| Small size, high efficiency and reliability make switching regulator have become apriority in electronic equipments’powering system.On the basis of the project of the ‘Key Lab of High-Speed Circuit Design andEMC Ministry of Education’, XD1213, a BUCK DC-DC converter is designed here.The device is an adaptive On-Time, valley-current mode synchronous step-downconverter. It used for3.3V and5V step-down systems where space is a consideration,high-performance and minimum external components count are required. It featuresfour switching frequency settings (up to1.5M), soft start, power good function,complete protection functions, output soft discharge.The paper firstly introduces the principle of DC-DC converter, including BUCK,BOOST and BUCK-BOOST. After that, the whole system of XD1213and the key partof the sub-blocks, such as BG, OSC, EA, PWM, TON, are proposed in detail. Simulationresults are presented in each part to verify the proper function of the blocks.XD1213was applied with0.18μm30V process. The BUCK converter’s goodperformance has been verified by theoretical analysis and simulation results in thispaper. |
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