TEA1521P

The TEA1521P is one member of the TEA152x series.The TEA152x family is a Switched Mode Power Supply (SMPS) controller IC that operates directly from the rectified universal mains. It is implemented in the high voltage EZ-HV SOI process, combined with a low voltage BICMOS process.The device includes a high voltage power switch and a circuit for start-up directly from the rectified mains voltage.A minimum ripple is obtained in a system designed for a maximum duty factor of 50% under normal operating conditions, and a minimized dead time. The magnitude of the ripple in the output voltage is determined by the frequency and duty factor of the converter, the output current level and the value and ESR of the output capacitor.

Features of the TEA1521P are:(1)operates from universal AC mains supplies(80 to 276 V); (2)adjustable frequency for flexible design; (3)RC oscillator for load insensitive regulation loop constant; (4)valley switching for minimum switch-on loss (not implemented in TEA152xAJM versions); (5)frequency reduction at low power output makes low standby power possible (<100 mW); (6)adjustable overcurrent protection; (7)under voltage protection; (8)temperature protection; (9)short circuit winding protection; (10)simple application with both primary and secondary(opto) feedback; (11)available in 8-pin DIP, 14-pin SO and 9-pin DBS packages.

The absolute maximum ratings of the TEA1521P can be summarized as:(1)junction temperature range:-20 to 145;(2)storage temperature:-55 to 150;(3)ambient temperature:-20 to 85;(4)low supply voltage:-0.4 to 40V;(5)oscillator input voltage:-0.4 to +3 V.The TEA152x family is the heart of a compact flyback converter, with the IC placed at the primary side.The auxiliary winding of the transformer can be used for indirect feedback to control the isolated output. This additional winding also powers the IC. A more accurate control of the output voltage and/or current can be implemented with an additional secondary sensing circuit and optocoupler feedback.Overvoltage protection can be achieved in the application by pulling pin REG above its normal operation level.The current primary stroke is terminated immediately, and no newprimary stroke isstarteduntilthe voltageonpin REG drops to its normal operation level. Pin REG has an internal clamp. The current feed into this pin must be limited.