High frequency high efficiency high dynamic range (3H) DC-DC converter IC

• Main Author: Xue, Yuanzhong
• Other Authors: Zheng Yuanjin
• Format: Theses and Dissertations
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits
• Online Access: https://hdl.handle.net/10356/61733
• Institution: Nanyang Technological University

As demanded by the increasing powerful performance of electronic devices ranging from computer systems, embedded systems, and portable devices, high performance microprocessors are required to handle large scale computing and complicated algorithm. Therefore, it is urgent to develop a voltage regulator with fast load transient response and large current delivery capability to power the next generation microprocessor. The scope of this thesis is to design a dc-dc converter which delivers large current and responses fast to the load transient without increasing the output capacitor for multifarious electronic devices. Hysteretic control method is a promising candidate to cope with the fast load transient response and tight voltage tolerance requirement due to its bandwidth closing to switching frequency. However, it suffers from wide variation of switching frequency which may result in an increasing output voltage ripple. Moreover, the harmonic components of variable switching frequency may close to the frequency of power supply resonant tanks formed by parasitic package inductance interconnects and on-die decoupling capacitances, therefore extra output voltage noise is excited. To address this issue, a fixed frequency hysteretic buck converter is proposed and presented in this thesis. It adopts a Phase Locked Loop to synchronise the switching clock with a reference clock to realize fixed frequency operation. The prototype achieves fixed 1MHz switching frequency and 2.5mV output ripple at 1A load current. In order to enable the fixed frequency hysteretic buck converter adopted to multiphase configuration for large current delivery capability in terms of thermal management and efficiency. Whereas it is difficult to apply multiphase configuration to hysteretic control method owing to its lack of synchronization. A multiphase hysteretic buck converter is proposed and presented in this thesis to explore how to apply the hysteretic control method to multiphase configuration. The proposed topology enables a multiphase configuration by adopting a Delay locked loop to achieve automatic phase synchronization. The Delay locked loop is used to generate multiphase synchronization accurate signals from the output of a hysteretic comparator directly without external synchronization signals.