How to Install & Design solar panels like a professional : Save thousands by doing it yourself Power all your projects with the power of the sun. by Westinghouse Phillip & Delfin Cota Alan Adrian

Author:Westinghouse , Phillip & Delfin Cota, Alan Adrian [Westinghouse , Phillip]
Language: eng
Format: azw3
Published: 2018-12-18T16:00:00+00:00

These properties can be improved to some extent by changing the DC-DC converter IC and external parts. Weightings of these four properties vary with individual applications. In the following, let’s consider how to select individual parts to improve these properties.

Яндекс.Картинки. (2018). Retrieved from https://yandex.ru/images/search?text=lets+consider+how+to+select+individual+parts+to+improve+these+properties

6.5 How to select the Switching Frequency

DC/DC converter circuits have their unique switching frequencies. In general, they affect the circuit properties as shown in Table below:

Relationships between switching frequency and properties

Figure 7 and Figure 8 show the relationships between switching frequencies and efficiencies of the step-down models XC9235/XC9236 (1.2MHz) and XC9235/XC9236 (3MHz), respectively, as examples. As you see, the Influences of switching frequency on efficiency as indicated in Table 2 are apparent. With two models, electric current values at the maximum efficiency are different. This is because if switching frequencies differ, complying inductance values differ too. With coils of the same structure, the larger the inductance is, the larger the direct-current resistance becomes, increasing the loss at times of heavy-load.

Thus, if the switching frequency becomes lower, the current value at the maximum efficiency moves toward the light-load side. On the contrary, if the switching frequency becomes higher, the charge/discharge frequency of the FET and the IC's unique quiescent current increase: On the 3MHz model, the efficiency at the light-load condition is substantially reduced compared to the 1.2MHz model. When totally reviewing these influences, we can see that the 1.2MHz model has a higher maximum efficiency (the peak value is higher than the 3MHz model on the graph) and the output current at the maximum efficiency is small (the peak is to the leftward of the 3 MHz model on the graph). Also, when PFM is actuated, the frequencies at the light-load time are lowered in both models, substantially improving the efficiencies.

LTD., T. (2018). Circuit Design Guide for DC/DC Converters（2/10） | Your analog power IC and the best power management, TOREX. Retrieved from https://www.torexsemi.com/technical-support/application-note/design-guide-for-dcdc-converter/selecting-switching-frequency/

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