■ Overview

The AN8027 and AN8037 are ICs developed for selfexcited switching regulator of RCC local resonance control type.

These ICs are designed to achieve stability and high efficiency over a wide input voltage range and loads range (light loads to heavy loads), for supporting input levels used worldwide and improved conformance with energy conservation laws.

■ Features

? Support improved conformance with energy conservation laws by providing two operating modes.

? Standby mode (light loads):

Achieves better efficiency due to reduced frequency .

? Normal mode:

Achieves high efficiency in RCC local resonance operation with zero-cross detection.

? Incorporating an input voltage compensation function available to a wide input range for worldwide use.

? This function compensates the maximum on-period in inverse proportion to the input voltage.

? Incorporating a timer latch function.

? The time period can be adjusted according to the overload in normal mode or standby mode.

? This function makes it possible to protect the IC from damage that may be caused by the short-circuiting of the ICs external capacitor for the timer.

? Incorporating an overvoltage protection function. (detects at VCC pin)

? Incorporating a pulse-by-pulse overcurrent protection function, which makes latch protection possible at the time of the short-circuiting of the transformers primary winding.

? Adopting a 9-pin single inline package (E-9S: available to manufacturing in overseas).

? AN8027: Transformer resetting is detected from the high- or low-level signal on the TR pin.

? AN8037: Transformer resetting is detected from the falling edge of the high-level signal on the TR pin.

Refer to the [1] operation descriptions 7. local resonance operation section in the application notes.

■ Applications

? Televisions, VCRs, facsimiles, and printers