QSPICE: Ordering and purchasing electronic components online (Part 9)

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QSPICE electronic circuit simulation software gains popularity every day among engineers and hobbyists due to its effectiveness and ease of use. Among the many peculiarities of the software, there is also one that allows integration with online ordering systems for the purchase of electronic components. With this possibility, designers can order and purchase electronic components for their diagrams directly, without changing software and without the need to carry out tedious component searches on various online sites. Let’s see how to use it.

Introduction

Imagine designing a circuit, simulating its behavior, and, with a simple click, ordering all the components necessary for its construction, directly from an online supplier. This is a reality with the QSPICE software. This important possibility undoubtedly revolutionizes the design and prototyping process, making it faster and more efficient. The idea is very simple and consists of combining the QSPICE software with an online purchasing system for electronic components. With the identification of the components necessary for the creation of the circuit in a single software, the design process becomes very efficient, as it is possible to directly order the components from an online supplier with a simple click. Design processes are noticeably faster, so the time spent searching for and manually purchasing components is saved; direct ordering of electronic components eliminates the risk of purchasing errors as well, and, last but not least, the entire procedure, from purchasing to planning, is managed within a single software. These are, therefore, the many advantages that improve the experience of electronic design.

A practical example

The best way to grasp this feature is to test it practically with a simple electrical test diagram. Let us begin to create a simple example of a power circuit concerning the delayed switching on of an incandescent light bulb, represented in the electrical diagram by a resistor. With appropriate measures it is possible to control large power loads, provided that all the critical parts of the electrical circuit are adapted. Figure 1 shows the electrical diagram, made up of the following electronic components:

• V1: it is a 25 V voltage generator used to activate the conduction of the SiC MOSFET
• R1: it is a 10K resistor, used to supply a small current to the electrolytic capacitor C1 for its progressive charging. Changing this value changes the time constant and, therefore, the timing parameters. The higher its value, the longer it takes to trigger the load
• C1: it is a 4700 uF electrolytic capacitor, used to accumulate energy and constitutes, in fact, a programmed timer for triggering the electronic switch. In this case, as well, modifying this value changes the time constant and, therefore, the timing parameters. The higher its value, the longer it takes to trigger the load
• M1: it is a SiC MOSFET model UF3C065030B3 from Qorvo present in the QSPICE library. Its features are very interesting
• R2: it is a 56 ohm power resistor, here as a load. It could be a lamp or a heater or even a motor.

The diagram shows some SPICE directives that control its execution. In particular:

• .tran 15,0,100u: this directive sets a transient simulation of 15 seconds
• .ic v(charge)=0: this directive forces the software to set the “charge” node to an initial voltage of 0 V, which implements a condition in which the electrolytic capacitor is initially discharged. With it, the simulation can be started at any initial voltage level
• .plot (v(vcc)-v(drain))*i(r2),v(drain)*i(R2): this plot directive displays a graph of an oscillogram with the powers dissipated by the load and the SiC MOSFET, according to the formula P=V*I
• .plot i(r2): this directive displays the current flowing through the load on the graph
• .plot v(charge),v(drain): this directive displays on the graph the voltage of the electrolytic capacitor, used as a timer, and the voltage on the drain of the SiC MOSFET.

The SiC MOSFET used is part of the QSPICE library and is produced by Qorvo. It has the following electrical characteristics and, as we will see later in the article, it can be easily purchased online with a few simple procedures:

• Model: UF3C065030B3 SiC
• Rds(ON): 27 milliOhm
• Drain-source voltage: 650 V
• Gate-source voltage: between -25 V and +25 V
• Continuous drain current: 65 A
• Pulsed drain current: 230 A
• Power dissipation: 242 W
• Maximum junction temperature: 175°C
• Thermal resistance, junction-to-case: 0.48 °C/W.

During the execution of the simulation (but also in a real equivalent circuit) the initial voltage on the capacitor C1, at the instant T=0, is equal to 0 volts. The voltage source V1 of 25 volts gradually charges the capacitor through the limiting resistor with an RC time constant equal to 47. When this voltage (which is the same as the gate of the MOSFET) reaches a certain threshold value (in the example relative to the component used it is approximately 6 V), the MOSFET enters into conduction and activates the load, which remains powered indefinitely, until the electrolytic capacitor is discharged again due to an external event. The circuit in question does not download it automatically. This operation can be carried out via a normally open button connected in parallel to the capacitor. However, it is always advisable to connect a low-value resistor (for example 10 ohm) in series with the button to avoid spark-striking during the discharging operation, for which the electrolytic capacitor must be short-circuited.

The graphs in Figure 2 show the trend of some parameters and in particular:

• The current graph (top): This graph shows the trend of the current flowing through the load R2 (green graph) and the DS channel of the MOSFET. In the first 12 seconds, there is no flow of current and the load is deactivated but, after this time, it activates in almost a second. The switching is not clear nor sudden but it is an analog variation in the face of an increasing analog voltage, with non-linear components
• The power graph (in the middle): This graph shows the power dissipated by the load (red graph) and the power dissipated by the MOSFET (green graph). The power of the load reaches more than 40 W when it is active, while that of the MOSFET is always very low, except for the few moments of its activation, during which a small switching loss can be observed
• The voltage graph (bottom): This graph shows the voltage present on the drain of the MOSFET with respect to ground (blue graph) which changes depending on the operating region of M1 and, above all, the progressively increasing voltage across the capacitor electrolytic, initially 0 V (red graph), always compared to ground. The trend of this last voltage is not linear but follows that of a normal RC filter with a fixed direct voltage connected to the input. As you can see, the switching of the MOSFET, combined with the activation of the load, occurs when the voltage on the capacitor reaches approximately 6 V.

Let’s order the components for the circuit

Now, let’s move on to the commercial part of the project, i.e. the online ordering and purchase of the electronic components used in the diagram. Not all the components of the circuit can be ordered online, as the traditional ones are extremely widespread and can also be found in local shops. To place the order online, simply right-click on the component of interest and choose the “Buy Now From Mouser” item, as shown in Figure 3. Regarding the electrical diagram of the item, the only component that can be purchased online is the SiC MOSFET UF3C065030B3. For the other components of the diagram, the context menu does not show this functionality.

After choosing the order, the default browser displays the Mouser supplier page with the selected component. At this point, it is possible to specify the quantities of the product to be ordered and it is possible to observe, in real time, the amount to be paid. Continuing with the purchase, we access the confirmation page for which, naturally, access credentials are required but it is also possible to order without having an account on the site. By completing the order, we access the payment section with ease.

Which components can be purchased online

As mentioned before, not all electronic components in the software can be ordered online. Naturally, generic components that do not contain a model code or voltage and current generators are excluded from this operation. However, it is possible to follow some simple rules to make almost all the other purchasable components. In the case of diodes, for example, simply right-click and select the “Selection Guide” function to access a list of commercial models which lists the model, manufacturer, maximum voltage supported, and current maximum. By associating the model with the generic component, we can order it online with the procedure described in the previous paragraphs. It is therefore possible to purchase a common 1N4007 diode or an MM3Z2V7T1G zener and add it to the shopping cart. The same reasoning can be extended to N- or P-channel JFET transistors, to N-channel JFET power transistors, and, of course, to all the other components that are part of the Qorvo library.

Conclusion

The integration of QSPICE with an online purchasing system for electronic components is, without a doubt, an evolution in the world of electronic simulators. The advantages in terms of efficiency, speed, costs, precision, and ease of use are quite evident and allow us to transform how electronic circuits are designed and built.

QSPICE Course – Previous Episodes

The post QSPICE: Ordering and purchasing electronic components online (Part 9) appeared first on Power Electronics News.

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