IdealizedOpAmpLimited

Idealized operational amplifier with limitation

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

Idealized operational amplifier with saturation:

  • Input currents are zero.
  • No-load amplification is high (but not infinite).
  • Output voltage is limited between positive and negative supply.

Supply voltage is either defined by parameter Vps and Vns or by (optional) pins s_p and s_n.

In the first case the necessary power is drawn from an implicit internal supply, in the second case from the external supply.

If initialization is problematic for a model containing this as a component you can set the homotopyType parameter. Using Linear ignores the saturation initially which simplifies the initialization, and may help if the component is connected with negative feedback; but generally fails if the feedback is positive. Using LowerLimit (or UpperLimit) gives a fixed value within the saturation bounds, which works with positive feedback. However, it does not work if the intent is to initialize the input to give a specific output.

Parameters (6)

V0

Value: 15000.0

Type: Real

Description: No-load amplification

useSupply

Value: false

Type: Boolean

Description: Use supply pins (otherwise constant supply)

Vps

Value: +15

Type: Voltage (V)

Description: Positive supply voltage

Vns

Value: -15

Type: Voltage (V)

Description: Negative supply voltage

strict

Value: true

Type: Boolean

Description: = true, if strict limits with noEvent(..)

homotopyType

Value: Modelica.Blocks.Types.LimiterHomotopy.NoHomotopy

Type: LimiterHomotopy

Description: Simplified model for homotopy-based initialization

Connectors (5)

in_p

Type: PositivePin

Description: Positive pin of the input port

in_n

Type: NegativePin

Description: Negative pin of the input port

out

Type: PositivePin

Description: Pin of the output port

s_p

Type: PositivePin

Description: Optional positive supply pin

s_n

Type: NegativePin

Description: Optional negative supply pin

Used in Examples (8)

DifferentialAmplifier

Modelica.Electrical.Analog.Examples.OpAmps

Differential amplifier

VoltageFollower

Modelica.Electrical.Analog.Examples.OpAmps

Reproduce input voltage

Comparator

Modelica.Electrical.Analog.Examples.OpAmps

Comparator

InvertingSchmittTrigger

Modelica.Electrical.Analog.Examples.OpAmps

Inverting Schmitt trigger with hysteresis

SchmittTrigger

Modelica.Electrical.Analog.Examples.OpAmps

Schmitt trigger with hysteresis

Multivibrator

Modelica.Electrical.Analog.Examples.OpAmps

Multivibrator with Schmitt trigger

SignalGenerator

Modelica.Electrical.Analog.Examples.OpAmps

Rectangle-Triangle generator

LCOscillator

Modelica.Electrical.Analog.Examples.OpAmps

LC oscillator

Used in Components (1)

PartialOpAmp

Modelica.Electrical.Analog.Examples.OpAmps.OpAmpCircuits

Partial circuit of operational amplifiers