Designing a PlayStation 1 PSU replacement board

May 27, 2026

Index

Motivation
Regulator selection
Circuit design
Validation setup
Efficiency and power-on
Comparison with Aliexpress option

1. Motivation

Five years ago, I bought a house and moved into it. One of the things I had always wanted was to have a kind of studio where I could set up an audio system—a place to work, study, play video games, and listen to music. Nothing very special, I guess.

I started buying vinyl records since I already owned a turntable. At some point, however, I thought it would be nice to acquire something to play audio CDs.

I came across a few articles that talked about how a PlayStation 1 (PS1) can be a good music player. I understand 'good' as the trade-off between price and sound quality:

Figure 1. PlayStation 1 SCPH-1001. Image taken from: https://twitteringmachines.com/the-sony-playstation-as-cd-player-an-epitaph/

By chance, at that time a friend brought me a PlayStation 1 SCPH-1001 (the one that has RCA audio connectors on the backplane) from a trip to Japan. He found it in the junk section for 100 yen (ridiculous). When he tried to test it, the original power supply unit (PSU) didn’t pass the smoke test and it died. He also said that some time ago he started to design a custom printed circuit board (PCB) to replace the old PSU. For some reason the project was on standby, and I thought it was a nice opportunity to continue it and bring the dead PS1 back to life.

2. Regulator selection

The TPS62135 was the switching regulator chosen to generate all the voltage rails needed to supply power to the PS1. These were our minimum requirements for the regulator:

We wanted to use a 12V wall-mounted AC/DC power supply (e.g., the RS 175-3326). Later on, using the 3D printer, we would replace the typical mains connector with a barrel-jack connector.
We needed an efficient switching regulator to minimize power dissipation and, thus, the thermal delta on both the PCB and the PS1. Old video game consoles do not tolerate high temperatures. As is well-known, exposing hardware to sustained high temperatures increases component aging and reduces its lifetime.
We wanted the ability to adjust the output voltage up to 12V so that it could be used not only for the PS1 but also for other consoles such as the Sega Dreamcast (3.3V and 5V), SNES (~9-10V), Gameboy (~5V), etc.
We needed enough output current (which translates to power output) to withstand the consoles' average and peak power consumption.
Low voltage ripple. Ripple in the output voltage signal can cause internal regulators in the console to misbehave or generate unwanted artifacts. In some cases, noise in the power supply can couple into audio or video signals, generating undesirable effects.
Low switching noise. Switching regulators are inherently noisy. However, if the switching is controlled (at a fixed frequency), we can mitigate this noise by implementing a filter at the output of the regulation stage.

As the manufacturer states, the TPS62135 is a 3-17V, 4.0A Step-Down Converter with 1% accuracy. It meets all our requirements and includes additional features:

Accepts input voltages from 3 to 17V
Output voltage can be configured from 0.8V to 12V
It can provide a continuous output current of 4A
It has an “enable” pin and soft-start control to reduce inrush currents caused by discharged capacitors during start-up.
The switching can be controlled either with forced PWM (2.5MHz) or with PFM to increase efficiency at low load.
… and as the datasheet says, it is recommended for gaming consoles!!!

The TPS62135 can be the “one to rule them all”

Link to the datasheet (DS): TPS62135 DC/DC Step-Down Converter

3. Circuit design

Designing a circuit with a switching regulator is always a challenge, especially during the PCB layout phase.

Decisions such as signal routing, component placement (e.g., the inductor), layer stack-up, power and ground planes, and others are critical to ensure good stability, thermal management, efficiency, low ripple, and minimal noise. For this reason, if an evaluation board (EVB) is available (TPS62135 EVB), it is highly advisable to use it as a reference for your design since it considers all the critical aspects mentioned above. And let’s be honest, it significantly reduces development time, as these optimizations have already been validated by the manufacturer.

Figure 2 shows a 3D view of our PCB (left), the layout suggested in the datasheet (right top) and the EVB top layer layout (right bottom). No need to say we have followed the recommendations to the letter: same components placement and very similar signals routing.

It can be noticed that we have included all the input and output capacitors, both the “mandatory” and the “optional” ones (section 1.2, TPS62135 EVB) . At least for the first prototypes, we wanted to make sure we got the minimum output voltage ripple.

Finally, we also added an LC filter to the output, adding an extra filter stage in case we need it.

Figure 2. 3D view of our PCB top layer (left). Layout suggested in the DS (right top). EVB top layer layout (right bottom)

We have also based the PCB 4-layer stack-up on the EVB (Figure 3):

A top layer with polygons for ground (GND), input and output voltages. The top layer does not have a GND plane.
An internal 1 layer with a GND plane.
An internal 2 layer with a GND plane and exactly the same input voltage polygons.
A bottom layer with a GND plane and the TPS62135 digital signals.
Polygon cutouts underneath the inductor.

Figure 3. Pix3lmods PS1 PSU PCB layers

Final Application Considerations

All of this sounds great, but let’s not forget the final application! In addition to the electrical design, the PCB must meet specific mechanical and compatibility requirements to ensure it fits seamlessly into the original PlayStation 1 system. These requirements include:

Compatible input and output connectors.
A board shape and mechanical holes that align with the original PS1 power supply unit (PSU).
A button that aligns with the PS1 power button, toggling the TPS62135 enable pin to control power flow to the console.
Another button that is placed underneath the PS1 reset button. Ideally, applying the same delay.
A selectable RGB LED to add a touch of style to the design (why not?).

While these features are important, their implementation is relatively straightforward compared to the challenge of designing a well-optimized adjustable DC/DC regulator.

Figure 4. Complexity of adapting the PCB shape, adding a power button, an RGB LED, etc.

4. Validation setup

Once we received the first prototypes, we conducted basic measurements to validate the DC/DC converter’s efficiency, as well as the ripple and noise present in the 8V output voltage signal. We focused on the 8V stage since it powers the PS1, whereas the 3.5V rail has a significantly lower current consumption.

For the performance analysis, we used the following electronic instrumentation:

Oscilloscope: Keysight MSOX3024T 200MHz 5GS/s
Power supply: Rigol DP711
Electronic load: BK PRECISION 8542B 150V/30A/150W DC electronic load
Digital Multimeter (DMM): Fluke 179 True RMS

Connected as shown in Figures 5 and 6. We ensured that both the power supply and electronic load connections used cables with the lowest possible resistance to minimize additional voltage drops and measurement inaccuracies.

Figure 5. Setup for measuring 8V output voltage rail

Figure 6. Picture of the real setup

5. Efficiency and power-on

To measure efficiency, we used the Rigol power supply and the BK electronic load, gradually increasing the current draw on the 8V rail in 0.1A steps. Before each measurement, we ensured that the input voltage was precisely 12V by fine-tuning the Rigol PSU to compensate for small voltage drops in the cables, verifying it with the DMM directly at the input connector. We then measured the output voltage directly at the output connector using the same DMM.

This analysis was performed from 0A to 3A for two different inductor part numbers: one using Wurth inductors (PN 74438357010) and the other using an alternative inductor suggested by JLPCB (we manufactured and assembled the prototypes with them). The purpose of having these two variants was to evaluate the impact of inductor selection on overall efficiency and voltage losses at the output voltage rail.

It is worth mentioning that the DC/DC converter can operate in two modes:

PWM (Pulse Width Modulation) mode
PFM (Pulse Frequency Modulation) mode.

In our prototype, the default configuration enabled PWM mode via a pre-mounted resistor. However, we observed that at higher loads, particularly between 2.5A and 3A, the inductor temperature increased significantly, and the 8V rail voltage dropped by almost 0.5V due to losses.

These voltage drops in PWM mode are primarily due to conduction and switching losses, as the inductor continuously operates at a fixed switching frequency, causing resistive losses in its winding. From the impedance graph of both inductors, we found that at 2.5 MHz, the Wurth inductor exhibits a resistance between 10 and 20 ohms, which contributes to these losses. For the alternative JLPCB inductor, we lack precise impedance data, but based on our analysis, its resistance at the switching frequency appears to be even higher.

Figure 7. Wurth inductor 74438357010 Impedance [Ω] vs Frequency [MHz]

In contrast, PFM mode, which dynamically adjusts the switching frequency based on load demand, significantly reduces inductor losses and improves voltage regulation by minimizing switching events at lower loads.

Figures 8 and 9 show the measured data for both inductor variants operating in PFM mode. As observed, the efficiency graph aligns well with the expected values from the datasheet.

Figure 8. Efficiency analysis data

As previously mentioned, the JLPCB inductor exhibits a slightly higher voltage drop at the output compared to the Wurth inductor.

Figure 9. Efficiency (%) of the 8V DC/DC stage. Measured efficiency (left) and datasheet efficiency (right).

EDIT: Upon further review, we determined that the voltage drop on the 8 V rail was not mainly caused by the buck-boost inductor. Instead, it originated in the output LC filter stage, which introduced additional losses. By short-circuiting the inductor of the LC filter and repeating the tests, we observed that the regulator’s output voltage remained stable across the 0–3 A load range.

A key takeaway, beyond considering the voltage drop itself, is that one must be cautious when adding LC stages at the output of a switching regulator. These converters are typically designed to maintain stability only within certain load conditions (capacitive and inductive), and external filters may push the system outside of those ranges.

To evaluate the power-on response at the output, we used the oscilloscope while setting the electronic load to 3A, representing the worst-case scenario. This allowed us to observe the behavior of the 8V rail under maximum load conditions.

Figure 10. Power-on response.

6. Comparison with Aliexpress option

For comparison, we performed the same analysis on an Aliexpress PS1 PSU replacement board, allowing us to benchmark our design against a commercially available alternative. Figures 11 and 12 show the measured data and the efficiency plot. It can be observed that in this case the efficiency is lower than with the Pix3lmods board.