Solid-state relays are semiconductor relay devices that incorporate a phototriac, phototransistor, or photothyristor as their output device. They are commonly used in applications requiring ON/OFF control of large electrical currents, such as industrial equipment (I/O relay outputs for PLCs, inrush current protection in power supplies, battery voltage monitoring in battery management systems, and ground fault detection, among others), as well as power and signal line switching in instrumentation applications.
A photovoltaic coupler like the new TLP3910 is a photorelay that contains the optical elements but not the MOSFET that performs the high-current switching functions. To easily configure an isolated solid-state relay capable of switching high voltages and currents (which is complicated for photorelays), designers often combine a photovoltaic coupler and a MOSFET.
To control a high-voltage power MOSFET with a gate voltage of 10V or higher, two Toshiba TLP3906s must currently be connected in series due to their low open-circuit voltage of approximately 7V. However, the new TLP3910 has a minimum open-circuit voltage (VOC) of 14V, twice that of the TLP3906, meaning only one device is needed to control the gate of a high-voltage power MOSFET. This reduces the number of components, improves reliability, takes up less space on the printed circuit board, and lowers the bill of materials cost.
The improvements made to the integrated discharge circuit in the TLP3910 have enabled a typical cutoff time (toff) of 0.1ms, which is about one-third that of the TLP3906 and thirty times lower than that of the TLP191B. The typical conduction time (ton) is 0.3ms, and together they ensure high-speed operation in end-user applications.
The TLP3910 is Toshiba's first photovoltaic coupler characterized by a minimum insulation voltage (BVS) of 5000Vrms, while maintaining the excellent performance of current products (TLP191B and TLP3906). This, along with its 8mm creepage distance and corresponding UL/cUL approvals, allows its use in industrial equipment powered by 400VAC systems and other applications where electrical safety is paramount.
The high temperature operating range (Topr) of -40 to +125°C ensures that the TLP3910 is suitable for a wide variety of applications in harsh environments.
