BUCK circuit working principle four stages
INDUSTRIAL LCD DISPLAYS / IGBT MODULES DISTRIBUTOR

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

BUCK circuit working principle four stages

Posted Date: 2024-02-01

BUCK circuit working principle four stages

BUCK circuit is a commonly used buck converter and is widely used in the field of power management. Its working principle can be divided into four stages: turn-on, turn-off, self-impedance, and feedback regulation.

1. Conducting stage:

During the conduction phase, the input power supply applies voltage to the inductor through the switching tube (MOSFET), causing its current to grow linearly, while the capacitor C stores energy.

2. Shutdown phase:

When the inductor current reaches a certain level, the controller will turn off the switch tube through the feedback circuit and cut off the connection between the input power supply and the inductor. At the same time, the magnetic field of the inductor begins to collapse, generating a self-inductance voltage that reversely biases the capacitor C. At this time, the capacitor C begins to release the stored energy as an output voltage to supply the load and inductor.

3. Self-impedance stage:

During the turn-off phase, the self-inductance voltage generated by the magnetic field collapse of the inductor gradually increases until it reaches an approximate value of the output voltage. At this time, as the capacitor C continues to discharge, its voltage will decrease, and the switch tube will be re-conducted through the feedback control power controller.

4. Feedback adjustment stage:

When the switch turns on again, the current in the inductor begins to increase linearly, and the capacitor C begins to store energy. When the output voltage rises to the value set by the controller, the controller will turn off the switch again through the feedback circuit to keep the output voltage stable. This is an iterative process, and through precise feedback control, a stable output voltage can be achieved and adapted to load changes.

To sum up, the working principle of the BUCK circuit can be divided into four stages: turn-on, turn-off, self-impedance and feedback adjustment. By cutting off the connection between the input power supply and the inductor, switching the switch tube on and off, and controlling the feedback circuit to maintain a stable output voltage, the BUCK circuit can provide an ideal voltage reduction function. This type of converter is widely used in most electronic devices.


#BUCK #circuit #working #principle #stages