Data sheet SDC4818 POWER SUPPLY PWM SUPERVISOR. Features. General Description. Applications. Pin Configuration. Pin Number Pin Name Function

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1 General Description The controller is designed for switching mode power supply for desktop PCs. Utilizing minimum number of external components, the includes all of the functions for push-pull and/or half-bridge topology,decreasing the production cost and PCB space, and increasing the MTBF for power supply. Two internal TL431 shunt regulators provide stable reference voltage for 3.3V and 5Vstandby regulator. Applications ATX Power Supply SFX(MICRO-ATX) Power Supply NLX Power Supply Features Over-voltage/Under-voltage protection for 3.3V/±5V/±12V Over-power protection Short-circuit protection AC input under voltage protection Power good circuitry PSON for remote controller Delay time for PSON and PG signal Two internal TL431 shunt regulators providestable reference voltage for 3.3V and 5Vstandby regulator Soft-start and maximum 93% duty cycle Pin Configuration Figure 1. Pin Configuration Pin Number Pin Name Function 1 PSON Remote on/off input 2 V33 OVP/UVP sense input for 3.3V 3 V5 OVP/UVP sense input for 5V 4 OPP Over-power sense input 5 UVAC Power good detection input January,2010 Rev /10

2 6 NVP UVP sense input for negative voltage 7 V12 OVP/UVP sense input for 12V 8 OP2 PWM totem-pole output 2 9 OP1 PWM totem-pole output 1 10 PG Power good signal 11 FB2 Output for second Opamp loop 12 VREF2 Input for second Opamp loop 13 VREF1 Input for first Opamp loop 14 FB1 Output for first Opamp loop 15 GND Ground 16 COMP Error amplifier output 17 IN Input of error amplifier 18 SS The soft-start function set through an external capacitor 19 RI Reference setting by an external resistor 20 VCC Supply voltage Table 1. Pin Description Functional Block Diagram Figure 2.Functional Block Diagram Absolute Maximum Ratings (NOTE:Stresses greater than those listed under Absolute Maximum Ratings may cause permanent January,2010 Rev /10

3 damage to the device.) Symbol Parameter Value Unit Vcc Supply voltage 12 V VFB FB1,FB2 Output 16 V IOUT PG Output 30 ma FB1,FB2 Output 30 ma PD Power dissipation(ta=25 ) 1.5 W PD Power dissipation(ta=90 ) 0.5 W RθJA thermal resistance 82.5 /W Tamb Operating temperature -30~+125 TSTG Storage temperature -55~+155 Table 2. absolute maximun ratings Electrical Characteristics (Vcc=5.0V, Ta=25, unless otherwise specified) Parameter Symbol Conditions Min Typ Max Unit VCC Supply voltage V ICC Standby supply current PG=High ma VOVP1 3.3VOVP V VOVP2 5VOVP V VOVP3 12VOVP V VUVP1 3.3VUVP V VUVP2 5VUVP V VUVP3 12VUVP V VUVS1 3.3VUVS V VUVS2 5VUVS V VUVS3 12VUVS V VOPPS Over power protection with VUVAC=1.5V V delay time VNVP Negative voltage protection V INVP NVP Source current RI=75KΩ ua TOVP OVP debounce Time RI=75KΩ ms TUVP UVP debounce Time RI=75KΩ ms TUVS UVS debounce Time RI=75KΩ ms TOPP OPP debounce Time RI=75KΩ ms TNVP NVP debounce Time RI=75KΩ ms REFERENCE VREF Reference voltage IFB=0.5mA, Ta= V REGLI-FB Regulation 4<VFB<16V mv/v IOUT-FB Output pull current VFB>2V ma January,2010 Rev /10

4 PG TPG PG delay time RI=75KΩ ms VUVAC UVAC sense voltage V TR PG output rise time CL=100pF,VPULLUP=5-1 - us TF PG output fall time V,RPULLUP=1KΩ ns VOL2 Output low voltage IPG=5mA V ION2 Sink current of PG VPG=5V ua REMOTE ON/OFF SECTION VPSON PSON input voltage V IPSON PSON drive current ma TPSON PSON to ON debounce (ON) time RI=75KΩ ms TPSON PSON to OFF debounce (OFF) time RI=75KΩ ms TPSOFF PSON to OFF delay time RI=75KΩ ms ERROR AMP SECTION V2.5 Reference voltage V IIB Bias current ua AVOL Open loop voltage gain db BW Unit gain bandwidth MHz PSRR Power supply rejection ratio db OSCILLATION SECTION FOSC Oscillation frequency RI=75KΩ KHz SOFT START SECTION ISS Charge current RI=75KΩ ua PWM OUTPUT SECTION VOL Output voltage low Io=5mA V VOH Output voltage high V12=12V V RO Output restance KΩ DMAX Max duty % Table 3. electrical characteristics January,2010 Rev /10

5 Function Description The is a power management IC for computers. It integrates various monitoring functions and protections, such as AC fail detection, over power protection, negative voltage protection, over/under voltage protection and provides power down signal for PG. Built-in high precision oscillator provides accurate protection and delay time for monitoring. And internal regulators TL431 are used for stable output 3.3V and 5V standby, with few peripheral components. Built-in soft-start decreases stress of transformer against saturation. SD4818 used for pull-push or half-bridge power system with high efficiency and stability. Remote Switch Control (PSON) The PC generates the remote switch control signal which is connected to PSON. When the control signal is low, PC power is on. And when the control signal is high, PC power is off. AC Fails Detection (UVAC) The AC line voltage is coupled from the primary side to the secondary side through the main transformer, and UVAC is connected to the secondary side by a resistor. When UVAC voltage drops below 0.7V and maintains this situation over 200us, the PG signal will be pulled low, and it indicates that the AC line is power-down. The voltage amplitude of the PWM switching signal from the secondary side is proportional to the AC line voltage. Adjusting the ratio of the voltage divider can set the threshold for the power-down. Lo R1 R2 Co C1 Figure 3. AC fails detection 0.7V +5V UVAC Over Power Protection (OPP) The over power protection is designed to detect over power and short circuit.. When the voltage of OPP is higher than 2.4V and maintain this situation over 7msec, PG will be pulled low and the power outputs will be locked. VDD R1 OP1 OP2 Figure 4. over power protection C1 R2 R3 OPP Negative Voltage Protection (NVP) The negative voltage protection is designed to provide under voltage protection for negative voltage output. Overload and short circuit can cause under voltage of negative voltage output.. When the voltage of NVP is higher than 2.1V and this situation exists for longer than 7msec, the power outputs will be off and be locked. Adjusting the resistor will set the threshold for locking the power outputs off. The threshold is determined by: January,2010 Rev /10

6 V NVP =I NVP (R 1 +R 2 )+V -12V V NVP =I NVP R 1 +V -5V -0.7V VCC -12V R2 R1-5V 2.1V Figure 5. negative voltage protection January,2010 Rev /10

7 Timing Diagram Vcc PSON 3.3V Tpson(on) 5V,12V NVP Tpson(off) Tovp Tuvp Tnvp SS(on/off) Tpsoff PG Tpg Figure 6 Vcc PSON Voltage<Vuvac UVAC OPP Topp SS(on/off) PG Figure 7 January,2010 Rev1.0 7/10

8 Typical Application LF2 EE25 CY3 102/250V LF1 T16*8 CX1 474/250V C1 470U/200V RX1 1M 1/2W ZNR1 TVR10471 XC1 CY4 102/250V 10 4/250V CY1 222/250V CY2 222/250V C R40 30K +5V +5VSB +12V +5V +3.3V HV R1 910K ZNR2 TVR05241 C3 105/250V C2 470U/200V R2 910K ZNR3 TVR05241 R25 1R C13 R29 4u7/50V 2K7 R26 1R C12 R27 4u7/50V 2K7 R53 启动电阻接于整流前, 100k/1W 降低电阻电压应力, 可大幅降低电阻损坏率, 使用普通 1/4W 碳膜电阻两串即可 R51 560k Dac 1 U2 SDC606P U3B PC817C R30 100R 3W C14 222M/1KV C28 102/1kV D23 1N4007 R63 0R8,1/2W R4 C7 102/100V L1A D5 STPS20H100CT C9 680u/16V R10 330R 1W R11 2K D19 STPS2045CT C U/10V C U/10V R33 100R 2W L3 L4 D18 STPS3045CT R31 47R T80-52 C15 472/100V R32 4R7 1/4W Q5 A928 R6*10 R23 22R R34 100R C11 1u/50V R62 2K7 VCC C29 47U/50V L5 DR6*8 +5VSB C31 C u/16V 470u/16V R65 47R R66 10K5 R61 470R R67 220R R58 10K Q6 A928 R56 10K C24 104/50V TH2A 10K C36 100u/16V R45 1K R57 10K +12V -12V +5V R37 4K7 +12V 1 2 R38 68R 2W +3.3V R7 +3.3VS R39 1K FAN1 CON PFC Inductor F1 UVAC R8 3K3-12V 5A/250V Dac D1 DIODE R15 T2 VCCD 1K2 EEL-16 D2 DIODE R14 1K2 D3 DIODE Q3 D12 D13 Q4 OP1 FR102 FR102 OP2 C945 C945 D8 D4 DIODE C10 1u/50V D7 D14 R20 560R R19 1K2 D9 VCCD D15 Q VCCD D10 R22 22R R17 30K R18 330K C22 R12 3K R16 68K 103 R9 R35 20K Q R21 PS/ON R50 33k 20 VCC U1 PS/ON 1 R68 1K R48 13K C R43 75K 19 RI V R +3.3V HV C26 R46 2K7 0.1uF C27 R41 3K9 0.47uF HV R52 560k D21 FR104 C21 104/50V 18 SS V5 C35 47u/16V R47 4K6 R36 100R 3 +5V 17 OPP 4 C34 R49 330K C23 R44 103/50V UVAC R PG FB2 FB2 1K D16 FR157 D17 FR157 R24 22R R64 4R7 T1A ERL-35 T3A D B C D E B 30K C R54 R42 75K 8 13 OP2 OP2 VREF1 Vref1 R3 NVP V VS12 FB1 FB1 D OP1 OP1 VREF2 Vref2 C4 102 FR204 L1B C8 3300u/16V R5 C5 102 L L1C L2 GND R6 C6 102 D20 C17 C19 UVAC 2200U/10V 1000U/10V FR104 D22 FR104 D11 N IN 16 COMP 15 GND PG FB2 C R59 3k3 D24 FR103 Q7 C945 VCCD R55 10k D26 Q8 R60 C945 22k 低待机功耗电路不需要安装短接 PCB 上 Q7 的 C\E 极 D27 PS/ON D25 SB540 C U3A PC817C R28 2K7 FB1 Vref1 Vref2 Package Dimension January,2010 Rev1.0 8/10

9 DIP20 SYMBOL mm inch MIN TYP MAX MIN TYP MAX A A A B b D E E E L Eb θ( 单位 : 度 ) January,2010 Rev1.0 9/10

10 Shaoxing Devechip Microelectronics Co.,Ltd IMPORTANT NOTICE Information in this document is provided solely in connection with SDC products. SDC reserves the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at anytime, without notice. Shaoxing Devechip Microelectronics Co.,Ltd does not assume any responsibility for use of any its products for any particular purpose, nor does Shaoxing Devechip Microelectronics Co.,Ltd assume any liability arising out of the application or use of any its products or circuits. Shaoxing Devechip Microelectronics Co.,Ltd does not convey any license under its patent rights or other rights nor the rights of others Devechip Microelectronics - All rights reserved Contact us: Headquarters of Shaoxing Address:, Tian Mu Road, No13 Easter City, Shaoxing, Zhengjiang,.China Zip code: Shenzhen Branch Address: 22A Shangbu building, Nan Yuan Road, NO.68 Futian District, Shenzhen Zip code: Tel:(86) Tel:(86) Fax:(86) Fax:(86) January,2010 Rev1.0 10/10