Saturday, February 26, 2022

4A Low-Noise High-Frequency Step-Up DC-DC Converter using MAX1709 with PCB

Fig. 1 - 4A Low-Noise High-Frequency Step-Up DC-DC Converter using MAX1709 with PCB

This is a DC-DC converter circuit that uses a MAX1709 series Integrated Circuit as the main component, it works with a Step-Up conversion system.

This powerful microcircuit is able to work with very few external components and deliver a fixed 3.3V or 5V or adjustable 2.5V to 5.5V voltage, with 4 Amperes of output current.

Integrated Circuit General Description

The MAX1709 sets a new standard of space savings for high-power,  step-up  DC-DC  conversion.  It  delivers  up to  20W  at  a  fixed  (3.3V  or  5V)  or  adjustable  (2.5V  to5.5V)  output,  using  an  on-chip  power  MOSFET  from  a +0.7V to +5V supply. 

Fixed-frequency PWM operation ensures that the switching noise spectrum is constrained to the 600kHz fundamental and its harmonics, allowing easy post filtering  for  noise  reduction.  

External  clock  synchronization capability  allows  for  even  tighter  noise  spectrum  control. Quiescent power consumption is less than 1mW to extend operating time in battery-powered systems. 

Two  control  inputs  (ONA ONB)  allow  simple  push-on, push-off  control  through  a  single  momentary  push button  switch,  as  well  as  conventional  on/off  logic  control. 

The  MAX1709  also  features  programmable  soft-start and current limit for design flexibility and optimum performance with batteries. 

The maximum RMS switch cur-rent  rating  is  10A.  For  a  device  with  a  lower  current rating, smaller size, and lower cost, refer to the MAX1708 datasheet.

The Circuit Schematic

In Figure 2, below, we can see the schematic diagram of 4A Low-Noise High-Frequency Step-Up DC-DC Converter using MAX1709.

The circuit is simple to assemble, there are few external components, and there is no need for adjustment, once assembled, it is ready to work, if everything is correct, of course!

The PCB tracks are bent, the main ones have their tracks at the bottom and at the top of the PCB, because the current is 4 amperes.

The capacitors are tantalum, however if you can't find them, electrolytic capacitors can be used, however for more sensitive circuits, the performance may not be as expected, but in most circuits they work very well.

The DC-DC converter supports input from 0.7V up to 5V, and at the output it maintains the stabilized voltage of 5V, however to get the promised 4 Amps, it is necessary to have at least 3.3V at the input.
Fig. 2 - Schematic Circuit 4A Low-Noise High-Frequency Step-Up DC-DC Converter using MAX1709

Components List

  • Semiconductors
    • U1 ...... MAX1709 SMD Integrated Circuit
    • D1 .....  B520C SMD Schottky Diode 5A

  • Resistor
    • R1 ..... 312KΩ SMD resistor (orange, brown, red, orange, gold
    • R2 ..... 2Ω SMD resistor (red, black, black, gold)
  • Capacitor
    • C1, C2, C6, C7 ... 150uF SMD Tantalum Capacitor
    • C3 ....................... 10nF SMD Ceramic Capacitor
    • C4 ....................... 220nF SMD Ceramic Capacitor
    • C5 ....................... 100nF SMD Ceramic Capacitor

  • Miscellaneous 
    • L1 .......... 1uH 5A SMD Inductor
    • P1, P2 .... 2-pin PCB soldering terminal blocks (Optional)
    • Others .... Printed Circuit Board, wires, etc.

Printed Circuit Board

In Figure 3, 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.
Fig. 3 - PCB - 4A Low-Noise High-Frequency Step-Up DC-DC Converter Using MAX1709

Files to download, Direct Link:

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

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!!!

Friday, February 25, 2022

3500W Dimmer for 110V or 220V using TRIAC TIC246M with PCB

Fig. 1 - 3500W Dimmer for 110V or 220V using TRIAC TIC246M with PCB

This is a dimmable load controller circuit, its operation is based on the control of the sine cycle, keeping it off during a small period of the wave. And work only for a specific part of the wave keeping the load with part of the wave controlled by period, similar to PWM.

With this type of circuit we can control the intensity of an incandescent light, ceiling fans, resistive load, among others, through the decay of the cycle regulated through a potentiometer.

The Dimmer Circuit 

The 3500W Dimmer for 110V or 220V using TRIAC TIC246M with PCB circuit diagram is shown in Figure 2 below. 

It uses a 16 Amp TRIAC TIC246, this is enough to handle loads up to a little over 3500W, obviously with heat sink.
Fig. 2 – Schematic Circuit 3500W Dimmer for 110V or 220V using TRIAC TIC246M

CAUTION!!!

This circuit works directly connected to the 110/220V electrical network, and has a high power load, any carelessness, or wrong connections, error in the project, or any other occasion, can lead to irreversible damage. 

We are not responsible for any type of event. If you do not have enough experience to assemble this circuit, do not do it, and if you do, when testing, be sure to have the proper protections and be accompanied by someone else.

How it works

When we connect the AC mains to the circuit, there is a charging of the capacitor C4 through the voltage set in the Trimpot RP1. When biased, there is a sending of this voltage to the DIAC through the current limiting resistor R3

The DIAC is a bidirectionally biased diode, and is triggered when it reaches its breakdown voltage, about 30V, as it is connected to the Gate of the TRIAC. As soon as it reaches its breakdown voltage, both positive and negative pulses are activated in the Gate of the TRIAC

However, this also charges the capacitor with reverse voltage from the negative half-cycle, and in this charging time the TRIAC stays open until the cycles compound.

This is repeated with each cycle of the AC sine wave signal from the grid, which maintains its drive and cut cycle repeatedly, leading to an output voltage lower than that of the input.

The network formed by capacitor C1 and coil L1 works as a filter to inhibit RF spurious propagation through the power network. While R1 and C2 are employed for transient reductions.

The network formed by C4 and R5 in parallel with the TRIAC, serves to prevent the TRIAC from burning out, because when the dimmer is controlling inductive loads, reverse voltage spikes are formed at the moment of switching. 

Thus, the capacitor absorbs the generated overvoltage and the resistor limits the discharge current from the capacitor onto the TRIAC.

The resistor R4 connected in parallel, is used to decrease the ohmic rating of variable resistor RV1, since the applicable value for RV1 is 150k ohms.

Since it is not easy to find this variable resistor, we made an association of resistors to get it close to 150k ohms.

The network formed by capacitor C1 and coil L1 works as a filter to inhibit RF spurious propagation through the power network.

The L1 coil consists of a small ferrite rod, 1/4" diameter and 11/4" long, wound with 55 turns of 28 SWG enameled copper wire.

You can be using the ferrite coil from a PC power supply to make your coil, or you can be buying a commercial 40uH coil. 

Components List

  • Semiconductors
    • U1 .............. TIC246M Triac
    • D1 .............. DB-3 DIAC Diode

  • Resistor
    • R1 ................ 56Ω (green, blue, black, gold
    • R2 ................ 2K2Ω (red, red, red, gold)
    • R3 ................ 5K6Ω (green, blue, red, gold)
    • R4 ................ 390Ω  (orange, white, brown, gold)
    • R5 ................ 250KΩ Potentiometer
  • Capacitor
    • C1, C2, C4 .... 100nF / 600V Polyester Capacitor 
    • C3 ................. 47nF Ceramic/Polyester Capacitor

  • Miscellaneous 
    • P1, P2 ......... 2-pin PCB soldering terminal blocks
    • F1 ................ Fuse 15A with soldering terminal blocks
    • L1 ................ 40uH Inductor *See Text
    • Others ......... PCB, heat sink, wires, etc.

Printed Circuit Board

We are offering the PCB - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.
Fig. 3 - PCB - 3500W Dimmer for 110V or 220V using TRIAC TIC246M with PCB

Files to download, Direct Link:


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!!!


Wednesday, February 23, 2022

160W High Fidelity Amplifier using Mosfet 2SK1058 and 2SJ162 with PCB

Fig. 1- 160W High Fidelity Amplifier using Mosfet 2SK1058 and 2SJ162 with PCB

This is a High Fidelity power amplifier, which uses 2 pairs of complementary MOSFETs output transistors, 2SK1058 and 2SJ162, which gives us a 160W power output. 

The circuit is simple to assemble, assuming you have advanced knowledge in electronics, you will be able to assemble this circuit without too much difficulty.

Basic operation of the circuit

This amplifier has a few many steps, and we could break down each component, but it would certainly be too long, so let's explain the main stage of the amplifier process. 

The 160W High Fidelity Amplifier circuit diagram is shown in Figure 2 below. It uses 4 output Mosfet power transistors, 2 transistors for the positive cycle and 2 transistors for the negative cycle.
Fig. 2 - Schematic Circuits 160W High Fidelity Amplifier using Mosfet 2SK1058 and 2SJ162

We will start with first Stage: 

It is formed by a pair of MPSA56 PNP transistors, they form the input of the differential amplifier. 
The main characteristic is to amplify the difference of the input signals without amplifying the common mode signal.

In the second stage:

We have two pairs of transistors, 2 NPN BD139 transistors and 2 PNP TIP140 transistors, they constitute a differential current source pair formed by the BD139 transistors pair. And with a current mirror formed by the BD140 transistors pair, in Cascade mode creating a telescopic amplifier stage.

In the third stage:

It is formed by the 4 Output MOSFETs transistors, two N-channel type transistors 2SK1058 and other two P-channel type transistors 2SJ162. They receive the signal from stage 2 which is a module in Cascade, as already explained, and deliver to the output load, formed by the speaker.

The output transistors should be equipped with a Heat Sink, and should be electrically separated with thermal insulators.

Power Supply

The power supply is a symmetrical source, +Vdc GND -Vdc, and must contain a current capable of supporting the total power of the Amplifier.

If the circuit is used in MONO mode "One channel", the recommended current is 4 Amperes. If a STEREO version "Two channels" is used, the current should be doubled to 8 Amperes.

The amplifier work voltage is ±45Vdc SYMMETRICAL, to be used with an output load between 4 to 8 ohms.

In Figure 3 below, we have a suggestion for a power supply that we use in our projects. In this article, besides having the schematic diagram with the Printed Circuit Board, you will understand how to easily calculate your own Power Supply, with the desired voltage.

You can in the link below:

Fig. 3 - Symmetrical Power Supply for Power Amplifiers

Components List

  • Semiconductors
    • Q1 .......................... MPSA56 PNP Transistor
    • Q3, Q4 ................... BD139 NPN Transistor
    • Q5, Q6 ................... BD140 PNP Transistor
    • Q7, Q8 ................... 2SK1058 N-Channel Mosfet Transistor
    • Q9, Q10 ................. 2SJ162 P-Channel Mosfet Transistor
    • D1, D2 ................... 1N4007 Diode

  • Resistor
    • R1, R2, R10 ................ 47KΩ (yellow, violet, orange, gold
    • R3, R4 ........................ 3K3Ω (orange, orange, red, gold)
    • R5 ............................... 1K2Ω  (brown, red, red, gold)
    • R6 ............................... 10KΩ  (brown, black, orange, gold)
    • R7, R8 ........................ 1KΩ (brown, black, red, gold)
    • R9 ............................... 2K2Ω (red, red, red, gold)
    • R11, R12, R13, R14 ... 47Ω (yellow, violet, black, gold)
    • R15, R16, R17, R18 ... 022Ω (red, red, silver, gold)
    • R19 ............................. 10Ω (brown, black, black, gold)
  • Capacitor
    • C1 ........................ 4.7uF / 65V Electrolytic Capacitor 
    • C2, C4, C5 ........... 470pF Ceramic Capacitor
    • C3 ........................ 47uF / 65V Electrolytic Capacitor 
    • C6 ........................ 100nF Ceramic Capacitor

  • Miscellaneous 
    • P1, P2 .......... 2-pin PCB soldering terminal blocks
    • P3 ................ 3-pin PCB soldering terminal blocks
    • Others ......... PCB, heat sink, power supply, wires, etc.


We are offering the PCB - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.

Fig. 3 - PCB 160W High Fidelity Amplifier using Mosfet 2SK1058 and 2SJ162

Files to download, Direct Link:


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!!!

Wednesday, February 16, 2022

Powerful Mini Audio Amplifier using only 5 Transistors with PCB

Fig 1 -  Powerful Mini Audio Amplifier using only 5 Transistors with PCB

This is a simple amplifier that uses only 5 transistors, and provides good power, by our tests, we get close to 90W, and amazingly enough, it has a very good sound given its ultra simplicity.

The circuit is quite simple, and very easy to building, which makes it a great option for those who want to build an amplifier with good power and great cost, because it uses discrete components, cheap and easy to acquire.

You might also be interested in:

The Amplifier Circuit

The amplifier circuit is very simple to assemble, as shown in Figure 2 just below, this amplifier is divided into three basic stages: 

  • The first is the pre-amplification stage: It is formed by a differential pair set of NPN 2N5551 transistors, they are working as differential pair, which gives a very good stability in the signal sent to the next stage.

  • The second is the driver stage: it is formed by the PNP TIP42 transistor, it is used as a current amplifier and serves to drive the output stage.

  • The third is the power stage: It is formed by a pair of differential power transistors, one is the NPN 2SC5200 and the other is the 2SA1943, they are in push-pull mode, configured to work in class AB, with base BIAS diodes.
  • Fig. 2 - Schematic diagram Powerful Mini Audio Amplifier using only 5 Transistors

Note

Place the power transistors on a heat-sink, because since you work with power, they will get hot, a small size radiator will help.

For those who like loud sound, to really force the amplifier to the maximum, it is recommended to put the BIAS diodes in series, on the heat sink along with the transistors. This will cause the base voltage to be controlled according to the temperature of the transistors.

Power Supply

The power is supplied through a 24 VAC transformer, after rectification the supply will provide 35 VDCThe current to power this amplifier is at least 3A, for those mounting two of these to form a stereo pair, you should double the current to 6 Amps. 

Component List

  • Semiconductor
    • Q1, Q2 .......... 2N5551 NPN Transistor 
    • Q3 ................. PNP BD140 Transistor
    • Q4 ................. 2SC5200 NPN Power complementary transistor
    • Q5 ................. 2SA1943 PNP Power complementary transistor
    • D1, D2, D3 ... 1N4007 Diode

  • Resistors
    • R1, R5 .......... 100K ohms Resistor - (brown, black, yellow, gold)
    • R2 ................. 6K8 ohms Resistor - (blue, gray, red, gold)
    • R3 ................. 620 ohms Resistor - (blue, red, brown, gold)
    • R4.................. 4K7 ohms Resistor - (yellow, violet, red, gold)
    • R6 ................. 1k5 ohms Resistor - (brown, green, red, gold)
    • R7, R8 ........... 0.22 ohms - 5W  Resistor - (red, red, silver, gold)
    • P1 .................. 10K ohm potentiometer

  • Capacitors
    • C1 ................ 2.2uF Polyester / Ceramic Capacitor
    • C2 ................ 47uF - 65V Electrolytic capacitor 

  • Miscellanies
    • P1 ................. Screw Terminal Type 5mm 2-Pin Connector
    • P2 ................. Screw Terminal Type 5mm 3-Pin Connector
    • J1 .................. Set of male connectors 2-Pin (Optional)
    • Other ............. PCB, Wires, Speaker, Heat Sink, etc.

Printed Circuit Board

In Figure 3, 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.

Fig. 3 - PCB - Powerful Mini Audio Amplifier using only 5 Transistors

Files to download, Direct Link:

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

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!!!

Tuesday, February 15, 2022

High Performance 56W Audio Power Amplifier using LM3876 IC with PCB

Fig. 1 - High Performance 56W Audio Power Amplifier using LM3876 IC with PCB

This is a High Performance 56W Audio Power Amplifier, based on the LM3876 Integrated Circuit, with great sound quality, powered by a symmetrical power supply.

The Amplifier responds very well in all audible frequency ranges from 20Hz to 20Khz, and has a minimalistic and very compact design, which makes this amplifier a good choice to be assembled with little difficulty.

LM3876 Integrated Circuit Description

The LM3876 is a high-performance audio power amplifier capable of delivering 56W of continuous average power to an load with 0.1% THD+N from 20Hz–20kHz.

The performance of the LM3876, utilizing its Self Peak Instantaneous Temperature (°Ke) (SPiKe) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area (SOA) SPiKe protection. 

Means that these parts are completely safe-guarded at the output against overvoltage, under-voltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks.

The LM3876 maintains an excellent signal-to-noise ratio of greater than 95dB (min) with a typical low noise floor of 2.0μV. It exhibits extremely low THD+N values of 0.06% at the rated output into the rated load over the audio spectrum, and provides exceptional linearity with an IMD (SMPTE) typical rating of 0.004%.

Feature

  • 56W Continuous Average Output Power into 8Ω
  • 100W Instantaneous Peak Output Power Capability
  • Signal-to-Noise Ratio ≥ 95 dB(Min)
  • An Input Mute Function
  • Output Protection from a Short to Ground or to the Supplies Via Internal Current Limiting Circuitry
  • Output Over-Voltage Protection against Transients from Inductive Loads
  • Supply Under-Voltage Protection, not Allowing Internal Biasing to Occur when |VEE| + |VCC| ≤ 12V, thus Eliminating Turn-On and Turn-Off Transients
  • 11-Lead TO-220 Package
  • Wide Supply Range 20V - 94V

The Schematic Circuit

In Figure 2 below we have components arrangement of the power amplifier circuit with the LM3876 IC, and as we can see, the difficulty is not extreme. 

Since there are few external components, making the amplifier circuit very simple to assemble, and a technician or hobbyist with medium experience can assemble it without much difficulty. 

Fig. 2 - Schematic Circuit High Performance 56W Audio Power Amplifier using LM3876 IC

It is important to remember to be careful when assembling the circuit, not to invert any component such as capacitor diodes, or even when connecting the symmetrical voltage of the power supply. Not to invert the voltage poles, because the integrated circuit or other components can be damaged.

The coil is formed is a 5uH coil, for those who are going to assemble it, you can assemble it with 10 turns of 18 AWG Wire with a 3/8" air core.

Components List

  • Semiconductors
    • U1 .............. LM3876 Integrated Circuit

  • Resistors
    • R1, R5 ....... 1K resistor (brown, black, red, gold)
    • R2, R3 ....... 18K resistor (brown, gray, orange, gold)
    • R4 .............. 10K resistor (brown, black, orange, gold)
    • R6, R7 ....... 22K resistor (red, red, orange, gold)
    • R8 .............. 100Ω resistor (brown, black, brown, gold)
    • R9 .............. 10Ω / 1W resistor (brown, black, black, gold)
    • RP1 ............ 10K Potentiometer

  • Capacitors
    • C1 ................. 2.2μF Ceramic/Polyester Capacitor
    • C2 ................. 220pF Ceramic/Polyester Capacitor
    • C3 ................. 47 Ceramic/Polyester Capacitor
    • C4, C5 .......... 22μF / 65V Electrolytic Capacitor
    • C6, C7, C8 .... 0.1uF Ceramic/Polyester Capacitor
    • C9, C10 ......... 2.200uF / 65V Electrolytic Capacitor
    • L1 .................. Inductor 5uH *Ver Texto

  • Others
    • P1, P2 ............ Screw Terminal Type 5mm 2-Pin Connector
    • P3 .................. Screw Terminal Type 5mm 3-Pin Connector
    • J1 ....................Set of male connectors 2-Pin (Optional)
    • Other .............. PCB, Wires, Speaker, Heat Sink, etc.

Power Supply

Power is supplied through a 24 VAC transformer with center tape, i.e. [+VAC | GND | -VAC], after rectification the source will supply 35 VDC

It is a standard power supply voltage for this amplifier to work with little heating and little distortion, as it works with a minimum of 18V and a maximum of 84V

The current to power this amplifier is of at least 2A, and if it is going to using in stereo mode, two of these same ones, this current has to be doubled to 4 Amperes

In Figure 3 below, we have a suggestion for a power supply that we use in our projects. In this article, besides having the schematic diagram with the Printed Circuit Board, you will understand how to easily calculate your own Power Supply, with the desired voltage.

You can in the link below:

Fig. 3 - Symmetrical Power Supply for Power Amplifiers

Printed Circuit Board

In Figure 3, 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.

Fig. 4 - PCB - High Performance 56W Audio Power Amplifier using LM3876 IC

Files to download, Direct Link:

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

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!!!


Saturday, February 12, 2022

12-36V 60A PWM DC Motor Speed Controller Using LM555 With PCB

Fig.1 - 12-36V 60A PWM DC Motor Speed Controller Using LM555 With PCB

The main reason for using pulse width modulation in DC motor control is to avoid excessive heat dissipation, as in linear power control circuits. 

Since in linear circuits there is a huge problem with heat dissipation. PWM control circuits greatly reduce this issue because of their much higher power conversion efficiency.

The circuit that we are going to build is a simple circuit, with the principle of operation by PWM control, based on the LM555 generator, already well known and with a super affordable price in the market. 

It is a width modulation control, which can be controlled through a potentiometer, or trimpot, or even with fixed resistors, this will depend on your project. 

Speed Control

There are several techniques used to control the speed of a motor, due to the demand of thousands of applications in industry, there has been a great need to control these speeds.

Long ago, when the technology of speed control did not exist electrically, industrial equipment had its speeds altered or adjusted mechanically, by means of stepping pulleys, change gear sets, variable speed friction clutch mechanism and other mechanical devices. 

Electric speed control has many advantages both economically and engineering over mechanical speed control.

The speed control for motor drives, depend on their type. Some drives require continuous speed variation for the entire range from zero to maximum speed, others demand a portion of this range, while others may require two or more fixed speeds.

How PWM Works

Pulse Width Modulation control works by very quickly turning on and off the power supplied to the motor. 

The DC voltage is converted into a square wave signal, alternating between fully on (Vdc Max) and zero, giving the motor a series of "kicks" of power.

Pulse width modulation (PWM) is a speed control technique that can overcome the problem of poor starting performance of a motor.

PWM for motor speed control works in much the same way. Instead of supplying a variable voltage to a motor, it is supplied with a fixed voltage value (Vdc Max) that causes it to spin immediately. 

The voltage is then removed and the motor "coasts". By continuing this on/off voltage cycle with a variable duty cycle, the speed of the motor can be controlled. 

How the Circuit Works?

The U1 is wired as a low-frequency, free-running Astable Multivibrator with Pulse Width Modulation (PWM). The R-C components like R1, VR1 and C1 determine the frequency oscillations.

When the wiper arm of potentiometer VR1 is in top position, capacitor C1 charges through R1 and D1/D2 and produces a pulse train at the IC's output with long negative and short positive pulse widths.
 
Therefore, the motor speed is slow. On the other hand, when the wiper arm of VR1 is at the bottom position, C1 charges through R1 and discharges via VR1 The resulting pulse train has long positive and short negative pulse widths.

Now the motor rotates at a high speed. The IC's output at pin 3, is fed to transistors pair, Q1 and Q2, which, in turn, drives the DC motor through high power switching MOSFETs Transistor Q3-Q6 at the selected speed. Resistor R4-R7 limits the base current of power transistors.

The Zener diodes D4 to D7 are 15V diodes, they serve to stabilize the base voltage of the Mosfet transistors, since they are very sensitive to gate voltages.

Diode D8, connected in antiparallel with the DC motor, limits the back E.M.F. generated by the rotation of the motor. 

The Power Supply

The control circuit is powered from a power supply formed by the LM317HV IC, this IC is a high voltage regulator, which receives voltages up to 60V and is set to a stabilized 9V output voltage to power the control circuit. 

This is important since the LM555 IC supports voltages up to 16V, and our circuit operates with voltages ranging from 12V to 36V.

The Schematic Circuit

The circuit diagram of the power amplifier is shown in Figure 2 below. It uses 8 output Mosfet power transistors, 4 transistors for the positive cycle and 4 transistors for the negative cycle. 

Fig. 2 - Schematic Circuit 12-36V 60A PWM DC Motor Speed Controller Using LM555

Components List

  • Semiconductors
    • U1 .......................... LM555 Integrated Circuit
    • U2 .......................... LM317HV High Voltage Regulator
    • Q1 .......................... BD140 PNP Transistor
    • Q2 .......................... BD139 NPN Transistor
    • Q3, Q4, Q5, Q6 ..... RFP70N06 Mosfet Power Transistor
    • D1, D2, D3 ............ 1N4007 Silicon Diode
    • D4, D5, D6, D7 ..... 1N4744 15V Zener diode
    • D8 .......................... 1N5408 3A Silicon Diode

  • Resistor
    • R1 ......................... 1KΩ  (brown, black, red, gold)
    • R2 ......................... 33Ω (orange, orange, black, gold)
    • R3 ......................... 10KΩ (brown, black, orange, gold)
    • R4, R5, R6, R7 ..... 10Ω  (brown, black, black, gold)
    • R8 ......................... 240Ω (red, yellow, brown, gold)
    • R9 ......................... 1K5Ω  (brown, green, red, gold)
    • VR1 ...................... 250KΩ Variable resistor
  • Capacitor
    • C1 ......................... 100nF Ceramic Capacitor
    • C2 ......................... 10nF Ceramic Capacitor

  • Miscellaneous 
    • P1, P2 ................... 2-pin PCB soldering terminal blocks
    • Others ................... Printed Circuit Board, heat sink, wires, etc.


We are offering the PCB - Printed Circuit Board, in GERBER, PDF and PNG files, for you who want to do the most optimized assembly, either at home.

If you prefer in a company that develops the board, you can is downloading and make the files in the Download option below.
Fig. 3 - PCB - 12-36V 60A PWM DC Motor Speed Controller Using LM555

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