UNISONIC TECHNOLOGIES CO., LTD UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT HIGH PRECISION CC/CV PRIMARY SIDE SWITCHING REGULATOR 6 DESCRIPTION 5 The UTC UPSRB02 is a primary control unit for switch mode 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) and Pulse Width Modulation (PWM) method to build discontinuous conduction mode (DCM) flyback power supplies. The UTC UPSRB02 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 UPSRB02 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. 1 2 3 SOT-26 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 * Driver BJT switch * Programmable cable drop compensation * Audio noise free operation 4 * Improved dynamic response * 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 UPSRB02G-AG6-R Package SOT-26 Packing Tape Reel UPSRB02G-AG6-R (1)Packing Type (1) R: Tape Reel (2)Package Type (2) AG6: SOT-26 (3)Green Package (3) G: Halogen Free and Lead Freee www.unisonic.com.tw Copyright © 2016 Unisonic Technologies Co., Ltd 1 of 7 QW-R103-079.b UPSRB02 Preliminary MARKING PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 2 3 4 5 6 PIN NAME VC CS BASE FB GND VDD LINEAR INTEGRATED CIRCUIT DESCRIPTION Low pass filter capacitor for cable compensation Current sense input. Base drive power BJT. The voltage feedback from auxiliary winding Ground Power supply BLOCK DIAGRAM Regulator &Ref VDD 6 I_drive Por Logic core 4V FB 4 2V Base drive 3 BASE OVP + - 5 GND + - CV controller + - 0.4V Tdemag detector LEB CC controller Drop comp Dynamic response 2 CS + 0.5V 1 VC UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 7 QW-R103-079.b UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT VDD Voltage VDD -0.3~30 V VC Voltage VC -0.3~7 V BASE Voltage VBASE -0.3~7 V CS Input Voltage VCS -0.3~7 V FB Input Voltage VFB -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. 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 Voltage Protection Operating Voltage Current Sense Input Section LEB Time Over Current Threshold SYMBOL MIN TYP MAX UNIT VTH(OFF) VTH (ON) VDD_OVP 6.0 11.5 25 1 400 6.8 12.5 27 3 500 7.6 13.5 29 25 μA μA V V V V TLEB VCS 400 0.5 450 500 μs mV IST IOP TEST CONDITIONS VDD=11V VDD=15V From OCP Comparator to Base Drive 100 nS OCP Propagation Delay TD_OC Maximum Source Current to CS Pin FB Input Section Reference Voltage for Feedback Threshold Minimum Pause Maximum Pause Maximum Cable Compensation Current BASE Drive Section Base Sourcing Maximum Current Base Sourcing Current After Pre-off Base Drive Low Side On Resistor ICS_MAX 41 45 49 μA VFB 1.98 2.00 2.02 V TPAUSE_MIN TPAUSE_MAX 780 2.0 800 820 μs μs ICABLE IOUT(SOURCE) IOUT(PRE) RDSON_L UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 27 20 0.5 30 1 1 μA 40 1.5 mA mA Ω 3 of 7 QW-R103-079.b UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION The UTC UPSRB02 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 UPSRB02 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 UPSRB02 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 UPSRB02 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 UPSRB02 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. Figure2. 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 UPSRB02 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-R103-079.b UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION (Cont.) Figure3. Adjustable output power by changing RCS Figure4. Secondary current waveform In CC operation, the CC loop control function of UTC UPSRB02 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 = × ×I × × IPK × TSW 4 NS PK 2 NS (3) Programmable Cable drop Compensation UTC UPSRB02 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. Improve dynamic response At light or no load, an internal current ICS is flowing into CS pin. The current ICS is inversely proportional to the voltage of VC pin, the maximum current ICS is limited to ICS_max. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 7 QW-R103-079.b UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT OPERATION DESCRIPTION (Cont.) At no load, the actual CS threshold is: VCS_no_Load=0.5-(ICS_MAX)×Rd (V) Current Sensing and Leading Edge Blanking Cycle-by-cycle current limiting is offered in UTC UPSRB02. 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. 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 output over-voltage protection, 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 UPSRB02 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-R103-079.b UPSRB02 Preliminary LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT 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-R103-079.b