Toshiba New Gate Driver Photocoupler Drives SiC Mosfet Technology

In order to drive silicon carbide (SiC) MOSFETs, Toshiba Electronic Devices & Storage Corporation has introduced the “TLP5814H,” a gate driver photocoupler with an output of +6.8A/-4.8A in a compact size SO8L package that also features an active Miller clamp function.

When the lower arm is turned off, a Miller current can produce gate voltage in circuits like inverters, which use MOSFETs or IGBTs in series.

This can lead to problems like short circuits in the upper and lower arms. Applying a negative voltage to the gate when it is switched off is a frequently used protection feature to stop this.

It is not possible to apply enough negative voltage between the gate and source for some SiC MOSFETs, which typically have higher voltage, lower on-resistance, and faster switching characteristics than silicon (Si) MOSFETs.

Without applying the negative voltage, the Miller current can be directed from the gate to ground in this situation using an active Miller clamp circuit, preventing the short circuit. On the other hand, gate drivers with an integrated active Miller clamp are a viable alternative for cost-cutting designs that lower the negative voltage provided to the gate when the IGBTs are off.

The novel device eliminates the requirement for external active Miller clamp circuits and a separate power supply for negative voltage because it features an integrated active Miller clamp circuit. In addition to giving the system a safety feature, this encourages system downsizing by lowering the number of external circuits.

With a peak clamp sinking current rating of 6.8A and a channel resistance of 0.69? (typ. ), the active Miller clamp circuit is appropriate for use as a gate driver for SiC MOSFETs, which are extremely sensitive to variations in gate voltage.

By improving the optical output of the infrared-emitting diode on the input side and refining the design of the photo detector devices (photodiode arrays) to increase optical coupling efficiency, the TLP5814H has an operating temperature rating of -40 to 125°C.

This makes it appropriate for industrial devices like photovoltaic (PV) inverters and uninterruptible power supply (UPSs) that need rigorous heat control. The operational temperature rating range also specifies its propagation delay time and propagation delay skew.

Its tiny SO8L package, which measures 5.85 × 10 × 2.1 mm (typically), contributes to increased system board part arrangement flexibility. It can also be used for situations that need good insulation performance because of its minimal creepage distance of 8.0mm.

Toshiba will keep creating photocoupler solutions that help improve industrial equipment’s safety features.

Applications

Industrial equipment

• PV inverters, UPSs, industrial inverters, AC servo drives, etc.

Availability

Volume shipments start today. 

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