Fully Integrated Switching Power Converters in Silicon Carbide Technology
Author | : Hua Zhang |
Publisher | : |
Total Pages | : 0 |
Release | : 2022 |
ISBN-10 | : OCLC:1356823932 |
ISBN-13 | : |
Rating | : 4/5 (32 Downloads) |
Book excerpt: Silicon Carbide (SiC) technology offers notable advantages over standard Silicon (Si) technology in terms of its high-voltage and high-temperature capabilities. These advantages make SiC a prime technology for implementing high voltage switching power converters. However, existing power converter solutions utilize SiC technology only for the realization of the high-voltage power switches, while the low-voltage analog and mixed-signal control circuitry continues to be realized in standard CMOS Silicon technology. As a result, multiple chips in different technologies are required, which significantly increases the cost, footprint, and complexity of the power converter. Moreover, in applications where the power converter must tolerate high temperature, such approach would require physical separation between the low-voltage control circuitry implemented in the Si chip and the high-voltage power stage implemented in the SiC chip, which is often unfeasible. In this research work, two versions of fully integrated switching power converters (specifically Buck converters) using a new SiC technology are presented. The Buck converters integrate the low-voltage analog and mixed-signal control circuitry and the high-voltage power stage together in a single SiC wafer, which allows for a single-chip power converter solution. The low-voltage control circuitry includes analog building blocks, such as error amplifiers, comparators, and oscillators, along with digital complementary metal-oxide-semiconductor (CMOS) logic gates, while the high-voltage power stage includes power switches and gate drivers. The differences between two versions of the Buck converter are the circuit topologies applied in the error amplifiers, and comparators and the gate drivers. The SiC process is a new 600V process with 500nm feature size and is being co-developed with the proposed Buck converter design. Therefore, the first goal of the work is to develop accurate models of the low-voltage and high-voltage devices in the technology to facilitate the circuit design and simulation of the converter. The development of these models is based on Level-3 SPICE parameters, which are manually adjusted to fit the Current/Voltage curves produced by the characterization of the devices. Based on these models, all building blocks in the fully integrated Buck converters have been designed and simulated. Furthermore, in order to verify the fully integrated Buck converters after fabrication, the corresponding physical design has to be implemented. Therefore, the parameterized cells of the low-voltage CMOS transistors are created by following the design rule from the foundry to enable automatically generating the devices of the same type while with various dimensions and the standard library consisting of simple digital gates are built to facilitate the digital circuit design in the low-voltage control circuitry of the converters. Based on these Pcells and the standard library, two versions of Buck converter have been laid out and are currently in fabrication. Data from the characterization of devices and the evaluation of the fully integrated Buck converters will be used to further enhance the accuracy of SPICE models and to enlighten the full integration of other power converters and power systems by employing the proposed SiC technology.