UNISONIC TECHNOLOGIES CO., LTD UC1100 Preliminary CMOS IC LOW-POWER HIGH PRECISION CC/CV PRIMARY SIDE SWITCHING REGULATOR 6 DESCRIPTION The UTC UC1100 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) method to build discontinuous conduction mode (DCM) flyback power supplies. The UTC UC1100 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 UC1100 achieves excellent regulation and high average efficiency, yet meets the requirement for no-load consumption less than 30mW. The UTC UC1100 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, feedback loop open protection, short circuit protection, leading edge blanking, VCC under voltage lockout, etc. 4 1 2 3 SOT-26 FEATURES * Primary side control for rectangular constant current and constant voltage output * 30mW no-load input power feasible * Tight CC regulation performance * Sub-microampere start-up current * Eliminates control loop compensation circuitry * Eliminates opto-coupler and secondary CV/CC control circuitry 5 * Random frequency modulation to reduce system EMI * Flyback topology in DCM operation * Open feedback protection * Built-in soft start * Short circuit protection ORDERING INFORMATION Ordering Number UC1100G-AG6-R www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd Package SOT-26 Packing Tape Reel 1 of 6 QW-R129-007.a UC1100 Preliminary MARKING INFORMATION PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 2, 5 3 4 6 CMOS IC PIN NAME OUT GND VCC CS FB DESCRIPTION This pin drives the base of external power NPN switch Ground Supply voltage The primary current sense The voltage feedback from the auxiliary winding BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 6 QW-R129-007.a UC1100 Preliminary CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Supply Voltage VCC -0.3~36 V Voltage at CS, OUT to GND -0.3~7 V FB Input -40~10 V Output Current at OUT Internally limited A ESD (Machine Model) 200 V 1000 ESD (Human Body Model) V Operating Junction Temperature TOPR 150 °C Storage Temperature TSTG -65~150 °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 RESISTANCES CHARACTERISTICS PARAMETER Junction to Ambient SYMBOL θJA RATINGS 250 UNIT °C/W ELECTRICAL CHARACTERISTICS (VCC=15V, TA=25°C, unless otherwise specified.) PARAMETER UVLO SECTION Start-Up Threshold Minimal Operating Voltage STANDBY CURRENT SECTION Start-Up Current Operating Current DRIVE OUTPUT SECTION Sink OUT Maximum Current Source CURRENT SENSE SECTION Current Sense Threshold SYMBOL MIN TYP MAX UNIT 16 7.2 18.5 9 21 10.2 V V 350 3 400 µA µA 50 40 60 80 mA mA VCS ∆ V Equivalent Current Sense Voltage CS , eq Note 1 VCS , eq Accuracy 455 510 545 mV 3 % Pre-Current Sense Leading Edge Blanking FEEDBACK INPUT SECTION Feedback Pin Input Leakage Current Feedback Threshold 365 410 500 455 mV ns 2.0 3.59 2.5 3.83 3.1 4.07 µA V VTH (ST) VOPR(min) IST VCC=VTH (ST)-0.5V, Before Start-Up ICC(OPR) Static IOUT VCS(PRE) Note: The output current is given by IOUT IFB VFB=4V VFB V , eq NP = CS × RCS NS UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw TEST CONDITIONS 3 of 6 QW-R129-007.a UC1100 Preliminary CMOS IC OPERATION DESCRIPTION The UTC UC1100 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 VCC pin of UTC UC1100 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 UC1100 is very low. When the VCC voltage reaches VTH (ST), the internal startup circuit is disabled and the IC turns on. Operating Current The Operating current of UTC UC1100 is as low as 320uA. 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 UC1100 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. Figure1. 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 4V 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 4V reference voltage and the error amplifier output reaches its maximum, thus UTC UC1100 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 6 QW-R129-007.a UC1100 Preliminary CMOS IC OPERATION DESCRIPTION (Cost.) Figure2. Adjustable output power by changing Rcs Figure3. Secondary current waveform In CC operation, the CC loop control function of UTC UC1100 will keep a fixed proportion between secondary inductance de-magnetization time (Tdemag) and switching cycle time (Tsw). The fixed proportion is Tdemag 4 = Tsw 7 (2) Thus the output current is given by: Iout = 1 NP Tdemag 2 NP × × Ipk × = × × Ipk 2 NS Tsw 7 NS (3) Current Sensing and Leading Edge Blanking Cycle-by-cycle current limiting is offered in UTC UC1100. 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 750ns 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 VCC. 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, feedback loop open protection, Cycle-by-cycle current limiting, short circuit protection, leading edge blanking and UVLO, etc. VCC is supplied by transformer auxiliary winding output. The output of UTC UC1100 is shutdown when VCC drops below VOPR(MIN) and the power converter enters power on start-up sequence thereafter. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 6 QW-R129-007.a UC1100 Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT F1 L 2 L1 BD1 4 1 2 1 C1 + N R13 C4 R4 C2 + 1 T1 C5 A 21V/0.3A D3 3 C6 + R1 R14 R5 4 GND B R2 D1 R3 D2 5 R6 3 3 CY1 VCC U1 C3 + Q1 R12 4 6 2 CS 5 2 OUT 1 GND GND FB C7 R11 R10 R8 BOM Reference F1 BD1 C1, C2 C3 C4 C5 C6 C7 L1 T1 D1 D2 D3 Q1 Component 0.5A/250V B6S EC 4.7μF/400V 105°C EC 4.7μF/50V 105°C CC 102P/1KV NC EC 220μF/35V 105°C NC 1.2mH EE-16 1N4007, SMA BAV21, SOD-123 MGBR3200, DO-201AD MJE13003, TO-126 Reference U1 R1, R2 R3 R4 R5 R6 R8 R10 R11 R12 R13 R14 CY1 Component UC1100, SOT-26 1MΩ 1206 1.5MΩ 1206 200kΩ 1206 22Ω 0805 3.9Ω 0805 940mΩ 1206 20kΩ 0805 4.3kΩ 0805 1kΩ 0805 NC 24kΩ 1206 Y1 102P/400V 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 6 of 6 QW-R129-007.a