80V synchronous SEPIC/negative output/boost controller IC

In today's new electronic systems, there is an increasing need for power conversion circuits that do more than simply convert one voltage to another. Some systems require a constant current output or a constant voltage output, while others may require current to flow from input to output or from output to input. All these are additional conditions under the standard requirements of high conversion efficiency and high operating voltage range.

Linear Technology's LT8710 is a synchronous SEPIC/inverting/boost controller IC with 3 regulation loops that can operate at input voltages up to 80V. When configured as a SEPIC or boost converter, the output voltage can be programmed from 1.3V to 80V. When the LT8710 is used as a negative output converter, the output voltage can be set from -0.1V to -80V. When the LT8710 is used as a SEPIC converter, it can operate with input voltages above, equal to, or below the desired output voltage. As long as the output voltage is above 4.5V, the input voltage can be reduced to nearly 0V and the converter will still operate normally, enabling very wide input range applications. Powerful integrated gate drivers allow a single LT8710 circuit to handle up to 100W of power.

The LT8710 has three built-in regulation loops. These loops can be programmed to regulate output voltage, output current, and input voltage. Any combination of these loops can be used in a given system. The FLAG pin on the LT8710 is an open-drain pin that functions as a power good and 1/10 charge current sense (C/10) pin. The C/10 function is useful for setting the body voltage and float cell voltage when charging sealed lead acid batteries. Input voltage regulation can be used to avoid collapse of high-impedance input sources such as solar panels. If input power is suddenly removed, the LT8710 can command current to flow from the output to the input so that the input voltage is maintained for a period of time (set by the input regulation loop), creating a backup power supply.

• Chapter 1：80V Synchronous SEPIC/Inverting/Boost Controller IC with 3 Regulation Loops (5 minutes and 48 seconds)