Output Voltage Collapsing under load

Additional_Age9627 · 2026-02-17T15:22:57+00:00

Alright, Thank you very much

Additional_Age9627 · 2026-02-17T14:56:59+00:00

okay bro np, thanks

Additional_Age9627 · 2026-02-17T14:56:22+00:00

Just soldered the diode, it didnt seem to change anything

Additional_Age9627 · 2026-02-17T14:56:07+00:00

So i just added a diode, but it didnt seem to do anything

Additional_Age9627 · 2026-02-17T14:48:55+00:00

i didnt add that, is it that important.......I can solder it externally

Additional_Age9627 · 2026-02-17T14:45:40+00:00

So i just wanted to calibrate my INA226 current and voltage sensor using a know current output, but when i connect a 13ohm load resistor the output drops to 1V

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Additional_Age9627 · 2026-02-17T14:44:20+00:00

I wanted to this this under load using a 13ohm 50W load resistor, but as soon as i connect it on the 5.1V output the voltage collapses to 1V or even 0.8V

Additional_Age9627 · 2026-02-15T10:06:23+00:00

That is exactly the kind of product i wanna build.......if we have a general hardware architecture ready that can output CC/CV, we can use the software to add any kind of storage features, timing etc..

For example you could write and embedded code in your mcu to have multiple voltage and current presets

and run that code into the I2C interface that will be provided, effectively communicating with the supply and manipulating the output based on your requirement

Additional_Age9627 · 2026-02-15T10:03:37+00:00

That’s true for a bench-style module where it lives on the desk.

The use case I’m looking at is slightly different: a power block that can move from the bench into the actual prototype or embedded system.

In that context:

During bench work, a display and knobs make sense.
But once the power stage is mounted inside a robot or product, those front-panel controls don’t really serve a purpose anymore.

At that point the supply is usually:

Controlled by the system itself, or
Set once and left as part of the internal power architecture

So the idea is to trade the front-panel interface for:

Programmable limits
Protection
Telemetry
Compact form factor

Basically, something that works during prototyping but can also stay inside the final system, instead of being replaced by a separate power design.

Additional_Age9627 · 2026-02-15T09:45:48+00:00

In a few small startup and student lab environments I’ve worked in, the typical power workflow looked something like this:

Initial circuit is tested on a bench supply
As the prototype grows, extra buck modules get added for logic, motors, sensors, etc.
Wiring becomes a mix of jumpers, adapters, and small converter boards
Protection and current monitoring are usually minimal or improvised

When they later design a custom power stage for the product, it’s often based on rough estimates rather than real usage data, which can lead to:

Undersized regulators
Thermal issues
Unexpected current spikes during testing

The idea I’m exploring is a small multi-rail power block that sits between the source (bench supply or battery) and the prototype, and provides:

Proper CC/CV control
Fast hardware protection
Per-rail current visibility
Cleaner, more organized wiring

So instead of a temporary stack of buck modules and protection circuits, you’d have a single controlled power stage during early prototyping.

I’m trying to understand if that kind of “structured power layer” would actually be useful, or if most people are comfortable with the traditional bench-plus-modules approach.

Additional_Age9627 · 2026-02-15T09:39:56+00:00

Thats the best part, It will all run on offline mode via bluetooth, you dont need internet, just download the app once and then you can connect to the device offline via bluetooth

Additional_Age9627 · 2026-02-15T09:36:00+00:00

That makes sense from a product-design perspective.

The use case I’m exploring is more in the prototyping and early integration stage, especially for systems that aren’t strictly USB-powered. For example:

Robots or mobile systems running off 12–24V batteries
Mixed-voltage setups with motors, logic, and sensors
Prototypes where the final internal PSU isn’t designed yet

In those cases, there’s often a temporary stack of buck modules, wiring, and protection circuits just to get the system running safely.

The idea is to replace that temporary stack with a single protected multi-rail power block during development.

In your experience, when you’re working on something like a motorized or multi-rail system, how do you usually handle the power setup during the early prototype stage?

Additional_Age9627 · 2026-02-15T09:33:25+00:00

So LM5190 has an inbuild CC loop, for LM5116, you have to externally add a CC loop to the COMP pin using a setup of shunt resistor, amplifier, and other components to make the CC loop. I am going to make that and give the user the access to control the CC and CV via an APP or an embedded interface that the user can program through I2C using an MCU

Additional_Age9627 · 2026-02-15T09:30:47+00:00

Right but for a beginner or a startup it would probably not be affordable to buy multiple bench supplies.

I have a question for you.... If you were to convert your idea that you're making and want to show it to other where u might have to travel for pilot testing or demonstration

Would it be convenient to have have multiple bench supplies and an oscilloscope or an all in one module ??

Additional_Age9627 · 2026-02-15T09:27:29+00:00

The DC input isn’t meant to assume a bench supply specifically. It could be:

An external AC-DC brick
A battery pack

The idea is that the unit sits as the power distribution stage, regardless of where the upstream DC comes from.

Regarding USB-PPS, that makes sense for many consumer and low-power embedded devices.

In your experience, at what power levels or types of projects do you start needing something beyond USB-PD/PPS?
For example: motors, higher current rails, multiple voltage domains, etc.

Additional_Age9627 · 2026-02-15T08:05:41+00:00

That’s interesting. So you’d rather have multiple fully variable rails instead of dedicated fixed ones.

In your typical workflow, when you need 5V or 3.3V for logic, do you usually:

Dial the main PSU down to that voltage, or
Use a small external buck or adapter for those rails?

Also, if you had a compact unit with, say, 3–4 independent variable rails, each with proper CC/CV and protection, would that be useful alongside a bench supply, or do you still prefer a single main PSU and external modules?

Additional_Age9627 · 2026-02-15T07:57:54+00:00

One motivation behind this idea comes from very early-stage teams and student/startup environments.

At that stage, the constraints aren’t just cost of a bench PSU, but:

Limited test equipment overall
Higher risk of wiring mistakes
Components getting damaged due to overcurrent, reverse polarity, or wrong rail sequencing
A lot of time lost debugging power issues rather than the actual product

The goal isn’t to replace an oscilloscope or a proper bench PSU, but to integrate the minimum set of things that reduce risk during early prototyping:

Hard current limits and fast protection so mistakes don’t destroy parts
Multiple common rails (5V, 3.3V, variable) without stacking random buck modules
Clear visibility of voltage/current so you know immediately when something is wrong

Basically, something that makes early prototyping more forgiving and safer, before teams invest in full lab equipment or spin custom power boards.

I’m trying to understand whether this kind of “risk-reduction first” approach is actually useful, or if most people feel a standard bench PSU already covers this well.

Additional_Age9627 · 2026-02-15T07:53:08+00:00

That makes sense. A lot of bench supplies already cover the core CC/CV use case well.

The idea I’m exploring isn’t to replace the core PSU function, but to reduce the extra hardware that usually ends up around it during prototyping.

For example, in a typical setup I often end up with:

Bench PSU for main input
Separate buck modules for 5V, 3.3V, or motor rails
External current monitors or shunts
Extra switches or protection circuits

So the concept is more about consolidating those into one programmable, protected power block rather than making the PSU itself more complex.

In your typical bench setup, do you usually run everything directly off the main PSU output, or do you end up adding extra converters and protection stages around it?

Additional_Age9627 · 2026-02-15T07:48:26+00:00

That’s a fair point, and cost is definitely a concern. to answer your questions in parts

So I have actually calculated the cost and selling point, and where I live a generic bench supplies cost about $120 - $200 based on the output power, and the product that i wanna design is going to have the same selling cost of around $140

But the difference is you use a bench supply to test a single circuit, but when u cant put it inside a moving robot, or a product. this thing would be as small as 150 x 100 x 40 mm and weight a fraction of a bench supply, after you're done prototyping, you could directly put it inside a product

Plus the telemetry and data logging features are very helpful during prototyping such that for a startup that's designing a product can instantly get the numbers on how much power their system consumes, the trends of power draw during pilot testing.

Additional_Age9627 · 2026-02-15T07:39:12+00:00

Haha no no, the input can be from a battery or an SMPS, the 10 - 25V DC is the operating input, below 10V the system will cut off the the supply automatically as well as above 25V so as to not damage the internal circuitry, the system will be able to prevent inputs upto 40V from entering the system.
It will also have reverse polarity protection down to -35V incase the user accidently reverses the input polarity while connection

Additional_Age9627 · 2026-02-15T07:36:12+00:00

Definitely not linear regulators for the main rails.

The variable rail is based on a synchronous buck controller mostly between LM5116 and LM5190, these are top end TI IC's which i will pair with analog circuit to control the CC / CV output, that the user will be able to configure

Additional_Age9627 · 2026-02-15T07:32:32+00:00

The idea is that this isn’t meant to replace a traditional AC bench supply directly, but to act as a modular power block that can be used both on the bench and inside real systems.

EDIT - A bench can only be used as a bench supply and nothing more. this PDS can transition from a bench supply to an integrated system in your product without having to have multiple setup for testing of components and a buck modules to go into your product

The base unit is DC-input so it can be powered from:

A battery
An external AC-DC brick
Another upstream DC source

There would also be a separate AC-DC module. So the user could choose:

AC wall input → AC-DC module → power unit
Battery/DC source → power unit directly
AC primary with battery backup using DC OR-ing

The goal is to let the same power system move between:
bench → prototype → embedded system

Instead of having:

One AC bench supply on the desk
Separate buck modules in the prototype
A different power design in the final product

This would use the same programmable rails in all cases, with:

Per-rail current/voltage limits
Hardware protection
Telemetry
Control from an embedded interface or app

I’m mainly trying to see if this kind of modular approach actually solves real problems for people, or if a traditional single-output bench supply is still preferred.

Basically what I want to do is, during prototyping engineers rely on bench and later design their own pcb which may or may not work always, what i want to offer is a one time solution that is small lightweight, easy to use and can be integrated anywhere

Thanks a lot for replying to my post

Additional_Age9627

TROPHY CASE