LT3782EUFD#TRPBF

Introduction

The LT3782EUFD#TRPBF device is a highly integrated power switchmode controller for positive and negative voltage rails. The device integrates an oscillator, error amplifier, high voltage power switch, and protection circuitry. The LT3782EUFD#TRPBF is intended for the use in dual tracking step-down, step-up and inverting applications where wide input supply range, output tracking and low output ripple are desired features.

Features

• Wide Input Range: 0V– 40V
• No External Sense Resistors Required
• High Efficiency: τ_r of 0.05A
• Programmable Oscillator Frequency: 2MHz to 4MHz
• Supports Output Currents of up to 4A
• Current Limit Ramping
• Low Quiescent Current: 17mA
• Wide Output Range: 0.8V to 40V
• Synchronizable to an External Clock
• Output Overvoltage Protection
• Output Current Monitoring
• Wide Operating Temperature Range: -40oC to +125oC
• Small 16-Lead 4mm x 4mm TSSOP Package

Application Fields and Working Principles

The LT3782EUFD#TRPBF is well suited for a wide range of applications in both positive and negative output voltage rails such as battery charging systems, distributed power supplies, motor drives and control systems, Buck-Boost and inverting power supply applications. It can drive up to four high side power switches to generate a wide output voltage range from 0V to 40V.The fundamental concept which makes the LT3782EUFD#TRPBF a versatile DC/DC controller is its ability to integrate a wide range of necessary components such as oscillator, error amplifier, high voltage power switch, and protection circuitry into a single IC. This versatility results in creating fewer external components and reducing board space, making the device ideal for first generation designs and advanced, high-performance power solutions.

The LT3782EUFD#TRPBF is designed to run with an operating frequency range of 2-4MHz and typically employs non-synchronous operation. Its oscillator allows the user to program the desired operating frequency by programming the OSC-FREQ pin voltage. The oscillator will then drive the UGATE and LGATE signals, along with the push-pull driver and the MOSFET gate drivers. The push-pull driver drives the output voltage, while the MOSFETs and the integrated synchronous rectifier provide full power switching.

The error amplifier (EA) controls the output voltage. The EA features a maximum voltage gain of 300kHz and unity gain of 0.5MHz. The EA also includes a voltage reference which is used to separate the load/maximum power from the reference voltage. The EA should be connected to the output voltage feedback pin (OVP). The device operates in a continuous conduction mode which allows for better tracking performance, minimizing noise and transients of the output voltage.

In order to properly protect the IC and the system, the protection circuitry is designed into the device. The LT3782EUFD#TRPBF has several features for output overvoltage protection, input undervoltage lockout, overload protection, and thermal shutdown.

Conclusion

The LT3782EUFD#TRPBF is an ideal DC/DC controller for positive and negative voltage rails, offering high-efficiency and wide input supply range for dual tracking step-down, step-up and inverting applications. It integrates an oscillator, error amplifier, high voltage power switch, and protection circuitry into a single IC, which results in creating fewer external components and reduces board space. Its wide operating frequency range of 2MHz to 4MHz, programmable oscillator frequency, output current limit ramping, and current monitoring feature make it an ideal solution for many portable and distributed power applications.