Off-Line Switching Regulators Handle Very High Voltages

The TC33370 through TC33374 off-line switching regulators include multiple on-chip functions, which allows implementation of off-line power converters using fewer external components and reduces converter cost and complexity. Designed using a very-high-voltage SmartMOS process, the regulators can operate from a rectified 85 to 276 vac universal line source. They operate at a switching frequency of 100 kHz, which minimizes power losses and enables use of smaller transformers. The regulators incorporate both a BiCMOS controller and a high-voltage and low-voltage transistors on the same chip. An integrated programmable state controller allows implementation of four on/off control methods.