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We’ve released a new video tutorial demonstrating how to analyze, design and implement appropriate input and output filtering for an RP506 Series Step-Down DC-DC Converter using TINACloud, and verify the results to ensure stable, low-noise operation.

DC-DC converters are indispensable in modern electronic systems for efficiently stepping voltages up or down. However, their inherent switching operation introduces conducted noise and ripple on both the input and output rails.

Although usually small in amplitude, these disturbances can become critical in sensitive applications such as precision measurement, RF front-ends, or high-speed digital circuits.

We will use the RP506K001C_#Steady.tsc file from the TINA Examples\ Nisshinbo folder.

First we will redesign the circuit using the Design Tool in TINACloud to obtain Vout = 4 V. The results of the quick analytic calculation appear instantly:

After closing this window, the resulting circuit with the changed components is displayed.

Next, calculate the ripple in the input current (Iin) and output voltage (Vout). Run Transient Analysis. The steady state waveforms appear:

Select Ripple… from the Process menu of the Diagram window to calculate the absolute and relative ripple of Vout and Iin.

As we can see, the ripple of the output voltage is quite small – only 2.78 mV, while the ripple in the input current is very high but may be acceptable due to the filtering in the main power supply. However, as mentioned in the introduction, these disturbances may cause problems in some applications and therefore must be filtered out.

To further filter the output voltage, a common solution is to add an LDO regulator, as it also acts as a low-pass filter that attenuates high-frequency components.
The result is a cleaner, more stable output voltage – which is especially important for sensitive analog or RF circuits, microcontrollers, or precision sensors.

Let’s add an NR1700 Adjustable Output LDO Regulator to the output (available in TINA), and an RLC filter to the input.
We get the following circuit:

Now, calculate the transient waveforms and the ripple of this circuit. Using transient analysis, we obtain the following waveforms:

Finally, let’s calculate the ripple values.

The ripple values are now very low – within the microvolt and microampere range – making them acceptable even in sensitive applications.

This concludes our presentation on filtering the input and output noise of DC-DC converters.

You can learn more about TINACloud here: www.tinacloud.com

You can learn more about TINA here: www.tina.com

Explore more content from our channel: https://www.youtube.com/@TinaDesignSuite

We’ve created a new video tutorial that explores how to quickly and accurately design and simulate power management circuits with TINACloud, this time using the LMR43620 Synchronous Buck Regulator as an example. You can also use the offline TINA program for analyzing this circuit.

The datasheet of this device can be found on the Texas Instruments website, and was used to create the SPICE model for TINA and TINACloud by DesignSoft. This model runs not only in TINA and TINACloud, but also in major SPICE programs including PSpice, SIMetrix, LTspice, and more.

We will cover the following topics:

• Startup Transient Analysis
• Steady State Analysis
• Line Step Analysis
• Load Step Analysis
• AC Analysis
• Efficiency Analysis

1. Startup Transient Simulation

The startup transient of a DC-DC converter is the period of time during which the converter is transitioning from its off state to its steady-state operating condition. In most simulators the Startup Transient simulation takes a long time since the whole process from the initial state to steady state is simulated.

However due to the built in average model in TINA and TINACloud the simulation takes only seconds both online and offline.

TINA and TINACloud can also be used to perform switching mode transient analysis. Due to the advanced multicore solvers in both software, switching mode transient analysis is still quite fast and results in more detailed waveforms.

In addition, TINA and TINACloud include a very fast calculation of the ripple voltages using the combination of the average and switching models.

Let’s load the LMR43620 Multiple Simulations.TSC circuit from the TINA Examples folder.

This circuit allows you to run all the necessary simulations for characterizing the LMR43620 from the same file, but separate circuit files for each simulation are also included in the folder.

For running Transient Analysis, click the Transient Analysis Fast link or select Transient… from the Analysis menu. Note that by default the Use switching model checkbox is not checked. This means that the fast average model is used.

By pressing the Run button, the time function of Startup Transient appears within a few seconds. If you click on the top-right of the Startup diagram and run a cursor on it, you can check that the output voltage is approx. 5 V.

Redesigning the circuit

TINA and TINACloud’s Design Tool can determine circuit parameters to achieve a predefined target output.

To use the Design Tool select Re-design this circuit from the Tools menu, or double click the text box on the left side of the current circuit. The Design Tool dialog appears. So far the Vout voltage has been 5V. Let’s redesign the circuit to generate a 3.3 V output voltage. To do this, change Vout to 3.3 and press Run. The following screen appears:

The Design Tool displayed a quick diagram of all the relevant analysis results, based on analytic calculations.

If you click on the top-left of the Startup diagram and run a cursor on it, you can check that the output voltage is now indeed 3.3 V.

You can also run a more accurate numerical Transient simulation on the redesigned circuit and see that it provides nearly the same result as the analytic result.

Finally, you can also run the switching model if you click the Transient Analysis Accurate link, or check the “Use switching model” checkbox at the Run Transient Analysis dialog.

Depending on cloud traffic, the simulation in TINACloud may take a few minutes, but the Vout output remains nearly identical to the result from the average method, which completes in seconds. Note, that compared to TINACloud, switching mode simulations typically run much faster in the offline TINA program- especially on high-performance, multi-threaded machines.

Let’s select  the output voltage. The only difference is in the Ripple which is not provided by the average model. If we zoom in, we can see the ripple voltage waveform more clearly.

However, switching mode analysis takes considerable time, and the small ripple voltage makes zooming in quite difficult. To solve this problem, TINA and TINACloud feature a fast and accurate method for the direct calculation of ripple voltages in steady state.

2. Steady State Analysis

Steady state analysis of a DC-DC power supply is the analysis of the circuit’s behavior when it has reached a steady state. This means that the output voltage is constant, except for the ripple voltage, and all the components in the circuit are operating in their steady state conditions. This method allows a very fast determination of ripple voltages for any circuit settings without the need of storing initial values of inductors and capacitors in the circuits. To demonstrate how this method works we will use the same circuit LMR43620 Multiple Simulations.TSC.

This circuit is identical with the previous circuit, except for some Global Parameter settings. The Global Parameter settings determine the starting time (7ms) of the switching mode transient analysis.

We will use TINACloud to analyze the circuit and determine the ripple voltage.

Let’s run Transient analysis. After a short calculation time the ripple voltages and current of the outputs appear in a diagram.

Similarly, you can also quickly simulate Line Stepping and Load Stepping circuit response.

3. Line Stepping Analysis

Line stepping analysis of DC-DC converters is used to determine how a DC-DC converter responds to changes in the input voltage.

TINA and TINACloud can simulate the circuit response extremely fast due to their built-in average models. Line stepping analysis of DC-DC converters is used to determine how a DC-DC converter responds to changes in the input voltage. TINA and TINACloud can simulate the circuit response extremely fast due to their built-in average models.

To see how the circuit responds to a step change in the Input Voltage,  click on the link “Line Step Analysis Fast”. In a few seconds, the circuit response will appear in a diagram.

To run the switching model, check the “Use switching model” checkbox in the Run Transient dialog and press run. The full ripple voltage appears:

4. Load Step Analysis

Load step analysis of DC-DC converters is a type of circuit simulation that is used to determine how a DC-DC converter responds to changes in the load current. In TINA and TINACloud you can also quickly simulate the circuit response to a load step.

To see how the circuit responds to a step change in the I_step current, click on the link: “Load Step Analysis Fast”. In a few seconds, the circuit response will appear in a diagram.

There is also a switching mode version to see the accurate simulation. Check the “Use switching model” checkbox in transient dialog and run the simulation.

5. AC Analysis

The built-in average models of DC-DC converters in TINA and TINACloud allow fast and accurate AC analysis. Click the  AC Transfer Characteristic link or select AC Analysis from the Analysis menu and Run AC Transfer. The AC Bode diagram of the Loop Gain appears.

6. Efficiency Analysis

TINA and TINACloud also allow fast and accurate calculation of efficiency as a function of load current.

The efficiency as functions of time and load current is calculated using a special time-dependent (Iout) load current. For this calculation a dedicated Efficiency Meter is available on the Meters menu of TINA and TINACloud. Click the link “Efficiency Analysis Fast link, or Run Analysis/Transient…

Click the TR XY Plot Tab. The Efficiency as a function of Output or Load current appears:

This concludes the video tutorial on analyzing the key characteristics of the LMR43620 Synchronous Buck Regulator using TINACloud.

You can learn more about TINACloud here: www.tinacloud.com

You can learn more about TINA here: www.tina.com

Explore more content from our channel: https://www.youtube.com/@TinaDesignSuite

We’ve released a new video tutorial demonstrating the design and simulation of a power management circuit—specifically, the RP506K001F Step-down DC/DC Converter—using TINACloud.

TINA and TINACloud allow fast and accurate simulation and design of power management integrated circuits both offline and online.

The datasheet of this device can be found on the Nisshinbo Micro Devices Inc. website: (https://www.nisshinbo-microdevices.co.jp/en/pdf/datasheet/rp506-ea.pdf) and was used to create the SPICE model for TINA and TINACloud by DesignSoft.

This model runs not only in TINA and TINACloud, but also in major SPICE programs including PSpice, SIMetrix, LTspice, and more.

Startup Transient Simulation

Fast Average Model: In most simulators, this process is slow, but TINA and TINACloud use a built-in average model that completes the simulation in just seconds (online or offline). First load the circuit from the TINA Examples folder. To run the simulation, select Transient… from the Analysis menu, and ensure the Use switching model checkbox is not checked. Pressing Run displays the startup transient time function in a few seconds. Next, we run a cursor on the startup diagram to check that the output voltage is 1.2V.

Switching Mode Analysis: TINA and TINACloud also support the more detailed switching mode transient analysis. Thanks to advanced multicore solvers, this is still fast and provides more detailed waveforms.

Redesigning the Circuit

TINA and TINACloud’s Design Tool allows you to quickly determine component values to achieve a target output. Select Re-design this Circuit… from the Tools menu (or double-click the circuit’s text box).

In the Design Tool dialog, change the target output voltage to 3.3V and press Run. The tool instantly provides analytic results, showing the required component changes (highlighted in red) and confirming the new output voltage.

You can then run the numerical Transient simulation again to confirm the result, which will be nearly identical.

Running the Switching Model for Accuracy

You can run the most accurate simulation by checking the “Use switching model” checkbox in the Transient Analysis dialog.

This calculation takes minutes (or around 10 minutes in TINACloud, depending on traffic) and the output voltage curve is very similar to the fast average method.

Note: Switching mode simulations typically run much faster in the offline TINA program, especially on powerful, multi-threaded machines.

The only difference this method reveals is the Ripple voltage, which is not provided by the average model.

However, switching mode analysis takes considerable time, and the small ripple voltage makes zooming in quite difficult.

To solve this problem, TINA and TINA Cloud feature a fast and accurate method for the direct calculation of ripple voltages in steady state. 

Steady State Analysis and Ripple

Steady state analysis of a DC-DC power supply is the analysis of the circuit’s behavior when it has reached a steady state. This means that the output voltage is constant, except for the ripple voltage, and all the components in the circuit are operating in their steady state conditions.

Fast Ripple Calculation: Standard switching mode analysis is time-consuming, and zooming in to see the small ripple can be difficult. TINA and TINACloud feature a fast and accurate direct calculation of steady-state ripple voltages.

This method uses average models to quickly reach the steady state, then switches to switching models to determine the precise ripple voltage without needing to store initial inductor and capacitor values.

Load the specified circuit (identical to the previous one but with Global Parameter settings to define a starting time for the switching mode analysis) and run Transient Analysis. The ripple voltages and currents will appear in a diagram after a brief calculation.

Line Stepping Analysis

This determines the converter’s response to changes in the input voltage (line step disturbance).

Load the appropriate circuit and run Transient from the Analysis menu. The circuit’s response to the input voltage step appears in a few seconds.

You can also run the switching model (by checking the box) to see the full ripple voltage during the step response.

Load Step Analysis

This determines the converter’s response to changes in the load current (load step disturbance). Load the corresponding circuit (which includes a load step applied to the output current).

Select Transient from the Analysis menu and click Run. The circuit’s response will appear in a few seconds.

To see the most accurate simulation, check the “Use switching model” checkbox in the transient analysis dialog and run the simulation.

AC Analysis

The built-in average models enable fast and accurate AC analysis. Load the AC analysis circuit from the TINA Examples folder.

Select AC Analysis from the Analysis menu, then select Run AC Transfer Characteristic… The AC Bode diagram of the Loop Gain will appear.

Efficiency Analysis

TINA and TINACloud can quickly calculate efficiency as a function of the load current.

Load the specific circuit, which uses a special time-dependent load current and an Efficiency Meter. Run Analysis\Transient…

The efficiency as a function of time is calculated. Click the TR XY Plot Tab to display the Efficiency as a function of the Output (Load) current.

Conclusion

This presentation covered the analysis of all important characteristics of the
RP506K001F Step-down DC/DC Converter including:

• Startup Transient Simulation (Fast average and detailed switching modes)
• Steady State Analysis (Fast ripple voltage calculation)
• Line Stepping Analysis
• Load Step Analysis
• AC Analysis
• Efficiency Analysis

You can learn more about TINACloud here: www.tinacloud.com

You can learn more about TINA here: www.tina.com

Check out our full collection of videos here: https://www.youtube.com/@TinaDesignSuite

We’ve put together a new video tutorial showing how to efficiently design and simulate power management circuits in TINACloud, using the Infineon’s TDA38826 DC-DC Point-of-Load (POL) regulator  as the featured example. While this video focuses on TINACloud, you can also use the offline TINA program.

The datasheet of this device can be found on the Infineon website and was used to create the SPICE model for TINA and TINACloud by DesignSoft.

This model runs not only in TINA and TINACloud, but also in major SPICE programs including PSpice, SIMetrix, LTspice, and more.

The video covers the following topics:

• Startup Transient Analysis
• Steady State analysis
• Line and Load Step Analysis
• AC Analysis
• Efficiency Analysis

Startup Transient Analysis

A startup transient is the time a DC-DC converter takes to go from an off state to a stable, steady-state condition. Traditionally, simulating this can be time-consuming. However, TINA and TINACloud use a built-in average model that significantly speeds up this process, taking only a few seconds.

For more detailed results, the software can perform a switching-mode transient analysis, which is still fast thanks to its advanced multi-core solvers. Additionally, TINA and TINACloud can quickly calculate ripple voltages by combining the average and switching models.

To begin, you’ll open the “TDA38826 DC-DC Point-of-Load (POL) regulator integrated” circuit file from the TINA Examples folder.

Running a Simulation

To perform a fast transient analysis, click the “Transient Analysis Fast” link or select “Transient…” from the Analysis menu. By default, the “Use switching model” checkbox is unchecked, ensuring the fast average model is used. After clicking “Run”, a diagram will show the startup transient’s time function, with an output voltage of 1V.

Redesigning the Circuit

TINA and TINACloud’s Design Tool can automatically adjust circuit parameters to meet a new output voltage target. For example, let’s change the output from 1V to 3.3V.

Select “Re-design this circuit” from the Tools menu or double-click the text box on the circuit. In the dialog box, simply change Vout to 3.3V and click “Run”. The Design Tool will automatically adjust the necessary components, highlighting them in red. After running the transient analysis again, you can use a cursor to confirm the new output voltage is approx. 3.3V.

For a more accurate simulation, you can run the switching model by clicking the “Transient Analysis Accurate” link or checking the “Use switching model” box in the Run Transient Analysis dialog. The calculation may take a few minutes, and the Vout curve will be very similar to the one from the average model. The key difference is that the switching model will show the ripple, which the average model does not. You can zoom in on the diagram to see the ripple voltage waveform more clearly.

Steady-State and Ripple Voltage Analysis

Steady-state analysis examines a circuit’s behavior after all transients have settled. This is crucial for quickly determining ripple voltages. This method is fast because it doesn’t require storing initial inductor and capacitor values. Using the same circuit file, you can perform a transient analysis to view the ripple voltages and currents.

Line and Load Step Analysis

TINA and TINACloud can quickly simulate how a DC-DC converter responds to sudden changes in input voltage (line step) or load current (load step).

Line Step Analysis

To see the circuit’s response to an input voltage change, click the “Line Step Analysis Fast” link. A diagram of the circuit’s response, including the full ripple voltage, will appear within seconds

Load Step Analysis

To see the circuit’s response to a load current change, click the “Load Step Analysis Fast” link. The diagram will appear almost instantly. You can also run a more accurate, switching-mode version of this analysis by checking the “Use switching model” box.

AC Analysis

The built-in average models also allow for fast and accurate AC analysis. By clicking the “AC Transfer Characteristic” link or selecting “AC Analysis” from the menu, you can display the AC Bode diagram of the loop gain.

Efficiency Analysis

TINA and TINACloud can quickly calculate and plot efficiency as a function of time and load current. Clicking the “Efficiency Analysis Fast” link will generate a diagram showing efficiency versus time. By switching to the TR XY Plot Tab, you can also view efficiency as a function of the output or load current.

This concludes the video tutorial on analyzing the key characteristics of the TDA38826 DC-DC Point-of-Load (POL) regulator using TINACloud.

You can learn more about TINACloud here: www.tinacloud.com

You can learn more about TINA here: www.tina.com

Explore more content from our channel: https://www.youtube.com/@TinaDesignSuite

We’ve created a new video tutorial that explores how to quickly and accurately design and simulate power management circuits with TINACloud, this time using the LT8609 synchronous step-down switching regulator as an example. You can also use the offline TINA program for this, which we’ll illustrate in another video. The SPICE model for this device, created by DesignSoft from the official Analog Devices datasheet, is compatible with most major SPICE programs, including TINA, TINACloud, PSpice, SIMetrix, and LTspice. 

Here is a summary of the video’s content:

• Startup Transient Analysis
• Output Voltage Ripple
• Line and Load Step Analysis
• AC Analysis
• Efficiency Analysis

1. Startup Transient Analysis

A startup transient is the period a DC-DC converter takes to transition from an off state to its steady-state operating condition. Typically, simulating this can be time-consuming. However, TINA and TINACloud’s built-in average model significantly speeds up the process, taking only a few seconds. For more detailed results, the software can also perform a switching mode transient analysis, which is still quite fast thanks to its advanced multi-core solvers. Additionally, TINA and TINACloud can quickly calculate ripple voltages by combining the average and switching models.

To begin, we’ll open the “LT8609 Multiple Simulations.TSC” circuit file. This single file allows you to run all the necessary simulations to characterize the LT8609.

Running a Simulation

To perform a fast transient analysis using the average model, click the Transient Analysis Fast link or select Transient… from the Analysis menu. By default, the “Use switching model” checkbox is unchecked, which ensures the fast average model is used. After you click Run, the startup transient’s time function will appear in seconds, showing an output voltage of approximately 5V.

Redesigning the Circuit

TINA and TINACloud’s Design Tool can automatically adjust circuit parameters to meet a new output voltage target. Let’s change the output voltage from 5V to 3.3V. Select Re-design this circuit from the Tools menu or double-click the text box on the circuit. In the dialog, simply change Vout to 3.3V and click Run. The Design Tool will automatically adjust components like the Rfb2 and Rload resistors to achieve the new output, providing an immediate diagram based on these changes. You can then run a more accurate numerical simulation to confirm the new voltage.

You can also run a more accurate simulation using the switching model. Just select the Transient Analysis Accurate link or check the “Use switching model” checkbox. This calculation takes longer (about a minute) but provides more detailed waveforms, including the ripple that the average model doesn’t show.

2. Steady State and Ripple Voltage Analysis

Steady-state analysis examines a circuit’s behavior once all transients have settled. This is crucial for quickly determining ripple voltages. This method is particularly fast because it doesn’t require storing initial inductor and capacitor values. Using the same circuit file, let’s perform a transient analysis to see the ripple voltages and currents. A diagram of these values will appear after a brief calculation.

TINA and TINACloud can also quickly simulate how a DC-DC converter responds to sudden changes in either input voltage or load current. These are known as line stepping and load stepping, respectively.

3. Line Step Analysis

To see how the circuit responds to an input voltage change, click the “Line Step Analysis Fast” link. Within a few seconds, a diagram of the circuit’s response, including the full ripple voltage, will appear.

4. Load Step Analysis

Similarly, to see the circuit’s response to a load current change, click the “Load Step Analysis Fast” link. The diagram will appear almost instantly. You can also run a more accurate, switching-mode version of this analysis by checking the “Use switching model” box in the transient dialog.

5. AC Analysis

The built-in average models also enable fast and accurate AC analysis. Simply click the AC Transfer Characteristic link or select AC Analysis from the menu. This will display the AC Bode diagram of the loop gain.

6. Efficiency Analysis

Additionally, TINA and TINACloud can quickly calculate and plot efficiency as a function of time and load current. By clicking the “Efficiency Analysis Fast” link, you can get a diagram showing efficiency versus time. By switching to the TR XY Plot Tab, you can also view efficiency as a function of output or load current.

Conclusion

TINA and TINACloud provide a comprehensive and efficient platform for analyzing all the key characteristics of a synchronous step-down regulator like the LT8609. Its built-in average models and advanced solvers make it easy to quickly get accurate results for various analyses, including transient, ripple, line/load step, AC, and efficiency.

Click here to watch our video.

You can learn more about TINACloud here: www.tinacloud.com

You can learn more about TINA here: www.tina.com