Op-amp (limited)

Op-amp with finite gain and output limited to the supply rails.

  • electrical
  • Modelica Standard Library
  • 3 ports
  • 3 parameters
BlockOp-amp (limited)KindopAmpLimitedLibraryElectrical

Description

An operational amplifier with finite open-loop gain whose output voltage is clipped to the supply rails. Use it where saturation matters, such as comparators or loops that can hit the rails.

Example

Op-amp amplifiers Two inverting amplifiers: an ideal op-amp with a gain of −10, and a limited one that clips at its ±15 V rails.

1 V 50 HzR in 1 kΩR f 10 kΩIdeal op-ampv outGroundGround +1 V 50 Hz (limited)R in 1 kΩ (limited)R f 20 kΩLimited op-ampv out (limited)Ground (limited)Ground + (limited)
In Gradara, select a Op-amp (limited) block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:Voltage sensorGroundResistorOp-amp (ideal)AC voltage

Ports

Conserving terminals 3

  • +in_pelectrical

    Non-inverting input. Draws no current.

  • −in_nelectrical

    Inverting input. Draws no current.

  • outelectrical

    Output pin, an ideal voltage source to Ground. Its current is unconstrained.

Parameters

  • Open-loop gainV015000

    ≥ 0

    Open-loop voltage gain, dimensionless. 0 or more.

  • Positive supplyVps15 V

    Positive supply rail, in volts: the highest output voltage.

  • Negative supplyVns-15 V

    Negative supply rail, in volts: the lowest output voltage. Set it below Vps.

Equations

Modelica
v_in = in_p.v − in_n.v
in_p.i = 0, in_n.i = 0
out.v = min(Vps, max(Vns, V0 · v_in))

Implementation

Modelica Standard Library 4.1.0Modelica.Electrical.Analog.Ideal.IdealizedOpAmpLimited
MSL documentation

Assumptions and limitations

  • The rails are fixed values, not pins; the block draws no supply current in the circuit.
  • No bandwidth, slew rate, offset, or output current limit. Saturation is a hard clip.

See also

Select a block in Gradara and press F1 to open its page offline.