“Compared with silicon carbide (SiC) FETs and silicon-based FETs, gallium nitride (GaN) field effect transistors (FETs) can significantly reduce switching losses and increase power density. These features are of great benefit to high switching frequency applications such as digital power converters, and can help reduce the size of magnetic components.
Compared with silicon carbide (SiC) FETs and silicon-based FETs, gallium nitride (GaN) field effect transistors (FETs) can significantly reduce switching losses and increase power density. These features are of great benefit to high switching frequency applications such as digital power converters, and can help reduce the size of magnetic components.
Designers in the power electronics industry need to adopt new technologies and methods to improve the performance of GaN systems. When using GaN technology to develop modern power conversion systems, C2000™ real-time microcontrollers (MCUs) can help meet various design challenges.
Advantages of C2000 real-time MCU
Digital controllers such as C2000 MCU have excellent applicability and are suitable for various complex topologies and control algorithms, such as zero voltage switching, zero current switching or Inductor-inductor-capacitor (LLC) resonance DC/ DC power supply.
C2000 MCU can provide the following advantages:
Complicated time-critical calculation processing. C2000 MCU has an advanced instruction set that can significantly reduce the number of cycles required for complex mathematical calculations. After the calculation time is reduced, the control loop frequency can be increased without increasing the MCU operating frequency.
Precise control. The high-resolution pulse width modulator (PWM) in the C2000 MCU can provide a resolution of 150ps, and the built-in analog comparator and configurable logic block (CLB) help safely handle various error conditions that occur.
Software and peripheral scalability. With the changes in system requirements, the C2000 platform supports the upward or downward expansion of real-time MCU functions while maintaining software investment, thereby reducing software investment and speeding up product launches. For example, low-cost C2000 MCUs such as TMS320F280029C can realize real-time processing and control in small server power supplies; and TMS320F28379D is a common device in high-frequency multiphase systems. But TMS320F28379D maintains the compatibility with TMS320F280029 code.
Use C2000 MCU to meet GaN switch challenges
As mentioned earlier, achieving a higher switching frequency can reduce the size of the magnetic components in the switching converter, but at the same time it will bring many control challenges. For example, in the Totem-pole PFC topology, reducing the size of the inductor will not only increase the current spike at the zero-crossing point, but also increase the third quadrant loss caused by the dead zone. These effects are combined This will increase total harmonic distortion (THD) and reduce efficiency.
To solve the above problems, the C2000 real-time MCU enables the soft-start algorithm through the feature-rich PWM to eliminate current spikes and improve THD. C2000 MCU also has an extended instruction set, floating-point arithmetic unit (FPU) and trigonometric accelerator (TMU), which significantly reduces the calculation time of parameters such as PWM on-time. The reduction in calculation time can also increase the control loop frequency, combined with the 150ps resolution of the PWM, can help reduce the third quadrant loss.
Use TI GaN technology to connect to C2000 MCU
As shown in Figure 1, C2000 MCUs, digital isolation devices and GaN FETs are all essential parts of the device connection.
Figure 1: Connect C2000 MCU, digital isolator and 600V GaN FET
Reinforced digital isolators can help suppress transient noise and protect C2000 MCUs. C2000 MCU does not require external logic devices, and uses its high-resolution PWM, configurable logic block and enhanced capture module to achieve all functions of GaN FET safety, temperature and error reporting, thereby providing precise control output. The integrated driver in the 600V GaN FET can reduce system design issues caused by induced ringing. The combined use of these devices eliminates the need to add additional external components, thereby reducing overall cost.
TI C2000 real-time MCU and GaN FET work in coordination to provide a flexible and simple solution for modern digital power systems, while also providing advanced functions to achieve high power density and efficient digital power systems. Our reference designs are fully tested and accompanied by comprehensive documentation, which can help accelerate the development of efficient and high-power-density digital power systems.