KA3501

www.fairchildsemi.com KA3501 PC SMPS Supervisory IC Features Complete House Keeping Circuit Few External Components Positive Voltage Protection Negative Voltage Protection High Current Drive Output for SCR Precision Voltage Reference for 5V/12V Outputs Power Good Signal Generator with Hysteresis Description The KA3501 is complete housekeeping circuits for use in the secondary side of SMPS(Switched Mode Power Supply). This IC(Integrated Circuit) contains a precision voltage reference, protection circuits and a power good signal generator. It also has a high current drive output for use in conjunction with an external "crowbar" SCR. The reference voltage is trimmed to ±2% for correct output voltages(+5V/ +12V) and power good signal generator is to monitor the voltage level of power good supply for safe operation in a microprocessor circuit. Using the KA3501 requires few external components to accomplish a complete housekeeping circuit for SMPS(Switched Mode Power Supply). The KA3501 is available in an 14-pin DIP. 14-DIP 1 Internal Block Diagram 4 VCC1(+5V) VCC 7 8 Vin1 Positive Voltage Protection START UP +5V Detecting COMP lchg Vin2 5 GATE 6 Feedback 14 2 Vref Negative Voltage Protection 11 PG INTERNAL BIAS VCC Detecting COMP +2.5V REFERENCE VOLTAGE 12 Ve VCC2(+12V) 3 1 Vcont 13 GND 9 Td 10 Timing Rev. 1.0.2 ©2002 Fairchild Semiconductor Corporation KA3501 Pin Assignments #1 Vcont Vref Vcc2 Vcc1 Vin2 Gate Vcc #7 #14 Feedback GND K A 3 5 ...