Product Specification STC6105 Power Supply Supervisor + Regulator + PWM FEATURES DESCRIPTION PC half-bridge (or 494) power supply supervisor + two 431 + PWM High integration & few external components Over-voltage protection for 3.3V, 5V and 12V Under-voltage protection for 3.3V, 5V and 12V Under-voltage protection for –12V and/or –5V Over-power and short-circuit protection Power-down warning circuitry Power good circuitry Delay time for PSON and PG signal Remote ON/OFF function On-chip oscillator and error amplifier Two shunt regulator for 3.3V and 5V-Standby Latching PWM for cycle-by-cycle switching Push-pull PWM operation and totem pole outputs Soft-start and maximum 93% duty cycle APPLICATIONS Switching mode power supply for Computers, such as: ATX NLX STC6105 controller is designed for switching mode power supply for desktop PCs. It provides all the functions necessary to monitor and control the output of the power supply. Remote ON/OFF control, power good circuitry, some protection features against over-voltage and over-power are implemented. It directly senses all the output rails for OVP without the need of external dividers. An innovated AC-signal sampling circuitry provides a sufficient power-down warning signal for PG. A built-in timer generates accuracy timing for control circuit including the PS-off delay. The cycle-by-cycle PWM switching prevents the power transformer from the saturation and ensures the fastest response for the short-circuit protection which greatly reduce the stress for power transistors. Two internal precision TL431 shunt regulators provide stable reference voltage and driver for 3.3V and 5V-standby regulation. Utilizing minimum number of external components, the STC6105 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. SFX (micro-ATX) MARKING DIAGRAMS PIN CONFIGURATION 20 STC6105 1 -1- PSON 1 20 VCC V33 2 19 RI V5 3 18 SS OPP 4 17 IN UVAC 5 16 COMP NVP 6 15 GND V12 7 14 FB1 OP2 8 13 VREF1 OP1 9 12 VREF2 PG 10 11 FB2 Product Specification STC6105 Power Supply Supervisor + Regulator + PWM ORDERING INFORMATION Part Number Package STC6105 20-Pin DIP PIN DESCRIPTIONS Name Pin Type Function VCC 20 Supply Supply voltage. 4.5V ~ 5.5V. It is connected to 5V-standby. PG 10 Logic output V33 2 Analog input 3.3V over-voltage/under-voltage control sense input. V5 3 Analog input 5V over-voltage/under-voltage control sense input. V12 7 Analog input 12V over-voltage/under-voltage control sense input. OPP 4 Analog input Power Good logic output, 0 or 1 (open-collector). PG = 1 means that the power is good for operation. The PG delay is 300 msec. Over-power sense input. This pin is connected to driver transformer or the output of current transformer. When not in use, this pin should be grounded. Remote On/Off logic input forʳCPU or controller. Turn on/off the PWM Output after the 7.5 msec / 26 PSON 1 Logic input NVP 6 Analog input msec delay. PSON = 0 means that the main SMPS is operational. PSON =1 means that the main SMPS is off and the latch is reset. The protection input for negative output, such as –12V and/or –5V. Trip voltage = 2.1V. UVAC 5 Analog input AC fail detection, detect main AC voltage under-voltage and/or failure. COMP 16 Analog output Error amplifier output and the input of the PWM comparator. IN 17 Analog input The negative input of error amplifier. The positive input of error amplifier is a 2.5V reference voltage. SS 18 Analog input OP1/OP2 9/8 Analog output The soft-start. It is settable through external capacitor. The current source output at this pin is 8uA and the voltage is clamped at 2.5V. The totem-pole output drivers of push-pull PWM. The output are enabled (low) only when the NAND gate inputs are high, the maximum duty cycle on an output (OP1 or OP2) is 46%. FB1 14 Analog output Output for first converter regulation loop. VREF1 13 Analog input Reference comparison input for first converter regulation loop. 2.5V. FB2 11 Analog output Output for second converter regulation loop. VREF2 12 Analog input Reference comparison input for second converter regulation loop. 2.5V. RI 19 Program. Connected to external resistor for the reference setting. GND 15 Analog input RI = 75k ohms. Supply Ground. -2- Product Specification STC6105 Power Supply Supervisor + Regulator + PWM BLOCK DIAGRAM V33 V5 V12 UVAC RI PG GND VCC 2 3 7 5 19 10 15 20 DSD Vref 2uA UV Detector 0.7V + Delay 3sec UV Protector 3.2V FB1 13 VREF1 11 FB2 12 VREF2 Delay 300msec OV Protector 5V 14 _ COMP _ COMP + 64uA 2.1V NVP 6 2.4V OPP 4 _ COMP 2.5V D D _ COMP _ 8uA Q Q CK _ Q + CK Delay 7msec + Buffer Vcc Delay 7msec + Buffer 9 OP1 8 OP2 COMP R + _ 1.4V PSON 1 _ COMP + On/Off Delay 26msec 7.5msec O.S.C Error Amp Delay 15msec Vcc S Delay 2msec R -3- 18 17 16 SS IN COMP Q Product Specification STC6105 Power Supply Supervisor + Regulator + PWM TIMING DIAGRAM VCC PSON 3.3/5/12V tpson(on) tuvp NVP tpson(off) SS(on/off) PG tnvp tpsoff tPG VCC PSON Voltage < VUVAC UVAC OPP tOPP SS(on/off) PG -4- Product Specification STC6105 Power Supply Supervisor + Regulator + PWM ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit VCC DC Supply Voltage at Pin 20 16 V VFB Shunt Regulator Output at Fb1, Fb2 Pins 16 V IOUT Output Current at PG, Fb1, Fb2 Pins 30 mA PD,25к Power Dissipation (TA=25к) 1.5 W PD,90к Power Dissipation (TA=90к) 0.5 W TSTG Storage Temperature Range -55 to +150 к RTJA Thermal Resistance, Junction-To-Air 82.5 к/W TJ,MAX Operating Junction Temperature 150 к TA,MAX Operating Ambient Temperature -30 to +125 к TL Lead Temperature (Soldering, 10sec) 260 к ESD Capability, HBM model 3.0 kV Note: All voltage values, except differential voltage, are with respect to network ground terminal. RECOMMENDED OPERATING CONDITIONS Symbol Parameter Value Unit VCC DC Supply Voltage at Pin 20 4.5 to 5.5 V VFB Shunt Regulator Output at Fb1, Fb2 Pins 4 to 16 V TOPER Operating Ambient Temperature Range -25 to +85 к ELECTRICAL CHARACTERISTICS (VCC = 5V, TA = 25qC) Symbol Parameter Test Condition Min. Typ. Max. Unit ICC Total Supply Current PG High - 5 10 mA VOVP1 Over-Voltage Protection 3.3V - 3.9 4.1 4.3 V VOVP2 Over-Voltage Protection 5V - 5.7 6 6.3 V VOVP3 Over-Voltage Protection 12V - 13.75 14.05 14.35 V VUVP1 Under-Voltage Protection 3.3V - 2.0 2.6 2.8 V VUVP2 Under-Voltage Protection 5V - 3.0 3.6 3.9 V VUVP3 Under-Voltage Protection 12V - 6.0 7.2 8.0 V VUVS1 Under-Voltage Sense 3.3V for PG Low - 2.5 2.8 3.0 V VUVS2 Under-Voltage Sense 5V for PG Low - 4.0 4.3 4.5 V VUVS3 Under-Voltage Sense 12V for PG Low - 9.4 10.1 10.4 V VOPPS* 1 Over-Power Protection. VUVAC = 1.5V 2.02 2.4 2.66 V VNVP Negative Voltage Protection: Voltage Level - 2.0 2.1 2.2 V INVP Negative Voltage Protection: Source Current RI = 75k 57 64 72 uA tOVP Timing for Over-Voltage Protection RI = 75k RI = 75k RI = 75k RI = 75k RI = 75k 35 50 65 us 0.8 2.4 3.75 ms 0.37 1.2 1.88 ms 3.3 7 11.3 ms 3.3 7 10.2 ms tUVP Timing for Under-Voltage Protection tUVS Timing for Under-Voltage Sense for PG Low tOPP Timing for Over-Power-Protection tNVP Timing for Negative Voltage Protection *1 Note : VOPPS = (2/3) x VOPP + (1/3) x VUVAC ; -5- ! Product Specification STC6105 Power Supply Supervisor + Regulator + PWM Shunt Regulator (FB1, VREF1, FB2, VREF2) Symbol Parameter Test Condition Min. Typ. Max. VREF VDEV, I *2 VDEV, T * 2 Deviation of VREF Over Temperature TA = -25к to 85к - Regli-fb*2 Line Regulation 4 < VFB < 16V - Iout-fb*2 Output Sinking Current Capability VFB > 2V 10 - Unit Reference Voltage IFB = 0.5mA, T A = 25к 2.475 2.5 2.525 V Deviation of VREF Over Load Current IFB = 0.5mA to 10mA - - 20 mV 10 30 mV 1 - mV/V - mA Note *2: Not tested in production test. Power Good Section Symbol Parameter Test Condition Min. Typ. Max. Unit tpg Timing for PG Delay RI = 75k 200 300 400 ms Vuvac UVAC Voltage Sense for PG - 0.65 0.7 0.75 V tR*2 PG Good Output Rising Time CL = 100pF - 1 - us tF*2 PG Good Falling Time CL = 100pF - 300 - ns Vol2 Power Good Output Saturation Level IPG = 5mA - - 0.5 V Ion2 Power Good Leakage Current Collector VPG = 5V - - 1 uA Unit Remote On/Off Symbol Parameter Test Condition Min. Typ. Max. Vpson PSON Input Threshold Level - 1 1.4 2.0 V Ipson Remote Input Driving Current - - - 0.5 mA RI = 75k 17 26 45 ms 5 7.5 28.8 RI = 75k 1.5 2 6.3 ms Timing PSON to On/Off tpson(ON) On tpson(OFF) Off (PS-off) tpsoff Timing PG low to Power Off Error Amplifier Symbol Parameter Test Condition Min. Typ. Max. Unit V2.5 Reference Voltage - 2.45 2.5 2.55 V IIB*2 Input Bias Current - - - 0.1 uA AVOL * 2 Open-Loop Voltage Gain - 50 60 - dB BW * 2 Unity Gain Bandwidth - 0.3 1 - MHz Power Supply Rejection Ratio - 50 - - dB PSRR *2 Oscillator Section Symbol Parameter Test Condition Min. Typ. Max. Unit Fosc PWM Frequency RI = 75k 60 65 70 KHz Soft-Start Section Symbol Parameter Test Condition Min. Typ. Max. Unit Iss Charge Current RI = 75k 6 8 9.3 uA -6- Product Specification STC6105 Power Supply Supervisor + Regulator + PWM Comparator Section Symbol Parameter Test Condition Min. Typ. Max. Unit DC Duty Cycle - 85 - 93 % Unit PWM Output Section (OP1, OP2) Symbol Parameter Test Condition Min. Typ. Max. Vol Output Voltage Low Io = 5mA - - 0.5 V Voh Output Voltage High V12 = 12V 4 - - V RO Output Impedance of VOH - 1.5 - 3.3 k -7- Product Specification STC6105 Power Supply Supervisor + Regulator + PWM APPLICATION 1 -12V + M AIN Transformer 12V + 5V + 3.3V + UVAC V33 V5 3.3V V12 VCC 5V sb V REF2 5Vsb 47~100ohm S TBY Transform er PG FB2 FB1 OP1 STC6105 SG6106 V REF1 + PSON Pok 1Kohm PSon NVP -12V RI -5V GND 5V Vdd IN COMP OP2 SS OPP -8- 12V Product Specification STC6105 Power Supply Supervisor + Regulator + PWM Example of Using STC6105 for the ATX Power Supply Protection against over-voltage, short-circuit and fault conditions is mandatory in PC power supplies. These protection circuits can be realized by using many discrete components and comparators, which occupy a lot of PCB space and also add to assembling costs. This single chip controller IC provides complete protection circuits, shunt regulators, and PWM control function and with less number of components. STC6105 is an ideal controller IC for PC switching mode power supplies. The features and benefits of this device are listed below: Over-voltage and under-voltage protection for 3.3V, 5V and 12V without external divider Over-power protection. UV protection for –12V and/or –5V. Power-down warning for power good signal. Power good signal and power-fail lockup Remote on/off control. Delay time for PSON and PS-off signal. Two shunt regulator for 3.3V and 5V-Standby regulation. Complete pulse width modulation (PWM) control circuitry. On-chip oscillator. Programmable Soft-Start. Maximum 93% duty cycle Few external components More reliable system Little space on PCB Easy trouble-shooting and implementation FEATURE DESCRIPTIONS Over voltage protection can be implemented without any additional components. Over-voltage sense Levels or 3.3V, 5V, 12V are 4.1V, 6.1V, 14.5V respectively. Over current and/or short circuit protection can also be achieved by using over-power protection, in which OPP pin is connected to the current transformer (driver transformer). The power good signal is asserted to indicate the 3.3V, 5V and 12V is above the under voltage threshold level. PG pin goes high when the above -9- condition is reached. A 2K pull up resistor may connect to5V. The VCC can be supplied from the 5V-standby. When the VCC voltage is higher than 7V, besides the shunt regulator, the circuit of STC6105 will be shutdown and reset. No extra power supply is needed. Two internal high precision 431 shunt regulators are built-in. It provides stable reference voltages. Complete PWM control circuitry including the error amplifier for push-pull or half-bridge operation. Supervisory Circuit Operation The PC generates the remote ON/OFF logic (PSON), which is “Low” for power supply “On” and “High” to switch off the power supply. The remote ON/OFF is connected to PSON input. APPLICATION GUIDES Introduction The application guide shows the key-feature of STC6105 and illustrates how to use in an ATX switching mode power supply (SMPS). STC6105 is suitable for half-bridge, push-pull topology. It incorporates with a 4-channel supervisor, including 5V-standby. The PWM section of STC6105 comprises a built-in 65kHz oscillator and high immunity circuits, which protect the system from noise interference and provide more noise margins for improper PCB layout. STC6105 has OVP and UVP for 12V, 5V and 3.3V. Besides, the NVP is used for negative voltage protection, such as –12V and/or –5V. The UVAC (AC fails detection) is applied to detect AC line condition. Two built-in internal precision TL431 shunt regulators can be used for 3.3V or 5V auxiliary standby power. AC Fails Detection Through a resistor divider, UVAC is connected to the secondary power transformer for detecting the AC line condition. Once the voltage of UVAC is lower than 0.7V for a period of time, such as 200usec, the PG (power good) signal will be pulled low to indicate an AC line power-down condition. The voltage amplitude of the Product Specification STC6105 Power Supply Supervisor + Regulator + PWM PWM switching signal in the secondary power transformer is proportional to the AC line voltage. Adjust the ratio of resistor divider to decide the threshold of power-down warning. A small capacitor is connected from UVAC to ground for filtering the switching noise. VS Vo Vin R1 + R2 C1 UVAC 0.7V Negative Voltage Protection The NVP provides an UVP (under voltage protection) for negative voltage outputs. An under-voltage represents the phenomenal of the overload condition in negative voltage output. For example, the –12V output may drop to –10V during the overload situation. A resistor determining the threshold of the protection is connected from pin NVP to the negative voltage output. Via this resistor, NVP outputs a 64uA constant current to the negative voltage output. When the NVP voltage is over 2.1V and the situation kept for longer than 7 msec, STC6105 will lock the power outputs off. VNVP = 64 uA u (R1 + R2) – V-12V The power outputs will be locked off when VNVP t 2.1V. Over Power Protection (OPP) The OPP (over power protection) is used for detecting over power and/or short-circuit conditions. When OPPS voltage (p.4, Note-1) is higher than 2.1V and this situation existed for longer than 7 msec,STC6105 will pull the PG low and lock off the power outputs. 64uA R1 + OP1 R1 OP2 R2 OPP C1 -12V 2.1V Vdd R3 - 10 - R2 -5V