【摘要】 电流检测电路是功率集成电路中重要的功能模块。一方面它可以大大提高整个系统环路的稳定性,另外一方面也可以避免功率管被大电流烧毁。目前已有多种拓扑结构的电流检测技术,通常采用的方法是在所要检测电流支路上加入一个小电阻,通过采样电阻上的压降来反映支路上的电流,或是利用MOS管的漏源电压的变化来采样流过该管的电流。前者将增加一个额外的功率损耗,而后者由于温度等变化导致电流检测精度的降低。文章设计了一种新型低功耗的高精度电流检测电路,采用2个MOS管串联的形式作为检测拓扑,利用三极管高增益的特性,克服了传统电流检测技术中增加额外功耗和精度较低的缺点,并通过电路的优化设计,降低了温度、电源电压和偏置电流对电流检测结果的影响。更多还原

【Abstract】 The current sense circuit is one of the most significant functional modules of power integrated circuits.Not only can it enhance the stability of the system loop,but it can also prevent the power MOS from being burned by large current.Some kinds of current sense circuits have been presented by now.One of the common methods is that a small resistor is introduced to sense the current by measuring the voltage across it.Another one is that the voltage between the source and drain of MOS is detected to sample the current.The former will increase an additional power consumption,while the latter will lead to the reduction of current sense accuracy due to temperature change.In the paper a new low-power and high-precision current sense circuit is proposed with two series MOSFETs sensing the power MOS current.Also with transistors’ high gain characteristics,the shortcomings of the traditional current sense technology which has an additional power consumption and low accuracy are overcome.The optimization of the circuit has reduced the effect of temperature,power supply and bias current.更多还原