Detailed Analysis of Dynamic Model and Evolutionary Circuit Simulation of Multilayer Ceramic Capacitors

In recent years, with the speed of electronic devices, the increase in the number of components, and the high-density mounting, the design difficulty has also increased. In order to reduce the cost of trial production, reduce the number of trial production experiments, and make full use of circuit simulation technology, designers must achieve high accuracy design in a short period of time. In order to achieve high-precision simulation, high-precision component samples must be set, especially in the case of high dielectric constants, which can show the dependence of temperature and DC bias voltage, because under different conditions, capacity and ESR (Equivalent Series) The change in the resistance, the equivalent series impedance, and the real component of the capacitor's impedance value cannot be ignored. For example, when designing a DC-DC converter, in addition to the dependence of the DC bias voltage, it is also necessary to consider the temperature dependence caused by heat, ceramic capacitors.

The dynamic model is suitable for the smoothing capacitor of the output circuit. For the convenience of comparison, it is combined with the calculated value when using the traditional static model (normal temperature, DV voltage 0V). The various factors for measuring conditions and calculation conditions are shown in Table 2. Figure 5 shows the ripple voltage (left) in the output terminal and the voltage transient response (right) due to load fluctuations. The ripple voltage is compared by removing the value of the DC component, and it can be seen that the dynamic model is closer. In addition, the transient response is the waveform of the electric wave when the load is changed from 55 Ω to 0.5 Ω (current is changed from 0, 5A to 5 A). After the load changes, the value of the output voltage drops rapidly, and the calculated value of the dynamic model is relatively consistent with the measured value. . The voltage will gradually increase as the DC current increases. Although the characteristics of the power inductor are affected, this power inductor is not suitable for the dynamic model, so many differences are generated.