Toshiba Introduces New Photovoltaic-Output Photocoupler for Isolated Solid-State Relays

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Toshiba Electronic Devices & Storage Corporation (Toshiba) has released a photovoltaic-output photocoupler (photovoltaic coupler), TLP3910, housed in a thin SO6L package, suitable for driving the gates of high-voltage power MOSFETs used as isolated solid-state relay (SSR) function.

An SSR is a kind of semiconductor relays that has a photo-triac, a photo transistor or photo thyristor as its output device. It is suitable for applications for performing ON/OFF control of large currents. 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 new TLP3910 has a minimum open voltage of 14 V, double that of 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 realized a typical turn-off time of 0.1 ms, about 1/3 that of TLP3906 and about 1/30 that of TLP191B, and this delivers higher speed operation.

TLP3910 is Toshiba’s first photovoltaic coupler to feature a minimum isolation voltage of 5000 Vrms while maintaining the basic performance of the current products, TLP191B and TLP3906. This allows use in industrial equipment driven by AC400 V systems. The scope of application has also been extended by its high-temperature operation of 125 °C.

Applications:

  • Isolated SSRs: gate drive of high-voltage power MOSFETs for switches.
  • Industrial Equipment: relay contact output for I/O of programmable logic controllers and the like; solenoid driver control parts of braking systems; main power supply circuits/inrush current protection circuits; battery voltage monitoring parts for battery management systems (BMS); ground fault detection parts.
  • Measuring Equipment: power supply line switching; measuring line switching

Features:

  • High open voltage: VOC = 14 V (min)
  • Short-circuit current: ISC = 12 μA (min) @IF = 10 mA, (C20 rank product) ISC = 20 μA (min) @IF = 10 mA
  • High isolation voltage: BVS = 5000 Vrms (min)
  • High operation temperature rating: Topr (max) = 125 °C
  • Creepage (Space Distance): 8 mm (min)

Main Specifications:


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