An ancient video but just playing with this chip. Very nice indeed. Simple to use. I'm using in buck configuration. 12V to 5V. Testing at 250mA and working perfectly 😊 Thanks for the tip of not using the sense resistor.
This chip has a little disadvantage, because it has no shut-down. But recently I have found out by chance that it is possible to stop its oscillation by drawing its CT-pin to operating voltage (not to ground, which works fine for other devices). This is a nice way to implement further stop conditions like undervoltage shut down or a real output current related shut down. So I like to use this chip as a pwm controller for high-power dc to dc converters.
I've "re programed" and repurposed a number of switcher type wall warts because of this and similar chips that are used in them. Some will have the divider resistors on the other side of and opto isolator with the TL413 used for the reference on the secondary of a ferrite transformer instead of just an inductor. Change the divider resistors and sometimes the output cap voltage rating depending on what your trying to do. 👍
I love your chip of the day videos, thank you for doing these. However when a chip is outdated, please mention that as well as what modern part we might want to look at.
A few points worth considering. First it is pretty important that the diode be either a Schottky or fast recovery type of diode. Otherwise you will be discharging the capacitor for the first part of the period when the transistor is turned on. This can be minimized to some extent by lowering the frequency, but then you need a larger inductor. A larger inductor may be more prone to saturation. I wouldn't leave out the current sense resistor as this is sensing the instantaneous inductor current and will switch off the transistor if the current gets too high. If the inductor saturates, then it looses its inductance and the current can quickly shoot through the roof. For low current applications, just put a 1 ohm resistor as the sense resistor, for higher current applications then the current sensing is an absolute must. Dave Jones did a great tutorial on this little switch mode chip which you can find at ruclips.net/video/qGp82xhybs4/видео.html
These are very important points. Especially the use of the current limit is important because it is the only protection of the output circuit against over current and short circuit. Another important point is the use of the non-Darlington configuration of the driver transistor (use of a resistor from pin 8 to V+) in order to saturate the output transistor for higher inductor currents. Allready at 1 A output current it reduces the output losses from 1 W down to 0.45 W improving the efficiency of the DC-DC converter significantly, especially in the case of lower operating voltages (for 5 V from 80% to more than 90%). It is important to mention that this IC has also no overtemperature protection. So you can kill the device very easily due to over current and over heating. Another point is that you can use this device not only as a DC-DC-converter but also as a DC-DC controller with external power switch (BJT and MOSFET) in Buck and Boost mode, with low additional effort. Also in these modes you can use the current limit of the device to protect your external power switch.
It sounds like you guys know a lot about SMPS. I always had this question. If you want to have a buck converter or simply low dropout PS, do you really need to have an inductor? For boosting the voltage you definitely need an inductor, but for reducing can you use only the output capacitor?
@@bayareapianist The reason you need an inductor for buck converters is because of efficiency. Without the inductor you would be pushing current through a voltage drop that means power is lost. You could use a resistive element to drop the voltage, but then that power is lost to heat. With an inductor, the power is stored and the stored power is then given to the load when the switch is off. This is what makes the switcher efficient. If you are only dropping a small amount of voltage, an ldo might make more sense as the power loss is proportional to the voltage drop in linear regulators.
Somehow I knew you’d have a good Video on this chip. Seems at the time posting this, I didn’t have an interest in the ic. Now you have my full attention. Thanks once again.
I'm curious why designers of a chip did choose to turn switching on and off hard. It creates quite noticeable ripple of output voltage. But what are the benefits of this approach compared to PWM?
I’m always overwhelmed by the number of dc-dc converter controller chip options. What is a “jelly bean”, cheap, ubiquitous, go to IC that can do buck boost?
@@marko.692 it support ZETA converter too (it is rearranged sepic with lower output ripple and high side switche), but it is not ideal for it (or sepic) due hysteresis control, but it is possible.
Наука
An ancient video but just playing with this chip. Very nice indeed. Simple to use. I'm using in buck configuration. 12V to 5V. Testing at 250mA and working perfectly 😊
Thanks for the tip of not using the sense resistor.
This chip has a little disadvantage, because it has no shut-down. But recently I have found out by chance that it is possible to stop its oscillation by drawing its CT-pin to operating voltage (not to ground, which works fine for other devices). This is a nice way to implement further stop conditions like undervoltage shut down or a real output current related shut down. So I like to use this chip as a pwm controller for high-power dc to dc converters.
Wow, it is amazing how easy you made everything seem by explaining it!
Thank you!👍🇺🇸
I've "re programed" and repurposed a number of switcher type wall warts because of this and similar chips that are used in them. Some will have the divider resistors on the other side of and opto isolator with the TL413 used for the reference on the secondary of a ferrite transformer instead of just an inductor. Change the divider resistors and sometimes the output cap voltage rating depending on what your trying to do. 👍
always a pleasure watching your contents. Thank you
I love your chip of the day videos, thank you for doing these. However when a chip is outdated, please mention that as well as what modern part we might want to look at.
A few points worth considering. First it is pretty important that the diode be either a Schottky or fast recovery type of diode. Otherwise you will be discharging the capacitor for the first part of the period when the transistor is turned on. This can be minimized to some extent by lowering the frequency, but then you need a larger inductor. A larger inductor may be more prone to saturation. I wouldn't leave out the current sense resistor as this is sensing the instantaneous inductor current and will switch off the transistor if the current gets too high. If the inductor saturates, then it looses its inductance and the current can quickly shoot through the roof. For low current applications, just put a 1 ohm resistor as the sense resistor, for higher current applications then the current sensing is an absolute must. Dave Jones did a great tutorial on this little switch mode chip which you can find at ruclips.net/video/qGp82xhybs4/видео.html
These are very important points. Especially the use of the current limit is important because it is the only protection of the output circuit against over current and short circuit.
Another important point is the use of the non-Darlington configuration of the driver transistor (use of a resistor from pin 8 to V+) in order to saturate the output transistor for higher inductor currents. Allready at 1 A output current it reduces the output losses from 1 W down to 0.45 W improving the efficiency of the DC-DC converter significantly, especially in the case of lower operating voltages (for 5 V from 80% to more than 90%).
It is important to mention that this IC has also no overtemperature protection. So you can kill the device very easily due to over current and over heating.
Another point is that you can use this device not only as a DC-DC-converter but also as a DC-DC controller with external power switch (BJT and MOSFET) in Buck and Boost mode, with low additional effort. Also in these modes you can use the current limit of the device to protect your external power switch.
It sounds like you guys know a lot about SMPS. I always had this question. If you want to have a buck converter or simply low dropout PS, do you really need to have an inductor? For boosting the voltage you definitely need an inductor, but for reducing can you use only the output capacitor?
@@bayareapianist The reason you need an inductor for buck converters is because of efficiency. Without the inductor you would be pushing current through a voltage drop that means power is lost. You could use a resistive element to drop the voltage, but then that power is lost to heat. With an inductor, the power is stored and the stored power is then given to the load when the switch is off. This is what makes the switcher efficient. If you are only dropping a small amount of voltage, an ldo might make more sense as the power loss is proportional to the voltage drop in linear regulators.
Somehow I knew you’d have a good Video on this chip. Seems at the time posting this, I didn’t have an interest in the ic.
Now you have my full attention.
Thanks once again.
Merci Guy.
I'm curious why designers of a chip did choose to turn switching on and off hard. It creates quite noticeable ripple of output voltage. But what are the benefits of this approach compared to PWM?
Why not to some experiments with a Arduino PWM as a boost or buck
I’m always overwhelmed by the number of dc-dc converter controller chip options. What is a “jelly bean”, cheap, ubiquitous, go to IC that can do buck boost?
What about TL497?
that's fine. I was asked about the 33063. The 33063 34063 are in more designs I believe.
Can it work in sepic topology?
I don't see why not
Yes, it will. Supported topology: Boost,Buck,Flyback,Forward,Inverting,SEPIC.
@@marko.692
Thanks 👍
@@marko.692 it support ZETA converter too (it is rearranged sepic with lower output ripple and high side switche), but it is not ideal for it (or sepic) due hysteresis control, but it is possible.
1N4007,...ARE YOU SERIOUS ...you need a fast diode like a schottky or ultra fast type. 1N4007 wil NOT cut it ...WAY TOO SLOW!
you are right. I just used what I had to demo the circuit
whay you like exploding .chill dude
@@yamanyusuf8263 ...huuuh?????