Analytical Model and Characteristics for High-Voltage Controllable C-SenseFET

An analytical model is proposed to describe the on-state current in linear and saturation regions for the high-voltage C-SenseFET. As C-SenseFET is an important sensing and charging integrated device, two key parameters--sensing ratio K and charging swing factor α are analyzed in detail and some optimizational structures are provided. For the practical application of C-SenseFET, K and α are required to satisfy the conditions of 0.001 <; K <; 0.01 and α <; 15% after taking into account sensing accuracy, power losses, and charging stability. According to the model, the expressions of K and α have been obtained. By applying the parameters of the 1 μm standard BCD process to the expressions, the values of K and α are 0.0066 and 8.94%, respectively. Based on the test results of static electrical characteristics, the test values of K and α are 0.007 and 8.82%, respectively, which are in agreement with the calculated values. Thus, the analytical model can be used to predict whether a certain process satisfies the conditions of K and α, which brings device designers with convenience due to the omission of simulation validation. Based on the test results of the sequential logic characteristics, the C-SenseFET can achieve the functions of sensing and charging.