Optocouplers enable automakers to replace mechanical relays for high-voltage isolation

     Toshiba Electronics Europe Ltd. has announced a new automotive compatible optical relay for 400V battery-related control systems. The TLX9152M has a minimum output withstand voltage (VOFF) of 900V to support applications such as battery and fuel cell control, as well as BMS in EVs, which can be used to monitor voltage in circuits, monitor mechanical relay adhesion and detect ground faults.

     The device consists of an infrared emitting diode optically coupled with a photoelectric mosfet. Its quick response (TON/TOFF) time of 1ms(Max) is a key defining specification for design engineers. The trigger current is 3mA(maximum), which reduces the system energy consumption. In addition, the device's off state current (IOFF) is 100nA(maximum) at ambient temperature, which means it consumes the least power when inactive. The infrared LED has a 20mA(maximum) forward current (IF), while its photoelectric detection element has a 50mA conducting current (ION).

     For a 400V automotive battery system, the Hi-Pot test has a test voltage of 1800V, and the same output voltage can be achieved using both products. In addition, the device is packaged in a SO16L-T package (the company's package code is 11-10N1A), which is widely used in high-voltage photorelays. Its existing product TLX9160T package is the same, providing 1500V output voltage withstand in an 800V battery system when the test voltage is set to 2600V. Therefore, this combination allows 400V and 800V battery systems to share the circuit board.

     The device is packaged in SO16L-T, which is an improved version of SO16L with only 12 pins. It has a space-saving 10.3mm x 10mm x 2.45mm form factor that helps simplify system integration. When used in 1kV systems, this normally open (1-Form-A) device displays a 5mm creepage and clearance distance on its output side, ensuring that effective isolation is maintained. The device can operate in a wide temperature range from -40 ° C to +125 ° C, fully complying with AEC-Q101 standards for automotive applications.