Is there any relationship between MOSFET power loss and diode loss?

Is there any relationship between MOSFET power loss and diode loss?

Is there any relationship between the power loss of mos and diode loss? Switch Mode Power Supply (SMPS for short), also known as switching power supply and switching converter, is a high-frequency power conversion device and a power supply. A sort of.

Switching loss includes conduction loss and cut-off loss. Conduction loss refers to the power loss generated by the power

 from cut-off to conduction. The cut-off loss refers to the power loss generated by the power

 from conduction to cut-off. Switching-Loss includes Turn-on Loss and Turn-of Loss, which are often discussed in Hard-Switching and Soft-Switching. The so-called turn-on loss (Turn-on Loss) means that when the non-ideal switches turned on, the voltage of the switch diode does no drop to zero immediately, but has a falling time, and its current does not immediately rise to the load current. There is also a rise time. During this period of time, there is an overlapping region between the current and voltage of the switch, which will cause loss, which is the turn-on loss.

Using this analogy, the cause of the turn-off loss can be obtained, so I won’t go into details here. Another meaning of switching loss is that in a switching power supply, when switching a large MOS, it is necessary to charge and discharge the parasitic capacitance, which will also cause loss.

In the process of device design and selection, it is necessary to calculate the working process loss of MOSFET in advance (the so-called early calculation refers to using the parameters provided by the device specification and the calculated value and expected waveform of the working circuit without being able to test each working waveform. Apply the formula for theoretical approximate calculation).

Generally speaking, power MOS s and diodes are basic components in electronic product design and electrical circuit systems, and their electronic components have limit parameters of conductive resistance and working environment. So, how do electronic engineers grasp electronic components? What about the performance quality of power consumption, service life, and power mos and diode losses?

Electronic product designers and engineer assistants need to consider two different situations, that is, the worst state of electronic products and the real situation of device working environments. Starting from the procurement brand and type selection of electronic components, select the correct components for circuit products, and then find close and consistent technical parameter values on the electronic component specifications according to actual applications, such as: the choice of MOS channel type, selection of current and voltage values.

In fact, the loss of the diode switch is also a very important indicator. The self-heating damage on the working circuit of electronic components, and the heat caused by the loss caused by the addition of DC power, can cause instantaneous and local heating to a certain extent and lead to damage. For example: the thermal resistance between the semiconductor junction of the packaged device and the environment, when the built-in diode is damaged, calculate the conduction loss of the power MOS, calculate the heat dissipation requirements of the system, etc.