UNISONIC TECHNOLOGIES CO., LTD USR3651S Preliminary CMOS IC HIGH PRECISION CC/CV PRIMARY-SIDE PWM POWER SWITCH DESCRIPTION The UTC USR3651S is a primary control switch mode charger and adapter applications. The controlled variable is transferred by an auxiliary winding from the secondary to the primary side. The device integrates PWM controller to enhance the performance of discontinuous conduction mode (DCM) flyback converters. The UTC USR3651S operates in primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. It also provides off-time modulation to linearly decrease PWM frequency under light-load conditions so that low standby power can be achieved. The UTC USR3651S achieves high precision CV/CC regulation and high power efficiency. It offers comprehensive protection coverage with auto-recovery features including Cycle-by-cycle current limiting, VDD over voltage protection, VDD clamp, OTP, leading edge blanking, VDD under voltage lockout, etc. FEATURES * High Voltage startup circuit * Built-in 600V Power MOSFET * ±5% constant voltage regulation at universal AC input * High precision constant current regulation at universal AC input * Primary side control without TL431 and opto-coupler * Programmable CV and CC regulation * Programmable cable compensation in CV mode * Flyback topology in DCM operation * Frequency hopping to reduce system EMI SOP-8 * Built-in leading edge blanking * Built-in primary winding inductance compensation * Power on soft start * Gate Output Maximum Voltage Clamped at 15V * Cycle-by-cycle current limiting * Over voltage protection * VDD under-voltage lockout ORDERING INFORMATION Ordering Number USR3651SG-S08-R www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd Package SOP-8 Packing Tape Reel 1 of 9 QW-R103-085.b USR3651S Preliminary MARKING PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1/2 3 4 5 6 7 8 PIN NAME DRAIN VDD COMP INV NC GND CS CMOS IC DESCRIPTION Power MOSFET Drain Pin Power Supply Loop Compensation The voltage feedback from the auxiliary winding NC Ground Current sense input UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC BLOCK DIAGRAM VDD 3 1/2 DRAIN Startup Por Regulator & VREF Logic core Power MOSFET OVP Softstart 28V Tdemag detector CC controller INV 5 LEB CV controller 2V 8 CS 0.9V Cable compensation 4 7 COMP GND UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw Drive 3 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Drain Voltage (Off State) BVDSS -0.3~Bvdss V VDD Zener Clamp Continuous Current IDD 10 mA COMP Voltage VCOMP -0.3~7 V CS Input Voltage VCS -0.3~7 V INV Input Voltage VINV -0.3~7 V Operating Junction Temperature TJ -20~150 °C Storage Temperature TSTG -55~150 °C Notes: 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. 2. Drain Pin Connected 100mm2 PCB copper clad. THERMAL RESISTANCES CHARACTERISTICS PARAMETER Junction to Ambient SYMBOL θJA RATINGS 90 UNIT °C/W OUTPUT POWER TABLE PARAMETER RATINGS UNIT 230VAC±15% 6 W Adapter (Note) 85-264VAC 5 W Note: Maximum practical continuous power in an Adapter design with sufficient drain pattern as a heat sink, at 50°C ambient. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC ELECTRICAL CHARACTERISTICS (TA=25°C, VDD=15V, unless otherwise specified) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT STARTUP SECTION Startup Voltage Vst VDD<VTH(ON) 25 V Startup Current Ist VDD<VTH(ON) 700 uA SUPPLY SECTION Turn-on Threshold Voltage VTH(ON) 13.5 14.5 16 V Turn-off Threshold Voltage VTH(OFF) 8.2 9 10.5 V VDD OVP Protection VDD_OVP 28 V Operating Current IDD-OP 1.6 2 mA Green-Mode Operating Current IDD-GREEN 1.3 mA OSCILLATOR SECTION Maximum Frequency fOSC 55 65 75 kHz Minimum Frequency at CCM fOSC-CM-MIN 17 kHz Minimum Frequency at No-load fOSC-N-MIN 300 Hz Frequency Hopping Range △f/freq ±5.0 % Frequency Hopping Period tFHR 3 ms INV SECTION Reference Voltage for EA VVR 1.97 2.00 2.03 V Reference Voltage for CCM VVR_CCM 0.5 V Max. Cable Compensation Current ICABLE_MAX 37 uA CURRENT SENSE SECTION Current Sense Threshold Voltage VCS 870 900 930 mV OCP Propagation Delay tD_OC 90 200 nS Leading Edge Blank Time tLEB 900 nS Soft Start Time tSS 10 mS POWER MOSFET SECTION MOSFET DS Breakdown Voltage BVDSS 600 V On Resistance RDS(ON) 11 15 Ω OTP SECTION Threshold Temperature of OTP (Note) TOTP +140 °C Note: When the over-temperature protection is activated, the power system enters auto restart mode and output is disabled. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC OPERATION DESCRIPTION The UTC USR3651S is a primary control switch mode charger and adapter applications. It operates in primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. Proprietary built-in CV and CC control can achieve high precision CV/CC performance. The device integrates PWM controller to enhance the performance of discontinuous conduction mode (DCM) flyback converters. Startup control The VDD pin of UTC USR3651S is connected to the line input through a resistor. A large value startup resistor can be used to minimize the power loss in application because the start current of UTC USR3651S is very low. When the VDD voltage reaches VTH(ON), the internal startup circuit is disabled and the IC turns on. Operating Current The Operating current of UTC USR3651S is as low as 1.6mA. Good efficiency and very low standby power can be achieved. Constant Voltage Operation The output voltage is defined by the transmission ratio between the secondary and auxiliary winding. The UTC USR3651S captures the auxiliary winding feedback voltage at INV pin and operates in constant-voltage (CV) mode to regulate the output voltage. The auxiliary voltage reflects the output voltage is given by: VAUX = NA ×（VO + ∆V） NS (1) Where △V indicates the drop voltage of the output diode. Figure 2. Auxiliary voltage waveform Via a resistor divider connected between the auxiliary winding and INV, the VAUX is sampled at the Tsampling end and it is hold until the next sampling. The sampled voltage is compared with 2.0V reference voltage and the error is amplified. The error amplifier output reflects the load condition and controls the TOFF time and the Ipk to regulate the output voltage, thus constant output voltage can be achieved. Constant Current Operation When the sampled voltage is below 2.0V reference voltage and the error amplifier output reaches its maximum, thus UTC USR3651S operates in constant-current (CC) mode. The CC point and maximum output power can be externally adjusted by external current sense resistor Rcs. The larger Rcs, the smaller CC point is, and the smaller output power becomes. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 6 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC OPERATION DESCRIPTION(Cont.) Large Rcs VOUT Small Rcs IOUT Figure 3. Adjustable output power by changing RCS Figure 4. Secondary current waveform In CC operation, the CC loop control function of UTC USR3651S will keep a fixed proportion between secondary inductance de-magnetization time (Tdemag) and switching cycle time (Tsw). The fixed proportion is Tdemag 1 = Tsw 2 (2) Thus the output current is given by: IOUT 1 2 NP NS IPK Tdemag Tsw 1 4 NP NS IPK (3) Programmable Cable Drop Compensation UTC USR3651S has a built-in cable voltage drop compensation to achieve good load regulation. An offset voltage is generated at INV pin by an internal current flowing into the resistor divider. The current is inversely proportional to the voltage of COMP pin. As a result, it is inversely proportional to the output load current. The voltage drop across the cable is compensated by this offset voltage at INV pin. It can also be programmed by adjusting the resistance of the divider to compensate the drop for various cable lines used. Current Sensing and Leading Edge Blanking Cycle-by-cycle current limiting is offered in UTC USR3651S. The switch current is detected by a sense resistor into the CS pin. When the power switch is turned on, a turn-on spike will occur on this resistor. A 900ns leading-edge blanking is built in to avoid false-termination of the switching pulse so that the external RC filtering is no longer needed. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 7 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC OPERATION DESCRIPTION(Cont.) Protection Control Good power supply system reliability is achieved with its comprehensive protection features including VDD over-voltage protection, VDD Clamp, GATE Clamp, Power on soft start, Cycle-by-cycle current limiting, short circuit protection, leading edge blanking, OTP and UVLO, etc. VDD is supplied by transformer auxiliary winding output. The output of UTC USR3651S is shutdown when VDD drops below VTH(OFF) and the power converter enters power on start-up sequence thereafter. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 8 of 9 QW-R103-085.b USR3651S Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT L Is Vo D1 N NP INV VDD DRAIN NS Co Io NA UTC USR3651S COMP CS GND RCS UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 9 of 9 QW-R103-085.b