TEA2018A

TEA2018A CURRENT MODE SWITCHING POWER SUPPLY CONTROL CIRCUIT . . . . . . . . . . . DIRECT DRIVE OF THE EXTERNAL SWITCHING TRANSISTOR POSITIVE AND NEGATIVE OUTPUT CURRENTS UP TO 0.5 A CURRENT LIMITATION TRANSFORMER DEMAGNETIZATION SENSING FULL OVERLOAD AND SHORT-CIRCUIT PROTECTION PROPORTIONAL BASE CURRENT DRIVING LOW STANDBY CURRENT BEFORE STARTING (< 1.6 mA) THERMAL PROTECTION DESCRIPTION The TEA2018A is an 8-pin DIP low-cost integrated circuit designed for the control of switch mode power supplies. Due to its current mode regulation, the TEA2018A facilitates design of power supplies with following features : High stability regulation loop Automatic input voltage feed-forward in discontinuous mode fly-back Automatic pulse-by-pulse current limitation Typical applications : Video Display Units, TV sets, typewriters, microcomputers and industrialapplications Where synchronization is required, use the TEA2019. For more details, see application note AN406/0591 PIN CONNECTIONS DIP8 (Plastic Package) ORDER CODE : TEA2018A OSCILLATOR GROUND COLLECTOR CURRENT SENSING NEGATIVE SUPPLY VOLTAGE 1 2 3 4 8 7 6 5 ERROR AMPLIFIER NON-INVERTING INPUT DEMAGNETIZATION SENSING POSITIVE SUPPLY VOLTAGE 2018A-01.EPS OUTPUT May 1993 1/7 TEA2018A BLOCK DIAGRAM VCC 6 TEA2018A IS 7 DEMAGNETIZATION SENSING V CC INTERNAL BIAS MONITORING V REF 2.4V 0.1V VCC ”Good” Undervoltage Rt Ct 1 OSCILLATOR & FLIP-FLOP Ic RECOPY 5 OUTPUT DELAY 500ns 1 MAXIMUM DUTY CYCLE 70% & 1 COMPARATOR 8 G ≅...