TK75002 Datasheet | TOKO

ERROR SIGNAL ISOLATOR Features s s s s s s s s s Eliminates Opto-coupler from Feedback Loop Replaces TL431 and Eliminates Parasitic Zero Pulse Transformer Driver Same Transformer for Any Output Voltage Peak Current Controlled Automatic Volt-Second Balancing Self-running Oscillator Hi-performance Op-amp & Bandgap Reference Functionally Integrated & Simplified 5-pin Design APPLICATIONS s s s s s s Power Supplies with Primary-Side Controller Low Isolation-Barrier Capacitance Equipment Instrumentation Industrial Process Control Test Equipment Data Acquisition DESCRIPTION The TK75002 monitors the output voltage of a power supply, generates an error signal, and transmits the error signal across an isolation barrier using a small pulse transformer. In conjunction with the pulse transformer, it replaces the TL431/opto-coupler bination and eliminates the undesirable zero created in the feedback loop by that bination. The transformer is driven with pulse amplitude modulation in a free-running oscillator configuration. The period of oscillation is proportional to the inductance of the pulse transformer. The magnitude of the voltage pulse is internally limited so that the pulse transformer design need not be changed for various output voltages. The TK75002 is available in an 8-pin DIP package. VCC NC NC NC INV BLOCK DIAGRAM ORDERING INFORMATION VCC TRANSFORMER RESET DETECTOR UVLO TK75002D Tape/Reel Code BANDGAP REFERENCE LEVEL SHIFTER VLS = K(2.5 V - VP) + + VLS Q BUFFER 2.5 V VP P 650 m V PAM LATCH S Temperature Code EXTENDED TEMP. RANGE I: -40 TO +85 C TAPE/REEL CODE MG: Magazine R PEAK CURRENT DETECTOR PAM SWITCH ERROR AMPLIFIER 4Ω 220 m V GND 1.35 V INV January 1999 TOKO, Inc. Page...