Electronic Circuits: Switched-Mode PS

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Friday, April 14, 2023

Mini Switching Power Supply 5V - 25V, 3A with TNY268 and PCB

Electronic Circuits Circuits to Assemble , Electronic Circuits

Mini Switching Power Supply 5V - 25V, 3A with TNY268 and PCB

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Compact 3A Mini Switching Power Supply: Build Your Own 5V-25V Solution with TNY268 and PCB

In this article, we will be discussing a mini switched power supply that provides 5V to 25Vdc output. This power supply is perfect for various electronic devices that require a stable and reliable power supply.

This is a power supply based on the TNY268 Integrated Circuit, which is part of a series of TinySwitch-II circuits: TNY263, TNY264, TNY265, TNY266, TNY267 and TNY268.

For a Flyback-type switched power supply like the one proposed, this IC is ideal, it integrates in its encapsulation the components necessary for it to work:

PWM Control, Power Mosfets
Overcurrent Protection
Over-Temperature Protection
Self-Feeding System

It does not need auxiliary windings, which makes it a complete IC, with DIP8 encapsulation, with a PWM working frequency of 132kHz and a voltage of up to 700V.

We will dive into the technical specifications, design, and features of this power supply and how it compares to other similar products in the market.

Technical Specifications

The mini switched power supply has an input voltage range of 80V to 260V AC, which makes it suitable for use in different parts of the world.

It provides an output voltage that can be regulated between 5V to 25V, with a current of up to 3A, depending on the configuration that we choose.

The power supply also has short-circuit protection and overvoltage protection, ensuring the safety of the connected devices.

Design

The mini switched power supply has a compact design, with dimensions of 55mm x 26mm x 21mm. The power supply is enclosed in a plastic case that protects the circuitry from dust and other environmental factors.

The power supply has a standard WJ2EDGVC-5.08-2P connector, making it easy to connect different electronic devices.

Caution!

"This circuit works directly connected to the electrical network, this is extremely dangerous, any carelessness, or wrong connections, design error, or any other occasion, can lead to irreversible damage.

We are not responsible for any type of occurrence. If you don't have enough experience, don't build this circuit, and if you build it, when testing it, be sure to have the proper protections and be accompanied by someone else."

Features

One of the standout features of this mini switched power supply is its efficiency. It has a high efficiency rating of up to 85%, which means that it wastes less energy as heat compared to other similar products.

This feature is especially important for electronic devices that are battery-powered, as it helps to extend their battery life.

Another feature of this power supply is its low ripple and noise. The power supply has a ripple voltage of less than 50mV, which ensures that the connected devices receive a stable and noise-free power supply.

This is especially important for audio devices, where any noise in the power supply can cause unwanted noise in the audio output.

TNY268 - Pinout and Description

The TNY268 is packaged in a DIP-8B structure for perforated pinouts and an SMD-8B package for SMD.

The package is similar to the well-known IC LM555, with the exception of pin 6 hidden in the TNY268, as we can see in the pinout of Figure 2, below.

Fig. 2 - Pinout - Pinout TNY268

We leave below the description of each pin of the TNY268 Integrated Circuit to facilitate our understanding.

DRAIN (D): Power MOSFET drain connection. Provides internal operating current for start-up and steady-state operation.
BYPASS (BP): Connection point for an external 0.1 µF bypass capacitor for the internally generated 5.8 V supply.
ENABLE/UNDERVOLTAGE (EN/UV): This pin has two functions: input enable and line undervoltage detection. During normal operation, power MOSFET switching is controlled by this pin. MOSFET switching is terminated when a current greater than 240 μA is drawn from this pin.

This pin also detects line undervoltage conditions through an external resistor connected to the DC line voltage. If there is no external resistor connected to this pin, TinySwitch-II detects its absence and disables the line undervoltage function.
SOURCE (S): Common control circuit, connected internally to the output MOSFET source.
SOURCE (HV RTN): MOSFET source connection output for high voltage feedback.

The Switched Power Supply Circuit

The Mini Switched Power Supply Circuit with TNY268 for 5V - 24V, 3A output is a simple yet powerful design, as shown in Figure 3 below.

However, due to the involvement of electricity, it requires careful handling and at least intermediate knowledge of electronics to assemble the circuit.

Fig. 3 - Schematic Diagram Mini Switching Power Supply 5V - 25V, 3A with TNY268

The schematic diagram of the Mini Switched Power Supply Circuit is well laid out and easy to understand. It includes a TNY268 controller that regulates the output voltage and current of the power supply.

The circuit has a few essential components such as capacitors, resistors, diodes, and an inductor, which work together to provide stable and efficient power.

Regulate The Output Voltage

The output voltage is adjusted through two parameters in the circuit:

The D4 diode, which is a 1W Power Zener diode.
The secondary winding of the transformer.

The Zener Diode

The zener diode D4, is the diode that will adjust the output voltage, we must configure it as follows,
when the desired voltage is Xv, the zener diode must have a voltage Xv - 1.

The diode should be 1V lower than the nominal voltage of the power supply, this lower voltage is due to the photocoupler being connected in series with the zener diode, and since it is an “LED” diode, we have the voltage drop on it.

For example:

To obtain a voltage of 5V at the power supply output:

The zener diode D4 = 4V. We use a commercial 4.3V, 1N4731 zener diode.

To obtain a voltage of 9V at the power supply output:

The zener diode D4 = 8V. We use a commercial 8.2V, 1N4738 zener diode.

To obtain a voltage of 12V at the power supply output:

The zener diode D4 = 11V. We use a commercial 11V, 1N4741 zener diode.

To obtain a voltage of 25V at the power supply output:

The zener diode D4 = 24V. We use a commercial 24V, 1N4749 zener diode.

The Transformer

The transformer used in this circuit was a high frequency transformer, often found in PC power supplies, as illustrated in Figure 4 below, a model EE-25 Ferrite transformer.

Fig. 4 EE-25 Ferrite Transformer

Primary coil winding

The primary will be wound to support a voltage between 85V and 260V, and this will be done by winding 140 turns of 33AWG enamelled wire, or 0.18 mm diameter wire.

Right after winding the primary, place appropriate insulation tape, with electrical and thermal insulation, to insulate the primary from the secondary.

Secondary coil winding

The secondary will be wound according to the desired output voltage, and this will be done in such a way that, for each desired 1V, 1.4 turns of 17AWG enameled wire or 1.15 mm wire are wound.

The calculation for an output voltage of 5V can be achieved using the formula below:

Formula: N = V * F

N = Number of Turns
V = Desired Voltage
C = Constant = 1.4

V = 5V
C = 1.4
N = ?

N = 5 * 1.4
N = 7 laps

For 5V on the output, we have 7 turns to wind in the secondary.

The calculation for an output voltage of 9V:

V = 9V
F = 1.4
N = ?
N = 9 * 1.4
N = 12.6 = ~13 Rounds

For 9V on the output, we have 13 turns to wind in the secondary.

The calculation for an output voltage of 12V:

V = 12V
F = 1.4
N = ?
N = 12 * 1.4
N = 16.8 = ~17 Rounds

For 12V output, we have 17 turns to wind in the secondary.

The calculation for an output voltage of 24V:

V = 25V
F = 1.4
N = ?
N = 25 * 1.4
N = 35 Turns

For 24V output, we have 37 turns to wind in the secondary.

The good thing is that with the formula, we can calculate any voltage we want to get at the output of our switching power supply.

Components list

Semiconductor

U1 ......... Integrated Circuit TNY268P
OPT....... TLP181 Opto-Coupler
D1, D2 ... Diode 1N4007
D3 ......... Fast Diode FR307
D4 ......... Zener Diode *See Text

Resistor

R1 .... Resistor 10Ω / 1W (brown, black, black, gold)
R2 .... Resistor 200KΩ / 1/4W (red, black, yellow, gold)
R3 .... Resistor 470Ω / 1/4W (yellow, violet, brown, gold)

Capacitors

C1 ....... Electrolytic Capacitor 47uF/400V
C2 ....... Polyester Capacitor 2.2nF
C3 ....... Polyester Capacitor 100nF
C4 ....... Electrolytic Capacitor 470uF/35V

Several

T1 ......... EE-25 Ferrite Transformer
P1, P2 ... Connector WJ2EDGVC-5.08-2P
Others... PCI, Wires, Solders, Etc.

Printed Circuit Board - Download

In Figure 5 below, we are making the PCI available in GERBER, PDF and JPEG files, for those who want to create a more optimized assembly, either at home, or if you prefer, at a company that prints the board.

PCB-Mini Switching Power Supply 5V - 25V, 3A with TNY268

You can download the files for free from a direct link in the Download option below.

Click Here!

Conclusion

In conclusion, the mini switched power supply that provides a programable 5V to 25Vdc output is an excellent choice for various electronic devices. Its compact design, high efficiency, and low ripple and noise make it stand out compared to other similar products in the market.

Its safety features, such as short-circuit protection and overvoltage protection, ensure that connected devices are protected from damage. If you are looking for a reliable and efficient power supply for your electronic devices, then this mini switched power supply is a great choice.

You can see the official post by clicking here! fvml.com.br

I hope you enjoyed it!!!

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

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Switched Power Supply SMPS 13.8V 10A using IR2153 IC and IRF840, with PCB

Electronic Circuits Circuits to Assemble , power supply

13.8V-SMPS-Power-Supply-Using-IR2153-IC-and-IRF840-Mosfet

Para Versão em Portugues, clique aqui!

Switched Power Supply SMPS 13.8V 10A using IR2153 IC and IRF840, with PCB

This circuit is a straightforward design for an SMPS power supply, utilizing the IR2153 IC. This chip, which has only 8 pins, functions as a PWM controller, enabling the creation of a high-performing and cost-effective unregulated switching power supply for basic projects.

The output voltage of this power supply is set at 13.8V and can be adjusted via the trimpot RV1. It also provides a steady current of 10A at its output.

The Circuit

The circuit basically consists of 8 main steps:

Protection Circuit: It comprises a 5A/250V fuse, which operates if there is a current greater than the fuse's breaking current.
At the same time we also have an NTC (Negative Temperature Coefficient), it is a surge current limiter, this same topology can be found in most SMPS power supplies, such as notebook power supplies, PC power supplies, computer AT / ATX power supplies, etc.
Transient Filter: This step consists of an initial capacitive filter that inhibits high frequencies from returning to the network, or vice versa, and soon after, the EMI filter coil, which serves to attenuate high frequency noise.
Primary Rectification: Made up of the D1 rectifier bridge.
Primary Filter: Composed of capacitors C4 and C5.
Switching: Composed of a PWM generator, and the IRF840 power MOSFETS transistors.
Transformer: The transformer is a high-frequency Chopper Trafo, and it performs the isolation and high-frequency transformation of the signal generated by the PWM set and switching transistors.
Fast Rectification: Formed by diode D3, this is a fast and double diode, since the oscillated frequency in the circuit is quite high.
Output filter: Composed of inductor L2 and capacitor C9.

Caution

This circuit works directly connected to the electrical network, this is extremely dangerous, any carelessness, or wrong connections, design error, or any other occasion, can lead to irreversible damage.

The PWM Circuit

The power supply for the IR2153 IC comes through a 27K 5W power-limiting resistor together with the C5 capacitor. In the internal package of this IC, there is already a 15.6V Zener diode, which stabilizes this voltage, but the current is low.

So, be careful not to put the resistor R3 with a smaller resistance, as it would increase the current at the input of the IC, and the Zener could break and consequently burn the IC.

An improved solution would be to put a 15V Zener diode to ensure voltage stabilization and IC protection, which you can be doing if you wish.

If you are using the IR2153D, there is no need to use the D2 diode which is the FR107 or BA159, as this IC already has this diode internally, if it is the IR2153 “without the letter D”, leave it as it is in the schematic, “ with diode D2”.

The complete schematic diagram is displayed just below in Figure 2, both the diagram and the materials are available for download at the link below.

Figure-2-Schematic-Diagram-SMPS-13.8V-10A-power-supply

The Transformer

The TR1 transformer was taken from a scrap ATX power supply, the model is the IE-35A, but you can be using practically any model of ATX power supply Trafo.

There is no need to rewind the transformer, just pay attention to the Pinout that we will use for the Trafo, as shown in Figure 3 below.

Fig.3-ATX-power-supply-Trafo-wire-connection-diagram

The Trafo model used was the EI-35A, but we can also use any other AT or ATX power supply that has the same standards, such as models EI-33, ER35, TM3341101QC, ERL35, EI28, etc., as shown in Figure 4 below.

Fig.4-ATX-power -supply-transformer-model-EI-35A

The L1 inductor is the same used in the ATX power supply, we removed it and didn't make any changes, and the L2 inductor, from the output EMI filter.

You can also use the AT/ATX power supply scrap, but if you want to wind your own filter, you can wind it on a Ferrite Toroidal core.

The winding must be carried out using a Toroidal core winding, with the coil using 0.6 mm super-enamelled copper wire with 25 turns.

Component List

Semiconductors
CI1 ......... Integrated Circuit IR2153D, or IR2153 (See Text)
Q1, Q2 ... IRF840 MOSFET transistors
D1 .......... KBU606 Diode Bridge (or Equivalent)
D2 .......... FR107 or BA159 Fast Diode (or Equivalent)
D3 .......... MBR3045PT Diodes Fast (or Equivalent)
Resistors
R1, R2 .... 150KΩ resistor - (brown, green, yellow, gold)
R3 .......... 27KΩ 5W resistor – (red, violet, orange, gold)
R4 ...........8K2Ω resistor – (gray, red, red, gold)
R5, R6 ... 10Ω resistor – (brown, black, black, gold)
RV1 ....... 47kΩ trimpot
NTC1..... 5Ω thermistor
Capacitors
C1, C2 ... 470nF - 400V Polyester Capacitor
C3, C4 ... 330uF - 200V Electrolytic capacitor
C5, C7 ... 100uF - 25V Electrolytic capacitor
C6 .......... 680pF Polyester Capacitor
C8 .......... 2.2uF - 400V Polyester Capacitor
C9 .......... 2200uF - 25V Electrolytic capacitor
Miscellaneous
L1, L2 .... Inductor *see text
TR1 ....... Transformer *see text
F1 .......... 5A Solderable fuse
Other...... Wire, Solder, Plate, Etc.

Printed Circuit Board

We provide the PCB - Printed Circuit Board, in GERBER, PDF and PNG files. These files are available for free download, on the MEGA server, in a direct link, without any bypass.

All to make it easier for you to do a more optimized assembly, either at home, or with a company that prints the board. You can download the files in the Download option below.

Files to download, Direct Link:

Click on the link beside: GERBER, PDF and PNG files

You can see the official post by clicking here! fvml.com.br

I hope you enjoyed it!!!

If you have any questions, suggestions or corrections, please leave them in the comments and we will answer them soon.

Subscribe to our blog!!! Click here - elcircuits.com!!!

My Best Regards!!!

5A, 1.22V to 26V, 500kHz Step-Down Converter Using RT8289 IC with PCB

Electronic Circuits Circuits to Assemble , Electronic Circuits

Fig. 1 - 5A, 1.22V to 26V, 500kHz Step-Down Converter Using RT8289 IC with PCB

Powerful 5A Step-Down Converter: Build a Versatile 1.22V to 26V Solution at 500kHz with RT8289 IC and PCB

This is a DC-DC 5A, 1.22V to 26V, 500kHz Step-Down Converter Using RT8289 IC, it works with a Step-Down conversion system.

This powerful chip manages to work with very few external components and provides a preset voltage between 1.22V to 26V, with 5 Amps of output current.

General IC Description

The RT8289 is a step-down regulator with an internal Power MOSFET. It achieves 5A of continuous output current over a wide input supply range with excellent load and line regulation.

Current mode operation provides fast transient response and eases loop stabilization. The RT8289 provides protections such as cycle-by-cycle current limiting and thermal shutdown.

In shutdown mode, the regulator draws 25A of supply current. The RT8289 requires a minimum number of external components, to provide a compact solution. The RT8289 is available in a SOP-8 (Exposed Pad) package.