STC6105 SUNTAC | Alldatasheet
Document overview
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Technical content
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FEATURES
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 SFX (micro-ATX)
DESCRIPTION
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. MARKING DIAGRAMS PIN CONFIGURATION STC6105 PSON V33 OPP UVAC NVP V12 OP2 OP1 PG FB2 VREF2 VREF1 FB1 GND COMP IN SS RI VCC STC6105 Power Supply Supervisor + Regulator + PWM
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ORDERING INFORMATION
PG 10 Logic output 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. 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 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. PSON 1 Logic input Remote On/Off logic input forʳCPU or controller. Turn on/off the PWM Output after the 7.5 msec / 26 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. NVP 6 Analog input 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 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. OP1/OP2 9/8 Analog output 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. Analog input Connected to external resistor for the reference setting. RI = 75k ohms. GND 15 Supply Ground. STC6105 Power Supply Supervisor + Regulator + PWM
- 3 - BLOCK DIAGRAM SS 2.5V 8uA Vcc NVP +6 Delay 7msecBuffer 2.1V 3.2V V33 V5 2 3 64uA UVACV12 7 5 UV Detector OV Protector UV Protector COMP_ COMP COMP_ DSD 0.7V + 2uA 2.4V OPP 4 Buffer Vcc PSON 1 + 1.4V _ Delay 2msec Delay 15msec COMP_ + Delay 7msec On/Off Delay 26msec 7.5msec COMP QD CK R OP1 PG RI GND 15 20 VCC Delay 300msec Vref Delay 3sec FB211 VREF113 FB114 VREF212 Error Amp COMP O.S.C COMP 1617 IN Q _CK DQ R SQ OP28 STC6105 Power Supply Supervisor + Regulator + PWM
- 4 - TIMING DIAGRAM VCC PSON 3.3/5/12V tpson(on) t uvp NVP t pson(off) t nvp SS(on/off) t psoff PG t PG VCC PSON Voltage < VUVAC UVAC OPP t OPP SS(on/off) PG STC6105 Power Supply Supervisor + Regulator + PWM
- 5 - 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 (T A=25к) 1.5 W PD,90к Power Dissipation (T A=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 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 35 50 65 us tUVP Timing for Under-Voltage Protection RI = 75k 0.8 2.4 3.75 ms tUVS Timing for Under-Voltage Sense for PG Low RI = 75k 0.37 1.2 1.88 ms tOPP Timing for Over-Power-Protection RI = 75k 3.3 7 11.3 ms tNVP Timing for Negative Voltage Protection RI = 75k 3.3 7 10.2 ms Note *1: VOPPS = (2/3) x VOPP + (1/3) x VUVAC ; STC6105 Power Supply Supervisor + Regulator + PWM
- 6 - Shunt Regulator (FB1, VREF1, FB2, VREF2) Symbol Parameter Test Condition Min. Typ. Max. Unit VREF Reference Voltage I FB = 0.5mA, TA = 25к 2.475 2.5 2.525 V VDEV, I *2 Deviation of V REF Over Load Current I FB = 0.5mA to 10mA - - 20 mV VDEV, T * 2 Deviation of VREF Over Temperature T A = -25к to 85к - 10 30 mV Regli-fb *2 Line Regulation 4 < V FB < 16V - 1 - mV/V Iout-fb *2 Output Sinking Current Capability V FB > 2V 10 - - 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 C L = 100pF - 1 - us tF *2 PG Good Falling Time C L = 100pF - 300 - ns Vol2 Power Good Output Saturation Level I PG = 5mA - - 0.5 V Ion2 Power Good Leakage Current Collector V PG = 5V - - 1 uA Remote On/Off Symbol Parameter Test Condition Min. Typ. Max. Unit Vpson PSON Input Threshold Level - 1 1.4 2.0 V Ipson Remote Input Driving Current - - - 0.5 mA tpson(ON) tpson(OFF) Timing PSON to On/Off On Off (PS-off) RI = 75k 17 7.5 28.8 ms tpsoff Timing PG low to Power Off RI = 75k 1.5 2 6.3 ms 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 PSRR * 2 Power Supply Rejection Ratio - 50 - - dB 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 STC6105 Power Supply Supervisor + Regulator + PWM
- 7 - Comparator Section Symbol Parameter Test Condition Min. Typ. Max. Unit DC Duty Cycle - 85 - 93 % PWM Output Section (OP1, OP2) Symbol Parameter Test Condition Min. Typ. Max. Unit Vol Output Voltage Low Io = 5mA - - 0.5 V Voh Output Voltage High V12 = 12V 4 - - V RO Output Impedance of V OH - 1.5 - 3.3 k STC6105 Power Supply Supervisor + Regulator + PWM
- 8 - APPLICATION 1 3.3V V33 V12 VCC GND PG RI PSON NVP STBY Transformer 5Vsb 3.3V FB2 VREF1 FB1 OPP UVAC VREF2 -5V -12V PSon Pok 5Vsb MAIN Transformer -12V 12V Vdd OP1 OP2 IN COMP SS 12V SG6106 1Kohm 47~100ohm STC6105 STC6105 Power Supply Supervisor + Regulator + PWM
- 9 - 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. S TC6105 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 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 STC6105 Power Supply Supervisor + Regulator + PWM
- 10 - R2R1 2.1V 64uA -12V -5V 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. 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. Vdd OPP OP2 OP1 R1 R2 R3C1 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. + UVAC Vo 0.7V R2 C1 VS Vin STC6105 Power Supply Supervisor + Regulator + PWM