Analysis And Design Of Two-Phase DC-DC Converter Chip Current Sharing Circuit

Power supply is an important element of electronic equipments. It is increasingly influencing the stability and reliability of electronic equipments. With the development of electronic technology, the type of electronic equipments is becoming more and more, therefore, the requirements for power supply are various.BICMOS process is studied and designed, which can fabricate bipolar transistor, CMOS transistor power transistor in the same die, and this process is characteristics of low power dissipation, high integration and strong drive. According to pulse width modulation technique of current mode, a monolithic DC-DC converter IC based on BICMOS process is studied and designed, which is integrated with many function modules. This DC-DC converter chip can control a two-phase converter work automatically, which can provide a large output current, but has low power dissipation. The chip can adjust the CPU core voltage accurately and balance the different channel current. The DC-DC converter chip can be detected on each channel of the current in order to obtain accurate current on each channel of information, and to share better and protect circuit.This article is given the design and simulation results of the DC-DC converter chip functional modules, such as: oscillator circuit, sawtooth circuit, comparator circuit, current sharing circuit, error amplifier circuit, detection circuit. All these circuit structures and operation principles are simulated and verified. This chip can constitute a DC-DC converter with a minimum number of external components; thus, it can be widely used in CPU power supply system, etc.The feasibility and validity of design method and theory analysis are proved by the simulation results of the chip main circuits with hspice offered by EDA tools. On the basis of circuits of each function module, layout of the IC is completed according to 0.8μm process design rule, DRC and LVS documents are compiled to confirm the validity of the layout. The monolithic DC-DC converter IC based on BICMOS process in the thesis can realize the target expected.