV Feedback pin. The LED current c equals to: t ILED= 100mmV FB 6 RISEET GND D 5(Expposed Paddle) COMP 4 OVP P 3 SS 2 EN/PW WM 1 Ground pinn External compensation pin. Connect RC C network from m this pin to GN ND to oop compensatee the control lo Over Voltagge Protection input i pin.The OVP O set point equals to : VOVP= 1 ROV22 (R OV! +R OV2 ) Soft start piin. Connect a capacitor c from this pin to GN ND to program the soft start time Enable and PWM dimmin ng input pin. Puull it high to tuurn on the chip p. Do not float this pin Absolu ute Maxim mum Ratin ngs (Note 1) IN,EN -------------------------------------------------------------------------------------------------------------------------------------------V GATE------------------------------------------------------------------------------------------------------------------------------ VC CC+0.3V All other pins p --------------------------------------------------------------------------------------------------------------------------------- V Power Disssipation, PD @ TA = 25°C, DFN3x3-10,SOP10 ------------------------------------------------------------ 2.6W/TBD Package Thermal T Resisttance (Note 2) θJA ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- 38°C C/W/TBD θJC -------------------------------------------------------------------------------------------------------------------------------------------------------------------- 130°C C/W/TBD Junction Temperature T R Range -------------------------------------------------------------------------------------------------------- 125°C Lead Tem mperature (Solddering, 10 sec.) ------------------------------------------------------------------------------------------- 260°C Storage Temperature T Raange ---------------------------------------------------------------------------------------------- 65°C to 150°C Recom mmended Operating O g Conditioons (Note 3) IN ------------------------------------------------------------------------------------------------------------------------------------- V to 25V Junction Temperature T R Range --------------------------------------------------------------------------------------------- 40°C to 125°C Ambient Temperature T R Range --------------------------------------------------------------------------------------------- 40°C C to 85°C SY77011 Rev. 0.2A Silergyy Corp. Connfidential- Prrepared for Internal I Usee Only 2 SY7701 Electrical Characteristics (VIN = 12V, TA = 25°C, unless otherwise specified) Parameter Input Voltage Range Quiescent Current Shutdown Current OVP Threshold FB Input Current Feedback Reference Voltage Internal Slope Compensation Gate Driver Output Peak Current EN Rising Threshold EN Falling Threshold Input UVLO threshold UVLO hysteresis Oscillator Frequency Min On Time Min Off Time Internal LDO Output Thermal Shutdown Thermal Hysteresis Symbol VIN IQ ISHDN VOVP IFB VREF VSLOPE ISOURCE ISINK VENH VENL VUVLO VHYS FOSC VVCC TSD THYST Conditions Min 3 VOVP=1.1V EN=0 0.98 -50 98 Typ 170 0.1 1 100 40 1.5 3 Max 25 1.02 50 102 1.5 0.4 2.9 VIN=5.5V 4.9 0.3 500 200 200 5 150 20 5.1 Unit V uA uA V nA mV mV/uS A A V V V V kHz ns ns V ℃ ℃ Note 1: Stresses beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 2: θ JA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard.Test condition: Device mounted on 2” x 2” FR-4 substrate PCB, 2oz copper, with minimum recommended pad on top layer and thermal vias to bottom layer ground plane. Note 3: The device is not guaranteed to function outside its operating conditions. SY7701 Rev. 0.2A Silergy Corp. Confidential- Prepared for Internal Use Only 3 SY7701 Block Diagram COMP CS IN 5V LDO 1V FB VCC Slope Comp 100mV Control Logic Driver GATE ISEN Soft-start Thermal Protection GND SY7701 Rev. 0.2A SS EN Silergy Corp. Confidential- Prepared for Internal Use Only 4 SY7701 Typical Performance Characteristics SY7701 Rev. 0.2A Silergy Corp. Confidential- Prepared for Internal Use Only 5 SY7701 SY7701 Rev. 0.2A Silergy Corp. Confidential- Prepared for Internal Use Only 6 SY7701 Operation SY7701 is a boost controller targetted for white LED lighting. It integrates a low side driver which is capable of sourcing 1.5A and sinking 3A current. External compensation can supply a flexible adjustment of control loop under different applications. OVP function can protect the part from LED open event, OVP point can be programmed using a voltage divider. Inductor L: There are several considerations in choosing this inductor. 1) Choose the inductance to provide the desired ripple current. It is suggested to choose the ripple current to be about 40% of the maximum average input current. The inductance is calculated as: L= Applications Information LED current programming resister RISET LED current is programmed by a resistor which is in series with the LED string. LED current is calculated as: ILED=100mV/Riset LED may be shorted if the current is higher than its rating. SY7701 will fold back the LED current from 100% to 30% when the OVP pin voltage changes from 0.5V to 0.15V. For typical application, it is recommended the OVP point is less than twice of the LED string voltage OVP point programming divider ROV1 and ROV2: Choose proper resistor ROV1 and ROV2 to program the output voltage OVP point. VOVP is calculated as: VOVP=1V*(1+ROV1/ROV2) Make sure the resister will not exceed its power rating when output voltage reaches the OVP point. Peak Current Sense Resistor An external sensing resistor Rsen is used to sense the current flow through the MOSFET. The sensed voltage is for peak current mode control and cycle by cycle peak current limit. Peak current limit will be triggered when the voltage on CS pin plus the internal slop compensation exceed 340mV, which is the typical clamping voltage of the PWM comparator. It is desirable to make the maximum value of sensing voltage plus the slope compensation to be about 70% of the clamping voltage during normal operation. Thus, Rs= 70% × 0.34-Vslope× D× Ts IPEAK Vslope is the slew rate of the internal compensation, IPEAK is the peak current through MOSFET. . SY7701 Rev. 0.2A ⎛ VIN ⎞2 (VOUT − VIN) ⎟ ⎜ ⎝ VOUT ⎠ FSW × IOUT, MAX × 40% where FSW is the switching frequency and IOUT,MAX is the maximum load current. The SY7701 regulator IC is quite tolerant of different ripple current amplitude. Consequently, the final choice of inductance can be slightly off the calculation value without significantly impacting the performance. 2) The saturation current rating of the inductor must be selected to be greater than the peak inductor current under full load conditions. ISAT,MIN > 3) ⎛ VOUT ⎞ × IOUT_MAX + VIN(VOUT − VIN) ⎜ V ⎟IN 2 × FSW × L× VOUT ⎝ ⎠ The DCR of the inductor and the core loss at the switching frequency must be low enough to achieve the desired efficiency requirement. It is desirable to choose an inductor with DCR