LT3840HFE#TRPBF

The LT3840HFE#TRPBF is a fixed frequency DC/DC step-up controller with a wide range of applications and a variety of operating modes. This controller, commonly referred to as a synchronous buck or step-up voltage regulator, can be used to create an adjustable voltage from a fixed input. It can be used to increase the output voltage from a low ideal diode voltage, to create a system supply in the 10 to 600V range, or in battery charging applications.

Application Field

The most common uses of the LT3840HFE#TRPBF include point-of-loads such as FPGA, ASIC, and SoC supplies, where high efficiency, fast transient response, and small size are needed. Other applications include automotive, battery charging, DC/DC converters, and solar inverters. The three operating modes, Continuous Inductor Current Mode, Low-power Burst Mode, and High-power Burst Mode, support a variety of low power, high power, and current-limited applications.

Working Principle

The LT3840HFE#TRPBF works by creating a loop between the input voltage, the output filter inductor, and two switches. The two switches, SW1 and SW2, are timed such that when one switch is active, the other is off. This alternate switching between the two results in a shifting of the current of the output filter to create an increase in the output voltage. The LT3840HFE#TRPBF can be used to create low-power, high-power, and current-limited applications.

Continuous Inductor Current Mode

The Continuous Inductor Current Mode is designed for high power applications and maintains the output current accordingly. It works by measuring the current in the inductor and switching the two switches in order to maintain the current at a predetermined level. This works by switching SW1 on at every cycle, allowing current to flow through it to the output filter inductor. SW2 then turns on until the current in the inductor has reached the set level.

Low-power Burst Mode

The Low-power Burst Mode is designed for low power applications and functions similarly to the Continuous Inductor Current Mode but switches the two switches at a much higher rate. This works by switching SW1 on at every cycle and then quickly turning it off after a set period of time. This reduces the amount of power consumed and improves efficiency.

High-power Burst Mode

The High-power Burst Mode is similar to the Low-power Burst Mode except that the current set point is much higher. This works by switching SW1 on at every cycle and then quickly turning off both switches once the current set point has been reached. This reduces the amount of power consumed and improves efficiency.

Conclusion

The LT3840HFE#TRPBF is a fixed frequency DC/DC step-up controller that can be used in a wide range of applications and is capable of operating in three different modes, the Continuous Inductor Current Mode, the Low-power Burst Mode, and the High-power Burst Mode. The LT3840HFE#TRPBF is commonly used in point-of-loads such as FPGA, ASIC, and SoC supplies, automotive, battery charging, DC/DC converters, and solar inverters.