| In recent years, the portable electronic products are becoming more and more popular in market, the power management IC demand is also increasing. Portable devices, which belong to energy limited battery powered system, require the utmost in efficiency in order to provide full system capability and maximum battery life. So efficient power management becomes a key factor in electronic design, and high conversion efficiency and stabilized output voltage are two main performance objectives. When the input and output voltage difference higher, or output current is very large, the power loss of the LDO is unbearable, which is our main purposes to design a wide input voltage step-down DC-DC converter.My work is the design and tape-out of a high efficiency current-mode step-down DC-DC converter. After the reverse pickup of some similar commercial chips, I accomplished the design of the whole system and internal circuit modules. This DC–DC converter has three features: current mode control, PWM, large current supply capacity.A type of step-down switching power supply management IC was designed based on current mode control method. In the article, we analysis the key operating principle, the structure of the system, and the stability of the system, use Slope compensation and Loop compensation to increase system stability. In the meantime, the all sub-circuits are also designed and emulated carefully including: bandgap voltage reference, current sensing circuit, internal voltage regulator circuit, OSC, Slope compensation circuit, Error-Amplifier, Drive circuit and so on. Finally, we posed these modules to simulate and debug the system, the simulation results show that the system can work well, and the performance is also essential to meet the design requirements.
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