一种带有温度和工艺双重补偿的环形振荡器的研究与设计

发布时间：2018-01-22 22:50

  本文关键词： 环形振荡器 压控振荡器 温度补偿 工艺补偿 最小二乘法　出处：《东南大学》2017年硕士论文　论文类型：学位论文

【摘要】：振荡器自问世以来,应用的范围就不断得到扩展。随着科技的进步和人们生活方式的变化,不断出现的新应用对电路中振荡器的性能要求也越来越高,所以国内外的学者们对它的研究从来都没有停止过——因为一种振荡器如果在某方面具有优势,那么在另一方面则难免带有这样那样的问题,"鱼"和"熊掌"不可得兼。具体说来,LC振荡器频率稳定,占用的芯片面积却很大,功耗也比较高(如几十μA的工作电流);晶体振荡器虽然能够提供较为理想的振荡源,却无法用标准的CMOS工艺集成到芯片内,即使采用MEMS工艺技术集成到芯片内部,也因高昂的成本而无法成为客户的首选。因此,一种集成度高、功耗低、频率稳定、成本也低的振荡器一直是许多电路设计者们不懈努力的方向和目标。基于以上这几个方面的考虑,本文对CMOS反相器级联而成的简单环形振荡器进行了温度和工艺的双重补偿。在这种补偿的过程中主要做了三项关键性的工作:(1)研究环形振荡器的频率温度特性和压控特性。频率温度特性是指环形振荡器在控制电压(即电源电压)一定的时候,其输出频率随温度的变化以及受工艺随机偏差影响的情况,而压控特性则是指在环形振荡器输出频率保持恒定的条件下,其控制电压应该随温度和工艺偏差做如何变化,这时环形振荡器就不言而喻地被当作压控振荡器来处理了。(2)分析了 MOS器件关键参数和BJT(双极型晶体管)基射极电压(集电极电流一定的条件下)随温度和工艺的变化情况,在此基础上设计了适当的补偿电压产生电路。(3)运用最小二乘法的原理,将不同的补偿电压以合适的系数进行线性组合,由此构成的电压在相当大的程度上接近环形振荡器的压控特性,由此达到对环形振荡器进行温度和工艺双重补偿的目的。本文的成果——带有温度和工艺双重补偿的环形振荡器,在不同的工艺角和温度组合下,最大频率偏差为1.5%(前仿真结果)和1.7%(后仿真结果),而在tt工艺角和-20℃到80℃的温度区间内,频率偏差仅有3‰,工作电流在400·600μA范围内(常温下为520μA左右)。整个电路基于SMIC 0.18μm混合信号CMOS工艺,在Cadence平台上进行设计、前仿真、版图设计和后仿真验证通过。
[Abstract]:With the development of science and technology and the change of people's way of life, the new applications are demanding the performance of the oscillator in the circuit more and more. So scholars at home and abroad have never stopped studying it-because if a kind of oscillator has an advantage in a certain aspect, then on the other hand it will inevitably have one kind of problem or another. "Fish" and "bear paw" are not available. Specifically, the LC oscillator has stable frequency, large chip area and high power consumption (such as tens of 渭 A operating current); Although the crystal oscillator can provide an ideal oscillator source, it can not be integrated into the chip by standard CMOS process, even if it is integrated into the chip using MEMS technology. Because of the high cost, it can not be the first choice of customers. Therefore, a kind of high integration, low power consumption, frequency stability. Low cost oscillator has been the direction and goal of many circuit designers. Based on these considerations. In this paper, the temperature and process of the simple ring oscillator cascaded by CMOS inverter are compensated. In the process of this compensation, three key tasks are done: 1). The frequency and temperature characteristics of the ring oscillator are studied. The frequency temperature characteristic is when the voltage of the ring oscillator is controlled (that is, the voltage of the power supply) is fixed. The output frequency varies with the temperature and is affected by the random deviation of the process, while the voltage control characteristic refers to the condition that the output frequency of the ring oscillator remains constant. The control voltage should vary with temperature and process deviation. The ring oscillator is automatically treated as a voltage-controlled oscillator. The key parameters of the MOS device and the basic emitter voltage of the BJT (bipolar transistor) are analyzed. The change of collector current with temperature and process. On this basis, a suitable compensation voltage generation circuit is designed. Using the principle of least square method, different compensation voltages are linearly combined with appropriate coefficients. The resulting voltage is close to the voltage control characteristics of the ring oscillator to a considerable extent. Thus the purpose of double compensation for temperature and process of ring oscillator is achieved. In this paper, the ring oscillator with double compensation of temperature and process is obtained under different process angles and temperature combinations. The maximum frequency deviation is 1.5 and 1.7 respectively, but in the TT process angle and the temperature range from -20 鈩，

本文编号：1455942