Research and Design of PWM Switching Power Supply Chip with Step-Up Current Mode

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

MOS power IC full range

Memory chip

Summary:

This paper combines the company's project and the development trend of power management today, designed a small current, micro power synchronous boost switching power supply. The chip is set to a fixed operating frequency of 2MHz. It can be operated in skip-pulse mode under light load conditions, and the quiescent current is only 65/zA, which maximizes the battery life in portable applications. The chip also includes 1 slave stop function, soft start control, over temperature shutdown and current limit and other auxiliary functions. The design circuit uses synchronous rectification technology to increase efficiency while reducing the area of ​​the PCB.

The main work of this paper is the design and verification of BOOST chip circuit. Firstly, from the perspective of the system, understand the system structure of the BOOST chip to determine the performance parameters of each module in the system. Secondly, use the circuit knowledge to design the sub-module circuit. Then, use the spetre software to simulate the circuit and system. The circuit meets the design requirements of the system.

This article is mainly composed of the following parts:
The first chapter: Introduction, briefly introduces the current situation and trend of analog integrated circuit design and its process implementation and power management IC research.
The second chapter: the topology and characteristics of the switching power supply system, and elaborates the working principle of the Boost switching power supply system.
The third chapter introduces the feedback mode and control mode commonly used in switching power supply, and then analyzes the stability and compensation principle of the system.
The fourth chapter: the system design of the chip, determines the system function and various electrical characteristics of the chip, and on this basis, for the chip characteristics and typical applications, the chip topology, working mode, control mode and sub-module division and Functional definitions, etc. are discussed in detail.
The fifth chapter: the design and simulation of the module circuit in the system, mainly for the design and simulation of CMOS error amplifier circuit, bandgap reference circuit, Oscillator circuit, comparator circuit, over-temperature protection circuit.
Chapter 6: System overall circuit simulation verification. Finally, the concluding remarks, thanks, references and research results of graduate students during their studies.

Small signal system model

Oscillator circuit diagram

PWM comparator design schematic

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