ILA4605-2 Control IC for Switched Mode Power Supplies using MOS Transistors The IC ILA 4605-2 controls the MOS - power transistor and performs all necessary regulation and monitoring function in free running flyback converters. Because of the fact that a wide load range is achieved, this IC is applicable for consumer as well as industrial power supplies. The serial circuit and primary winding of the flyback transformer are connected in series to the input voltage. During the switch - on period of the transistor, energy is stored in the transformer. During the switch - off period the energy is fed to the load via the secondary winding. By varying switch - on time of the Power transistor, the IC controls each portion of energy transferred to the secondary side such that the output voltage remains nearly independent of load variations. The required control information is taken from the input voltage during the switch - on period and from a regulation winding during the switch - off period. A new cycle will start if the transformer has transferred the stored energy completely into the load. FEATURES: • • • • • • • • Fold - back characteristics provides overload protection for external components Burst operation under secondary short - circuit condition implemented Protection against open or short of the control loop Switch - off if line voltage is too low (undervoltage switch - off) Line voltage depending compensation of fold - back point Soft start for quiet start - up without noise generated by the transformer Chip - over temperature protection (thermal shutdown) On - chip ringing suppression circuit against parasitic oscillations of the transformer P-DIP-8-1 In the different voltage ranges the switched - mode Power supply (SMPS) behaves as follow: No load operation. The Power supply is operating in the burst mode at typical 20 to 40 kHz. The output voltage can be a little bit higher or lower than the nominal value depending on the design of the transformer and the resistors of the control voltage divider. Nominal operation. The switching frequency is reduced with increasing load and decreasing AC voltage. The duty factor primarily depends on the AC voltage. The output voltage is only depends on the load. Overload point. Maximum output Power is available at this point of the output characteristic. Overload. The energy transferred per operation cycle is limited at the top. Therefore the output voltages declines by secondary overloading. PIN DEFINITION Pin # 1. 2. 3. 4. 5. 6. 7. 8. Function Information Input Concerning Secondary Voltage Information Input Regarding the Primary Current Input for Primary Voltage Monitoring Ground Output Supply Voltage Input Input for Soft Start and Integrator Circuit Input for the Feedback of the Oscillator 1 ILA4605-2 Block Diagram 6 5 V2B Reference Voltage typ. 3V 4 2 Supply Voltage Monitor V6min V6A VREF Primary Current Voltage Converter Output Stage and Current Control Circuit VST V6E V6max Start Pulse Generator Logic Current Source VR 1 Control & Overload Amplifier Stop Comparator Zero Crossing Detector VV Fold-back Point Correction Primary Voltage Supervision 3 7 8 ABSOLUTE MAXIMUM RATINGS Ta=-20 to 85oC; all voltages relatives to Vpp Parameter Voltages pin 1 pin 2 pin 3 pin 4 pin 5 pin 6 pin 7 Current pin 1 pin 2 pin 3 pin 4 pin 5 pin 6 pin 7 pin 8 Junction temperature Storage temperature Operating Range Supply voltage Ambient temperature Symbol V1 V2 V3 V4 V5 V6 V7 I1 I2 I3 I4 I5 I6 I7 I8 Tj Tstg Limit Values min max -0.3 3 -0.3 -0.3 -0.3 -0.3 V6 -0.3 20 -0.3 3 3 3 -1.5 -0.5 1.5 0.5 3 -5 3 125 -40 125 V6 Ta 7.5 -20 15.5 85 * tp= pulse width v = duty circle 2 Unit V V V V V V V mA mA mA A A A mA mA o C o C V C o Notes Supply voltage tp≤50µs; v≤0.1 * tp≤50µs; v≤0.1 tp≤50µs; v≤0.1 IC is on ILA4605-2 CHARACTERISTICS Ta=25oC; VS=10V Parameter Symbol Start - Up Hysteresis Start-up current drain Switch-on voltage Switch-on current Voltage Clamp (V6=10V; IC is off) At pins 2,3 (V6≤V6E) Control Range Control input voltage Voltage gain of the control circuit in the control value Push-Pull Output Stage Saturation voltages Pin 5 sourcing Pin5 sinking Protection Circuit Undervoltage protection for V6: voltage at pin 5 = V5min if V6< V6min Undervoltage protection for V6: voltage at pin 5 = V5min if V6> V6max Limit Values min. max. I6EO V6E I6E1 11 Vmax V1R -VR Units 1.6 13 16 mA V mA 5.6 9.0 V 370 150 430 mV 2.2 1.4 V V 8 V 16.7 V Vsat0 VsatV 6 V6min V6max Test Condition V6=V6E V6=V6E I2,3=1mA I5=-0.1A I5=+0.1A APPLICATION DIAGRAM R3 4.7 D6 FU1.25 +124Â 180...260 V R4 330k R2 27K 4W R11 820k C1 150F 385V CR1 BYW76 C4 33nF/630V n5 4x1N4007 n2 C5 4.7 nF R1 75k R10 5.1k D5 R16 0.1 C3 220pF T1 BUZ90 n4 n3 D1 1N4148 C8 220nF47µF 7 2 ЭКР1087EY1 (TDA4605-2) 3 R8 47 5 R9 10k 8 R6 1K 1 4 R7 2.5k D3 n1 1N4148 C6 R5 220 1µF 3 C10 470µF R17 27 D4 BYW72 R13 47 C2 47µF 100V +17.5Â BYW72 R15 0.1 6 R12 47k C11 47µF D2 BA159 C7 4.7nF +8.5Â C9 1000µF