V-to-I and I-to-V Converters PDF

1. Voltage-to-Current Converter (V-to-I Converter)  Definition: A V-to-I converter converts an input voltage into a proportional output current. It is commonly used to drive devices that require current as the input, like LEDs, motors, and transducers.  Basic Circuit: o Op-Amp in In...

1. Voltage-to-Current Converter (V-to-I Converter)  Definition: A V-to-I converter converts an input voltage into a proportional output current. It is commonly used to drive devices that require current as the input, like LEDs, motors, and transducers.  Basic Circuit: o Op-Amp in Inverting Configuration: The input voltage is applied at the inverting terminal of the Op-Amp, and the feedback loop contains a resistor that controls the output current. o The output current IoutI_{out}Iout is proportional to the input voltage VinV_{in}Vin, and it flows through the load connected in series with the output.  Operation: o The Op-Amp maintains a virtual ground at the inverting terminal, ensuring that the current through the load is directly proportional to the input voltage. o Output Current Equation: Iout=VinRI_{out} = \frac{V_{in}}{R}Iout=RVin where RRR is the feedback resistor.  Key Features: o High Input Impedance: The input voltage is applied to the non-inverting terminal, maintaining high input impedance. o Low Output Impedance: The output is a low impedance current source.  Applications: o Driving current-based loads like LEDs, laser diodes, and actuators. o Analog signal transmission over long distances using current. 2. Current-to-Voltage Converter (I-to-V Converter)  Definition: An I-to-V converter converts an input current into a proportional output voltage. It is widely used in sensor applications where the output of the sensor is in the form of current (e.g., photodiodes, current transducers).  Basic Circuit: o Op-Amp in Inverting Configuration: The input current is applied to the inverting terminal, and a feedback resistor converts the current into a voltage. o The output voltage VoutV_{out}Vout is proportional to the input current IinI_{in}Iin.  Operation: o The Op-Amp keeps the inverting terminal at a virtual ground. The input current flows through the feedback resistor, developing a voltage across it. o Output Voltage Equation: Vout=−Iin×RfV_{out} = - I_{in} \times R_fVout =−Iin×Rf where RfR_fRf is the feedback resistor.  Key Features: o High Accuracy: Provides a precise voltage output proportional to the input current. o High Sensitivity: Especially useful in amplifying small currents, such as those from photodiodes. o Low Input Impedance: Ensures that the input current is accurately converted without significant losses.  Applications: o Photodiode amplifiers (converting light-induced current into voltage). o Sensing applications where output is in the form of current (e.g., current transducers). o Current measurement in electronic systems. Comparison of V-to-I and I-to-V Converters: Converte Input Output Op-Amp Key r Type Configuratio Application n s Voltage- Voltag Proportiona Inverting with Driving to- e l Current Load current- Current Signal based loads (V-to-I) (e.g., LEDs, motors) Current- Current Proportiona Inverting with Photodiode to- Signal l Voltage Feedback amplifiers, Voltage Resistor current (I-to-V) sensing