pcb打样、小批量、首选捷多邦，品质佳，交货快！ UNISONIC TECHNOLOGIES CO., LTD U3848/A/B/C LINEAR INTEGRATED CIRCUIT HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS DESCRIPTION The UTC U3848/A/B/C is designed to provide several special enhancements to satisfy the needs: Power-Saving mode for low standby power, Over Current Protection (OCP), Over Voltage Protection (OVP), Over Load Protection (OLP), Over Temperature Protection (OTP) etc protection features. IC will be shutdown when either protection arise and can auto-restart. Its frequency may be defined by user through resistor RT to external ground. UVLO featuring typical start-up current 20µA, and VCC(ON) 12.6V, VCC(OFF) 8.1V. Lower typical operation current Icc 3.7mA at inactive output. The output stage, suitable for driving N-Channel MOSFETs, can operate to duty cycles approach 70%. The U3848/A/B/C are fully pin-to-pin compatible with UC3842. But pin RT only connected a resistor to ground to decide switch frequency, and pin FB with an 4kΩ pull up resistor to internal reference voltage. The U3848/A/B/C also have soft-start function avoiding overshoot, and controlled driver output rise edge time tR for low EMI. DIP-8 SOP -8 *Pb-free plating product number: U3848L/U3848AL/U3848BL/U3848CL FEATURES * Low startup and operation current * User defined switching frequency(Norm is 70kHz) * Max duty cycle 70% * Power-saving mode for low power * Under voltage lockout with hysteresis * Over temperature protection * Overload protection * Over voltage protection * Leading edge blanking * Soft start ORDERING INFORMATION Order Number Normal Lead Free Plating U3848-D08-T U3848L-D08-T U3848-S08-R U3848L-S08-R U3848-S08-T U3848L-S08-T U3848A-D08-T U3848AL-D08-T U3848A-S08-R U3848AL-S08-R U3848A-S08-T U3848AL-S08-T U3848B-D08-T U3848BL-D08-T U3848B-S08-R U3848BL-S08-R U3848B-S08-T U3848BL-S08-T U3848C-D08-T U3848CL-D08-T U3848C-S08-R U3848CL-S08-R U3848C-S08-T U3848CL-S08-T www.unisonic.com.tw Copyright © 2005 Unisonic Technologies Co., Ltd Package Packing DIP-8 SOP-8 SOP-8 DIP-8 SOP-8 SOP-8 DIP-8 SOP-8 SOP-8 DIP-8 SOP-8 SOP-8 Tube Tape Reel Tube Tube Tape Reel Tube Tube Tape Reel Tube Tube Tape Reel Tube 1 of 13 QW-R103-033.B U3848/A/B/C LINEAR INTEGRATED CIRCUIT ORDERING INFORMATION(Cont.) U3848L-D08-T (1)Packing Type (2)Package Type (3)Lead Plating UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw (1) R: Tape Reel, T: Tube (2) D08: DIP-8, S08: SOP-8 (3) L: Lead Free Plating, Blank: Pb/Sn 2 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT PIN CONFIGURATION SS 1 8 VREF FB 2 7 VCC CS 3 6 OUT RT 4 5 GND PIN DESCRIPTION PIN 1 2 3 4 5 6 7 8 SYMBOL SS FB CS RT GND OUT VCC VREF FUNCTION Soft-start Feedback Controller current sense input The resistor controlling switch frequency Ground Output to the gate of external power MOS Supply voltage Inter 6.3V reference voltage, connected with the filter capacitor UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT BLOCK DIAGRAM VCC VREF RT 7 8 4 UVLO Reference voltage OVP OLP OTP SS 1 Oscillator Soft Start Latch S Q Power-Saving Unit FB 2 PWM COMP R Driver 6 OUT 3 CS Q Current Limiting LEB 5 GND Explain:OLP(Over Load Protection) OVP(Over Voltage Protection) OTP(Over Temperature Protection) UVLO(Under Voltage Latch-Out LEB(Led Edge Blanking) SS(Soft Start) UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATINGS (Ta＝25°C, VCC=15V, RT=75kΩ, unless otherwise specified) PARAMETER SYMBOL RATINGS UNIT Supply Voltage VCC 26 V Input Voltage to FB Pin VFB -0.3 ~ 6.2 V Input Voltage to CS Pin VCS -0.3 ~ 2.8 V Input Voltage to RT Pin VRT -0.3 ~ 6.2 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 SYMBOL VCC Supply Voltage RATINGS 8.2 ~ 21 UNIT V ELECTRICAL CHARACTERISTICS (Ta＝25°C, VCC=15V, RT=75kΩ, unless otherwise specified) PARAMETER SUPPLY SECTION Start Up Current SYMBOL ISTR OFF IOFF Supply Current with switch ON ION UNDER-VOLTAGE LOCKOUT SECTION Start Threshold Voltage VTHD(ON) Min. Operating Voltage VCC(MIN) Hysteresis VCC(HY) INTERNAL VOLTAGE REFERENCE Reference Voltage VREF CONTROL SECTION Switch Frequency Duty Cycle VFB Operating Level Normal Power-Saving MAX MIN MIN MAX Feedback Resistor External Resistor for controlling Current Source of OSC F(SW) TEST CONDITIONS TYP MAX UNIT 27 3.7 4.0 45 5.5 6.0 µA mA mA 11.8 7.6 12.6 8.1 4.5 13.4 8.6 V V V 6.1 6.3 6.6 V 85 61 17 65 0 0.5 95 68 20 70 105 75 23 75 2.6 3.8 4.4 5.0 kHz kHz kHz % % V V kΩ VCC=12.5V VSS = 0, IFB = 0 VSS = 5V, IFB = 0 measured at pin VREF VFB = 4V U3848/B(Note1) U3848A/C(Note2) VFB = 1V DMAX DMIN VMIN VMAX RFB MIN VFB < 0.5V RT CSS=0.05uF Soft-Start Time PROTECTION SECTION OVP threshold OLP threshold OTP threshold OVP Disable threshold OLP Enable threshold Spike Blanking time CURRENT LIMITING SECTION LEB TSS V(OVP) VFB(OLP) T(THR) VSS(DEACT) VSS(ACT) TSB CSS=0.1uF CSS=1uF VSS < 3.5V, VFB > 5V VSS > 5.4V VFB > 5V, VCC > 17V VFB > 5V tLEB UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 15.2 4.4 120 3.7 4.9 75 kΩ 6 12 120 ms ms ms 16 4.6 135 3.9 5.1 7.2 220 16.8 4.9 150 4.2 5.4 V V °C V V µs ns 5 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT ELECTRICAL CHARACTERISTICS(Cont.) PARAMETER DRIVER OUTPUT SECTION Output Voltage Low State Output Voltage High State SYMBOL VOL VOH TEST CONDITIONS ISOURCE = 200 mA ISINK = 200 mA U3848B CL = 1.0 nF Output Voltage Rise Time tR U3848C CL = 1.0 nF U3848/A CL = 1.0 nF Output Voltage Fall Time tF CL = 1.0 nF Note: 1. RT=65kΩ should be connected for U3848/ U3848B. 2. U3848A/C denote U3848A and U3848C. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw MIN TYP MAX UNIT 2.5 V V ns ns ns ns 12.2 70 200 300 50 150 300 400 90 6 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION The internal reference voltages and bias circuit work at VCC>12.6V, and shutdown at VCC< 8.1V. (1) Soft-Start When every IC power on, driver output duty cycle will be decided by voltage VSS on soft-start capacitor and VCS on current sense resistor at beginning. After VSS reach 5.1V, the whole soft-start phase end, and driver duty cycle depend on VFB and VCS. The relation among VSS, VFB and VOUT as followed FIG.3, here soft-start phase Tsoft-start should more than VOUT start-up phase Tstart-up, otherwise, IC will enter false OLP protection state. Because after the soft-start phase end, if VOUT remain in lower voltage, VFB more than 4.6V, then IC enter false OLP state. 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. Finally soft-start also set OVP active phase. OVP active phase between VSS=0 and VSS=3.8V, OVP will not be sensed after VSS reach 3.8V.The Soft-start phase TSS： TSS = 6 ms 12 ms 120 ms (CSS=0.05uF) (CSS=0.1uF) (CSS=1uF) VSS 5.1V TSOFT-START t VFB 4.6V t VOUT TSTRAT-UP t Driver t FIG.3 Soft-start phase UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 7 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION(Cont.) (2) Switch Frequency Set The maximum switch frequency decided by an external resistor RT connected between pin RT and ground. Then the maximum switch frequency will depend on user requirement. The relation curve between fSW and RT as followed FIG.5 under the condition of POUT=8W. The equation between fSW and RT as followed (1-2) for U3848A/C, (1-3) for U3848/B: fSW = -0.61*RT+115.7--------------------------(1-2) fSW = -1.1*RT+167.5--------------------------(1-3) After RT connected, switch frequency is also modulated by output power POUT during IC operating. So lower switch frequency at lower load, which more and more improve IC’s efficiency at light load. Switch frequency is decreased minimum at no load, then the U3848/B will operate at Power-Saving mode for Lower standby power. The relation curve between fSW and POUT as followed FIG.4 under the condition of RT=75kΩ. The frequency wave of U3848A/C is similar with U3848/B’s, and for them, maximum frequency point is 70kHz. 90 80 70 fsw (kHz) 60 110V 50 220V 40 30 20 10 0 0.6 1.2 1.8 2.4 3 3.6 4.8 6 7.2 12 POUT(W) (RT=75KΩ) FIG.4 The relation curve between fSW and output power POUT 100 90 80 fsw (kHz) 70 60 50 40 30 20 10 55 60 65 70 75 80 85 90 95 RT (kΩ) (POUT=8W) FIG.5 The relation curve between fSW and RT UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 8 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION(Cont.) (3) Protection section U3848/A/B/C takes on more protection functions such as OLP, OVP and OTP etc. In case of those failure modes for continual 7.2µs (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 soft-start phase end (VSS>5.1V), IC will shutdown driver if over load state occurs (corresponding to VFB>4.6V) for continual 7.2µs. OLP function will not inactive during soft-start phase. OLP case as followed FIG.6. The test circuit as followed FIG.8 for U3848/A/B/C. VCC VCC 12.6V 16V 12.6V 8.1V 8.1V T restart t VOUT VFB t 7.2µs Blanking 7.2µs Blanking 4.6V t Driver ON/OFF VFB t 7.2µs Blanking 7.2µs Blanking 4.6V t VSS VSS 5.1V t SS Phase 5.1V 3.9V SS Phase OVP Phase t FIG.6 OLP case t FIG.7 OVP case OVP Power supply VCC’s OVP function are enabled only when VSS<3.9V & VFB>4.6V during soft-start phase. During above condition, driver will be shutdown if over voltage state occurs (VCC>16V) for continual 7.2µs. OVP function will not inactive after soft-start phase. OLP case as followed FIG.7. The test circuit as followed FIG.9 for U3848/A/B/C. OTP OTP will shut down driver when junction temperature TJ of internal circuits is more than threshold 135°C for continual 7.2µs. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 9 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION(Cont.) 15V VCC C4 VCC C13 C4 IC3 5.5V 1 IC3 1 8 7 2 VFB 3 6 4 5 R17 4.6v VFB C3 8 2 Driver UTC U3848/A/B/C V FB C13 C3 7 Driver UTC U3848 /A/B/C 3.5V 3 6 4 5 16v VCC 7.2us RT R17 FIG.8 OLP test circuit 7.2us RT FIG.9 OVP test circuit (4) Driver Output Section Rise edge time of driver output is about 200ns for avoiding Low EMI. When driver output VOL(MAX) is less than 2.5V with 200mA source current, and VOH(MIN) is more than 12.2V with 200mA sink current. 15v C4 VCC 15v C13 C4 IC3 1 2 C13 IC3 C3 8 1 7 2 UTC U3848 A/ B/C VFB VCC 3 6 4 5 VOH C3 8 7 Isource=200mA UTC U3848 /A/B/C VFB (MIN ) 3 6 4 5 VOL (MIN) Isink=200mA R17 RT FIG.10 driver test circuit with sink current R17 RT FIG.11 driver test circuit with source current (5) External power switch MOS transistor Because U3848/A/B/C driver output voltage Low level threshold is about 2.5V, User may apply power MOS transistors with bigger threshold. 4N60 is recommended normally. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 10 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT D3 BD1 AC IN C8 CD1 RD1 CX1 R10 C12 UTC 2 U3848 / 7 A/B/C R 8 1 5V 3A + C5 GND Q1 5 6 + C9 R8 4 3 + D2 R6 IC3 R7 C15 R12 TR1 ZD1 F1 TH1 L3 D1 R2 R5 R4 R3 IC1 R11 C3 RF + C4 R17 C14 C2 IC2 CY1 FIG.12 U3848/A/B/C Typical Application Circuit Table1 Components Reference description for U3848/A/B/C application circuit C12 CC 10nF/1000V D3 Diode UF1007 R C14 CC 100nF/50V IC1 IC PC817 TH1 C2 CC 33nF/50V IC2 IC TL431CLP BD1 R KBP-208 104/275V IC3 IC U3848/A/B/C RD1 R 10Ω 1/8W R 3.3kΩ 1/8W CX1 R 470KΩ 1/8W SCK-103 C5 EC 1000uF/15V L3 L 1.2uH R12 C4 CC 22uF/50V Q1 MOS 4N60 TR1 C8 EC 68uF/400V R7 R 68KΩ 1/8W RF R 4.7kΩ C9 EC 1000uF/16V R17 R 1.2Ω/1W 1/8W C15 CC 0.1µF/50V CD1 CC 1nF/1KV R2 R 680Ω 1/8W CY1 CC 4.7nF/250V R3 R ADJ 1/8W D1 Diode C63-004 R4 R 5.6KΩ 1/8W D2 Diode 1N4148 R5 R 5.6KΩ 1/8W optional 1/8W Note: C5 and C9 are lower ESR capacitors. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 11 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT TYPICAL CHARACTERISTICS(Cont.) Feedback Voltage During Loadjump From10% Up To 100% Load (VDCIN=120V) Ch1 1.00V M 400 μs A Ch1 ∫ Feedback Voltage During Loadjump From10% Up To 100% Load (VDCIN=350V) 120mV 3.86V 60.0 mV 3.30 V 1.64kHz 850 Hz 3.29kHz 1.70kHz Ch1 max 6.00V Ch1 max 5.90V Ch1 min 460 mV Ch1 min 40.0mV Ch1 frequency 785 .5 Hz Ch1 frequency 1.906kHz Ch1 3.18V 1.00 V M 200μ s A Ch1 ∫ 2.68 V Startup With Full Load Condition At VDCIN=350V, Vc4 and Vout Startup With Full Load Condition At VDCIN=120V, Vc4 and Vout 12.3V 12.3V 12.3V 12.3V VC4 VC4 2.00V Ch1 max 5.04V Ch1 min 1.32V Ch1 min -120 mV Ch1 frequency ----- Hz VOUT Ch1 Ch1 max 5.04V Ch2 5.00V M 10.0ms A Ch1 ∫ Ch1 3.16V Startup Behavior At Nominal Load Condition VDCIN =120 V Ch1 Ch3 2.00V VFB VSS V SS Ch2 2.00V M 4 .00 ms A Ch3 ∫ 4 .96 V UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5.00V M 10.0ms A Ch1 ∫ 3.16V 240 mV 12.0V 1.79kHz 147 Hz VC4 VFB 2.00V 2.00V Ch2 Startup Behavior At Nominal Load Condition VDCIN =350 V 120mV 12.3V 357Hz 21.2Hz VC4 Ch1 frequency ----- Hz VOUT Ch1 Ch3 2.00 V 2.00 V Ch2 2.00V M 4.00ms A Ch3 ∫ 4.96V 12 of 13 QW-R103-033,B U3848/A/B/C LINEAR INTEGRATED CIRCUIT TYPICAL CHARACTERISTICS(Cont.) NO Load Input Power vs. Line Voltage (Normal Mode) Frequency vs. Output Power 1 120 0.9 0.8 80 60 Vdcin=120V 40 Input Power (W) Frequency (KHZ) 100 0.7 0.6 0.5 0.4 0.3 0.2 20 Input Power NO Load (PoUT=0W) 0.1 0 0 2 4 6 8 10 12 14 16 18 20 Output Power (W) 0 100 150 200 250 300 DC Input Voltage(V) 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 13 of 13 QW-R103-033,B