UNISONIC TECHNOLOGIES CO., LTD US3702 Preliminary LINEAR INTEGRATED CIRCUIT HIGH PERFORMANCE CURRENT MODE POWER SWITCH WITH ZERO CURRENT DETECTION DESCRIPTION DIP-8 The UTC US3702 is an integrated PWM controller and SenseFET specifically designed for switching operation with minimal external components. The UTC US3702 is designed to provide several special enhancements to satisfy the needs, for example, Power-Saving mode for low standby power (<0.3W), Frequency Hopping , Constant Output Power Limiting , Slope Compensation ,Over Current Protection (OCP), Over Voltage Protection (OVP), Over Load Protection (OLP), Under Voltage Lock Out (UVLO), Short Circuit Protection (SCP) , Over Temperature Protection (OTP) etc. IC will be shutdown or can auto-restart in situations. FEATURE * Internal high voltage SenseFET(700V) * Frequency hopping for Improved EMI performance. * Lower than 0.3W standby power design * Linearly decreasing frequency to 26KHz during light load * Internal soft start * Internal slope compensation * Constant power limiting for universal AC input range * Gate output maximum voltage clamp(15V) * Over temperature protection * Overload protection * Over voltage protection * Leading edge blanking * Cycle-by-cycle current limiting * Under voltage lock out * Short circuit protection ORDERING INFORMATION Ordering Number Lead Free US3702L-D08-T Halogen Free US3702G-D08-T Package Packing DIP-8 Tube US3702L-D08-T (1)Packing Type (1) T: Tube (2)Package Type (2) D08: DIP-8 (3)Green Package (3) L: Lead Free, G: Halogen Free and Lead Free www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd 1 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT 1 8 DRAIN PGND 2 7 DRAIN VCC 3 6 DRAIN FB 4 5 NC MARKING PIN CONFIGURATION SGND PIN DESCRIPTION PIN NO. 1 2 3 4 5 6 7 8 PIN NAME SGND PGND VCC FB NC DRAIN DRAIN DRAIN DESCRIPTION Ground MOSFET Ground Supply voltage Feedback Power MOSFET drain Power MOSFET drain Power MOSFET drain UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT BLOCK DIAGRAM Notes: OLP (Over Load Protection) OVP (Over Voltage Protection) OTP (Over Temperature Protection) OCP (Over Current Protection) UVLO (Under Voltage Latch-Out) LEB (Led Edge Blanking) ABSOLUTE MAXIMUM RATING (TA=25°C, unless otherwise specified) PARAMETER SYMBOL RATINGS UNIT Supply Voltage VCC 30 V Input Voltage to FB Pin VFB -0.3~6.5 V Junction Temperature TJ +150 °C Operating Temperature TOPR -40~+125 °C Storage Temperature TSTG -50~+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. OPERATING RANGE PARAMETER Supply Voltage SYMBOL VCC RATINGS 7~23 UNIT V ELECTRICAL CHARACTERISTICS (TA＝25°C, VCC=15V, unless otherwise specified) PARAMETER SUPPLY SECTION Start Up Current Supply Current with switch UNDER-VOLTAGE LOCKOUT SECTION Start Threshold Voltage Min. Operating Voltage CONTROL SECTION SYMBOL IST IOP VTHD(ON) VCC(MIN) UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw TEST CONDITIONS MIN VCC = VTHD(ON)-1V VFB=4V GATE Without CLOAD 12 7 TYP MAX UNIT 5 15 μA 2 3 mA 13.5 8 14 9 V V 3 of 9 QW-R119-022.c US3702 Preliminary Feedback Source Current VFB Open Level Burst-Mode Out FB Voltage Reduce-Frequency end FB Voltage Burst-Mode Enter FB Voltage Normal initial Switching frequency Power-Saving Duty Cycle Frequency Hopping Frequency Variation VS VCC Deviation Frequency Variation VS Temperature Deviation Soft-Start Time PROTECTION SECTION OVP threshold OLP threshold Delay Time Of OLP OTP threshold CURRENT LIMITING SECTION Peak Current Limitation Threshold Voltage For Valley IFB VFBMAX VFB(OUT) VFB(END) VFB(IN) F(SW) DMAX △FJ(SW) FDV FDT ILIM ILIM-L UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw VFB=0 VCC=10~20V 80 ±6 5 mA V V V V kHz kHz % % % T=-25~105°C 5 % 6 ms VCS =0 VCS =0 VCS =0 VFB=4V Before enter burst mode VFB=4V，vCS=0 TSoftS VOVP VFB(OLP) TD-OLP T(THR) LINEAR INTEGRATED CIRCUIT 69 20 70 ±3 75 ±4.5 2 4 35 130 23 4.7 65 145 VFB=4V VCS=0 VFB=4.4V VFB=4.4V 2 5.0 1.2 2.4 1.0 75 1.06 1.2 1.14 81 95 1.34 V V ms °C A A 4 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT ELECTRICAL CHARACTERISTICS (Cont.) PARAMETER POWER MOS-transistor SECTION Drain-Source Breakdown Voltage Turn-on voltage between gate and source Drain-Source Diode Continuous Source Current Static Drain-Source On-State Resistance Rise Time SYMBOL VDSS VTH TEST CONDITIONS VGS=0V, ID=250mA VDS=VGS, ID=250mA TYP MAX UNIT 4 V V 2 A 5 Ω 45 100 NS 35 80 NS 700 2 IS RDS(ON) TR VGS=10V, ID=2.25A VDD=300V, ID=4.0A RG=25Ω (Note 1,2) Fall Time TF Notes: 1. Pulse Test: Pulse width≤300μs, Duty cycle≤2% 2. Essentially independent of operating temperature UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN 5 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION The internal reference voltages and bias circuit work at VCC> VTHD (ON), and shutdown at VCC<VCC (MIN). (1) Soft-Start When every IC power on, driver output duty cycle will be decided by inter-slope voltage VSOFTS and VCS on current sense resistor at beginning. After the whole soft-start phase end, and driver duty cycle depend on VFB and VCS. The relation among VSOFTS, VFB and VOUT as followed Fig.3. Furthermore, soft-start phase should end before VCC reach VCC (MIN) during VCC power on. Otherwise, if soft-start phase remain not end before VCC reach VCC (MIN) during VCC power on, IC will enter auto-restart phase and not set up VOUT. Fig.3 Soft-start phase (2) Switching Frequency Set The maximum switching frequency is set to75kHz. Switching frequency is modulated by output power POUT during IC operating. At no load or light load condition, most of the power dissipation in a switching mode power supply is from switching loss on the MOSFET transistor, the core loss of the transformer and the loss on the snubber circuit. The magnitude of power loss is in proportion to the number of switching events within a fixed period of time. So lower Switching frequency at lower load, which more and more improve IC’s efficiency at light load. At from no load to light load condition, The IC will operate at from Burst mode to Reducing Frequency Mode. The relation curve between fSW and POUT/POUT (MAX) as followed Fig.4. Fig. 4 The relation curve between fSW and relative output power POUT/ POUT (MAX) UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 6 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION(Cont.) (3) Internal Synchronized Slope Compensation Built-in slope compensation circuit adds voltage ramp onto the current sense input voltage for PWM generation, this greatly improves the close loop stability at CCM and prevents the sub-harmonic oscillation and thus reduces the output ripple voltage. (4) Frequency Hopping For EMI Improvement The Frequency hopping is implemented in the IC; there are two oscillators built-in the IC. The first oscillator is to set the normal switching frequency; the switching frequency is modulated with a period signal generated by the 2nd oscillator. The relation between the first oscillator and the 2nd oscillator as followed Fig.5. So the tone energy is evenly spread out, the spread spectrum minimizes the conduction band EMI and therefore eases the system design in meeting stringent EMI requirement. Fig. 5 Frequency Hopping (5) Constant Output Power Limit When the primary current, across the primary wind of transfer, reaches the limit current, around 1.2A, the output GATE drive will be turned off after a small propagation delay tD. This propagation delay will introduce an additional current proportional to tD×VIN/Lp. Since the propagation delay is nearly constant regardless of the input line voltage VIN. Higher input line voltage will result in a larger additional current and hence the output power limit is also higher than that under low input line voltage. To compensate for this output power limit variation across a wide AC input range, the limit current in primary winding is adjusted by adding a positive ramp. This ramp signal rises from 1.14A to 1.2A, and then flattens out at 1.2A. A smaller limit current forces the output GATE drive to terminate earlier. This reduces the total PWM turn-on time and makes the output power equal to that of low line input. This proprietary internal compensation ensures a constant output power limit for a wide AC input voltage range (90VAC~264VAC). (6) Protection section The IC takes on more protection functions such as OLP, OVP and OTP etc. In case of those failure modes for continual blanking time, the driver is shut down. At the same time, IC enters auto-restart, VCC power on and driver is reset after VCC power on again. OLP After power on, IC will shutdown driver if over load state occurs for continual TD-OLP. OLP case as followed Fig. 6. The test circuit as followed Fig.8 OVP OVP will shutdown the switching of the power MOSFET whenever VCC>VOVP. The OVP case as followed Fig.7. the test circuit as followed Fig.9. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 7 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION(Cont.) Fig.6 OLP case Fig.7 OVP case 15V VCC 470u 33n 500Ω IC3 1 8 2 7 15V VDD 470u 33n Drain US3702 3 6 4 5 2.5V Fig.8 OLP test circuit VOVP VCC Fig.9 OVP test circuit OTP OTP will shut down driver when junction temperature TJ>T (THR) for continual a blanking time. (7) Driver Output Section The driver-stage drives the gate of the MOSFET and is optimized to minimize EMI and to provide high circuit efficiency. This is done by reducing the switch on slope when reaching the MOSFET threshold. This is achieved by a slope control of the rising edge at the driver’s output. The output driver is clamped by an internal 15V Zener diode in order to protect power MOSFET transistors against undesirable gate over voltage. (8) Inside power switch MOS transistor Specific power MOS transistor parameter is as “POWER MOS TRANSISTOR SECTION” in electrical characteristics table. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 8 of 9 QW-R119-022.c US3702 Preliminary LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT YC1 R5 LINE F1 ZNR1 L1 XC1 R1 R2 NEUT BD1 1 2 4 3 4 3 10 R3 1 C1 t° 2 C2 C8 L2 1 2 5V/2.4A D2 C4 9 R4 C5 C10 3 GND 4 TR1 D1 D3 8 7 C3 3 IC1 8 VCC DRAIN 7 DRAIN 6 DRAIN 2 T1 6 R6 R9 IC2 PGND FB 4 SGND 1 4 1 3 2 R12 C7 IC3 C9 R7 C11 R8 Fig.10 UTC US3702 Typical Application Circuit Table1. Components reference description for UTC US3702 application circuit DESIGNATOR C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 PART TYPE 33μF 202pF 22μF 470μF 470μF 0.1μF 102pF 0.001μF 0.1μF 220μF 1μF (Optional) DESIGNATOR R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 PART TYPE 2.2MΩ 2.2MΩ 100KΩ 1MΩ 15Ω 820Ω 1KΩ 22KΩ 22KΩ 15~25MΩ 68KΩ 2KΩ DESIGNATOR D1 D2 D3 IC1 IC2 IC3 YC1 T1 L1 L2 F1 ZNR1 TR1 XC1 BD1 PART TYPE FR107 SB540 RS1D US3702 PC-817 TL431 222 EE25 UU10.5 2μH 2A/250V 7D471K SCK102R55A 334/275V KBP205 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 9 of 9 QW-R119-022.c