Power

A Power object is extra information that is used for:

• ERC: by setting Pin types to power_out or power_in
• voltage compatibility checks
• automatic trace width calculation via powerInfo

A Power object represents a physical set of pins, not an abstract concept of power or ground.

Options for the Power class are:

• power — pin that supplies power
• gnd — pin that supplies ground
• voltage — voltage of the power source
• current — current capacity
• direction — 'output' (default) for power sources, 'input' for power consumers

How Pin Types Are Set

When a Power object is created, pin types are set automatically for ERC:

• The power pin is set to power_out when direction is 'output', or power_in when direction is 'input'.
• The gnd pin is always set to power_in, regardless of direction.

Additionally, voltage and current are propagated to the pins’ powerInfo property, which is used by ERC for voltage compatibility checks and by the routing system for automatic trace width calculation.

Output Power

An output Power object defines a source of electrical power within your design. If direction is omitted, it defaults to 'output'.

import { Component, Power } from '@typecad/typecad';

let bt1 = new Component({ footprint: 'Battery:BatteryHolder_Keystone_3008_1x2450' });
let coin_cell = new Power({
    power: bt1.pin(1),  // Pin 1 is the positive terminal → type set to 'power_out'
    gnd: bt1.pin(2),    // Pin 2 is the ground terminal → type set to 'power_in'
    voltage: 3.7,       // Nominal voltage
    current: 0.5,       // Current capacity
    direction: 'output' // This is a power source (default)
});

In this example:

• bt1.pin(1) gets type: 'power_out' and powerInfo: { minimum_voltage: 3.7, maximum_voltage: 3.7, current: 0.5 }
• bt1.pin(2) gets type: 'power_in' and powerInfo: { current: 0.5 }

Shared Ground Pins

Components like voltage regulators often have both power inputs and outputs that share the same ground pin. Since the gnd pin is always set to power_in regardless of direction, this typically works without conflict. However, if you need to override the pin type for ERC purposes, you can set it manually:

// U1 is a voltage regulator, pin 2 is shared ground
let vin = new Power({ power: U1.pin(1), gnd: U1.pin(2), voltage: 5, direction: 'input' });
let vout = new Power({ power: U1.pin(3), gnd: U1.pin(2), voltage: 3.3, direction: 'output' });

// Both Power objects set U1.pin(2) to 'power_in', so no conflict here.
// If needed, override manually:
// U1.pin(2).type = 'passive';

Input Power

An input Power object specifies the power requirements for a component or sub-circuit. It is commonly passed into reusable packages so users can connect a suitable power source.

// 'vin' is an input Power object passed as a parameter
// U1 is a component within your design that needs power

typecad.net(vin.power, U1.VCC);
typecad.net(vin.gnd, U1.GND);

When direction is 'input', the power pin is set to power_in and the gnd pin is also set to power_in.

Voltage checks

A package can check that the voltage levels coming in are correct as well.

if (vin.voltage != 3.3) {
    throw new Error('Voltage must be 3.3v');
}