The Design Of The Otp Memory Charge Pump System Research

OTP memory, that is one-time programmable memory, with the characteristics ofpermanent preservation of data, low power consumption, simple structure, high speedand so on, is widely used as embedded memory, which is used to store systemconfiguration information, parameters value, calibration table and code. OTP memory isalso used in many other situations where exchange of data is not required or rarelyrequired. Currently on the market there are two main kinds of OTP memory, type offuse and anti-fuse.The process of traditonal OTP memory is complex, requiring specialmaterials,that make it difficult to apply in the SOC.For the above reasons, our team design a OTP memory which is suitable forapplying in the SOC. In this paper, a charge pump system is designed to provideprogramming voltage for the OTP memory under the standard process. How to generatethe programming voltage of bit line is the key point of this design. First of all, a certaincharge pump circuit structure which is suitable to generate the programming voltage ofOTP memory was selected for this paper, after analyzing the several commonly highvoltage generated structures. Second, after analyzing several commonly classical typesof the charge pump, and contrasting their advantages and disadvantages, we concludethat the switching charge pump with two threshold voltage pulled is best choice. Thereare two basic principles in the designing of the charge pump system. First, avoidgenerating a high voltage which beyond the range of breakdown voltage that ordinarytransisters can bear, to ensure the charge pump system work normally duringprogramming. Secondly, focus on improving the programming success rate, reducingthe chip area and the ripple of the bit voltage during programming. Third, improve theread range of programming node, to avoid misreading of stored data led by thenonlinerarity of broken resistance value.The charge pump system designed, has the following features during thesimulation. First, there is no high voltage generated which beyond the endurace of thenormal trasister, the ripple of bit voltage is small, with a high programming success rateand a large read range of stored data. Finally the charge pump system was tapeouted in the commercial process, and could work normally.