Frequently PCB designers need to reuse a particular circuit module. In these cases, for maximum efficiency it is desirable to use a PCB design tool to easily create re-usable sub-circuits both at the schematic and PCB layout stages of a design. NI provides a platform of PCB design tools which combines the ease-of-use, powerful capture features, and advanced simulation of NI Multisim, with the quick and flexible layout environment of NI Ultiboard.
In this specially featured article we will learn how to begin applying hiearchical design decisions both in NI Multisim and NI Ultiboard. Hierarchical blocks are re-usable circuit modules which exist at the circuit level. To learn more about hierarchical blocks, view the Creating Hierarchical Blocks in NI Multisim
In this article we will learn how to apply a modular design practice for PCB layout (similar to a hierarchical block at schematic level) in NI Ultiboard for repeating common circuit elements.
Hierarchical design organizes and modularizes any design. In schematic capture, hierarchical blocks and sub-circuits are common practices (to learn more about hierarchical blocks click here), however at PCB layout the process is not as well documented.
In this article we will follow a simple step-by-step process in order to re-use and repeat circuit elements at a PCB level, in order to make our final design quicker and easier. This same process can be used for panelization to copy and re-use an entire board design multiple times in a single Ultiboard file for manufacturing purposes.
Imagine a design in which you have eight digital synthesizer circuits. Each synthesizer circuit has the exact same components (resistors, capacitors, and logic chips). At a schematic level in NI Multisim, you would create a Hierarchical Block which contained this design, which could be easily copied and re-used as many times as necessary (eight in this example).
As the board is prepared for layout in Ultiboard we can also similarly layout, route and configure "PCB modules" which can then be copied and re-used readily to effectively compete a board-level design. In many cases each of these PCB modules represents a Hierarchcial Block in Multisim.
Therefore if one was to create a Hierarchical Block in Multisim which contained a resistor and capacitor), you could use it multiple times in a design. Therefore:
- Hiearchical Block 1 (HB1) contains a resistor (10k) and a capacitor (10u)
- Hiearchical Block 2 (HB2) contains a resistor (10k) and a capacitor (10u)
- Hiearchical Block 3 (HB3) contains a resistor (10k) and a capacitor (10u)
- ...and so on.
Basically by copying and pasting HB1 multiple times, you can reduce the time and effort to complete a schematic.
As you transition to Ultiboard and layout, each of these hierarchical blocks will be represented in their landpattern (or footprint) form. Therefore again you will want to reduce the work and time involved with the design, by taking the elements of hierarchical block 1 (HB1), configuring placement and defining the copper traces, and then effectively copying and pasting these elements. The most effective manner in which to repeat common PCB circuit elements in Ultiboard consists of four steps:
- Create a Unique Group in Ultiboard
- Assign Components to a Unique Group
- Lay Out and Route a Complete PCB Module
- Copy and Re-Use the PCB Modules
Prepare for this example by opening NI Ultiboard. You can find Ultiboard at Start > All Programs > National Instruments > Circuit Design Suite 11.0 > Ultiboard.