| Band-gap reference voltage circuit is one of the key circuits of power management chip .It applied for DC-DC, A/D converter, D/A converter in integrated circuit. Nowadays, foreign enterprises almost occupy the whole market of power management IC. it is necessary to dominate such a big market. Therefore, it is of great significance to research and develop domestic power management IC. Moreover, it is very important to study the LDO linear regulator circuit. The typical application of the chip includes the Mobile phones, Wireless communication equipment, PDA, portable AV equipment, Battery powered equipment.According to LDO linear regulator require, it designs a band-gap reference circuit in this paper. The chip is manufactured by 0.5um ,2P3M, BICMOS process. For improving the power rejection, it adopts the low voltage cascode mirror structure, and designs the operation amplifier. In the other hand, it takes up a temperature compensate technology to improve temperature stability. The characteristic of this design is combination between soft start-up circuit and reference voltage circuit to assure the safe of establishing reference. By means of capacity charge principle, it designs the circuit which can cut off when reference voltage reached. So, it decreases the quiet current and the power consumption.In the first part, this paper introduces the background and significance of this research. In the second chapter, the basic of the key knowledge is narrated. And then, It is a detailed description about the band-gap reference voltage design .It has successfully designed an reference voltage .HSPICE simulation results which include temperature drift, PSRR (Power Supply Rejection Ration), quiet current, time sequence. Therefore, the results have shown the circuit has rejection of temperature drift and power supply. Soft startup circuit protects the core circuit. The circuit hold advantages of simply, low voltage and low consumption. |
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