Month: May 2016

Mixed Circuit Simulation in TINA and TINACloud (Spice – HDL – MCU co-simulation)

TINA  includes a very powerful mixed mode circuit simulator engine. It is based on the XSPICE mixed mode algorithm, extended with MCU and HDL (VHDL, Verilog, Verilog A & AMS) components. In your circuits you may freely mix any analog or digital components of TINA, including microcontrollers (MCUs) and macros with Spice or HDL content. You can modify these components on the fly along with the code in the MCUs. TINA will analyze the analog parts in analog, the digital parts in digital, and will automatically create the interfaces among the components. This ensures synchronization and fast convergence.

Let’s explore some of the uses of this mode through a few examples.

1. Waveform generation with VHDL and Spice subcircuits

The following circuit generates an analog sine or sawtooth signal depending on the status of the left SW-MODE switch:   Mixed Mode Simulation in TINA and TINACloud-blog5

 Click the picture to run this circuit online with TINACloud

The Digital Wave box on the left of the circuit includes VHDL code with a lookup table (Sine_LUT ) for the sine wave and a counter for the sawtooth signal. The essential part of the VHDL code is:  

   process(Reset, Clk) 
   begin 
       if (Reset = '1') then 
           Wave <= (others => '0'); 
           LUT_index <= 0; 
       elsif rising_edge(Clk) then 
           if (Enable = '0') then 
               Wave <= (others => '0'); 
           elsif (Sel = '0') then 
               Wave <= Sine_LUT(LUT_index); 
           else 
               Wave <= conv_std_logic_vector(LUT_index,5); 
           end if;
           if (LUT_index = LUT_index_max) then 
               LUT_index <= 0; 
           else 
               LUT_index <= LUT_index + 1; 
           end if;
       end if; 
   end process; 
   d0 <= Wave(0); d1 <= Wave(1); d2 <= Wave(2); d3 <= Wave(3); d4 <= Wave(4);

 The digital output of the counter is converted into an analog signal in the 5 bit DA converter of TINA shown in the middle of the circuit. The DAC sine wave output needs to be cleaned up with a low pass filter. We will use a Spice opamp model of the TL081 in a Sallen and Key low pass filter configuration. Press the Enter Macro button on the property dialog and TINA will open the macro. You can review and, if necessary, modify the Spice code inside the macro.

Here are the final waveforms of the full circuit, including the five counter output waveforms. SW_MODE is in the High state, selecting the sawtooth signal:

Mixed Mode Simulation in TINA and TINACloud-1diagram

If we change the SW-MODE switch to Low and run Transient analysis again, the waveforms are:

Mixed Mode Simulation in TINA and TINACloud-2diagram

To see the effect of the analog filter, delete curves d0 to d4 from the diagram by clicking the curves and pressing the Del key:

Mixed Mode Simulation in TINA and TINACloud-3diagram

2. MCU controlled SMPS circuit

The mixed mode simulator of TINA not only allows MCUs, but also any linear or nonlinear parts in TINA’s libraries. As an example, let’s study the following circuit, which realizes a DC-DC converter, converting 5V DC to 13V DC, and operating in boost mode:

Boost Converter with PIC control

Mixed Mode Simulation in TINA and TINACloud-BoostconverterwithPICcontroll-blog6
Click the picture to run this circuit online with TINACloud

The waveforms below demonstrate how the analog parts and the MCU interact in TINA.

Mixed Mode Simulation in TINA and TINACloud-4diagram

3. Mixed circuit example consisting of simple analog and digital components

PSK demodulator

Mixed Mode Simulation in TINA and TINACloud-PSK Demodulator-blog4
Click the picture to run this circuit online with TINACloud

You can display the results in one diagram or as separate diagrams shown below by simply appending a colon ( : ) and  a number to each output name.
Mixed mode results:

Mixed Mode Simulation in TINA and TINACloud-5diagram

Download the FREE trial demo of TINA Design Suite and get:

  1. One year free access to TINACloud (the cloud-based, multi-language, installation-free online version of TINA now running in your browser anywhere in the world.)
  2. An immediate 20% discount from the offline version of TINA
  3. Free license for your second computer, laptop etc.

Click here to download the FREE trial demo of TINA

Dr. Michael Koltai

www.tina.com
www.tinacloud.com

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Symbolic Analysis of Analog Circuits using TINA

TINA Design Suite is a powerful yet affordable circuit simulator and PCB design software package for analyzing, designing, and real time testing of analog, digital, HDL, MCU, and mixed electronic circuits and their PCB layouts. You can also analyze SMPS, RF, communication, and optoelectronic circuits; generate and debug MCU code using the integrated flowchart tool; and test microcontroller applications in a mixed circuit environment.

A great number of  electrical engineers find TINA an easy to use, high performance tool, while educators welcome its unique features for the training environment. TINA also includes a unique feature, Symbolic Analysis.

symbolicanalysis10-blog

  Symbolic analysis producing the closed form expression of the transfer function

Symbolic analysis produces the closed form expression of the transfer function, equivalent resistance, impedance, or response of analog linear networks. In DC and AC analysis mode, TINA derives formulas in full-symbolic or semi-symbolic form. In transient analysis, the response is determined as a function of time. Circuit variables can be referenced either as symbolic names or by value on a component-by-component basis. Through symbolic analysis, poles and zeros of linear circuits can be calculated and plotted. You can efficiently prepare reports and paper presentations by printing or by copying and pasting your expressions to any Windows program.

Watch our tutorial video to see how to use the Symbolic Analysis of  Analog Circuits in TINA.

Download the FREE trial demo of TINA Design Suite and get:

  1. One year free access to TINACloud (the cloud-based, multi-language, installation-free online version of TINA now running in your browser anywhere in the world.)
  2. An immediate 20% discount from the offline version of TINA
  3. Free license for your second computer, laptop etc.

Click here to download the FREE trial demo of TINA

Dr. Michael Koltai

www.tina.com
www.tinacloud.com

Share and Enjoy

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  • Twitter
  • Delicious
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  • StumbleUpon
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