The LTC3706/26 secondary-side synchronous controller and its companion smart gate driver, the LTC3705/25, make it possible to create an isolated forward converter with the simplicity and performance of the familiar buck converter
The document introduces the LTC3706 secondary-side synchronous controller and its companion smart gate driver, the LTC3705. These components enable the creation of isolated forward converters with the simplicity and performance typically associated with buck converters by eliminating the need for optoisolators and simplifying loop compensation.
Key features discussed include secondary-side control architecture, PolyPhase operation for improved efficiency and transient response, and various start-up sequences. The text provides circuit examples for single-switch and dual-switch topologies, detailing component selection and performance characteristics such as output voltage accuracy and current sensing methods.
| Output Voltage Accuracy (LTC3706) | 1% accuracy output voltage |
|---|---|
| Remote Sense Feature (LTC3706) | remote-sense differential amplifier |
| Max Duty Cycle Limit (LTC3706) | selectable maximum duty cycle limit of either 75% or 50% |
| High Side Gate Driver Voltage (LTC3705) | 80V (100V transient) |
| Package Type (LTC3706) | 24-lead SSOP package |
| Package Type (LTC3726) | 16-lead |
A dual-switch forward converter is preferred for applications with limited input voltage variation or where a robust and simple design is a priority.
The LTC3706 includes an output overvoltage crowbar as well as current-limiting and over-current protection.