UNISONIC TECHNOLOGIES CO., LTD USRB02 Preliminary LINEAR INTEGRATED CIRCUIT HIGH PRECISION CC/CV PRIMARY SIDE SWITCH DESCRIPTION The UTC USRB02 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 operates in Pulse Frequency Modulation (PFM) in CC mode as well at large load condition and it operates in Pulse Width Modulation (PWM) with frequency reduction at light/medium load condition. The UTC USRB02 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 USRB02 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 * Multi-mode operation for efficiency improving SOP-8 * Programmable cable drop compensation * Built-in leading edge blanking * Built-in primary winding inductance compensation * Built-in line voltage compensation * Audio noise free operation * Open circuit protection * Output over voltage protection * VDD over voltage protection * Short circuit protection * Over temperature protection ORDERING INFORMATION Ordering Number USRB02G-S08-R USRB02G-S08-R Package SOP-8 (1)Packing Type (1) R: Tape Reel (2)Package Type (2) S08: SOP-8 (3)Green Package (3) G: Halogen Free and Lead Free www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd Packing Tape Reel 1 of 7 QW-R103-087.a USRB02 Preliminary MARKING PIN CONFIGURATION LINEAR INTEGRATED CIRCUIT VDD 1 8 GND FB 2 7 GND NC 3 6 C CS 4 5 C PIN DESCRIPTION PIN NO. 1 2 3 4 5~6 7~8 ` PIN NAME VDD FB NC CS C GND DESCRIPTION Power supply The voltage feedback from the auxiliary winding NC Current sense input The collector of the power NPN Ground BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 7 QW-R103-087.a USRB02 Preliminary ` LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT VDD Voltage -0.3~30 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 Minimum Over Current Threshold Maximum Over Current Threshold Minimum CS threshold Maximum Ton OCP Propagation Delay SYMBOL IST IOP TEST CONDITIONS TLEB Vth_ocp_min Vth_ocp_max Vcs_mini Ton_max FB Input Section Reference Voltage for Feedback VFB Threshold Minimum Toff Tpause_min Minimum frequency F_min Maximum Cable Compensation Icable Current Output over voltage threshold V_ovp Power BJT Section Collector-emitter breakdown voltage VCEO Collect Peak Current IC Collector-Base Breakdown Voltage VCBO On Chip Over Temperature Section Over Temperature Protection T_otp Over Temperature Protection T_otp_rec recovery point MAX UNIT 6.5 18.4 26.5 5 0.72 7.1 19.4 28 15 1.0 7.8 20.4 29.5 26 485 From OCP Comparator to Base Drive 0.5 500 555 100 50 515 100 2.475 2.5 720 2.0 800 2.85 IC=10mA, IB=0 450 IC=10mA 700 3.00 μA mA V V V V μS mV mV mV uS nS 2.525 V 880 uS Hz 48 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw TYP VDD= VTH (ON)-1V VTH(OFF) VTH (ON) VDD_OVP TD_OC MIN μA 3.15 V 0.6 V A V 165 °C 130 °C 3 of 7 QW-R103-087.a USRB02 Preliminary ` LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION The UTC USRB02 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) and Pulse Width Modulation (PWM) method to build discontinuous conduction mode (DCM) flyback power supplies. Startup control The VDD pin of UTC USRB02 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 USRB02 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 USRB02 is as low as 720μA. 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 USRB02 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 2.5V 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 2.5V reference voltage and the error amplifier output reaches its maximum, thus UTC USRB02 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-R103-087.a USRB02 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 USRB02 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 USRB02 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. 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 USRB02. 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-R103-087.a USRB02 Preliminary ` LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION (Cont.) Protection Control Good power supply system reliability is achieved with its comprehensive protection features including VDD over voltage protection, Output 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 USRB02 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-R103-087.a USRB02 Preliminary ` LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT (5V/1A) BOM Reference BD1 L1 C1 C2 C3 C4 C6 D1,D3 D2 Component BD 1A/600V CHOKE EC 4.7u F 400V 105°C EC 4.7u F 400V 105°C EC 4.7u F 50V 105°C CC 1n F 1000V 1206 EC 680u F 25V 105°C Diode UTC 1N4007 Diode UTC SB340 Reference R3 R1,R2 R10 R7 R8 R11 T1 F1 Component R 2.4kΩ 1206 ±5% R 2M2Ω 1206 ±5% R 200kΩ 1206 ±5% R 18kΩ 0805 ±1% R 4.3kΩ 0805 ±1% R 1.2Ω 1206 ±5% EE-16 FUSE 1A 250VAC 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-R103-087.a