In today’s modern electronic systems, the need for power conversion circuits that can do more then simply convert one voltage to another is growing. Some systems require a constant current, constant voltage output, while others may require a limit on the maximum current that can be drawn from the input. Still others may require the power conversion chip to be interfaced to a micro-controller so that other parameters can be both measured and controlled. All of these requirements are in addition to the normal requirements of very high conversion efficiency and high operating voltage ranges.
Linear Technology’s LT®8705 is a buck-boost controller IC with 4 regulation loops which can operate from an input voltage up to 80V and generate an output voltage up to 80V. The LT8705 can operate with input voltages above, equal to, or below the desired output voltage and do so while achieving over 98% conversion efficiency. It smoothly transitions from buck region to buck-boost region to boost region as the relationship between input and output voltage changes. The integrated strong gate drivers allow a single LT8705 circuit to process up to 250 Watts of power.
The LT8705 has 4 regulation loops built in. These loops can be set up to regulate output voltage, output current, input current and input voltage. Any combination of these loops can be used in a given system. Status pins can be used to indicate which loop or loops are active at a given moment. The LT8705 also includes a built in linear regulator, useful for powering other loads such as a micro-controller.