LT8722 Monolithic Full Bridge DC/DC Converter

ADI's LT8722 is a high-performance, high efficiency, monolithic full-bridge DC/DC converter. One side of the full-bridge is driven by a pulse width modulation (PWM) buck power stage, while the other side is driven by a linear power stage. The LT8722 can deliver up to 54 W of power to meet the needs of the latest thermoelectric coolers (TEC). An integrated 25-bit digital-to-analog converter (DAC) controls the output voltage and minimizes temperature variation.

The analog output telemetry pin can be used to monitor serial peripheral interface (SPI) selectable parameters such as V_IN, V_OUT, I_OUT, or the LT8722 junction temperature. The SPI can be used to configure and control the LT8722 allowing for flexibility to set the desired output voltage, output current limits, voltage limits, switching frequency, and control ON/OFF behavior. The SPI operates at up to 10 MHz allowing for fast readback and control. The LT8722 operates from a single 3.1 V to 15 V supply. Silent switcher techniques are used to minimize EMI/EMC emissions while delivering high efficiency at high switching frequencies. The LT8722 is available in a 3 mm x 3 mm LQFN package.

The demonstration circuit DC3145A shows a high-efficiency thermoelectric cooler driver and features the LT8722 monolithic driver. The input voltage range of the DC3145A is from 3.1 V to 15 V, and the output is an SPI programmable differential voltage output. The maximum output current is 4 A. The switching frequency SPI is programmable from 500 kHz to 3 MHz.

The LT8722 is controlled through an SPI, and therefore, the demonstration circuit also interfaces through SPI. For demonstration purposes, the manual provides instructions on connecting the DC2026C Linduino board to monitor and control the DC3145A with a PC using a command line Arduino IDE interface.

Features

• 25-bit digital output voltage control
• Silent switcher techniques minimize EMI/EMC emissions to reduce or eliminate shielding requirements
• Small solution size (3 mm x 3 mm LQFN) reduces PCB space and BOM list for a cost-effective solution