Toshiba TLP3910 photovoltaic-output photocoupler

Toshiba Electronic Devices & Storage has launched the TLP3910 — a photovoltaic-output photocoupler (photovoltaic coupler) housed in a thin SO6L package, suitable for driving the gates of high-voltage power MOSFETs used as isolated solid state relays (SSR). A photovoltaic coupler is a photorelay with its optical devices but without the MOSFET used to perform switching functions. In configuring an isolated SSR, high-voltage, large-current switching — which photorelays handle with difficulty — can be implemented easily by combining a photovoltaic coupler and a MOSFET.

Driving a high-voltage power MOSFET with a gate voltage of 10 V or higher requires connecting two of Toshiba’s current product, the TLP3906, in series, as it has a low open voltage. In contrast, the TLP3910 has a minimum open voltage of 14 V — double that of the TLP3906 — and only one is required to drive the gate of a high-voltage power MOSFET. This contributes to part-count reduction. Improvement to the built-in discharge circuit has realised a typical turn-off time of 0.1 ms — about one-third that of the TLP3906 — delivering higher-speed operation.

The photovoltaic coupler features a minimum isolation voltage of 5000 V_rms while maintaining the basic performance of the current products, the TLP191B and TLP3906. This allows use in industrial equipment driven by AC 400 V systems. The scope of application has also been extended by its high-temperature operation of 125°C.

Applications include isolated SSRs, industrial equipment and measuring equipment.