Transimpedance Amplifier Circuit

The presenter welcomes the viewers and introduces an important circuit used in real-world electronic system design. This circuit is widely utilized in applications such as pulse oximeters, blood pressure monitors, and temperature sensing devices.
Circuit Identification and Description
The circuit in question is identified as an operational amplifier (op-amp) based design. It has:
A positive pin grounded.
An input applied to the negative or inverting input of the amplifier.
The circuit is biased in an inverting amplification configuration.
The output of the amplifier is fed back to the negative input through a resistor.
A capacitor is included for stability and to prevent oscillations.
Input and Output Characteristics
The input to this circuit is a current source (DC or time-varying).
The output is a voltage.
The transfer function of this circuit is voltage divided by current (V/I), representing resistance (R).
The circuit functions as a current-to-voltage converter, also known as a trans-resistance amplifier. With the capacitor, it is called a trans-impedance amplifier.
Practical Application
The output of this circuit is fed directly to an analog-to-digital converter (ADC) on a PCB for complete electronic systems.
The LM 7332 operational amplifier is used due to its wide input and output range. However, the choice of op-amp can vary based on specific application requirements.
Simulation Setup
The presenter explains the process of adding the spice model of the amplifier to the simulation environment.
The simulation environment (likely KiCad) setup is discussed, emphasizing zero errors in the ERC (Electrical Rule Check).
Analysis Types
DC Sweep Analysis:
Sweeping the range of input currents from 0 to 30 microamperes and plotting the corresponding output voltage.
The relationship between the input current and output voltage is visualized.
AC Sweep Analysis:
Analyzing the frequency response of the circuit.
The gain at DC is around 100 dB, and it remains constant up to the -3dB point, which is approximately 2-3 kHz.
Conclusion
The presenter concludes by highlighting the usefulness of the circuit and encourages viewers to share the video and stay tuned for more content.
Detailed Breakdown and Steps for Simulation
1. DC Sweep Analysis
Setup: Choose "DC Sweep" from the analysis options.
Configuration:
Sweep Type: Current Source
Current Source: i1 (input current source in the schematic)
Start Value: 0 A
Stop Value: 30 µA
Increment: 1 µA
Execution: Run the simulation and plot the input current (i1) and output voltage (Vo).
2. AC Sweep Analysis
Setup: Choose "AC Sweep" from the analysis options.
Configuration:
Number of Points: 1000
Start Frequency: 1 Hz
Stop Frequency: 100 MHz
Execution: Run the simulation to obtain the gain-frequency plot. Analyze the gain at DC and the bandwidth up to the -3dB point.
Practical Considerations
Component Selection: Choose components that suit the desired application requirements, including gain bandwidth product and input current range.
Power Supply: Dual power supply (Vcc and Vee) with decoupling capacitors (100 nF) to reduce noise.
Spice Model: Ensure correct mapping of the spice model pins to the schematic symbols for accurate simulation results.
Conclusion
This video provides a comprehensive guide to designing and simulating a trans-impedance amplifier circuit. It covers both theoretical aspects and practical steps, making it a valuable resource for those involved in electronic circuit design.
#ElectronicsDesign #OperationalAmplifier #TransimpedanceAmplifier #CircuitDesign #Simulation #AnalogElectronics #KiCad #SpiceModel #DCAnalysis #ACAnalysis #EngineeringEducation #ElectronicsTutorial #DIYElectronics #OpAmp #CurrentToVoltageConverter #TechTutorial #ElectronicsProjects #EmbeddedSystems #ElectricalEngineering #TechEducation #learnelectronicsindia

[@AllenSA_airohaSun]

Thank you

[@vpachkawade]

Welcome!

[@gean7917]

very nice.

[@vpachkawade]

Cheers

[@AllenSA_airohaSun]

thank you