UNISONIC TECHNOLOGIES CO., LTD USRB01 Preliminary LINEAR INTEGRATED CIRCUIT HIGH PRECISION CC/CV PRIMARY SIDE SWITCH DESCRIPTION The UTC USRB01 is a primary controller for charger and adapter applications. The controlled variable is transferred by an auxiliary winding from the secondary to the primary side. The device uses Pulse Frequency Modulation (PFM) method to build discontinuous conduction mode (DCM) flyback power supplies. The UTC USRB01 operates in primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. It also eliminates the need of loop compensation circuitry while maintaining stability. The UTC USRB01 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, output over voltage protection, VDD over voltage protection, feedback loop open protection, short circuit protection, leading edge blanking, OTP, VDD under voltage lockout, etc. FEATURES * ±5% constant voltage regulation at universal AC input * Primary side control without TL431 and opto-coupler * High precision constant current regulation at universal AC input * Programmable CV and CC regulation * Eliminates control loop compensation circuitry * Flyback topology in DCM operation * Random frequency modulation to reduce system EMI * Built-in power NPN SOP-8 * Programmable cable drop compensation * Built-in leading edge blanking * Built-in primary winding inductance compensation * Open circuit protection * Output over voltage protection * VDD over voltage protection * Short circuit protection * Over temperature protection ORDERING INFORMATION Ordering Number USRB01G-S08-R Package SOP-8 Packing Tape Reel USRB01G-S08-R (1)Packing Type (1) R: Tape Reel (2)Package Type (2) S08: SOP-8 (3)Green Package (3) G: Halogen Free and Lead Free MARKING www.unisonic.com.tw Copyright © 2016 Unisonic Technologies Co., Ltd 1 of 7 QW-R103-080.c USRB01 Preliminary PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 2 3 4 5~6 7~8 PIN NAME VCC VC FB CS C GND ` LINEAR INTEGRATED CIRCUIT DESCRIPTION Power supply Low pass filter capacitor for cable compensation The voltage feedback from the auxiliary winding Current sense input The collector of the power NPN Ground BLOCK DIAGRAM VCC 1 I_ drive Regulator & Ref 5/6 Por Base drive Logic core FB 3 + - OVP + - CV controller Tdemag detector + - + - Drop comp www.unisonic.com.tw 4 CS LEB CC controller UNISONIC TECHNOLOGIES CO., LTD C 2 7/8 VC GND 2 of 7 QW-R103-080.c USRB01 Preliminary ` LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT VDD Voltage -0.3~30 V VC Voltage -0.3~7 V C Voltage -0.3~700 V CS Input Voltage -0.3~7 V FB Input Voltage -0.3~7 V Junction Temperature TJ -40~150 °C Storage Temperature TSTG -55~150 °C Lead Temperature (Soldering, 10 secs) TOPR 260 °C Note: 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. THERMAL DATA PARAMETER Junction to Ambient SYMBOL θJC RATINGS 150 UNIT °C/W ELECTRICAL CHARACTERISTICS (TA=25°C, VDD=15V, if not otherwise noted) PARAMETER Supply Voltage (VDD) Section Start up Current Static Current Turn-off Threshold Voltage Turn-on Threshold Voltage VDD Over Protect Voltage Operating Voltage Current Sense Input Section LEB Time Over Current Threshold OCP Propagation Delay FB Input Section Reference Voltage for Feedback Threshold Maximum Cable Compensation Current Power BJT Section Collector-emitter breakdown voltage Collect Peak Current Collector-Base Breakdown Voltage On Chip Over Temperature Section Over Temperature Protection SYMBOL IST IOP TEST CONDITIONS TLEB VCS MAX UNIT 6.0 11.5 25 1 300 6.8 12.5 27 3 400 7.6 13.5 29 25 μA μA V V V V 470 2.5 500 520 μS mV From OCP Comparator to Base Drive 200 nS VFB 1.98 2.00 2.02 V Icable 47 52 56 μA VCEO IC VCBO IC=10mA, IB=0 IC=10mA T_otp UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw TYP VDD=11V VDD=15V VTH(OFF) VTH (ON) VDD_OVP TD_OC MIN 450 0.6 V A V 150 °C 700 3 of 7 QW-R103-080.c USRB01 Preliminary ` LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION The UTC USRB01 is a primary control unit for 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. It uses Pulse Frequency Modulation (PFM) method to build discontinuous conduction mode (DCM) flyback power supplies. Startup control The VDD pin of UTC USRB01 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 USRB01 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 USRB01 is as low as 400μA. 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 USRB01 captures the auxiliary winding feedback voltage at FB pin and operates in constant-voltage (CV) mode to regulate the output voltage. The auxiliary voltage reflects the output voltage is given by: N VAUX = A ×（VO + ∆V） (1) NS 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 FB, the VAUX is sampled at the Tsampling end and it is hold until the next sampling. The sampled voltage is compared with 2V reference voltage and the error is amplified. The error amplifier output reflects the load condition and controls the Toff time to regulate the output voltage, thus constant output voltage can be achieved. Constant Current Operation When the sampled voltage is below 2V reference voltage and the error amplifier output reaches its maximum, thus UTC USRB01 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 4 of 7 QW-R103-080.c USRB01 Preliminary ` LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION (Cont.) Large Rcs Vout Small Rcs Iout Figure3. Adjustable output power by changing Rcs Figure4. Secondary current waveform In CC operation, the CC loop control function of UTC USRB01 will keep a fixed proportion between secondary inductance de-magnetization time (Tdemag) and switching cycle time (Tsw). The fixed proportion is Tdemag 1 (2) = TSW 2 Thus the output current is given by: Iout = Tdemag 1 NP 1 NP × × IPK × = × ×I 2 NS TSW 4 NS PK (3) Programmable Cable drop Compensation UTC USRB01 has a built-in cable voltage drop compensation to achieve good load regulation. An offset voltage is generated at FB pin by an internal current flowing into the resistor divider. The current is inversely proportional to the voltage of VC 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 FB 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 USRB01. 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 500ns 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 5 of 7 QW-R103-080.c USRB01 Preliminary ` LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION (Cont.) Drive BJT The driver is a push pull stage with the supply voltage VDD. It provides the driving current for the external power bipolar transistor. The output signal is current-limited to IOUT(SOURCE). Protection Control Good power supply system reliability is achieved with its comprehensive protection features including VDD over voltage protection, OTP, feedback loop open protection, Cycle-by-cycle current limiting, short circuit protection, leading edge blanking and UVLO, etc. VDD is supplied by transformer auxiliary winding output. The output of UTC USRB01 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 6 of 7 QW-R103-080.c USRB01 Preliminary ` LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT L Is Vo D1 N NS NP FB VCC Co NA C UTC USRB01 VC GND CS 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 7 of 7 QW-R103-080.c