ME8202SG-BB

ME8202 Current Mode PWM Controller With Frequency Shuffling ME8202 General Description Features ME8202 is a highly integrated current mode PWM ●Extended Burst Mode Control For Improved Efficiency and control IC optimized for high performance, low Minimum Standby Power Design standby power and cost effective offline flyback ●Audio Noise Free Operation converter applications. PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load ●External Programmable PWM Switching Frequency ●Internal Synchronized Slope Compensation condition, the IC operates in extended ‘burst mode’ ●Low VDD Startup Current (3μA) and Low Operating Current to minimize switching loss. Lower standby power and (1.8mA) higher conversion efficiency is thus achieved.VDD ★External programmable over temperature protection (OTP) low startup current and low operating current ★With or without On-chip VDD OVP for system OVP contribute to a reliable power on startup design with ★Under Voltage Lockout with Hysteresis (UVLO) ME8202. A large value resistor could thus be used in the startup circuit to minimize the standby power. The internal slope compensation improves system large signal stability and reduces the possible ★Gate Output Maximum Voltage Clamp (16V) ★ Line Input Compensated Cycle-by-Cycle Over-current Threshold Setting For Constant Output current Limiting Over subharmonic oscillation at high PWM duty cycle Universal Input Voltage Range(OCP). output. Leading-edge blanking on current sense ★Over load Protection (OLP) input removes the signal glitch due to snubber circuit ● Available in SOP8 and DIP8 package diode reverse recovery and thus greatly reduces the external component count and system cost in the design. ME8202 offers complete protection coverage Typical Application Offline AC/DC flyback converter for  Battery Charger  PC/TV/Set-Top Box Power Supplies protection (OLP), VDD over voltage clamp and under  Laptop Power Adaptor voltage lockout (UVLO). The Gate-drive output is  Open-frame SMPS clamped at 16V to protect the power MOSFET. In SelectionGuide with automatic self-recovery feature including Cycle-by-Cycle current limiting (OCP), over load ME8202,OCP threshold slope is internally optimized to reach constant output power limit over universal AC input range. Excellent EMI performance is achieved with frequency shuffling technique together with soft switching control at the totem pole gate drive output. Tone energy at below 20KHZ is minimized in the design and audio noise is eliminated during operation. V1.0 www.microne.com.cn Page 1 of 12 ME8202 Pin Configuration The ME8202 is offered in SOP8 and DIP8 packages shown as below. SOP8 DIP8 PIN Assignments Pin Num. Symbol Description 1 GND 2 FB Feedback input pin. The PWM duty cycle is determined by voltage level into this pin and current-sense signal level at PIN6. 3 VIN Connected through a large value resistor to rectified line input for startup IC supply and line voltage sensing. 4 RI Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets the PWM frequency. 5 RT Temperature sensing input pin. Connected through a NTC resistor to GND. 6 SENSE 7 VDD Chip DC power supply pin. 8 GATE Totem-pole gate drive output for the power MOSFET. Ground Current sense input pin. Connected to MOSFET current sensing resistor node. Absolute Maximum Ratings Parameter Range Unit VDD/VIN DC Supply Voltage 30 V VDD Zener Clamp VoltageNote VDD_Clamp+0.1V V 10 mA -0.3 to 7 V Min/Max Operating Junction Temperature TJ -20 to 125 °C Min/Max Storage Temperature Tstg -55 to 150 °C VDD DC Clamp Continuous Current VFB ,VSENSE ,VRI,VRT (Voltage at FB,SENSE,RI,RT to GND) RθJA thermal Resistance V1.0 SOP8 150 DIP8 90 °C/W www.microne.com.cn Page 2 of 12 ME8202 Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Note: VDD_Clamp has a nominal value of 35V. Recommended Operating Condition Parameter Range Unit VDD Supply Voltage 12 to 23 V RI Resistor Value 24 to 31 KΩ TA Operating Ambient Temperature -20 to 85 °C ESD Information Symbol parameter Test conditon Min. Typ. Max. Unit HBMNote Human body model on all pins except VIN and VDD MIL_STD - 2.5 - KV Block Diagram V1.0 www.microne.com.cn Page 3 of 12 ME8202 Electrical Characteristics(TA = 25°C,VDD=16V,RI=24KΩ, if not otherwise noted) Symbol Parameter Test Conditions Min Typ. Max Unit VDD=15V, Measure current into VDD - 3 10 μA VFB=3V - 1.8 - mA Supply Voltage (VDD) IVDD_Startup IVDD_Operation VDD Start up Current Operation Current UVLOON VDD Under Voltage Lockout Enter 9.5 10.5 11.5 V UVLOOFF VDD Under Voltage Lockout Exit (Recovery) 15.5 16.5 17.5 V VDD_Clamp VDD Zener Clamp Voltage - 35 - V IVDD = 5 mA OVPON VDD Over voltage protection enter 23.5 25 26.5 V OVPOFF VDD Over voltage protection exit(recovery) 21.5 23 24.5 V OVPHys OVP Hysteresis - 2 - V TD_OVP VDD OVP debounce time - 80 - μS - 2.8 - V/V - 5.8 - V - 0.8 - mA 0.95 V OVPON-OVPOFF Feedback Input Section(FB Pin) AVCS VFB_Open ΔVFB /ΔVCS PWM Input Gain VFB Open Loop Voltage Short FB pin to GND, measure current IFB_Short FB pin short circuit current VTH_0D Zero Duty Cycle FB Threshold Voltage - VTH_BM Burst mode FB threshold voltage - 1.7 - V VTH_PL Power Limiting FB Threshold Voltage - 4.4 - V TD_PL Power limiting Debounce Time - 80 - mS ZFB_IN Input Impedance - 7.2 - KΩ Leading edge blanking time - 250 - nS Input Impedance - 30 - KΩ CL=1nF at GATE - 120 - nS IVIN=0μA 0.80 0.9 0.95 V IVIN=150μA - 0.81 - V 60 65 70 KHz Current Sense Input(Sense Pin) T_blanking ZSENSE_IN TD_OC Over Current Detection and Control Delay VTH_OC_0 Current Limiting Threshold at No Compensation VTH_OC_1 Current Limiting Threshold at Compensation Oscillator FOSC Normal Oscillation Frequency ∆f_Temp Frequency Temperature Stability -20°C to 100 °C 2 % ∆f_VDD Frequency Voltage Stability VDD = 12-25V 2 % RI_range Operating RI Range V1.0 12 www.microne.com.cn 24 60 Page 4 of 12 KΩ ME8202 V_RI_open F_BM RI open load voltage - 2 - V Burst Mode Base Frequency - 22 - KHz DC_max Maximum duty cycle 75 80 85 % DC_min Minimum duty cycle - - 0 % Gate Drive Output VOL Output Low Level IO = -20 mA - - 0.3 V VOH Output High Level Io = 20 mA 11 - - V Output Clamp Voltage Level VDD=20V - 16 - V T_r Output Rising Time CL = 1nF - 120 - nS T_f Output Falling Time CL = 1nF - 50 - nS - 70 - μA 1.015 1.065 1.115 V OTP Recovery threshold voltage - 1.165 - V TD_OTP OTP De-bounce time - 100 - μS V_RT_Open RT Pin open voltage - 3.5 - V 3 % VG_Clamp Over Temperature Protection I_RT VTH_OTP VTH_OTP_off Output current of RT pin OTP Threshold Frequency Shuffling ∆f_OSC f_shuffling Frequency Modulation range /Base frequency RI=100KΩ -3 -- Shuffling Frequency RI=24KΩ - 32 Hz Operation Description The ME8202 is a highly integrated PWM controller capacitor to provide a fast startup and low power IC optimized for offline flyback converter applications . dissipation solution. The extended burst mode control greatly reduces the ●Operating Current standby power consumption and helps the design The Operating current of ME8202 is low at easily meet the international power conservation 1.8mA. Good efficiency is achieved with ME8202 low requirements. operating current together with extended burst mode ●Startup Current and Start up Control control features. Startup current of ME8202 is designed to be very low so that VDD could be charged up above UVLO ●Frequency shuffling for EMI improvement The frequency Shuffling/jittering (switching (exit) threshold level and device starts up quickly. A frequency modulation) is implemented in ME8202. large value startup resistor can therefore be used to The oscillation frequency is modulated with a random minimize the power loss yet provides reliable startup in source so that the tone energy is spread out. The application. spread spectrum minimizes the conduction band EMI For a typical AC/DC adaptor with universal input range design, a 2 MΩ, 1/8 W startup and therefore reduces system design challenge. resistor could be used together with a VDD V1.0 www.microne.com.cn Page 5 of 12 ME8202 ●Extended Burst Mode Operation ●Current Sensing and Leading Edge Blanking At zero load or light load condition, majority of the Cycle-by-Cycle current limiting is offered in power dissipation in a switching mode power supply is ME8202 current mode PWM control. The switch from switching loss on the MOSFET transistor, the core current is detected by a sense resistor into the sense loss of the transformer and the loss on the snubber pin. An internal leading edge blanking circuit chops circuit. The magnitude of power loss is in proportion to off the sense voltage spike at initial MOSFET on the number of switching events within a fixed period of time. Reducing switching events leads to the reduction on the power loss and thus conserves the energy. state due to Snubber diode reverse recovery so that the external RC filtering on sense input is no longer required. The current limit comparator is disabled and thus cannot turn off the external MOSFET during ME8202 self adjusts the switching mode according to the loading condition. At from no load to light/medium load condition, the FB input drops below burst mode threshold level (1.8V). Device enters Burst Mode the blanking period. PWM duty cycle is determined by the current sense input voltage and the FB input voltage. ●Internal Synchronized Slope Compensation control. The Gate drive output switches only when Built-in slope compensation circuit adds voltage VDD voltage drops below a preset level and FB input is ramp onto the current sense input voltage for PWM active to output an on state. Otherwise the gate drive generation. This greatly improves the close loop remains at off state to minimize the switching loss thus stability at CCM and prevents the sub-harmonic reduce the standby power consumption to the greatest oscillation and thus reduces the output ripple voltage. extend. The nature of high frequency switching also ●Gate Drive reduces the audio noise at any loading conditions. ME8202 Gate is connected to an external MOSFET gate for power switch control. Too weak the ●Oscillator Operation A resistor connected between RI and GND sets the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive constant current source to charge/discharge the internal cap and thus the PWM oscillator frequency is determined. The relationship between RI and switching output compromises the EMI. A good trade-off is achieved through the built-in totem pole gate design with right output strength and dead time control. The frequency follows the below equation within the low idle loss and good EMI system design is easier to specified RI in KΩ range at nominal loading operational achieve with this dedicated control scheme. An condition. internal 16V clamp is added for MOSFET gate protection at higher than expected VDD input. V1.0 www.microne.com.cn Page 6 of 12 ME8202 ●Over Temperature Protection helps to compensate the increased output power A NTC resistor in series with a regular resistor should connect between RT and GND for temperature sensing and protection.NTC resistor value becomes lower when the ambient temperature rises. With the fixed internal current IRT flowing through the resistors, the voltage at RT pin becomes lower at high temperature. The internal OTP circuit is triggered and shutdown the MOSFET when the limit at higher AC voltage caused by inherent Over-Current sensing and control delay. A constant output power limit is achieved with recommended OCP compensation scheme on ME8202. At overload condition, FB voltage is biased higher. When FB input exceeds power limit threshold value for more than TD_PL, control circuit reacts to shut sensed input voltage is lower than VTH_OTP. down the output power MOSFET. Similarly, control ●Protection Controls circuit shutdowns the power MOSFET when an over Good power supply system reliability is achieved with its rich protection features including Cycle-by-Cycle current limiting (OCP), Over Load Protection (OLP), over temperature protection(OTP), on-chip VDD over voltage protection (OVP, optional), and Under Voltage Lockout (UVLO). temperature condition is detected. ME8202 resumes the operation when temperature drops below the hysteresis value. VDD is supplied by transformer auxiliary winding output. It is clamped when VDD is higher than threshold value. The power MOSFET is shut down when VDD drops below UVLO limit and The OCP threshold value is self adjusted lower at device enters power on start-up sequence thereafter. higher current into VIN pin. This OCP threshold slope adjustment Typical Performance Characteristics V1.0 www.microne.com.cn Page 7 of 12 ME8202 V1.0 www.microne.com.cn Page 8 of 12 ME8202 TYPICAL APPLICATION V1.0 www.microne.com.cn Page 9 of 12 ME8202 Packaging Information Package type:DIP8 Unit:mm(inch) Dimension (mm) Dimension (Inches) Character Min Max Min Max A 6.200 6.600 0.244 0.260 B 9.000 9.400 0.354 0.370 C 7.620(Typ.) D 3.200 3.600 0.126 0.142 E 3.000 3.600 0.118 0.142 a 0.360 0.560 0.014 0.022 b 1.524(Typ.) 0.060(Typ.) c 2.54(Typ.) 0.100(Typ.) c1 0.204 e  V1.0 0.300(Typ.) 0.360 0.008 0.510(Min) 00 0.014 0.020(Min) 150 www.microne.com.cn 00 150 Page 10 of 12 ME8202 Package type:SOP8 Unit:mm(inch) Dimension (mm) Dimension (Inches) Character Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.1 0.3 0.004 0.012 B V1.0 1.27(Typ.) 0.05(Typ.) b 0.330 0.510 0.013 0.020 D 5.8 6.2 0.228 0.244 E 3.800 4.000 0.150 0.157 F 4.7 5.1 0.185 0.201 L 0.675 0.725 0.027 0.029 G 0.32(Typ.) 0.013(Typ.) R 0.15(Typ.) 0.006(Typ.) 1 7  8 ° ° www.microne.com.cn 7 8 ° ° Page 11 of 12 ME8202      V1.0 The information described herein is subject to change without notice. Nanjing Micro One Electronics Inc is not responsible for any problems caused by circuits or diagrams described herein whose related industrial properties, patents, or other rights belong to third parties. The application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass-production design. Use of the information described herein for other purposes and/or reproduction or copying without the express permission of Nanjing Micro One Electronics Inc is strictly prohibited. The products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of Nanjing Micro One Electronics Inc. Although Nanjing Micro One Electronics Inc exerts the greatest possible effort to ensure high quality and reliability, the failure or malfunction of semiconductor products may occur. The user of these products should therefore give thorough consideration to safety design, including redundancy, fire-prevention measures, and malfunction prevention, to prevent any accidents, fires, or community damage that may ensue. www.microne.com.cn Page 12 of 12