FAN7685MX

www.fairchildsemi.com FAN7685/FAN7686/FAN7687 PC Power Supply Output Monitoring IC Features • • • • • • • • • • • • • PC Power Supply Outputs Supervisory Circuitry Few External Components Over Voltage Protection for 3.3V, 5V and 12V Outputs Under Voltage Protection for 3.3V, 5V and 12V Outputs Over Current Protection for 3.3V, 5V and 12V Outputs Dual Over Current Portection for 12V Outputs(FAN7687) Fault Protection Output With Open Drain Output Open Drain Power Good Output 300ms Power Good Delay 38ms PSON On/Off Delay 73us Debounce 2.3ms PSON to FPO Turn Off Delay Latch Function Controlled by PSON Description The FAN7685/FAN7686/FAN7687 is a complete output supervisory circuitry intended for use in the secondary side of the switched mode power supply. It provides overvoltage protection (OVP), undervoltage protection(UVP), overcurrent protection (OCP), and power good signal generator to monitor and control the outputs of the switching power supply system. Remote on/off(PSON) control and some precision protection features are also implemented. It directly senses all the output rails for OVP, UVP, and OCP without external divider resistors. As for output control, power good output(PGO) and fault protection output(FPO) are included. The FAN7685/FAN7686/FAN7687 offers a simple and cost effective solution with minimum number of external components and greatly reduces PCB board space for power supply. 14DIP Typical Application • PC Switching Mode Power Supply 1 14SOP 1 Rev. 1.1.0 ©2004 Fairchild Semiconductor Corporation FAN7685/FAN7686/FAN7687 Internal Block Diagrams Vcc 13 Vcc REF. Start-up POR 3.6V Vref PSON clr Delay 2.3ms CLK Oscillator Reset CLK VS12 10 VS5 12 VS33 11 (9) UVP L L H Delay 75ms CLK R R L Debounce 73us R L S Q L L H FPO L 3 FPO CLK L PWR clr L PGI_O OVP L L L Vref 3.6V H Q L L L PSON L Debounce 38ms R CLK L R Vcc 150uA 3.6V L L 4 PSON 14 PGO 2 GND IS33 9 (8) H IS5 8 L UVP H L L L 8*Iref 8*Iref 8*Iref H H (7) Vcc Iref R H CLK L H Short Detector when AC ON IS12 5 Debounce 73us H Delay clr 300ms CLK 1.2V Vref PSON 6 1 FAN7685 (FAN7686) RI PGI VCC12 13 Vcc REF. Start-up POR Power On Reset 3.6V Vref PSON clr Delay 2.3ms CLK Oscillator Reset CLK R L L Q L H FPO UVP Block VS12 10 VS5 12 UVP L 3 FPO L H Delay 75ms CLK R L Debounce 73us R L S CLK clr L L PGI_O R Vcc 150uA 3.6V VS33 11 OVP Block OVP L PSON L Debounce 38ms R CLK L L 4 PSON 3.6V H 14 PGO 2 GND IS33 9 Q L L L IS5 8 OCP COMPs Vcc Iref H H L L H Short Detector when AC ON IS12 5 UVP R H CLK H H ISVCC12 7 8*Iref L L L Vref PSON Debounce 73us 1.2V H Delay clr 300ms CLK 6 1 RI PGI FAN7687 FAN7687A 2 FAN7685/FAN7686/FAN7687 Pin Assignments PGI 1 GND 2 14 PGO 13 VCC PGI 1 GND 2 14 PGO 13 VCC PGI GND FPO 1 2 14 PGO 13 VCC12 F A N 7687 FAN7687A F A N 7 685 F A N 7 686 FPO 3 PSON 4 IS12 5 RI 6 NC 7 12 VS5 11 VS33 10 VS12 9 IS33 8 IS5 FPO 3 PSON 4 IS12 5 RI 6 IS5 7 12 VS5 11 VS33 10 NC 9 VS12 8 IS33 3 12 VS5 11 VS33 10 VS12 9 IS33 8 IS5 PSON 4 IS12 RI 5 6 ISVCC12 7 Pin Definitions Pin Number 1 2 3 4 5 6 7 Pin Name PGI GND FPO PSON IS12 RI NC IS5* ISVCC12** 8 9 10 11 12 13 14 IS5 IS33* IS33 VS12* VS12 NC* VS33 VS5 Vcc VCC12** PGO I I I I O I I I I I I I I/O I O I I O Power Good Input Ground Fault Protection Output, Open Drain Output Remote On/Off Control Input 12V Over Current Protection Reference Current Setting Resistor No Connection(FAN7685) 5V Over Current Protection(FAN7686) 12V-II Over Current Protection(FAN7687) 5V Over Current Protection(FAN7685/7) 3.3V Over Current Protection(FAN7686) 3.3V Over Current Protection(FAN7685/7) 12V Output Over/Under Voltage Protection(FAN7686) 12V Output Over/Under Voltage Protection(FAN7685/7) No Connection(FAN7686) 3.3V Output Over/Under Voltage Protection 5V Output Over/Under Voltage Protection Supply Voltage(FAN7675/6) Supply Voltage & 12V-II OV/UV Protectioin(FAN7687) Power Good Output, Open Drain Output Pin Function Description Notes : * : FAN7686 Pin Definitions ** : FAN7687/FAN7687A Pin Definitions 3 FAN7685/FAN7686/FAN7687 Absolute Maximum Ratings Parameter Supply Voltage Input Voltage Symbol VCC, VCC12 VPSON, VS5, VS33, VPGI, IS5, IS33 VS12, IS12, ISVCC12 Output Voltage Operating Temperature Storage Temperature Power Dissipation VPGO VFPO Topr Tstg PD Value 16 8 16 8 16 -40 ~ 125 -55 ~ 150 1 V °C °C W Unit V V *Note : Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. Recommended Operating Conditions Characteristic Supply Voltage Input Voltage VCC, VCC12 VPSON , VS5, VS33, VPGI, IS5, IS33 VS12, IS12, ISVCC12 Output Voltage Output Sink Current Supply Voltage Rising Time, See Note1 Output Current for RI Note 1. VCC slew rate must be less than 14V/ms. Min. 4 1 12.5 Typ. Max. 15 Unit V V V V mA mA ms uA - 7 15 7 15 30 10 62.5 VPGO VFPO IFPO IPGO tr IO(RI) 4 FAN7685/FAN7686/FAN7687 Electrical Characteristics(VCC = 5V, Ta=25°C, unless otherwise specified) Over Voltage Protection, Under Voltage Protection and FPO Parameter VS33 VS5 VS12, VCC12 VS33 VS5 VS12, VCC12 Ratio of Current Sense Sink Current to Current Sense Setting Pin(RI) Source Current Offset Voltage of OCP Comparator Leakage Current(FPO) Low Level Output Voltage(FPO) PGI and PGO Input Threshold Voltage(PGI) Leakage Current(PGO) Low Level Output Voltage(PGO) PSON Control Input Pull-up Current High-Level Input Voltage Low-Level Input Voltage Total Device Supply Current Switching Characteristics Debounce Time(PSON) Noise Debounce Time PGO Delay Time(PGI to PGO) Internal UVP Delay Time ICC VPSON = 5V 25 50 200 FPO goes low and every time PGI > 1.2 FPO goes low and everytime PGI