WS2259 Features General Description ■ Burst Mode function ■ Low startup current (4uA) ■ Low operation current (1.7mA) ■ Built in Leading edge blanking (LEB) ■ Built in Synchronous slope compensation ■ Current mode operates ■ External programmable switching frequency ■ Cycle by cycle Over Current Protection ■ over temperature protection(OTP） ■ Soft-start ■ VDD over voltage protection and clamp ■ under voltage lockout with hysteresis(UVLO） ■ Driver Output clamped(13V) ■ Soft-driver function for lower EMI ■ Frequency jitter ■ Constant output power limited ■ Over load protection(OLP) ■ Free audio noise operation WS2259 which is optimized for high performance is a highly integrated current mode PWM control IC. It is applied for switch power of the small-sized and medium-sized for example the power adaptor. For lower the standby power and higher RoHS compliant, the IC has the Burst Mode function and very low startup current and working current. At the condition of no load or light load, the IC operates in extended ‘burst mode’ to minimize switching loss by lower the switching frequency. The low startup current and low operating current contribute to a reliable power on startup design with WS2259. A large value resistor could thus be used in the startup circuit to minimize the power consumption and improve the efficiency of the power convert. The internal synchronous slope compensation circuit improves system large signal stability and reduces the possible subharmonic oscillation at high PWM duty cycle output. Leading-edge blanking on current sense(SENSE) input removes the signal glitch due to snubber circuit diode reverse recovery and thus greatly reduces the external component count and system cost in the design. WS2259 offers complete protection coverage with automatic self-recovery feature including cycle by cycle over current protection (OCP), over load protection (OLP), over temperature protection (OTP), VDD Over Voltage Protection, under voltage lockout (UVLO). The gate-driven output is clamped to maximum 13V to protect the external MOSFET. Excellent EMI performance is achieved by using the frequency jitter and the soft-switching at the totem pole gate drive output. The tone energy at below 20KHZ is minimized in the design and audio noise is eliminated during operation. The IC can be used as the best alternative products of the linear power supply or the RCC-mode power to improve the whole performance of the switch power system and lower the cost. WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages. Applications Universal switch power supply and offline AC/DC flyback converter: ■ Battery Charger ■ Power Adaptor ■ Set-Top Box Power Supplies ■ Open-frame SMPS Typical Application Circuit Rev.A Apr.2011 Copyright@Winsemi Microelectronics Co., Ltd., All right reserved. WS2259 Pin Definition and Device Marking WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages，as shown below： 1 6 GND GATE 2 S O T 2 3 -6 FB 3 VDD 4 RI GATE 59: WS2259 Y: Year Code (1:2011; 2:2012……) WW: Week Code (1-52) 5 SENSE 1 8 2 7 VDD 3 GND D IP 8 SOP8 FB WS2259XP 6 NC NC 4 Dvf 5 SENSE YWW RI X: D = DIP8 ， S = SOP8 P: P = Pb-free package D: 芯片代码 V: 内部版本号 (可选 1-9) f: 工厂代码 Y: Year Code (1:2011; 2:2012……) WW: Week Code (1-52) Ordering Information Package 8-Pin DIP8, 8-Pin SOP8, Pb-free Pb-free 6-Pin SOT23-6, Pb-free IC Marking Information Purchasing Device Name WS2259DP WS2259DP WS2259SP WS2259SP 59XXX WS2259YP（SOT23-6） 2/11 Steady, keep you advance WS2259 Pin Function Description Pin Name Pin No. /SOT2 DIP8 DIP8/SOT2 /SOT233 Pin Type Function Description GATE 1/6 Output Totem-pole gate drive output for the power MOSFET VDD 2/5 Power Power Supply Floating Floating Current Current sense input. NC 3 SENSE 4/4 RI 5/3 NC 6 FB 7/2 GND 8/1 Monitoring Frequency Internal oscillator frequency setting pin. A resistor which is Setting connected between RI and GND sets the PWM frequency Floating Floating Feedback Feedback input pin. The PWM duty cycle is determined by voltage into Input this pin and the current-sense signal at Pin 4 Ground Ground Block Diagram OSC VDD clamp Soft driver Logic OCP Slope UVLO Internal Supply PWM OLP Soft Start LEB compensation Voltage Divider Burst Mode 3/11 Steady, keep you advance WS2259 Recommended Operating Condition Symbol Parameter Value Unit VDD VDD Supply Voltage 10~30 V RI RI Resistor 100 Kohm TA Operating temperature -20~85 ℃ Absolute Maximum Ratings ( Note 1) Symbol Parameter Value Unit VDD DC Power Supply 30 V VFB FB input voltage -0.3~7 V VSENSE SENSE input voltage -0.3~7 V VRI RI input voltage -0.3~7 V TJ Operation Junction Temperature -20~150 ℃ TSTG Storage Temperature -40~150 ℃ VCV Vcc Clamp Voltage 31 V ICC Vcc Clamp Continuous Current 10 mA Note 1: Stresses above those listed under 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 Recommended Operating Conditions section are not implied. Exposure to absolute maximum-rated conditions for extended periods may affect device reliability. ESD Information Symbol Parameter Value Unit VESD-HBM Human body model on all pins 3 KV VESD-MM Machine model on all pins 300 V 4/11 Steady, keep you advance WS2259 Electrical Characteristics (TA=25℃，VCC=16V, if not otherwise noted) Supply Voltage (VDD) Parameter Symbol Test condition Min Operation voltage VDD_OP Turn on threshold Voltage UVLO_ON 6.8 Turn-off threshold Voltage UVLO_OFF 13.5 Start up current I_VDD_ST Operation Current I_VDD_OP VDD=13V,RI=100K Typ Max Unit 30 V 7.5 8 V 14.5 15.5 V 4 10 uA 1.7 2.3 mA VDD=16V,RI=100K,VFB=3V GATE with 1nF to GND VDD_OVP VDD Zener Clamp Voltage 29 V 31 V VDD_Clamp IVDD=10mA VFB Open Loop Voltage VFB_Open VDD=16V,FB open, 5.4 5.9 6.4 V FB Pin Short Current IFB_Short FB Shorted to GND 0.3 0.45 0.6 mA Power limiting FB Threshold VTH_PL VDD=16V, RI=100K 3.2 3.65 4.0 V Power limiting Debounce TD_PL VDD=16V,FB open,RI=100KΩ 48 60 72 ms Input Impedance ZFB_IN VDD=16V,FB=2V/3V,CS open 11.5 14.5 18 kΩ Maximum duty cycle Max_Duty 72 77 82 % Feedback Input Section VDD=16V,FB open, CS=0,RI=100KΩ Current Sense Section Leading edge Blanking Time TLEB OCP control delay TD_OC GATE with 1nF to GND OCP threshold TTH_OC FB＝3.2V 330 ns 70 ns 0.68 0.78 0.78 60 65 70 V Oscillator Section Frequency Fosc VDD=16V,RI=100K,,FB=3.2V Jitter period For 65K Jitter range khz 4 ms ±5 % Burst mode frequency Fosc_BM VDD=9.5V,RI=100K, FB=1V 22 khz Frequency variation versus temp. Deviation ∆f_temp TEMP = -20 to 85℃ 5 % Frequency variation versus VDD ∆f_VDD VDD = 12 to 25V 5 % VRI VDD=16V,RI=100KΩ,CS=1V RI Section RI voltage 1.94 2 2.06 V Thermal protection Thermal shutdown temperature T_shutdown ℃ 150 GATE Output Section Output voltage Low VOL VDD = 16V, Io = -20mA 0.8 V Output voltage high VOH VDD = 16V, Io = 20mA 9 Output clamp voltage VClamp VDD = 20V 11 Rising time Tr VDD = 16V, GATE with 1nF to GND 250 ns Falling time Tf VDD = 16V, GATE with 1nF to GND 75 ns V 13 14.5 V 5/11 Steady, keep you advance WS2259 Typical Operating Characteristics 6/11 Steady, keep you advance WS2259 Function Description WS2259 is a highly integrated current mode PWM control At very light load or no load condition, the IC operates in IC which is optimized for high performance. It is applied Burst Mode. In this condition, the voltage at FB is below for switch power of the small-sized and medium-sized for burst mode threshold level, thus system goes into burst example the power adaptor. The low startup current, mode. The gate dive output switches only when VCC operation current and burst mode function at the condition voltage drops below a preset level or FB input is active to of no load and low load can decrease the standby power output an on state. Otherwise the gate drive remains at off of the system, and improve the power convert efficiency. state to minimize the switching loss thus reduce the The internal synchronous slope compensation, the standby power consumption. The standby current of leading edge blanking function of the Sense pin not only WS2259 is low as 800uA, Thus the standby of WS2259 decrease the component number, but also improve the can be low than 100mW. The frequency control also stability of the system and avoid the harmonics generation. eliminates the audio noise at any loading conditions. WS2259 also have multiform general recovery protection mode. The main function is described as below. Oscillator Operation A resistor connected between RI and GND sets the Startup Current and Startup Control charge/discharge time of the constant current source to Startup current of WS2259 is designed to be very low the internal cap and thus the PWM oscillator frequency is （4uA） so that VDD could be charged up above UVLO determined. The relationship between RI and switching threshold level and starts up quickly. A large value startup frequency follows the below equation: resistor can therefore be used to minimize the power loss, predigest the design of startup circuit and provides FOSC = reliable startup in application. For the design of AC/DC adaptor with universal input range, a startup resistor of 2 MΩ, 1/8 W could be used together with a VDD capacitor 6500 (Khz ) RI(Kohm ) If RI floating, the frequency will be internal set at 50 KHz to provide a fast startup and low power dissipation solution. Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in WS2259. The Operating Current switch current is detected by a sense resistor into the The operating current of WS2259 is very low .Good SENSE pin. The internal Leading-edge blanking chops off efficiency is achieved with low operating current together the sense voltage spike at initial MOSFET on state due to with extended burst mode control circuit which can easy snubber diode circuit reverse recovery and thus reduce the design of VDD capacitor. the external RC filter circuit. The current limit comparator is disabled and cannot turn off the external MOSFET during the blanking period. PWM duty cycle is determined by voltage level into SENSE pin and FB pin. Soft-start As soon as VDD reaches UVLO(on), the soft-start function operates, the peak current is then gradually increased from zero. Every restart attempt is followed by Internal Synchronized Slope Compensation 4ms soft-start. Built-in slope compensation circuit adds slope voltage onto the current sense input voltage for PWM generation. This greatly improves the close loop stability at CCM and prevents the sub-harmonic oscillation and thus reduces Burst Mode the output ripple voltage. Rev.A Apr.2011 7/11 Steady, keep you advance WS2259 Gate Driver Protection Controls GATE pin of WS2259 is connected to the gate of an Good power supply system reliability is achieved with external power switch. The gate drive strength which is auto-recovery too weak leads to over switch loss of MOSFET while too Cycle-by-Cycle strong gate drive output compromises in the over EMI. A Protection (OLP), Under Voltage Lockout on VDD (UVLO), good tradeoff between output strength and dead time Over Temperature Protection (OTP), and VDD Over control is achieved through the design of the built-in totem Voltage Protection & VDD clamp. pole gate in WS2259. The low standby dissipation and Internal line voltage compensation of OCP help to achieve good EMI system design is easier to achieve through this constant output power limit over the universal input dedicated devise. For MOSFET gate protection, an voltage range. protection current limiting features (OCP), including Over Load internal 13V clamp is added at higher than expected VCC input. 8/11 Steady, keep you advance WS2259 ge Dimension SOT23-6 Packa Package 9/11 Steady, keep you advance WS2259 ckage Dimension DIP-8 Pa Package 10/11 Steady, keep you advance WS2259 SOP-8 Package Dimension Unit: mm 11/11 Steady, keep you advance