8.1 Application Information
The UCC21739-Q1 device is very versatile because of the strong drive strength, wide range of output power supply, high isolation ratings, high CMTI and superior protection and sensing features. The device is suitable in >10kW power applications such as the traction inverter in HEV/EV, on-board charger and charging pile, motor driver, solar inverter, industrial power supplies and etc. The device can drive the high power SiC MOSFET module, IGBT module or paralleled discrete device directly without traditional buffer drive circuit based on NPN/PNP bipolar transistor in totem-pole structure, which allows the driver to have more control to the power semiconductor and saves the cost and space of the board design. The input side can support 3V, 3.3V, 5V power supply and microcontroller signal, and the device level shifts the signal to output side through isolation barrier. The device has wide output power supply range from 13V to 33V and support wide range of negative power supply. This allows the driver to be used in 20V and -5V SiC MOSFET applications, 15V and -15V IGBT application and many others. The 12V UVLO benefits the power semiconductor with lower conduction loss and improves the system efficiency. As a basic isolated single channel driver, the device can be used to drive either as a low-side or high-side driver.
UCC21739-Q1 device features extensive protection and monitoring features, which can monitor, report and protect the system from various fault conditions.
- Fast detection and protection for the overcurrent and short circuit fault. The feature is preferable in a split source SiC MOSFET module or a split emitter IGBT module. For the modules with no integrated current mirror or paralleled discrete semiconductors, the traditional desaturation circuit can be modified to implement short circuit protection. The semiconductor is shutdown when the fault is detected and FLTb pin is pulled down to indicate the fault detection. The device is latched unless reset signal is received from the RST/EN pin.
- 2-level turn-off feature to protect the power semiconductor from catastrophic breakdown during overcurrent and short circuit fault. The shutdown energy can be controlled while the overshoot of the power semiconductor is limited.
- UVLO detection to protect the semiconductor from excessive conduction loss. Once the device is detected to be in UVLO mode, the output is pulled down and RDY pin indicates the power supply is lost. The device is back to normal operation mode once the power supply is out of the UVLO status. The power good status can be monitored from the RDY pin.
- Analog signal seensing with isolated analog to PWM signal feature. This feature allows the device to sense the temperature of the semiconductor from the thermal diode or temperature sensing resistor, or dc bus voltage with resistor divider. A PWM signal is generated on the low voltage side with isolated from the high voltage side. The signal can be fed back to the microcontroller for the temperature monitoring, voltage monitoring and etc.
- The active miller clamp feature protects the power semiconductor from false turn on by driving an external MOSFET. This feature allows the flexibility of the board layout design and the pulldown strength of miller clamp FET.
- Enable and disable function through the RSTb/EN pin.
- Short circuit clamping.
- Active pulldown.