Simulation tools make it easier to design LED driver application circuits

During the LED lighting design process, engineers can start the specific LED lighting circuit design after selecting the LED driver solution. This circuit design process is not easy, and involves determining specific design requirements (such as voltage, current and number of LEDs, etc.), drawing application circuit diagrams, performing design analysis and determining the final bill of materials (BOM), etc., which requires engineers to spend a lot of time and energy.

If there is an easy-to-use online design simulation tool, engineers can easily perform the above series of tasks while sitting at their workbench. As the leading high-performance silicon solution supplier for energy-efficient electronic products, ON Semiconductor, thinking about what engineers think, has jointly launched the interactive GreenPoint® online design simulation tool with Transim Technology, an online design solution supplier for the semiconductor industry, for energy-efficient LED lighting applications.

This article will briefly introduce the main functions of this online design simulation tool, and how engineers can easily use this tool to design LED lighting through four main steps: "finding the entry", "determining requirements", "reviewing the design", and "determining the BOM", and significantly shorten the development time and speed up the product launch process.

Main functions and currently supported LED drivers

The GreenPoint® Design Tool provides an interactive online design and verification environment to help accelerate the circuit board design of solid-state lighting (SSL) solutions. Based on user design requirements such as LED configuration, voltage, current or switching frequency, the GreenPoint® Design Tool automatically calculates the optimal circuit configuration, selects the appropriate inductor and capacitor values, and displays the final design in an interactive online schematic. The GreenPoint® Design Tool then uses Transim's proprietary WebSIM® technology to help test the proposed solution. This tool is essentially a virtual test bench that provides a variety of analyses to enable engineers to effectively and efficiently test the performance of their solutions.

Once the design is verified, the GreenPoint® design tool generates a bill of materials (BOM) and a comprehensive design report, including simulation results, circuit diagrams, and design data. The GreenPoint® design tool incorporates ON Semiconductor's e-commerce tools, allowing users to select different components from suppliers and obtain a bill of materials that meets the requirements. Users can also save design documents in a secure and private workspace for subsequent reference and further modification.

The devices that ON Semiconductor can currently design online using the GreenPoint® design tool include the CAT4201 high-efficiency buck LED driver , the NCL30000 power factor correction TRIAC dimmable LED driver, the NCP1010/1/2/3/4 current mode regulator, the NCP1529 high-efficiency buck converter, the NCP3065/6 multi-topology switching regulator, the NCP5030 buck-boost converter, the NCP5050 flash white LED boost driver, and multiple devices in the NSI45 series of constant current regulators and LED drivers. More devices from ON Semiconductor will support this design tool in the future.

Analysis of key application design steps

As mentioned above, engineers can easily design high-efficiency LED driver application circuits by using four main steps. Engineers may be very eager to use this tool for design, and naturally they may ask such questions: Where is such a useful tool? How can we use this tool quickly? We will reveal the answer to you immediately.

(I) Select the entrance

ON Semiconductor provides multiple entrances to facilitate engineers to quickly use this tool for application circuit design. For Chinese engineers, a necessary preparatory work is to log in to the ON Semiconductor Chinese website www.onsemi.cn, click the "MyON" tab on the homepage, and register your personal account on the ON Semiconductor website. It only takes a few easy steps to complete. Don't underestimate this work, because it is an indispensable foundation for you to apply the GreenPoint® design tool, allowing you to easily save, modify and even share your design with other registered users in subsequent design work.

Figure 1: Example of the online portal to the GreenPoint® design simulation tool.

After registration is completed, you only need to select one of the multiple optional entrances to enter the tool page. The simplest and most direct entrance is the tool navigation area located in the upper right part of the homepage (see the red oval box in Figure 1a). After clicking, you can enter the specific design tool page (see Figure 2).

Some other entry methods are also very simple. For example, move the mouse to the "Application" tab on the homepage of the website and select "LED Lighting" in the pop-up menu to enter the LED lighting application area. You can also see the navigation bar of the design tool in a prominent position (see Figure 1b). Another way is to directly click the "MyON" tab on the homepage, enter your login ID and password, and then enter the MyON area. You can also enter the design tool page through the relevant navigation bar (see Figure 1c). Of course, design engineers can also select "Design Resources" from the drop-down menu on the "Design Support" tab on the homepage and follow the tool navigation bar to enter. In addition to these entry methods, there are other ways to choose from, such as selecting products with "Design it" related icons from the LED driver list on the "Product" tab on the homepage, or entering the specific device model in the search box and then clicking the navigation bar on the relevant product summary page, and so on.

Figure 2: Click “Design it” in front of the selected LED driver column on the design tool page to start designing.

Once you enter the specific GreenPoint® design tool page (see Figure 23), click the "Design it" button in front of the column where the pre-selected LED driver is located to start online design. This article will use the NCL30000 power factor correction TRIAC dimmable LED driver as an example to show how to use this design tool.

(II) Set requirements

As mentioned above, after entering the design page of NCL30000, you need to select the design requirements according to the specific application, such as minimum and maximum input voltage, LED forward voltage drop, LED current, LED impedance, number of LEDs in series, etc. (see the left side of Figure 3). The units of the relevant values ​​have been determined and listed on the right side of the input box. Be careful to avoid confusion between the numerical units.

As shown in Figure 4, in order to facilitate engineers to refer to the data sheet of the selected LED driver, this tool provides a link to the relevant data sheet at the top, which can be used by clicking the relevant icon. In addition, in order to provide engineers with the greatest convenience and save design time, this tool prompts the maximum and minimum values ​​allowed for each value (see the right side of Figure 3). Just hover the mouse over the relevant parameter name (such as LED Forward Voltage, i.e., LED forward voltage drop), and a prompt box will pop up to inform you of the range that can be selected.

After confirming the design requirements, click the “Generate Design” button below to quickly generate the design circuit diagram.

(III) Design review

Following the previous step, the tool automatically generates the NCL30000 circuit diagram shown below. By comparing this circuit diagram, we can further examine each external component. If you need to modify the value of a component, just use the mouse to click the blue numerical part below the component code, and a dialog box will pop up. You can enter the target value in this dialog box, and then click the "OK" button to save. If you want to modify the resistance value of resistor R3, click the blue font "5.60 kΩ" under "R3" to pop up a dialog box, and then modify it in the dialog box. After saving, the system will update the circuit diagram.

Figure 4: You can further modify component values ​​in the circuit diagram (part) and perform DC or AC simulation tests. Once all component values ​​are confirmed, you can click the corresponding button to perform DC input transient simulation or AC input transient simulation . After waiting for several seconds, click the "Result" button under "DC Input Transient" or "AC Input Transient" to enter the simulation result page (see Figure 5). After the simulation is completed, click the "Waveforms" button on the left side of Figure 4 to easily obtain waveforms such as "Feedback", "IC", "Switching", "Input" or "Output".

As shown in Figure 4, engineers can also click the floppy disk icon to the right of the device model at this stage to save the design at any time to prevent rework due to loss of the design.

Figure 5: Simulation test results.

(IV) Determine BOM

After the simulation test is completed, you can proceed to the next step: determine the optimal BOM for the design (see Figure 6). As shown in Figure 6, the table lists the models of all components in the circuit. Currently, the agent that supports the selection of components in this process is Digi-Key, so the table lists the Digi-Key models and original models of the relevant devices accordingly. In addition, given that RoHS has become an important factor affecting engineers' designs, this tool can also be used to select components that comply with the RoHS directive. Just click the checkbox in front of "RoHS Compliant" and click the "Apply" button below.

Figure 6: Select components and determine BOM.

After confirming the BOM, as shown in Figure 6, the engineer can click the "Download" button to download the selected BOM to the local hard disk for backup.

After completing the above steps, the application circuit design process is basically over. Of course, engineers can also click on the "Design Summary" tab to systematically view the design requirements, generated circuit diagrams, determined bills of materials, and simulation circuit diagrams selected in the previous steps, and save them as PDF documents for further review or examination of the design. Finally, on the "My Designs" tab, engineers can also easily view all their designs, reopen or delete a design, or share their designs with another MyON registered user.

Summarize:

The solid-state lighting market continues to grow and develop, and both new and old suppliers expect to take advantage of the performance, cost, reliability and energy efficiency advantages of LEDs over traditional lighting solutions. As the leading supplier of high-performance silicon solutions for energy-efficient electronic products, ON Semiconductor provides a wide range of energy-efficient LED driver solutions and related GreenPoint® reference designs for a variety of LED lighting applications, and further provides new GreenPoint® design tools, allowing designers of emerging lighting applications to easily design at their workbench, helping them significantly shorten development time and accelerate product launch.