Custom regulators, an explanation and guide

Discussion in 'Guide Hub' started by BitBuiltBot, Nov 11, 2016.

  1. BitBuiltBot . Site Robot

    Joined:
    Jan 28, 2016
    Messages:
    48
    Likes Received:
    294
    Custom regulators, an explanation and guide
    If you're new to portablizing, you've probably come across the term "custom regulators" quite a few times. This guide will attempt to explain what they are, and why you need them, all while keeping things in the simplest terms possible.

    What are custom regulators?
    To understand custom regulators, first you need to understand a few rules of voltage. Here's all you really need to know for now:
    All grounds must be connected together.
    1. AC power and DC power are different, meaning you can't put DC(direct current) power into an AC(alternating current) line.
    2. Most electronics use DC power. Game consoles are no different(most of them come with "wall-warts" that convert AC to DC)
    3. Batteries are also DC power, from AA's to car batteries.
    4. To Directly apply Current to an electronic, you must connect both voltage and ground.
    5. Sometimes voltage needs to be regulated to a certain level so that the electronic will work properly.
    6. It is usually more practical to step-down voltage than step-up voltage.
    7. Volts x Amps = Watts, or V*A=W. This formula is used for calculating power values, and will be used to help calculate battery life.
    8. The more power you have, the thicker your wires need to be.​

    Why do I need them?
    In consoles, voltage regulation is usually first handled within the wall-wart converting the main AC power line into the main DC power line, and then by additional on-board regulators to further adjust the voltage to whatever the console needs. These voltage regulation systems are designed by engineers to work a specific way; basically you only have one plug to plug into the AC coming from the wall, and the wall-wart turns it into DC and the console takes care of the rest. If you've ever plugged in a game console, you should be familiar with this first block diagram:
    [​IMG]

    So, keeping our main objective(to use DC batteries with the console) and our currently available options in mind(an AC-to-DC wall-wart,) we'll notice we have our first problem: we have a DC power source, and an AC plug. This means we can't just plug our batteries into the wall-wart and expect things to work. So, what are our options? Well, it depends on what the console is, but in true BitBuilt fashion, we'll say it's a Wii. Let's add a few things we can find with some basic research to our block diagram:
    [​IMG]

    Now we know a little bit about what voltages the Wii is looking for in each step. We'll come back to this in a moment, but we need to briefly talk about batteries.

    For many ages, portablizers have looked to 7.4v batteries as the solution, as most consoles didn't care what the voltage was, and popular screens like the PS1 screen would only accept around 7.5v. This made 7.4v our standard, as most rechargeable battery packs are rated in terms of what the individual 3.7v cells add up to; so we have 3.7v packs, 7.4v packs, 11.1v packs, 14.8v packs, etc. Modern screens have become more flexible, usually working correctly on anything above 5v, maintaining that the closest voltage to be found from a standard battery pack is 7.4v. Numerically, a 3.7v pack is closer, but remembering rule 6 of our initial set of rules, it's easier to step-down than step-up.

    With all of this in mind, we now understand that has been an option already available to us, bringing us to further expand our block diagram:

    [​IMG]

    In the case of powering a Wii, we can choose a 14.8v pack as it's the closest to the 12v requirement of the Wii. However, this is a problem for multiple reasons: a 14.8v pack means at least 4 cells, which means a larger/heavier portable, and the voltage level may be too high for any other components we might be using, like any screens, LEDs, or fans. But by far the biggest reason of all is that most modern motherboard trims remove the on-board regulators, meaning that in making our motherboard smaller, we've removed the original power system developed by the engineers. This leaves us with only one option and brings us to the whole point of this guide: custom regulators! But first, another history lesson.

    Once upon a time, portablizers looked to free samples of switching regulators from Texas Instruments, as portablizing is an expensive hobby and portablizers are usually limited in finances. What made these switching regulators so wonderful was that they only required two easily found components to properly regulate voltage, all while doing so more efficiently than the linear regulators we were once fond of using. These wonderful free sample regulators, specifically the PTH08080 families, were a mainstay for years until TI sadly ended samples for them. They are still commonly used today, although we have to buy them now(which is fine, because TI did help us out for many years.) So, chances are when someone mentions "custom regulators," they're talking about a couple of PTH08080 boards, and maybe a PTR08060 too.

    Back to custom regulators, there's another factor to consider, and that's amperage draw. Amperage is communicated a variety of different ways. Let's say for example that a Wii draws up to 2.6A on it's 12v line. This means we need a source that's capable of providing up to 12v at 2.6A, or we can also communicate this as requiring 31.2 watts. Remember, Volts x Amps = Watts, so 12v x 2.6A = 31.2W.

    A power source such as batteries can also be expressed similarly, however a few things are different. You will find battery packs listed in a fashion like this: 14.8V 2.6Ah (38.48Wh). Notice the additional "h" listed next to amps and watts? It stands for hours. This basically translates to "I can provide 14.8v at 2.6A for an hour, or 38.48 watt hours." So, we can use all of this information to roughly calculate battery life(because realistically, the Wii won't always be drawing 2.6A.)

    We only need the value in watts to calculate battery life. So, we have a battery pack rated at 38.48Wh and our system draws 31.2W, so 38.48Wh divided by 31.2W equals 1.23, meaning these batteries will last for 1.23 hours!

    Another things to consider is wire gauge. Basically the more power you have, the thicker your wires need to be. Multistrand is usually preferred over single core as well. There are plenty of tables and calculators online to help you figure out what's best for your application. In a pinch, you can also run multiples of the same wire, a useful trick if you wan to use old IDE wire for everything.

    Now, that we understand amperage, let's do a little more power research and update our block diagram again to complete our power requirements, which help us choose the right custom regulators:

    [​IMG]

    The Wii requires 3.3v at 0.66A, 1.15v at 1.8A, and 1v at 1.53A. Now that we know exactly what the Wii draws, we can use this information to pick out regulators that will fit these specifications. In the case of the Wii, we only need 4x PTH08080 regulators, as the datasheet(attached below) tells us that the regulator is capable of outputting any voltage between 0.9v - 5.5v at 2.25A, which means that the regulator outputs more than enough power at any given point, assuming that our batteries are outputting enough power as well.

    NOTE: This guide is only going to cover PTH08080 and PTR08060 regulators, as they are the most commonly used among our community, however you should have enough understanding to research and choose other regulators if they better serve your purpose.

    Lets update our block diagram to simplify our process:

    [​IMG]

    We also added a power switch here, which is simply just a break between the regulators and the batteries, as the regulators will output power the moment that input power is applied.

    The last thing we need to figure out is any components that the regulators need to work properly. So far, everything as been expressed as simple blocks and power lines, but within the datasheet you'll find more complex circuit diagrams that require some learning to read. For the ease of our users, we'll have a literal diagram of the two required components to make the PTH08080 and PTR08060 work properly posted below, to help understand exactly what components to connect where. After these are connected to the regulators, we'll be ready to connect them to the batteries via the switch, the console, and of course, we'll also be CONNECTING ALL OF THE GROUNDS TOGETHER. Rule 0 is the first thing to check whenever something is not working; are all grounds connected together? If they're not connected, the circuit will not be complete, and therefore will not work.

    In the case of the PTH08080 and the PTR08060 regulators, we only need 1 resistor to set the voltage level and up to 2 capacitors to filter/stabilize the input and output voltages.

    Capacitors:
    The datasheet calls for the input and output capacitors to be 100uF electrolytic capacitors, and as a rule of thumb it's better for them to be above the input voltage. The most common capacitors used are 16v 100uF caps, and a cheap way to get some is to order a handful of them from eBay. There's nothing wrong with buying in bulk, as you never know when you're going to need some again. In addition, many users often skip the output capacitor, as most of our applications don't require them, but these guides will show them connected anyways, and it's recommended to include one on each regulator.

    Resistors:
    The most flexible part of the regulator setup is the resistors. Resistors have three main values: resistance(Ohms), maximum power(Watts), and percent error(tolerance.) The Ohms value will be different based on whatever output voltage you need, and is the most important value to consider. Watts and tolerance are important too, however the PTH08080 is rated for resistors with a 0.05W at a 1% tolerance, so a wide variety is accepted. The last thing to mention is that resistors can be combined in series to add resistance, so if for example you need 2k Ohms, but only have a few 1k Ohm resistors, you can connect two of them end-to-end to effectively have 2k Ohms of resistance.

    Here's a good resource to help learn how to determine resistor values: http://www.dannyg.com/examples/res2/resistor.htm

    Finally, here are the literal diagrams for connecting resistors and capacitors to the PTH08080 and PTR08060, as well as some tables with resistance values for voltages found commonly in portablizing.

    Regulator diagrams

    PTH08080 (2.25A)
    [​IMG]

    PTR08060 (6A) (also applies to the 10A PTR08100)
    [​IMG]

    Regulator setups per-console:
    • N64: 1x PTH08080 (3.3v)
    • GC: 1x PTR08100 (1.9v) + 2x PTH08080 (3.3v and 5v) OR 2x PTR08060 (split CPU/GPU 1.7v and 1.5v) 2x PTH08080 (3.3v and 5v)
    • Wii: 4x PTH08080 (1v, 1.15v, 3.3v, 5v*)

    *5v only required on GC for rumble/stock DD, and only required on Wii for USB.

    Outro
    This guide was written by @ShockSlayer to help teach basic regulator-related principles to the portablizing community, and therefore does not prioritize technical correctness over practical application, and values available resources and financial practicality over pursuing optimal conditions. Such is the path of the portablizer. Any complaints can be emailed to [email protected]
     
    Last edited by a moderator: May 10, 2019
    Jerd, Ekterm, JHammerstrike and 33 others like this.

Share This Page

Loading...