11 A High Voltage Isolated Bipolar Gate Driver with Fault Detection, Miller Clamp

The ADuM4146 is a single-channel gate driver specifically optimized for driving silicon carbide (SiC), metal-oxide semiconductor field effect transistors (MOSFETs). Analog Devices, Inc., iCoupler® technology provides isolation between the input signal and the output gate drive.

The ADuM4146 includes a Miller clamp to provide robust SiC turn off with a single-rail supply when the gate voltage drops to less than 2 V. Operation with unipolar or bipolar secondary supplies is possible with or without the Miller clamp operation.

The Analog Devices chip scale transformers also provide isolated communication of control information between the high voltage and low voltage domains of the chip. Information on the status of the chip can be read back from dedicated outputs. Control of resetting the device after a fault on the secondary side is performed on the primary side of the device.

Integrated onto the ADuM4146 is a desaturation detection circuit that provides protection against high voltage short-circuit SiC operation. The desaturation protection contains noise reducing features, such as a 300 ns masking time after a switching event to mask voltage spikes due to initial turn on (see Figure 17 in the data sheet). An optional internal 500 μA current source allows low device count, and the internal blanking switch allows the addition of an external current source if more noise immunity is needed.

The secondary undervoltage lockout (UVLO) is set to 14.5 V (typical) for Grade A and is set to 11.5 V (typical) for Grade B and Grade C with common SiC and insulated gate bipolar transistor (IGBT) levels taken into consideration.

APPLICATIONS

* SiC/MOSFET/IGBT gate drivers

* Photovoltaic (PV) inverters

* Motor drives

* Power supplies

* 11 A short-circuit source current (0 Ω gate resistance)

* 9 A short-circuit sink current (0 Ω gate resistance)

* 4.61 A peak current (2 Ω gate resistance)

* Output power device resistance: <1 Ω

* Output voltage range up to 30 V

* Multiple UVLO options on VDD2

* Grade A: 14.5 V (typical) UVLO on VDD2 positive going threshold

* Grade B and Grade C: 11.5 V (typical) UVLO on VDD2 positive going threshold

* VDD1 input voltage range from 2.5 V to 6 V

* Desaturation protection

* Soft shutdown on desaturation fault