Linear Technology recently announced the LT8310, which is a resonant-reset forward converter controller that drives an external low side N-channel MOSFET from an internally regulated 10-V supply. The LT8310 features duty mode control to generate a stable, regulated, isolated output using a single power transformer. With the addition of output voltage feedback, via optocoupler (isolated) or directly wired (nonisolated), current mode regulation is activated, improving output accuracy and load response. A choice of transformer turns ratio makes high step-down or step-up ratios possible without operating at duty cycle extremes.
The switching frequency is programmable from 100 kHz to 500 kHz to optimize efficiency, performance or external component size. A synchronous output is available for controlling secondary side synchronous rectification to improve efficiency. User programmable protection features include monitors on input voltage (UVLO and OVLO) and switch current (overcurrent limit). A soft-start feature helps prevent transformer flux saturation.
The LT8310 main features include:
- Input voltage range: 6 V to 100 V
- Duty mode control regulates an isolated output without an opto
- High efficiency synchronous control
- Short-circuit (Hiccup mode) overcurrent protection
- Programmable OVLO and UVLO with hysteresis
- Programmable frequency (100 kHz to 500 kHz)
- Synchronizable to an external clock
- Positive or negative polarity output voltage feedback with a single FBX pin
- Programmable soft-start
- Shutdown current < 1 μA
The LT8310 is available in an FE20 TSSOP with high voltage pin spacing