UNISONIC TECHNOLOGIES CO., LTD US1651 Preliminary CMOS IC PRIMARY-SIDE REGULATION PWM POWER SWITCH DESCRIPTION The UTC US1651 is a primary control switch mode charger and adapter applications. The controlled variable is transferred by an auxiliary winding from the secondary to the primary side. The device integrates PWM controller to enhance the performance of discontinuous conduction mode (DCM) flyback converters. The UTC US1651 operates in primary-side sensing and regulation. Opto-coupler and TL431 could be eliminated. It operates in fixed frequency mode at large load conditions, frequency reduction mode at light/medium load and ‘Extended burst mode’ at No/light load conditions. So that low standby power can be achieved. The UTC US1651 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, VDD over voltage protection, VDD clamp, OTP, leading edge blanking, VDD under voltage lockout, etc. FEATURES * Programmable CV and CC regulation * Primary-side sensing and regulation with No TL431 and opto-coupler * Multi-mode operation for high efficiency * Adjustable constant current and output power setting * Power on soft-start time (4ms) * Frequency shuffling and adjustable gate drive greatly improving EMI SOP-8 * ”Extended burst mode control” for improved efficiency and minimum standby design * Built-in leading edge blanking (LEB) * VDD under voltage lockout * VDD over voltage shutdown and clamp * Cycle-by-Cycle current limiting * Fail-safe protection for open loop fault condition * Auto-restart in over voltage condition ORDERING INFORMATION Ordering Number Package Packing US1651G-S08-R SOP-8 Tape Reel www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd 1 of 7 QW-R129-005.a US1651 Preliminary MARKING PIN CONFIGURATION VDDG 1 8 GND VDD 2 7 GND INV 3 6 Drain CS 4 5 Drain PIN DESCRIPTION PIN NO. 1 2 PIN NAME VDDG VDD 3 INV 4 5, 6 7, 8 CS Drain GND CMOS IC DESCRIPTION Internal gate driver power supply IC DC power supply input Inverting input of error amplifier (EA). Connected to resistor divider from primary sensing winding reflecting output voltage. PWM duty cycle is determined by EA output and current sense signal at pin 4. Current sense input HV MOSFET Drain Pin. The Drain pin is connected to the primary lead of the transformer Ground BLOCK DIAGRAM VDD 2 VDDG 1 5/6 Drain Regulator & Por Vref Logic core Drive Power MOSFET OVP Softstart 30V CC/CV controller INV 3 LEB PWM 1.25V 4 CS 0.82V 7/8 GND UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 7 QW-R129-005.a US1651 Preliminary CMOS IC ABSOLUTE MAXIMUM RATING (TA=25°C, unless otherwise specified) PARAMETER SYMBOL RATINGS UNIT Drain Voltage (Off State) BVDSS -0.3~650 V VDD Voltage VDD -0.3~33 V VDDG Voltage VDDG -0.3~33 V VDD Zener Clamp Continuous Current IDD_clamp 10 mA CS Input Voltage VCS -0.3~7 V INV Input Voltage Vinv -0.3~7 V Operating Junction Temperature TJ -20~150 °C Storage Temperature TSTG -55~150 °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. ELECTRICAL CHARACTERISTICS (TA=25°C, VDD=VDDG=16V, unless otherwise specified) PARAMETER Supply Voltage (VDD) Section Standby Current Operation Current SYMBOL IDD ST IDD op VDD Under Voltage Lockout Enter VDD Under Voltage Lockout Exit UVLO(ON) UVLO(OFF) Over Voltage Protection Voltage OVP(ON) IDD=10mA Current Sense Input Section LEB Time VTH_OC_test Propagation Delay Input Impedance Soft Start Time CV Section Normal Mode Frequency Burst Mode Base Frequency Frequency Shuffling Range CC Section Oscillation Frequency Error Amplifier section Reference Voltage for EA DC Gain of the EA Unity Gain Bandwidth Power MOSFET Section Mos Drain-Source Breakdown Voltage Static Drain to Source On Resistance OTP SECTION Threshold Temperature of OTP (Note) TEST CONDITIONS TYP MAX UNIT 5 10 μA 1.0 2.0 mA 7.5 14.0 8.5 15 9.5 16.0 V V 28.5 30.0 31.5 V VDD=13V Operation Supply Current INV=1.25V, CS=0V, VDD=VDDG=20V CS=0V,INV=1V Ramp up VDD Until Gate Clock is Off VDD_clamp 33 TLEB Vth_oc Td_oc 780 ZSENSE_IN T_ss Freq Freq_Burst △f/Freq Freq 45 Minimum frequency Maximum frequency VREF_EA Gdc GBW 1.2 820 300 50 4 50 22 ±4 V 860 55 12 50 1.21 1.25 50 37.5 μs mV ns KΩ ms KHz KHz % KHz KHz 1.29 V dB kHz BVDSS 650 V RDS(ON) 12 Ω TOTP +150 °C UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN 3 of 7 QW-R129-005.a US1651 Preliminary CMOS IC OPERATION DESCRIPTION The UTC US1651 is a primary control 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 achievegood CV/CC performance. The device integrates PWM controller to enhance the performance of discontinuous conduction mode (DCM) flyback converters. Startup Current and Start up Control The VDD pin of UTC US1651 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 US1651 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 US1651 is as low as 1mA. Good efficiency and very low standby power can be achieved. Soft Start Control The UTC US1651 features an internal 4ms soft start to minimize the component electrical over-stress during power on startup. As soon as VDD reaches UVLO (OFF), the control algorithm will ramp peak current voltage threshold gradually from nearly zero to normal setting of 0.82V. Every restart is a soft start. Constant Voltage Operation The UTC US1651 is designed to produce good CC/CV control characteristic as shown in the Fig. 1. To support UTC US1651 proprietary CC/CV control, system needs to be designed in DCM mode for flyback system. When INV is equivalent or larger than 1.25V, the system works in CV control, In CV operation, the output voltage is sensed on the primary side and the sensed signal controls the duty cycle through a built-in error amplifier (EA). Connected to a resistor divider from the primary side sensing winding, the inverting input of the Error Amplifier (EA) is compared to an internal reference voltage of 1.25V to regulate the output voltage. The EA output is internally connected to the PWM generator and controls the duty cycle. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 7 QW-R129-005.a US1651 Preliminary CMOS IC OPERATION DESCRIPTION (Cont.) Constant Current Operation When INV lower than 1.25V, the system works in CC control, In CC operation, the CC point and maximum output power can be externally adjusted by external current sense resistor Rcs. The larger Rcs, the saller CC point is, and the smaller output power becomes, and vice versa as shown in Fig.2. VO Large RS Small RS IO Fig 2. Adjustable output power by changing RS In charger applications, a discharged battery charging starts in the CC portion of the curve until it is nearly full charged and smoothly switches to operate in CV portion of the curve. In an AC/DC adapter, the normal operation occurs only on the CV portion of the curve. The CC portion provides added cycle-by-cycle current limiting protection. Extended Burst Mode Operation At light load or zero load condition, most of the power dissipation in a switching mode power supply is from switching loss, the core loss of the transformer and the loss on the snubber circuit. The magnitude of power loss is in proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus conserves the energy. The UTC US1651 self adjusts the switching frequency according to the loading condition. The switch frequency is reduced at light/no load condition to improve the conversion efficiency. At light load/no load condition, the output of the Error amplifier (EA) drops below the burst mode threshold level and device enters Burst Mode control. The frequency control also eliminates the audio noise at any loading conditions. Operation switching frequency The switching frequency of UTC US1651 is internally set and adjusted according to CC/CV operation. No external frequency setting components are required. Frequency shuffling for EMI improvement The frequency Shuffling/jittering (switching frequency modulation) is implemented in UTC US1651. The oscillation frequency is modulated with a pseudo random source so that the tone energy is spread out. The spread spectrum minimizes the conduction band EMI and therefore eases the system design. Current Sensing and Leading Edge Blanking Cycle-by-cycle current limiting is offered in UTC US1651. 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-R129-005.a US1651 Preliminary CMOS IC OPERATION DESCRIPTION (Cont.) Adjustable Drive Capability The internal power MOSFET in UTC US1651 is driven by a dedicated gate driver for power switch control. Too weak the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive compromises EMI. A good tradeoff is achieved through the built-in totem pole gate design with right output strength control. The gate drive strength can be adjusted externally by a resistor connected between VDD and VDDG, The low idle loss and good EMI system design is possible with this dedicated control scheme. Protection Control Good power supply system reliability is achieved with its comprehensive protection features including VDD over-voltage protection, VDD Clamp, GATE Clamp, Power on soft start, Cycle-by-cycle current limiting, short circuit protection, leading edge blanking, OTP and UVLO, etc. VDD is supplied by transformer auxiliary winding output. The output of UTC US1651 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-R129-005.a US1651 Preliminary CMOS IC TYPICAL APPLICATION CIRCUIT (9V/0.5A) L F1 3 BD1 4 1 2 N C1 Is L1 T1 R4 R2 R1 C2 R3 D4 C4 D3 Ns C6 Np Vo R8 Vo Io D2 C3 C5 R9 R5 D1 VDD VDDG DRAIN UTC INV US1651 CS R6 BOM Reference BD1 L1 C1,C2 C3 C4 C5 C6 D1, D2, D4 D3 R1 Component BD 1A/600V 1mH 6x8mm EC 4.7μF 400V 105°C EC 4.7μF 50V 105°C CC 1n F 1000V 1206 CC 0.33μF 50V 0805 EC 560μF 10V 105°C Diode UTC 1N4007 Diode UTC SB360 R 2.4KΩ 1206 ±5% GND Reference R2,R3 R4 R5 R6 R7 R8 R9 T1 F1 CY1 Na CY1 R7 Component R 1.5MΩ 1206 ±5% R 200KΩ 1206 ±5% R 47KΩ 0805 ±1% R 3KΩ 0805 ±1% R 3Ω 1206 ±5% R 2.4KΩ 1206 ±5% R 470Ω 0805 ±5% EE-16 FUSE 1A 250VAC Y/C 1000p F 250V 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-R129-005.a