The LTC3705IGN is a controller for a 2-switch forward converter and includes on-chip bottom and top gate drivers that do not require external transformers. For secondary-side control, combine the LTC3705IGN with the LTC3706 PolyPhase® secondary-side synchronous forward controller to create a complete forward converter using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals across the isolation barrier through a tiny pulse transformer. The on-chip rectifier and the same pulse transformer provide gate drive bias power.
Alternatively, the LTC3705IGN can be used as a standalone voltage mode controller in a primary-side control architecture with optoisolator feedback. Voltage feedforward provides excellent line regulation and transient response.
Feature
- High-Speed Top and Bottom Gate Drivers for
- 2-Switch Forward Converter
- On-Chip Rectifier and Self-Starting Architecture
- Eliminate Need for Separate Gate Drive Bias Supply
- Wide Input Voltage Supply Range: 18V to 80V
- Tolerant of 100V Input Voltage Transients
- Linear Regulator Controller for Fast Start-Up
- Precision UVLO with Adjustable Hysteresis
- Overcurrent Protection
- Volt-Second Limit Prevents Transformer Core Saturation
- Voltage Feedforward for Fast Transient Response
- Available in 16-Lead Narrow SSOP Package
Applications
- Isolated 48V Telecommunication Systems
- Internet Servers and Routers
- Distributed Power Step-Down Converters
- Automotive and Heavy Equipment
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