Circuit board design is a critical and time-consuming task, and any problems require engineers to check the entire design of the components one by one. It can be said that the design requirements of the circuit board as much as the chip design.

A typical circuit board design flow consists of the following steps:
The first three steps spend the most time, because the schematic check is a manual process. Imagine a SoC circuit board with 1000 or more connections. Manually checking each connection is a tedious task. In fact, it is almost impossible to check each connection, which can lead to problems with the final circuit board, such as the wrong connection, the suspension node and so on.

Schematic capture phase generally faces the following types of problems:
● Underline errors: such as APLLVDD and APLL_VDD
 Case case questions such as VDDE and vdde
● misspelled
● Signal short circuit problem
... there are many
In order to avoid these errors, there should be a way to check the complete schematic in a few seconds. This method can be used to achieve the schematic simulation, and schematic simulation in the current circuit board design process is also rarely seen. The schematic simulation can be used to observe the final output at the desired node, so it can automatically check all connection problems.

The following is explained by a project example. Consider a typical block diagram of the board:
In complex circuit board designs, the number of connections may reach thousands, and very few changes are likely to waste a lot of time to check.
Schematic simulation not only saves design time, but also improves board quality and improves the efficiency of the entire process.
A typical device under test (DUT) has the following signals:
The device under test will have a variety of signals after some pre-adjustment, and there are various modules, such as regulators, op amps, etc., for signal conditioning. Consider a power supply signal obtained by a regulator. Example:
In order to verify the connection relationship and perform the overall inspection, schematic simulation is used. Schematic simulation consists of schematic creation, test platform creation and simulation.
During the test platform creation process, an excitation signal is given to the necessary input and then the output is observed at the signal point of interest.
The above process can be achieved by connecting the probe to the node to be observed. The node voltage and waveform can indicate that the schematic has no error. All signal connections are automatically checked.
Let's take a look at the top of the picture above, where the nodes and voltages are clearly visible:
Therefore, with the help of simulation, we can directly observe the results, to confirm the circuit board schematic is correct. In addition, a survey of design changes can be achieved by carefully adjusting the excitation signal or component values. So schematic simulation can save board board design and inspection staff a lot of time, and increase the design of the correctness of the opportunity.