Saber Power Supply Simulation - Basic Application

As a necessary supplement and demonstration method for circuit calculation, circuit simulation plays an increasingly important role in engineering applications. Skillful use of simulation tools can discover major errors in scheme design and parameter calculation at the beginning of the design. In the process of product development, accurate modeling and simulation can replace a large amount of actual debugging work, save considerable manpower and material resources, and greatly improve development efficiency.

Saber simulation software is a very powerful circuit simulation software, especially suitable for time domain and frequency domain simulation in the field of switching power supply. However, since domestic academic institutions and companies do not pay much attention to simulation applications, there are few related studies and no systematic documentation system has been formed, which has caused a lot of trouble for engineers who want to learn simulation software applications and always wander outside the door without being able to enter.

I have been engaged in the research and development of switching power supplies for more than 4 years. I went from being completely ignorant of simulation software in the beginning to exploring it hard alone. After several years, I have only gained a superficial understanding of it. I feel deeply the insignificance of my personal power. I hope that this article will serve as an introduction to stimulate everyone's interest and accumulate everyone's wisdom, so that we can have a new understanding of the Saber simulation software, be able to use it more skillfully in development work, and improve our development efficiency.

The following is just a simple example to introduce the basic application of Saber for reference by beginners.

After the installation of Saber is complete, click to enter Saber Sketch, then select File—》New—》Schematic to enter the schematic drawing screen, as shown below:

After entering the schematic drawing interface, we can draw the circuit schematic according to our own needs. First, let's draw a simple triode common emitter circuit.

The first step is to add components. Right-click on a blank space and select the menu Get Part—》Part Gallery.

There are two ways to select devices. The left picture above is the search screen, where you can type keywords in the search box to search. The right picture is the borrow screen, where you can search for the device you need in the relevant file directory.

Generally speaking, it is faster to choose the search method, and you can quickly locate the device you want based on keywords.

As shown in the figure below, enter the abbreviation bjt for bipolar transistor and press Enter to confirm. All devices containing the keyword bjt are displayed in the list. We select the third option, which is an ideal NPN transistor. After double-clicking, the device is added to the schematic diagram.

According to this method, we first input voltage source to find the voltage source, and then select voltage source general purpose to add it to the schematic. Input resistor, select resistor［I］ to add it to the schematic (add 2). Input GND, select ground (saber node 0) to add it to the schematic. Ground (saber node 0) is required, otherwise the saber simulation will not be able to proceed because there is no reference ground.

After adding the components, drag each component with the left mouse button to arrange the position reasonably. Double-click the component with the left mouse button to modify the necessary parameters. In this example, you only need to modify the voltage of the voltage source and the resistance value of the resistor. No other changes are required.

Then press the W key on the keyboard, and the cursor will turn into a cross, which means you can draw a wire to connect all the devices. As shown in the following figure:

The voltage source is 12V, the base resistor is 10k, the collector resistor is 1k, and the emitter is connected in common.

Select the analysis method. Since this is a large signal system, we are looking for a static DC operating point, so we select the DC operating point shown in the figure below, select Yes for the display after analysis item in basic, and click OK when completed.

The simulation results of the DC operating point are as follows:

The base voltage of the transistor is 0.8422V and the collector voltage is 0.06869V, that is, when deeply saturated, Vbe is about 0.84V and Vce is about 0.069V.

Most debugging work can be replaced by simulation. Most design work can be verified for rationality and feasibility through simulation. Once you master the simulation method and can use it skillfully, you will benefit from it for life. You can get rid of most inefficient debugging work, save a lot of time and energy, and you can see your design results intuitively, not just the calculation formulas and boring numbers in the calculation book.

When you have a new idea for a circuit, if you want to verify it, you may have to spend days or even months preparing devices, soldering boards, debugging, and getting results. But if you use simulation methods, it may only take a few minutes, and by changing circuits and parameters, many inspirations will emerge.

For many circuits that cannot be deduced through precise calculations, we can obtain accurate results through simulation. This is really twice the result with half the effort for the solution of nonlinear systems. Why solve complex matrix equations? All I need is the result. I will leave the derivation of the process to university teachers. Simulation can free us from complex calculations, change circuit parameters at will, and then obtain intuitive results. When you master the trick, you can increase your development efficiency tenfold!