Secondary-Side Optocoupler Driver

Description: The LT4430 drives the opto-coupler that crosses the galvanic barrier in an isolated power supply. The IC contains a precision-trimmed reference, a high bandwidth error amplifier, an inverting gain of 6 stage to drive the opto-coupler, and unique overshoot control circuitry. The LT4430's 600mV reference provides ±0.75% initial accuracy and ±1.25% tolerance over temperature. A high bandwidth 9MHz error amplifier permits simple frequency compensation and negligible phase shift at typical loop crossover frequencies. The opto-coupler driver provides 10mA of output current and is short-circuit protected. A unique overshoot control function prevents output overshoot on start-up and short-circuit recovery with a single capacitor.

The LT4430 integrated circuit is designed specifically for driving opto-couplers within isolated power supply applications, effectively managing the electrical isolation required between high-voltage and low-voltage sections of a circuit. This device features a precision-trimmed 600mV reference voltage that ensures reliable operation with an impressive initial accuracy of ±0.75% and a temperature tolerance of ±1.25%.

The LT4430 incorporates a high bandwidth error amplifier with a frequency response of 9MHz, facilitating straightforward frequency compensation while maintaining minimal phase shift at standard loop crossover frequencies. This characteristic is crucial for ensuring stability and performance in feedback control systems.

The inverting gain stage, with a gain factor of 6, is specifically tailored to drive the opto-coupler effectively, allowing the output to reach a maximum current of 10mA. This output capability is essential for ensuring that the opto-coupler operates within its specifications, providing reliable signal transmission across the galvanic barrier.

Furthermore, the LT4430 includes robust short-circuit protection to safeguard the device and connected components during fault conditions. The innovative overshoot control function is particularly noteworthy, as it prevents excessive output voltage during startup and short-circuit recovery events, enhancing system reliability. This function operates with the aid of a single capacitor, simplifying the design and minimizing component count while ensuring optimal performance.

Overall, the LT4430 is a versatile and efficient solution for applications requiring isolated power supply configurations, combining precision voltage regulation, high-speed performance, and protective features in a single package.The LT ®4430 drives the opto-coupler that crosses the galvanic barrier in an isolated power supply. The IC contains a precision-trimmed reference, a high bandwidth error amplifier, an inverting gain of 6 stage to drive the optocoupler and unique overshoot control circuitry. The LT4430`s 600mV reference provides ±0. 75% initial accuracy and ±1. 25% tolerance over temperature. A high bandwidth 9MHz error amplifier permits simple frequency compensation and negligible phase shift at typical loop crossover frequencies. The opto-coupler driver provides 10mA of output current and is short-circuit protected. A unique overshoot control function prevents output overshoot on start-up and short-circuit recovery with a single capacitor.