DC-DC converter has excellent performance. In this article, we will discuss the structure of the DC-DC converter and the control module of the DC-DC converter.
The system of DC-DC converter consists of three parts, which are main circuit, the drive board, and the control board.
Main circuit: Also called the power module, it is the main body of the whole DC-DC. The input voltage needs to pass through the DC-DC circuit to get a desired output voltage at the output side. The primary side switching circuit, which modulates the input current into a rectangular wave, is a process that relies on the controller to modulate a PWM wave with a specific duty cycle, which is used to drive four switching tubes to open and close according to a set sequence and time, thus realizing the current inversion process. The primary input voltage can be adjusted by the duty cycle, and the output voltage increases when the duty cycle increases and decreases when the duty cycle decreases.
Drive Module: For the four PWM drive signals output from the control chip, it does not directly drive the four power switching tubes. Therefore, in general, the switching power supply is required to support a driver circuit to drive the power switching tubes. There are many types of driver circuits, mainly from the following three:
Direct-coupled type: The control chip output PWM drive signal of each way through the amplifier circuit composed of two transistors to drive the power switching tubes. This method can not achieve the isolation of the control part and the main circuit.
Pulse transformer-coupled drive circuit: This circuit is based on the direct-coupled type with a pulse transformer to achieve the isolation of the control circuit from the main circuit.
Driver chip drives circuit: To drive power switching tubes more easily, many companies have developed driver chips, which can output larger power to drive switching tubes, and with the development of miniaturization of chips, the size of driver chips is now very small, with various package forms.
What is the control module of the DC-DC converter?
Control module: The feedback of the main circuit has three main control modes: voltage control mode, peak current control mode, and average current control mode.
Voltage control mode: It belongs to the voltage feedback, using the output voltage for correction, is a single-loop feedback mode, the output voltage sampling, and input reference voltage comparison, the output signal obtained and a sawtooth voltage comparison, the output PWM wave signal.
Peak current control mode: The difference between peak current control mode and voltage control mode is that the peak current control mode, the voltage control mode of that way sawtooth waveform, converted into the transient current of the inductor with a small sawtooth waveform superimposed.
Averaging current control mode: It belongs to the double-loop control mode, and the output signal of the voltage loop is used as the reference current to compare with the feedback signal of the inductor current. The error amplifier is set to average some high-frequency components of the input current. The output averaged current is then compared with the sawtooth waveform generated by the chip to output a suitable PWM waveform.
The structure of the DC-DC converter is complex and precise. In more than a decade of power supply and sensor research and development. We always adhere to the purpose of "customer first, the brand first, technology to improve life" and the commitment of "quality, integrity, the best service, the latest technology", committed to wholehearted service, provide quality products, to meet the needs of diverse customers, to meet the Diversified market demand. If you have relevant needs, welcome to visit our official website: https://www.smunchina.com. for consultation and understanding. Thank you very much for your support.
