UNISONIC TECHNOLOGIES CO., LTD UC1108 Preliminary CMOS IC LOW-POWER OFF-LINE PRIMARY SIDE REGULATION CONTROLLER DESCRIPTION The UTC UC1108 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 UC1108 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 UC1108 achieves excellent regulation and high average efficiency, yet meets the requirement for no-load consumption less than 30mW. The UTC UC1108 has the built-in programmable cable voltage drop compensation function, which make it flexible to accommodate various cables with different gauges and lengths The UTC UC1108 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. SOP-8 FEATURES * 30mW No-load Input Power * Primary side control for eliminating opto-coupler and secondary CV/CC control circuitry * Proprietary CC tightening technique to achieve vertical CC profile * Programmable output cable voltage drop compensation * Compensation for external component temperature variations * Random frequency adjustment to reduce system EMI * Flyback topology in DCM operation * Built-in soft start * Over voltage protection * Short circuit protection ORDERING INFORMATION Ordering Number UC1108G-S08-R UC1108G-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 8 QW-R103-098.a UC1108 Preliminary MARKING PIN CONFIGURATION PIN DESCRIPTION PIN NO. 1 2 3 4 5 6 7 8 PIN NAME CS VCC OUT GND CPC FB CPR BIAS CMOS IC DESCRIPTION The primary current sense Supply voltage This pin drives the base of external power NPN switch Ground This pin connects a capacitor for output cable compensation The voltage feedback from the auxiliary winding Connects a resistor to FB pin for adjustable output cable compensation This pin sets the bias current inside UC1108 with an external resistor to GND BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 8 QW-R103-098.a UC1108 Preliminary CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS UNIT Voltage at VCC Pin to GND -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 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 RATING 190 UNIT °C/W ELECTRICAL CHARACTERISTICS (VCC=15V, TA=25°C, unless otherwise specified.) PARAMETER UVLO SECTION Start-Up Threshold Minimal Operating Voltage Reference Voltage BIAS Pin Voltage STANDBY CURRENT SECTION Start-Up Current SYMBOL TEST CONDITIONS VTH (ST) VOPR(min) VBIAS IST RBIAS=200kΩ, After Turn On TYP MAX UNIT 17 8.2 18.5 9.2 21 10.2 V V 1.0 1.1 1.2 V 0.6 µA 390 480 µA 28 36 44 mA 490 390 513 413 500 535 435 mV mV ns 1.8 3.97 -2.0 2.4 4.03 -1.7 3.0 4.09 -1.4 µA V V 3.5 200 V µA 9 V VCC=VTH (ST)-0.5V, RBIAS=200kΩ,Before Start-Up RBIAS=200kΩ Operating Current ICC(OPR) DRIVE OUTPUT SECTION OUT Maximum Current Source IOUT RBIAS=200kΩ CURRENT SENSE SECTION Current Sense Threshold VCS Pre-Current Sense VCS(PRE) Leading Edge Blanking FEEDBACK INPUT SECTION Feedback Pin Input Leakage Current IFB VFB=4V Feedback Threshold VFB Enable Turn-on Voltage VFB(EN) OUTPUT VOLTAGE COMPENSATION SECTION CPR Voltage VCPR Dons (Tons/T): From 55% to 0.02% CPR Sink Current ICPR PROTECTION SECTION Over Voltage Protection VFB(OVP) UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN 1.5 7 8 3 of 8 QW-R103-098.a UC1108 Preliminary CMOS IC OPERATION DESCRIPTION The UTC UC1108 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 voltage regulator provides the internal power supply VDD. For VCC and VDD external capacitors are required. The current biasing of UTC UC1108 is adjustable by an external resistor. Internal time constants, thresholds and the output current depend from the value of this resistor. The startup circuit activates the IC after startup and deactivates the IC in case of UVLO. Operating Current The Operating current of UTC UC1108 is as low as 400uA. 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 UC1108 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 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. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 8 QW-R103-098.a UC1108 Preliminary CMOS IC OPERATION DESCRIPTION (Cont.) Constant Current Operation When the sampled voltage is below 4V reference voltage and the error amplifier output reaches its maximum, thus UTC UC1108 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. Figure3. Adjustable output power by changing Rcs Figure4. Secondary current waveform In CC operation, the CC loop control function of UTC UC1108 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 UC1108. 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 VCC. It provides the driving current for the external power bipolar transistor. The output signal is current-limited to IOUT(SOURCE). UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 8 QW-R103-098.a UC1108 Preliminary CMOS IC OPERATION DESCRIPTION (Cont.) Output Cable Compensation The UTC UC1108 senses the auxiliary winding feedback voltage at FB pin and operates in constant-voltage (CV) mode to regulate the output voltage. In CV mode, FB pin voltage VFB is a constant of 4.0V. The CPR pin voltage VCPR is generated by the internal circuit of UTC UC1108. It linearly decreases with the rise of the output load directly. Where Dons is the duty cycle of secondary diode, and is equal to Tdemag/Tsw, which is directly proportional to the output loading. The maximum Dtdemag is 4/7 and the minimal Dtdemag is close to zero in CV mode of UTC UC1108. 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 UC1108 is shutdown when VCC 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 8 QW-R103-098.a UC1108 Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT (5V/1A) BOM Reference BD1 L1 C1 C2 C3 C4 C5 C6 D1,D2 D3 R1 Component BD 1A/600V Inductor, com-choke EC 4.7u F 400V 105°C EC 4.7u F 400V 105°C CC 2.2u F 50V 105°C CC 0.47u F 50V 0805 CC 1n F 1000V 1206 EC 1000u F 10V 105°C Diode UTC 1N4007 Diode UTC SB340 R 2.4KΩ 1206 ±5% UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw Reference R2 R3 R4 R5 R6 R7 R8 R9 T1 F1 Q1 Component R 6.8MΩ 1206 ±5% R 6.8MΩ 1206 ±5% R 30KΩ 0805 ±1% R 9.1KΩ 0805 ±1% R 27KΩ 0805 ±5% R 200KΩ 0805 ±5% R 1.0Ω 1206 ±5% R 200KΩ 1206 ±5% EE-16 FUSE 1A 250VAC NPN Transistor UTC MJE13003 7 of 8 QW-R103-098.a UC1108 Preliminary CMOS IC 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 8 of 8 QW-R103-098.a