ISL78233ARZ-T

ISL78233ARZ-T Application Field and Working Principle

The ISL78233ARZ-T is a 3.3V/5.5V dual-output DC/DC Synchronous Buck Switching Regulator with exceptional performance in both peaks of efficiency and+ output current. The ISL78233ARZ-T provides Two Independent buck regulators, each with a maximum output current up to 3.6 A on the 3.3V channel, and up to 4 A on the 5.5V channel.

DC/DC Synchronous Buck Switching Regulators provide multiple charging paths, allowing either one or two power supplies to be connected to the input. The cycling of the two buck switches will correspond to changes in the input supply voltage, providing an always-onrail and improved dynamic load transient accuracy. This flexibility is beneficial for applications requiring multiple supply buses and isolation of sensitive sections on the system board.

The ISL78233ARZ-T is designed as a multi-function part and easy to use in different applications. Its applications are focused on a wide range of industrial, consumer, computing and communications products and end equipment like desktops, PC, laptops, panel PCs, smart TVs, and automotive infotainment systems.

Working Principle of ISL78233ARZ-T

The ISL78233ARZ-T is a synchronous buck switching regulator for multipurpose application. It is suitable for high step-down voltage ratios and is a versatile device for both single- and dual-output configurations. The ISL78233ARZ-T comprises of an input voltage regulator with an LC filter, and two synchronous buck switching converters with internal power MOSFETs, current limit, and soft-start.

Once the input voltage regulator has regulated the input voltage, it connects the two output voltage buck converters simultaneously and provides the two output channels with an efficient, synchronized regulation. The voltage of both output channels can be precisely adjusted by means of an external RSENSE resistor.

The frequency of the output channels is synchronized in either the 180-degree or likemode of operation. The 180-degree mode reduces the number of output capacitors by one-half, while the spread-spectrum frequency operation allows any preprogrammed frequency and spread up to +/-3% around the nominal frequency.

The ISL78233ARZ-T offers two integrated dynamic current limit circuits to help optimizepower supply performance and prevent thermal shutdown during overload or short-circuit events. The two-step current limit mechanism ensures accurate current limiting behaviour. The internal MOSFETs of the buck converter combine with the current limit protection to reduce power losses and reduce the operating temperature of the device.

The ISL78233ARZ-T also provides a soft-start feature, which prevents inrush current from flowing into the output channels and helps reduce the stress on the power supply. The soft-start time can be adjusted as needed by setting the external capacitor connected to the SS pin.