L4990

® L4990 L4990A PRIMARY CONTROLLER CURRENT-MODE CONTROL PWM SWITCHING FREQUENCY UP TO 1MHz LOW START-UP CURRENT < 0.45mA HIGH-CURRENT OUTPUT DRIVE SUITABLE FOR POWER MOSFET (1A) FULLY LATCHED PWM LOGIC WITH DOUBLE PULSE SUPPRESSION PROGRAMMABLE DUTY CYCLE 100% AND 50% MAXIMUM DUTY CYCLE LIMIT PROGRAMMABLE SOFT START PRIMARY OVERCURRENT FAULT DETECTION WITH RE-START DELAY PWM UVLO WITH HYSTERESIS IN/OUT SYNCHRONIZATION DISABLE LATCHED INTERNAL 100ns LEADING EDGE BLANKING OF CURRENT SENSE PACKAGE: DIP16 AND SO16W DESCRIPTION This primary controller I.C., developed in BCD60II technology, has been designed to implement off BLOCK DIAGRAM SYNC 1 RCT 2 TIMING 25V DC-LIM 15 MULTIPOWER BCD TECHNOLOGY DIP16 SO16W ORDERING NUMBERS: L4990/L4990A(DIP16) L4990D/L4990AD (SO16W) line or DC-DC power supply applications using a fixed frequency current mode control. Based on a standard current mode PWM controller this device includes some features as programmable soft start, IN/OUT synchronization, disable (to be used for over voltage protection and for power management), precise maximum Duty Cycle Control, 100ns (typ) leading edge blanking on current sense, pulse by pulse current limit and overcurrent protection with soft start intervention. VCC 8 VREF 4 3 DC 14 DIS 2.5V + + T DIS Vref + 16V/10V - PWM UVLO 9 VC 13V BLANKING S R PWM 10 OUT Q OVER CURRENT ISEN 13 + FAULT SOFT-START VREF OK CLK DIS 11 PGND SS 7 1.2V 2.5V + E/A 2R 1V R 12 SGND 6 COMP - 5 VFB D98IN1002...