The AP3984 integrated high-voltage (HV) start-up circuit from Diodes is a power switcher for line-powered chargers and adaptors targeting consumer and industrial applications. Designed as a primary-side controller, the AP3984 realizes excellent transient characteristics when combined with secondary-side ICs such as the AP4341/2, supplying outputs above 4.3 V. This is achieved with current and voltage tolerances of just ±5%. The built-in start-up circuit with integrated 700-V bipolar junction transistor also eliminates external resistors, simplifying system design and allowing the AP3984 to directly switch the line input. The device also has a programmable line voltage drop-compensation function.
With protection features such as over-voltage, open- and short-circuit protection, and over-temperature protection with auto-restart, the AP3984 provides a highly integrated solution that also meets Energy Star 6.0 efficiency criteria with a standby power of less than 10 mW. Multiple PWM/PFM switching modes combined with a frequency dithering function further aid efficiency while improving EMC performance and reducing audible noise. Diodes, Inc.: www.diodes.com