# Pulse Current Source

Periodic square wave current source

**Libraries:**

Simscape /
Electrical /
Sources

Simscape /
Electrical /
Additional Components /
SPICE Sources

## Description

The Pulse Current Source block represents a current source whose output current value is a periodic square pulse as a function of time and is independent of the voltage across the terminals of the source. The following equations describe the current through the source as a function of time:

$${I}_{out}\left(0\right)={I}_{1}$$

$${I}_{out}\left(TD\right)={I}_{1}$$

$${I}_{out}\left(TD+TR\right)={I}_{2}$$

$${I}_{out}\left(TD+TR+PW\right)={I}_{2}$$

$${I}_{out}\left(TD+TR+PW+TF\right)={I}_{1}$$

$${I}_{out}\left(TD+PER\right)={I}_{1}$$

Where:

*I*is the output current at time zero._{1}*I*is the output current when the output is high._{2}*TD*is the time at which the pulse first starts.*TR*is the time that it takes the output current to rise from*I*to_{1}*I*._{2}*TF*is the time it takes the output current to fall from*I*to_{2}*I*._{1}*PW*is the time width of the output pulse.*PER*is the period of the output pulse.

The block determines the values at intermediate time points by linear interpolation.

The specified values for *PW* and *PER* have the
following effect on the block output:

If both

*PW*and*PER*are infinite, the block produces a step response at time*TD*.If

*PER*is infinite and*PW*is finite, the block produces a single pulse of width*PW*and infinite period.If

*PW*is infinite and*PER*is finite, the block produces a step response with pulses of width*TR*to a value*I*every_{1}*PER*seconds.If

*PW*>*PER*, the block produces a step response with pulses of width*TR*to a value*I*every_{1}*PER*seconds.

The block uses a small conductance internally to prevent numerical simulation issues.
The conductance connects the + and - ports of the device and has a conductance
*GMIN*:

By default,

*GMIN*matches the**GMIN**parameter of the Environment Parameters block, whose default value is`1e–12`

`1/Ohm`

.To change

*GMIN*, add an Environment Parameters block to your model and set the**GMIN**parameter to the desired value.

## Ports

### Conserving

## Parameters

## Extended Capabilities

## Version History

**Introduced in R2008a**