Directive reference¶

padne is controlled by placing special text directives inside your KiCad schematic file. Each directive wires a lumped element (voltage source, current source, resistor, regulator) to one or more pads in your PCB geometry, or injects a global parameter into the simulation.

This page is the complete reference of every directive padne understands.

Endpoint and value syntax¶

Every directive that connects to PCB geometry takes one or more endpoints. Endpoints follow these conventions:

The format is DESIGNATOR.PAD, such as R1.1 or U14.A2.
Multiple pads can be specified as a comma-separated list, e.g. p=R1.1,R2.1.

Numeric values accept SI prefixes and units, e.g. 1k or 500mA.

Specifying multiple pads¶

The directives support specifying multiple physical pads connected to a single lumped element node. Internally, this is implemented by connecting the pads with small resistors in a “star” topology. For a single pad, these resistors are omitted. For voltage sources, they are always omitted and the coupling is implemented with 0 V voltage sources instead.

This is particularly useful for multi-pad consumers (where you do not care or even know which pads will be ingesting the specified current) or for switching elements with intrinsic internal resistance such as multi-pad transistors. For example:

!padne CURRENT i=1.5A f=U1.12,U1.3,U1.21 t=U1.15,U1.5

results in the following lumped elements being wired into the mesh:

The resistance of the coupling resistors can be adjusted with the optional coupling parameter (defaults to 1 mΩ).

Lumped element directives¶

These directives specify a discrete lumped element connected somewhere in the geometry.

VOLTAGE¶

Creates an ideal voltage source between the specified terminals.

Parameters:

p=ENDPOINTS — Positive terminal(s)
n=ENDPOINTS — Negative terminal(s)
v=VALUE — Voltage

Example:

!padne VOLTAGE v=3.3V p=U1.VCC n=U1.GND

CURRENT¶

Creates an ideal current source flowing from one terminal to another.

Parameters:

f=ENDPOINTS — From terminal(s) (current source)
t=ENDPOINTS — To terminal(s) (current sink)
i=VALUE — Current magnitude
coupling=VALUE — (Optional) Coupling resistance for multi-pad terminals

Examples:

!padne CURRENT i=1.0A f=R2.1 t=R2.2
!padne CURRENT i=3A f=TP2.1,TP3.1,TP4.1 t=TP1.1 coupling=1

RESISTANCE¶

Creates a resistor between two terminals.

Parameters:

a=ENDPOINTS — Terminal A
b=ENDPOINTS — Terminal B
r=VALUE — Resistance value
coupling=VALUE — (Optional) Coupling resistance for multi-pad terminals

Examples:

!padne RESISTANCE r=0.1 a=R2.1 b=R2.2
!padne RESISTANCE r=10000 a=R3.1,R2.1 b=R3.2 coupling=0.1

REGULATOR¶

A current-controlled current source that can also set a voltage between its “sense” terminals. This is useful for modeling dependent sources such as LDOs or DC-DC converters.

Parameters:

p=ENDPOINTS — Positive voltage sense
n=ENDPOINTS — Negative voltage sense
f=ENDPOINTS — Current source terminal (from)
t=ENDPOINTS — Current sink terminal (to)
v=VALUE — Target voltage (V_p - V_n = v)
gain=VALUE — Current gain factor
coupling=VALUE — (Optional) Coupling resistance for multi-pad terminals

The idea is that you pre-compute the gain factor based on the nominal values for the regulator input voltage, output voltage and efficiency. For an LDO the gain is always 1. For a DC-DC converter stepping 12 V down to 5 V with 80 % efficiency, the gain factor is about 0.52. This is illustrated by the schematic below:

Other directives¶

These do not create new lumped elements; they inject simulation parameters instead.

COPPER¶

Specifies a custom copper conductivity for all copper layers in the project, overriding the default.

Parameters:

conductivity=VALUE — Copper conductivity in S/m

Example:

!padne COPPER conductivity=5.97e7

Note

The surface conductivity is computed inside padne by extracting the stackup (copper layer thickness in particular) info from your PCB file. See File → Board Setup → Physical Stackup inside pcbnew.