In the design process of the module power supply, if engineers can reasonably utilize the working principle knowledge and performance characteristics of DC-DC converters for product development, it can not only improve the efficiency but also effectively save the testing time and speed up the launch of new products. Below we will briefly analyze and introduce the principle of the DC-DC converter, hoping to help new engineers in their R&D and design work.
In fact, the familiar DC-DC converter is often called a switching regulator in the actual application process. This important component has the advantages of high working efficiency and small quiescent current, so it can be seen in different fields. to its figure. Generally speaking, a basic DC-DC converter is composed of a control chip, an inductor coil, a thyristor, a triode, and different types of capacitors.
After understanding the basic structure of the DC-DC converter, let's take a look at how it usually works. As a conversion device, in normal work, the main work of the DC-DC converter in the circuit system is to first invert the DC power transmitted in the circuit (perform boost or step-down work) to make it into AC power and then rectified into another DC voltage. Commonly used DC-DC converters are generally composed of DC-DC conversion modules, monitoring modules, user interface boards, and DC power distribution units that are matched with them. In this working system, multiple DC-DC conversion modules run in parallel to share the load, convert the 48V DC voltage into 24V (or +12V, +5V) DC voltage, and then output to the load through the output shunt insurance. The monitoring module is responsible for monitoring the working status and performance of the converter module and the entire system and is incorporated into the upper-level monitoring system through the RS232 communication port. In the process of DC voltage conversion, the converter module of the DC-DC converter will convert the 48V DC voltage into 24V DC voltage, and this conversion work is completed by the power circuit and the control circuit. The power circuit provides the conversion operation from DC input to DC output, while the control circuit provides all control signals required for power conversion, including feedback loop, DC signal processing, analog and switching processing circuits, etc.
Through the above introduction, we can summarize the complete working process of a DC-DC converter for voltage conversion as follows: First, the output voltage is connected to the FBpin sampling amplifier through the FB feedback circuit. At this time, the feedback voltage VFB is compared with the set comparison voltage Vcomp, and an error voltage signal is generated at the same time. The error voltage signal will be input to the PWM module through the internal circuit of the converter, and then the PWM will adjust the duty cycle according to the size of the error voltage, so as to achieve the purpose of adjusting the output voltage.
To have a deep insight into the DC-DC converter.
