TOP271VG

TOP271VG is a robust and compact high-efficiency integrated off-line switcher suitable for variety of single-ended primary inductance converter (LLC) based applications. It is providing up to 390V DC bus for ultra wide range AC input. It combines a series of superior power management functions in a single monolithic IC, such as inrush current limit control and under-voltage lockout (UVP).

TOP271VG is widely nowadays used in variety of discrete and integrated AC/DC applications. These applications are offered in a wide range of input voltage levels and power output capacities, including (but not limited to) adapters and chargers, DC/DC converters, on-line UPS systems and power supplies for white goods and industrial machinery.

TOP271VG is a step-down switcher integrated circuit and part of PMIC (Power management IC) family. It is based on a current-mode control, that contains a built-in current sense amplifier and a start-up regulator.

Features of TOP271VG

• Input voltage range from 85Vac to 305Vac
• VCC range from 10V to 15V
• PFC switching frequency selectable up to 500KHz
• Off-time control
• High efficiency
• Over-voltage protection
• Thermal protection
• Under-voltage soft-start
• Power synchronous rectification

Working Principle

The TOP271VG integrates a number of discrete components into one monolithic IC, such as start-up charges, over-current and over-voltage protection, under-voltage lockout (UVP). The TOP271VG works by providing an adjustable current-mode control to limit output power. When the output current exceeds the current threshold, the TOP271VG reduces the output current by increasing the off-time pulse-width.

The internal MOSFET drive circuit of TOP271VG includes a driver stage, an internal regulator and a power switch, that is controlled by a high-speed current-mode control loop. Moreover, the TOP271VG features a soft-start/inrush current limit control circuit to prevent large in-rush currents.

The TOP271VG also offers comprehensive thermal protection through an externally programmable thermal protection circuit. The reference voltage is provided by an internal temperature sensitive voltage source. When the junction temperature exceeds the programmed temperature, the output will be switched off.

Applications

TOP271VG is primarily used in power supplies, adapters and chargers, DC/DC converters and on-line UPS systems. It is suitable for applications such as general-purpose switched-mode power supply (SMPS) for ubiquitous consumer electronic products and other future electronic products such as LED lighting and energy management systems.