Toshiba Launches Photocoupler with Built-in Protective Functions for Medium to High Current IGBT/MOSFET

TOKYO—Toshiba Electronic Devices & Storage Corporation (“Toshiba”) has introduced “TLP5231,” a pre-drive photocoupler for medium to high current insulated gate bipolar transistor (IGBT) and MOSFET, for industrial inverters and photovoltaic (PV) power conditioning systems. The new pre-drive photocoupler delivers various built-in functions[1], including an overcurrent detection by monitoring collector voltage. 

The new pre-drive photocoupler controls the gates of medium to high current IGBT and MOSFET by using external p-channel and n-channel complementary MOSFET as buffers.

Current products[2] require the use of buffer circuits composed of bipolar transistors for current amplification, which consume base current during operation. The new product eanbles use of external complementary MOSFET buffers, limiting current consumption to during charge or discharge of the buffer MOSFET gate, which reduces power consumption.

By changing external complementary MOSFET buffer sizes, the TLP5231 can produce required gate currents for various IGBT and MOSFET. A configuration of the TLP5231, the MOSFET buffer, and the IGBT and MOSFET can be used as platforms to cover the power requirements of systems, contributing to the easier design.

Other features include control of “gate soft turn-off time” with another external n-channel MOSFET after VCE(sat) overcurrent detection, and, in addition to VCE(sat) overcurrent detection by monitoring the collector voltage, UVLO[3] detection that outputs any fault signal to the primary side. These new features, not found in current products[2], make it easier for users to design gate drive circuits.

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