You can connect 555 DIS to Q and get even more current to close MOSFET Gate faster. Usually MOSFETS drive inductive loads so fast close is more important than fast open.
I'm glad you uploaded this excellent video. Maybe someone will also sort out the 555's open input bug (open input results in high output on pin 3). I still find it fascinating that 2 components which are considered toys by most engineers can perform so well in this configuration. I use it to drive 2 paralleled TBI injectors in a 90's Chevrolet, by the way. It works great (unless the Arduino crashes, but it's mostly about filtering resistors, capacitors and keeping spark plug wires away from the Arduino cables). The Arduino is fed by a dedicated external 5V regulator and the 555 is fed by another 12V regulator (for increased reliability). Have a good day!
If you take a complementary pair - say BC547 and BC 557, and put them in emitter-follower, you can achieve the same effect with - Lower pin-count - Lower cost - Lower quiescent current - Better performance. 555s are good to learn the basics, as illustrated in the fantastic book by Forrest M. Mims III, but let's leave it at that.
No, let's not "leave it at that." It's better to have knowledge of all the different ways to use all the tools in your toolbox (so to speak) as you can never anticipate all the circumstances that can arise. Maybe you're in the middle of a build and don't *have* BC547 and BC557 transistors available, nor any kind of dedicated MOSFET driver... but do have a box full of 555's. Then it could very easily be the case that the 555 is the perfect solution - in context. I don't think anybody is saying that a 555 should be the MOSFET driver of choice, but knowing that it's capable of performing that function is potentially a damn handy bit of knowledge. It's just another arrow in the quiver.
It's hilarious to me that every time the 555 is suggested as a gate driver, someone pushes back. No one is suggesting the 555 be used in a 1.2 MHz buck converter or your latest energy harvesting application! But for very many routine applications they're gold. Ever since the idea showed up in the August 29, 2012 issue of Electronic Design, I've never _not_ had a 555 on-hand. Meanwhile, your totem pole solution fails fundamentally, as has been pointed out. BTW, Asian 555 clones work just fine, and Amazon sells 50 of them for $6.99.
I'm using the TLC555CP the CMOS version for a MOSFET driver for over 30 years. Not only that, I use the 555 also as the PWM controller, fixed on time, variable frequency, including the soft start function. It is one of my early designs and still in use after 30 years. Manufacture hundreds of DC to DC converters a month using it. Not everybody can use that topology but in my case is just what the doctor ordered.
If the microcontroller crashes, the 555 output on pin 3 gets high and that's not desirable; when its input is disconnected, the output should be low. Do you know how that bug could be solved?
@@esoterex yes the 555 is used in professional products, I worked on one HID lamp driver for office projectors with the 200W buck controlled with an NE556😂, built a few million pieces with high quality. Was the current output of the TLC not too low? Perfect ZVS?
Maybe that's what I was looking for. It should do the trick for me. I'm interested in running a motor, lamp with pwm signal. Whereas for a motor I would like it "independent" and manage it through the digital signal. I don't know if I explained myself. :)
This general setup works well for PWM driving low impedance (1 ohm) injectors in an automobile, it's what I've been using it for. The big issue with it is that if for some reason the Arduino crashes, the 555 output will become High. That translates to a steady full flow of fuel into the engine (drowning). If you have any idea how to fix it, please share.
Looks like there are some improvements to be made. Looking at the internal schematic of a 555, you’ve got the Set and Clear pins of the SR latch both held high at once, which isn’t really in-spec. I think. Also you really should put a resistor on the reset pin as to not be undefined when the MCU is in a startup state.
If the microcontroller crashes, the 555 output on pin 3 gets high and that's not desirable; when the input is disconnected, the output should be low. Do you know how that bug could be solved?
@@soupflood if the MCU output goes high-z (like it does when it’s initialising) then you could avoid it by having a pull-down resistor on the reset pin. But if the MCU output goes high and stays high, there’s nothing you can do besides put a fuse on your power input.
@@Scrogan if the 555 timer's input (pin 4 reset) gets disconnected (or the MCU crashes) the 555's pin 3 output gets high. That's a 555 specific bug in this setup. I already tried resistor across the 555 input (between reset and ground) and it didn't work. The fuse wouldn't solve this either
Just google the data sheet. Most of them show the full internals, although it doesn't help understanding the chip's functions unless you are a silicon designer.
Awesome technical content, theory and practical science meet here ,thank you very much do you have any future plans to make a video about h-bridge or bldc mosfet switching performance, similar to your MOSFET series
It’s possible to use 555 in a high side driver for 12v, just use one more 555 as a voltage doubler with diode and capacitor. So using cheap PC817 optocopler we can switch +12v high power loads
I was researching for a way to drive an led power supply from Meanwell that is working with 0-10V or 10V PWM. So this seams an Intresting alternative when connected it to the pwm input without the mosfet.
im quite confused when you said you were gonna build the circuit. i just saw a load there with a reverse diode, then you added a transistor and stuff. i got lost after that point.
The transistor, 4k7 resistor, zener diode and the 100nF capacitor are added to make 12Volt for the NE555. You can also use a lab power supply for that. I wanted to show exactly how I test the circuit to make sure I show the actual performance :-)
So as far as the mosfet is concerned its just seeing the npn and pnp switching transistor in the 555. I would just use a a pair of transistors and not waste a 555. in fact real mosfet driver IC's are possibly same cost as a 555. saw a guy use some optocouplers a few years ago for driving P channel fets from logic lines.
You are clearly a professional! The transistor pair will give you the current gain, however for the voltage gain you need a 3d transistor, see this video: th-cam.com/video/wv4uAz8FV2w/w-d-xo.html .
Maybe the NE555 drives a serial RS232 with 12V = Low and 0V = High? Or an ATMega HV programming? This requires 12V on the reset pin of the ATMega. Then you can still delete the program from a locked IC and reset the fuses to normal.
Good idea, it is fast enough for RS232, I have never tried Atmega HV programming, did not know you can use it to erase a locked IC, so I learned something today, thank you!
This doesn't work with the B555 from GDR production. On the NE555, the Set input is overruled by the Reset input. However, with the B555 the Reset input is overruled by the Set pin. The reason is that the NE555 takes the /Q output from flipflop and inverts it again in the driver stage. That's why Reset is dominant. However, the B555 takes the Q output from flipflop and does not invert it in the driver stage. That's why Set is dominant. For most applications, however, this difference is irrelevant. Most 555 clones do it like the NE555.
Thank you, you seem to be an NE555 expert! I tried all the 555's I had lying around and they worked OK except the TLC555, but there are many variants of the 555....
Really great and explanatory video ı really liked your explanation. But what happens if we were to do like an H bridge configuration? This time we need drain voltage + gate thresold voltage to use the mosfet on the High side right? That would mean 12v is not sufficient and maximum 16v rating of ne555 is also not sufficient. Or am ı wrong can you please answer me ı don't know and ı am just asking.
Thank you! For H-Bridge you will need to make a bootstrap supply of 12V like in this video: th-cam.com/video/M5lETaqI9JM/w-d-xo.html. Suggest you use the IC solution, much easier and robust. You can also use a motor drive IC like ST's L293D for low voltages and frequencies.
@@smartpowerelectronics8779 ı am trying to design a brushless ESC with microcontrollers and wanted to make a H bridge first. Most Motor driver IC's cannot handle a lot of current and voltage and ı don't want to throw an IC to the problem to be honest ı want to learn how to do it myself. But Thanks for your answer you have some really good content. ❤
@@doganertan7259 bootstrapped... i also prefer discrete components over ICs... only issue with the charge pump bootstrap in a h-bridge is it cant be used for say, direction control on a motor? all good as a driver, for PWM, but they cant be constantly "on" (or "off"?) as the charge pump capacitor does slowly discharge. depending on the value, you still have approximately half a minute to a day or two though! but as the value gets larger it also means it requires a longer "dwell" time to recharge that capacitor... so you keep them small for high speed operation... as most H bridges run PWM at a reasonable frequency, its not an issue. some people do use them for polarity reversal though. better to use a single throw double pole switch/relay for that application.
@@paradiselost9946 I saw a lot of commercial ESC models don't have a mosfet driver inside. Most of them uses a discrete circuit it seems. Using discrete components are a lot cheaper than using driver IC's. Discrete circuits can "off" the mosfet but they can't make the mosfet stay "on" that long. For a High side mosfet can we just put a boost converter circuit and switch it with a transistor on the mosfets gate? Because in my country there is a boost converter called mt3608 that is cheaper than that driver IC and ı did not see any circuits online about using a boost converter. Or there is another method that ı don't know?
@@doganertan7259 go look up "high side charge pump". diode, capacitor, and a bjt/opto (preferable). its pretty simple. theres a few good schematics for full discrete h-bridges with charge pumps. boost convertor is leading away from simplicity ;)
Hmmm, sure its one way. You could use one or two super cheap transistors, a logic gate, a schmidt trigger, a comparator, an opamp, all sorts! but its OK that you did this.... but its not the only way. The right method depends on space and cost limitations.
Hello, Master! First of all, thank you for sharing your knowledge. I have two questions: 1) Can this circuit be used to control a 24V Polygonal Laser Printer Motor? And how should it be connected? The Motor has 4 wires: Red: Positive up to 24V; Black: Negative; White: for Speed Control; Pink: I couldn't figure it out. 2) What is Pin 4 of the 555 that goes to D4 (PWM) of the Arduino for, since isn't Pin 3 of the 555 the PWM Control output? If you can answer me, I would be very grateful. Greetings from Brazil.
@@AdamTheBot that is frustrating, did you check all voltages pin by pin? What I of the do is test by attaching an LED with 1k at the output and then use a wire to touch the input to 12V and 0 V while watching the LED😆
Overkill using 555 because you can't get sufficient mosfet drive. Use a transistor driver just like anybody else would ! Lack of understanding simple analogue electronics.
@@smartpowerelectronics8779 A better starting point to develop your knowledge would be to read "Electronics Fundamentals" by Floyd and Buchla. It was the go-to book in the 1990's for a Electronics Diploma.
You can connect 555 DIS to Q and get even more current to close MOSFET Gate faster. Usually MOSFETS drive inductive loads so fast close is more important than fast open.
That is a good idea, I did not think of that!
This will work nicely even if you don't require PWM, just ON &OFF states. Thank you for showing us the results of your testing.
Thank you!
I'm glad you uploaded this excellent video.
Maybe someone will also sort out the 555's open input bug (open input results in high output on pin 3).
I still find it fascinating that 2 components which are considered toys by most engineers can perform so well in this configuration. I use it to drive 2 paralleled TBI injectors in a 90's Chevrolet, by the way. It works great (unless the Arduino crashes, but it's mostly about filtering resistors, capacitors and keeping spark plug wires away from the Arduino cables). The Arduino is fed by a dedicated external 5V regulator and the 555 is fed by another 12V regulator (for increased reliability).
Have a good day!
If you take a complementary pair - say BC547 and BC 557, and put them in emitter-follower, you can achieve the same effect with
- Lower pin-count
- Lower cost
- Lower quiescent current
- Better performance.
555s are good to learn the basics, as illustrated in the fantastic book by Forrest M. Mims III, but let's leave it at that.
The totem pole will give you the current gain, for the voltage gain you need a 3d transistor, see this video: th-cam.com/video/wv4uAz8FV2w/w-d-xo.html
No, let's not "leave it at that." It's better to have knowledge of all the different ways to use all the tools in your toolbox (so to speak) as you can never anticipate all the circumstances that can arise. Maybe you're in the middle of a build and don't *have* BC547 and BC557 transistors available, nor any kind of dedicated MOSFET driver... but do have a box full of 555's. Then it could very easily be the case that the 555 is the perfect solution - in context.
I don't think anybody is saying that a 555 should be the MOSFET driver of choice, but knowing that it's capable of performing that function is potentially a damn handy bit of knowledge. It's just another arrow in the quiver.
@@PhillipRhodes To be clear, I'm not talking about "could" but rather "should".
It's hilarious to me that every time the 555 is suggested as a gate driver, someone pushes back. No one is suggesting the 555 be used in a 1.2 MHz buck converter or your latest energy harvesting application! But for very many routine applications they're gold. Ever since the idea showed up in the August 29, 2012 issue of Electronic Design, I've never _not_ had a 555 on-hand. Meanwhile, your totem pole solution fails fundamentally, as has been pointed out.
BTW, Asian 555 clones work just fine, and Amazon sells 50 of them for $6.99.
Lol a 555 now as a totem pole...
I'd say I've seen it all but every time I do, another use for this chip pops up out of the breadboard 🤣🤷♂️
Thanks. I use to use 555 timers back in the 80' and 90's quite a bit. Mostly for making variable freq. clock sources.
I'm using the TLC555CP the CMOS version for a MOSFET driver for over 30 years. Not only that, I use the 555 also as the PWM controller, fixed on time, variable frequency, including the soft start function. It is one of my early designs and still in use after 30 years. Manufacture hundreds of DC to DC converters a month using it. Not everybody can use that topology but in my case is just what the doctor ordered.
If the microcontroller crashes, the 555 output on pin 3 gets high and that's not desirable; when its input is disconnected, the output should be low.
Do you know how that bug could be solved?
@@esoterex yes the 555 is used in professional products, I worked on one HID lamp driver for office projectors with the 200W buck controlled with an NE556😂, built a few million pieces with high quality. Was the current output of the TLC not too low? Perfect ZVS?
Excellente tutorial. Alsof ik terug op MTS ben bij mijn favorite docent.
Just amazing! Known chip used in new way.
Maybe that's what I was looking for.
It should do the trick for me. I'm interested in running a motor, lamp with pwm signal. Whereas for a motor I would like it "independent" and manage it through the digital signal. I don't know if I explained myself. :)
This general setup works well for PWM driving low impedance (1 ohm) injectors in an automobile, it's what I've been using it for.
The big issue with it is that if for some reason the Arduino crashes, the 555 output will become High. That translates to a steady full flow of fuel into the engine (drowning).
If you have any idea how to fix it, please share.
Looks like there are some improvements to be made. Looking at the internal schematic of a 555, you’ve got the Set and Clear pins of the SR latch both held high at once, which isn’t really in-spec. I think.
Also you really should put a resistor on the reset pin as to not be undefined when the MCU is in a startup state.
If the microcontroller crashes, the 555 output on pin 3 gets high and that's not desirable; when the input is disconnected, the output should be low.
Do you know how that bug could be solved?
@@soupflood if the MCU output goes high-z (like it does when it’s initialising) then you could avoid it by having a pull-down resistor on the reset pin. But if the MCU output goes high and stays high, there’s nothing you can do besides put a fuse on your power input.
@@Scrogan if the 555 timer's input (pin 4 reset) gets disconnected (or the MCU crashes) the 555's pin 3 output gets high. That's a 555 specific bug in this setup.
I already tried resistor across the 555 input (between reset and ground) and it didn't work. The fuse wouldn't solve this either
It would be nice to show the internal circuit diagram of the NE555 thereby increasing our understanding of this NE555 chip. Thanks.
Just google the data sheet. Most of them show the full internals, although it doesn't help understanding the chip's functions unless you are a silicon designer.
Very nice video.
I was pleased
indeed needed for IRFZ44 but you can get IRLZ44 which is the same mosfet but with logic level gate which can go direct to the MCU
Awesome technical content, theory and practical science meet here ,thank you very much
do you have any future plans to make a video about h-bridge or bldc mosfet switching performance, similar to your MOSFET series
Nice forgotten idea! One 555 costs about as one middle powerful transistor. So for 3.3v controllers it looks like a winner - no additional components.
Thanks, indeed. I use it already in a project
It’s possible to use 555 in a high side driver for 12v, just use one more 555 as a voltage doubler with diode and capacitor. So using cheap PC817 optocopler we can switch +12v high power loads
Thanks for the video.
I was researching for a way to drive an led power supply from Meanwell that is working with 0-10V or 10V PWM. So this seams an Intresting alternative when connected it to the pwm input without the mosfet.
This is GREAT!
im quite confused when you said you were gonna build the circuit. i just saw a load there with a reverse diode, then you added a transistor and stuff. i got lost after that point.
The transistor, 4k7 resistor, zener diode and the 100nF capacitor are added to make 12Volt for the NE555. You can also use a lab power supply for that. I wanted to show exactly how I test the circuit to make sure I show the actual performance :-)
So as far as the mosfet is concerned its just seeing the npn and pnp switching transistor in the 555. I would just use a a pair of transistors and not waste a 555. in fact real mosfet driver IC's are possibly same cost as a 555.
saw a guy use some optocouplers a few years ago for driving P channel fets from logic lines.
You are clearly a professional! The transistor pair will give you the current gain, however for the voltage gain you need a 3d transistor, see this video: th-cam.com/video/wv4uAz8FV2w/w-d-xo.html .
Nice :)
Maybe the NE555 drives a serial RS232 with 12V = Low and 0V = High?
Or an ATMega HV programming?
This requires 12V on the reset pin of the ATMega. Then you can still delete the program from a locked IC and reset the fuses to normal.
Good idea, it is fast enough for RS232, I have never tried Atmega HV programming, did not know you can use it to erase a locked IC, so I learned something today, thank you!
can you share the code?
@@smartpowerelectronics8779 Een Atmega die op slot zit, stop ik altijd mijn TL866, die met hoog voltage de boel weer op poten kan zetten.
Very powerfull video...thankyou I will also (A)buse it....:)
Thank you, have fun!
Can the circuit be tested for 1% PWM and 99% PWM at 100 kHz?
@@BVRamesh100 the off delay is about 180ns, 100k 1% is only 100ns so unfortunately it cannot work
This doesn't work with the B555 from GDR production.
On the NE555, the Set input is overruled by the Reset input.
However, with the B555 the Reset input is overruled by the Set pin.
The reason is that the NE555 takes the /Q output from flipflop and inverts it again in the driver stage. That's why Reset is dominant.
However, the B555 takes the Q output from flipflop and does not invert it in the driver stage. That's why Set is dominant.
For most applications, however, this difference is irrelevant.
Most 555 clones do it like the NE555.
Thank you, you seem to be an NE555 expert! I tried all the 555's I had lying around and they worked OK except the TLC555, but there are many variants of the 555....
Could we use 555 to drive a p channel mosfet too? As a high side switch capable of switching the power to another circuit
Really great and explanatory video ı really liked your explanation. But what happens if we were to do like an H bridge configuration? This time we need drain voltage + gate thresold voltage to use the mosfet on the High side right? That would mean 12v is not sufficient and maximum 16v rating of ne555 is also not sufficient. Or am ı wrong can you please answer me ı don't know and ı am just asking.
Thank you! For H-Bridge you will need to make a bootstrap supply of 12V like in this video: th-cam.com/video/M5lETaqI9JM/w-d-xo.html. Suggest you use the IC solution, much easier and robust.
You can also use a motor drive IC like ST's L293D for low voltages and frequencies.
@@smartpowerelectronics8779 ı am trying to design a brushless ESC with microcontrollers and wanted to make a H bridge first. Most Motor driver IC's cannot handle a lot of current and voltage and ı don't want to throw an IC to the problem to be honest ı want to learn how to do it myself. But Thanks for your answer you have some really good content. ❤
@@doganertan7259 bootstrapped... i also prefer discrete components over ICs...
only issue with the charge pump bootstrap in a h-bridge is it cant be used for say, direction control on a motor?
all good as a driver, for PWM, but they cant be constantly "on" (or "off"?) as the charge pump capacitor does slowly discharge. depending on the value, you still have approximately half a minute to a day or two though!
but as the value gets larger it also means it requires a longer "dwell" time to recharge that capacitor... so you keep them small for high speed operation...
as most H bridges run PWM at a reasonable frequency, its not an issue. some people do use them for polarity reversal though. better to use a single throw double pole switch/relay for that application.
@@paradiselost9946 I saw a lot of commercial ESC models don't have a mosfet driver inside. Most of them uses a discrete circuit it seems. Using discrete components are a lot cheaper than using driver IC's. Discrete circuits can "off" the mosfet but they can't make the mosfet stay "on" that long. For a High side mosfet can we just put a boost converter circuit and switch it with a transistor on the mosfets gate? Because in my country there is a boost converter called mt3608 that is cheaper than that driver IC and ı did not see any circuits online about using a boost converter. Or there is another method that ı don't know?
@@doganertan7259 go look up "high side charge pump". diode, capacitor, and a bjt/opto (preferable). its pretty simple.
theres a few good schematics for full discrete h-bridges with charge pumps.
boost convertor is leading away from simplicity ;)
Hmmm, sure its one way. You could use one or two super cheap transistors, a logic gate, a schmidt trigger, a comparator, an opamp, all sorts! but its OK that you did this.... but its not the only way. The right method depends on space and cost limitations.
Hello, Master! First of all, thank you for sharing your knowledge. I have two questions:
1) Can this circuit be used to control a 24V Polygonal Laser Printer Motor? And how should it be connected?
The Motor has 4 wires: Red: Positive up to 24V; Black: Negative; White: for Speed Control; Pink: I couldn't figure it out.
2) What is Pin 4 of the 555 that goes to D4 (PWM) of the Arduino for, since isn't Pin 3 of the 555 the PWM Control output? If you can answer me, I would be very grateful. Greetings from Brazil.
what the code for arduino
@@abeditani8293 it is linked in the comments for download!
But can not see in mobile app, pc windows should have the link visible
IDK why it's not working .
@@AdamTheBot that is frustrating, did you check all voltages pin by pin? What I of the do is test by attaching an LED with 1k at the output and then use a wire to touch the input to 12V and 0 V while watching the LED😆
Overkill using 555 because you can't get sufficient mosfet drive. Use a transistor driver just like anybody else would ! Lack of understanding simple analogue electronics.
If you like transistors: watch this: th-cam.com/video/wv4uAz8FV2w/w-d-xo.html
@@smartpowerelectronics8779 A better starting point to develop your knowledge would be to read "Electronics Fundamentals" by Floyd and Buchla. It was the go-to book in the 1990's for a Electronics Diploma.
Why not use a real driver chip?
I am to electronics, I learn from youtube, i make it,
3 months ago, I fucked by brains out trying to drive a non logic level mosfet from esp...
Thanks man, great to hear that. The ESP32 is a cool mcu!
I thought 555 is just an irrelevant timing ic