AN8027W

■ 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