hybridfree/eevblog-posts huggingface dataset:
Boolean expressions to circuit - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: August 26, 2019, 07:32:17 am
content: Hi,I have two boolean expressions:Y1 = AY2 = (not A) and BI have to select cheapest solution to realize this on my PCB (cheapest IC, only one IC prefered). Can you please give me an advise?A and B are slowly changing signals so it will be great if the input gates have schmitt trigger. Vcc = 5 V. Switching speed is not important.

author: magic
author_rank: Super Contributor
timestamp: August 26, 2019, 07:39:42 am
content: They should be making 4x2bit PROMs in SOT23-6 for that kind of thing.Also 8x3bit in DIP8/SO8 if we are at that.You know, you can always use some SOT23 µCeditAlternatively, if PCB space isn't critical, a hex inverter with Schmitt-triggered inputs like 74HC14 could be used for input denoising and output drive plus two external diodes to implement AND.

author: mikerj
author_rank: Super Contributor
timestamp: August 26, 2019, 10:53:01 am
content: A 74HC132 costs pennies and gives you four 2 input NAND gates with schmitt triggers.Two of these gates wired as inverters in series will give you /A and Y1. Feed /A and B into another gate, the output is /Y2. Use the final gate wired as an inverter to get Y2.

author: zzattack
author_rank: Regular Contributor
timestamp: August 26, 2019, 11:08:33 am
content: Well Y1 is simple, seems a copper trace will do.For Y2 = (not A) and B you can try rewriting it to a combination or NAND or NOR gates and pick a 7400 ic.Use the ideas that (not X) == (x nand x), not (x and y) == x nand y, and rewrite your expression by replacing all logical operators by their equivalent using only NAND operators.I.e.,Code:1. Y2 = (not A) and B==2. (A nand A) and B==3. not not ( (A nand A) and B) )==4. not ( (A nand A) nand B)==5. ( (A nand A) nand B) nand ( (A nand A) nand B)So a single 7400 would work. Equivalent using NOR gates is also possible, and mux ic's can very often be used just the same.

author: gaminn
author_rank: Frequent Contributor
timestamp: August 26, 2019, 12:23:24 pm
content: Thanks for your advises guys.I also came accross these multi-gate (configurable) ICs: 74LVC1G58 and similar. I will probably use them. Two of them do what I need.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 26, 2019, 02:07:41 pm
content: A single IC with 4 NAND gates, as said above, which are ubiquitous, would do the trick.As I got it, a single 74LVC1G58 should do it as well. I have a Nexperia datasheet which shows your configuration on figure 6 ( /B and C).Cost will be similar to a 74LVC00 or 74HC00, but the 74LVC1G58 will be smaller if you're going for SOT/SOIC packages.

author: ebclr
author_rank: Super Contributor
timestamp: August 27, 2019, 05:28:53 am
content: This family may help youhttp://www.ti.com/product/SN74LVC1G3208

author: mikerj
author_rank: Super Contributor
timestamp: August 27, 2019, 09:38:50 am
content: Quote from: zzattack on August 26, 2019, 11:08:33 amOP wants Schmitt triggers to clean up slowly varying inputs, so a straight connection is not suitable.
Boost Buck DC-DC Converter - Page 1
Forum section: electronics / projects

author: bilko
author_rank: Frequent Contributor
timestamp: June 12, 2011, 11:42:19 pm
content: Any experts here any DC-DC converters. I've been looking for info on a boost buck converter to run from a car battery and provide 12V DC, low noise at up to 10A output. What is the best way of achieving this ?Input voltage 10-15VDCOutput voltage 12VDCOutput current around 10AEfficiency > 90%The converter needs to be quiet as far as RF is concerned as it will be running at the same time as a hf transceiverMost laptop chargers I've seen are boost converters and not suitable, they are very noisy as far as rf is concerned.Appreciate any guidance on schematics or even finished product.

author: sacherjj
author_rank: Frequent Contributor
timestamp: June 12, 2011, 11:55:32 pm
content: You are looking for something like a Single-ended primary-inductor convertor. I'm not sure how easy it will be to clean up the RFI.http://en.wikipedia.org/wiki/Single-ended_primary-inductor_converterhttp://www.national.com/an/AN/AN-1484.pdf

author: Psi
author_rank: Super Contributor
timestamp: June 13, 2011, 01:49:20 am
content: I have one of these powering my VIA micro atx car computer.It works well for me, never had any problems with it.i dunno how much rf it puts out thoughHigh Output Current (12A Typical, 15A Peak)Wide Input Voltage Range (6-24V operating) (8-16V full load)Extremely Efficient (>95%)No Load Operating Current of < 70mASleep Current (All Rails Off) of < 4mA12.0 Volts +/- 2%Small Profile (1.9” x 3.5” x 0.75”)0.25” Spade Faston ConnectorsOn/Off Jumper HeaderFuse ProtectionReverse Voltage ProtectionLoad Dump Input Protection (Over Voltage)Short Circuit ProtectionPower On LEDVery Low standby power (100 uA Typical)Does not “Brown Out” during Engine CrankFast Transient Response12V Fan ConnectorAdjustable OutputCan get them here..http://store.mp3car.com/DSX12VD_140W_DC_DC_Regulator_p/pwr-025.htmMore info..http://www.mp3car.com/products/DSX12VD/DSX12VD_Manual.pdfAll the serial port codes to monitor/change settings can be found in this user manual for a slightly different model..http://www.mp3car.com/products/DSATX/DSATX_Manual.pdf

author: bilko
author_rank: Frequent Contributor
timestamp: June 13, 2011, 03:21:24 pm
content: Thanks guys for your help. You've put me on the right path, I'm sure I'll be able to find something now. Brilliant!
Boost converter at low current - Page 1
Forum section: electronics / projects

author: ubbut
author_rank: Regular Contributor
timestamp: June 15, 2021, 07:20:12 pm
content: Hi,for a project I need to convert 12V to 15V at relatively low output current (10-50mA). Usually my go-to switching controller is the AP3012. Low cost, high frequency.However as it turns out at such low currents, the AP3012 has far worse ripple as compared to higher currents. The reason seems to be, that the 3012 goes into "pulse skipping" mode, effectively lowering the frequency significantly and thus creating a large output ripple.I also tested the LT1615 with basically the same results.Looking for an alternative part designed for lower current I found the LT1615-1, but even before the supply shortage it could not be obtained.I did have success with LT3460, it is however much too expensive for my application.AP3015 seems to have a undefined, much lower operation frequency. Have not tested yetSo basically this results in my 2 questions:(1) Are there alternative parts I could use? Something I am not aware of? Recommendations?(2) Is it possible to somehow reduce the ripple of the AP3012? I tried altering the feedback network, reducing and increasing the inductance and output cap - all with little to no positive effect.thank you!

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 15, 2021, 07:38:00 pm
content: I can suggest the TPS61099, or equivalent in the same series.

author: harerod
author_rank: Frequent Contributor
timestamp: June 15, 2021, 07:58:20 pm
content: Hi ubbut, I think you are on the right track. The "pulse skipping" is to counter saturation of the inductor due to low load current. The minimumrequiredload current depends on inductance and lowest duty cycle. AP3012 Figure 9 shows 20..90% duty cycle.Caveat: Higher inductivity may result in a more sluggish response to changing load current.Regarding a feasible component - just have a look at the distri sites, what's available today... Digikey has some LT1930 in stock.I second EVB149's LDO recommendation. While supply ripple current is low for boost topology, output ripple is high. Depending on your application filter+LDO might be indicated.

author: Weston
author_rank: Regular Contributor
timestamp: June 16, 2021, 02:57:09 am
content: I cant think of any specific boost converters that fit your application off-hand, but the feature you want is "forced-PWM" mode, which means that the converter will never enter pulse skipping mode, regardless of load current.Often dc/dc converters will have part variants that are always in forced PWM mode, or they have a pin you can tie to the supply / ground to define the behavior.
Boost converter capable of 50w 3.2v to 12v? - Page 1
Forum section: electronics / projects

author: Snake____1
author_rank: Contributor
timestamp: July 21, 2019, 07:11:40 pm
content: Hello, I'm struggling to find a suitable boost converter capable of about 50w from single cell li-ion to 12-15v output. Does anybody know of anything I could use or do I have to parallell up several IC's.

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 21, 2019, 07:33:19 pm
content: You are almost certainly going to need an external switch controller IC, rather than an integrated switch regulator IC; peak current is going to be >20A, after all.

author: Snake____1
author_rank: Contributor
timestamp: July 21, 2019, 08:56:54 pm
content: Thanks for the tip! Might have found the chip I'm looking for, (LM5155).I'm aiming for 1-3 IMR18650 cells in parallel, so >20A will be no sweat. I will admit, I was hoping for an integrated switch solution. But this one supports single N-Channel mosfet, this might bee good!

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 21, 2019, 09:20:39 pm
content: You're welcome, and here's a bonus: plug your input voltage, output voltage/current and switching frequency parameters into the calculator on this site:http://schmidt-walter-schaltnetzteile.de/smps_e/aww_smps_e.htmlAnd it will calculate the necessary boost inductor value, plot some waveforms and even generate a table of potential magnetic components ("coil data") with core size, number of turns, and the gap (confusingly referred to in the "ident" column in mm), etc., specified. I've spot checked the output from this site numerous times against my own calculations and it gives reasonable results (which I can't say for most online magnetics calculators). Even if you don't wind your own boost inductor you can use the coil data it outputs to help ensure a commercially available inductor will work (though I suspect you are going to have to wind your own here).EDIT - your -> you're... grrr...
Boost Converter Compensation with Variable VOUT - Page 1
Forum section: electronics / projects

author: Evan.Cornell
author_rank: Regular Contributor
timestamp: December 10, 2021, 03:20:34 pm
content: I'd like to use a boost converter with trim-pot in feedback loop to generate VOUT=20-35V at IOUT_max=4A from VIN=8-16V.Obviously the switching FET and diode need to be sized for the highest output voltage and lowest input voltage operating point.Is there any similar rule of thumb for calculating the compensation components, i.e. at lowest VIN and highest VOUT to guarantee converter stability under all conditions?

author: David Hess
author_rank: Super Contributor
timestamp: December 10, 2021, 07:21:45 pm
content: Quote from: Evan.Cornell on December 10, 2021, 03:20:34 pmThe worse case compensation happens when the most feedback is applied, so at the highest input voltage and lowest output voltage where closed loop gain is lowest *if* the feedback is used to adjust the output voltage. This does not always have to be the case. An alternative is to use a fixed feedback network stabilized at the highest output voltage and lowest input voltage, in other worse highest gain where stability is easiest, and adjust the reference.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 10, 2021, 07:28:13 pm
content: Note that, in addition to the above, the "plant" is also worst under the opposite condition -- assuming current-mode control with slope compensation, and moderate ripple fraction (33-50%?). Current is high (i.e., into CCM) at low input voltage and full output power, and the response is different in CCM (higher modulator gain and lower pole, isn't it?) vs. DCM. For other conditions (light load, possibly high VIN and VOUT as well, depending on the range of each and the ripple fraction) it will tend towards DCM.The quoted range shouldn't be a big deal. Check the operating point corners, and find the worst conditions, compensate to that. Other conditions will be somewhat overcompensated, which is fine.Tim

author: David Hess
author_rank: Super Contributor
timestamp: December 10, 2021, 08:32:00 pm
content: I should have mentioned that I was assuming CCM. In DCM, the gain inside the loop varies so the compensation changes with the output current making things much worse.
Boost converter cycle-by-cycle enable/disable? - Page 1
Forum section: electronics / projects

author: Manul
author_rank: Super Contributor
timestamp: August 28, 2024, 05:41:42 pm
content: I'm considering a boost converter for my project, actually 3 separate ones. For noise reasons, I want to be able to disable them for a short periods of time (tens of µs, maybe into hundreds). For that I need almost cycle-by-cycle control. There are switching converters which have fast switching enable/disable functionality (for instance TPS62840, with it's RUN/STOP pin). Yet most generic converters are quite slow with their enable/disable, cause they start/stop the oscillator, do a soft-start ramp, things like that. At least that's what I see in datasheets.Question: is there a good way of implementing such functionality with generic, jelly bean converters? Like for example, pulling the feedback high or inhibiting gate drive signal (for external switch type converters)? Have you ever done it? What are the caveats? Or should I be looking at something more flexible, like PWM controller for this?Any comments are welcome. Cheers.
Boost converter DCM- Measuring current with current sense resistor - Page 1
Forum section: electronics / projects

author: FerdinS
author_rank: Contributor
timestamp: August 18, 2020, 08:00:25 pm
content: Hello everyone;My project is to make boost converter. From 18V approx 0.5 A to approx 100V and max 0.085A.I am using those components:- 220 uH inductor- 3uF capacitor- SQJ454EP-T1_GE3 - mosfet.Because I have to measure income current and output current I am using 2 current resistors, as it is shown on the picure :because I have to make this "voltage drop" current sense resistors I am using rail to rail operational amplifiers so that voltage goes to max. 3.3 V, bcs my ADC on IC is measuring max that.It is shown on the picture:When I am measuring current now it is shown that the voltage drop on current sense resistors is too high. Also tried to put on output voltage around 100 V and it seems my resistors got burned, so it really has to be too high voltage drop on current sense resistor.I am asking now, is 0.5 and 0.05 ohm too high ?Also what resistor should I use on the out put ? I tried with 1k - and also 20k ohm and it seems that it gives me same result.Thank you a lot for your kind answers.
Boost Converter for 50W LED - Page 1
Forum section: electronics / projects

author: lja246
author_rank: Contributor
timestamp: October 07, 2022, 02:41:15 am
content: Hi all,I'm looking at making a portable light and was wondering if anyone had some suggestions for the boost converter IC I could use.I'm looking at running it off a 7s Li-Ion battery pack and the LED in question runs at 32v at 1.5A (48W). For most of the time I plan to run the LED at 1A (30W) but the circuit needs to be capable at running it at full power.I was wondering if anyone has any suggestions for what boost converter IC I should use for this application that is readily available and preferably the supporting components takes up a small amount of space on a PCB as it needs to be as compact as possible.Thanks in advance

author: Marco
author_rank: Super Contributor
timestamp: October 08, 2022, 11:13:29 am
content: If it needs to be compact as possible, you're going to be looking at a MHz level converter. The toroid is going to determine the minimum size ona 100 kHz level converter.Just from parametric search, AL8822/AL8823?PS. on second thought might not be a good IC, that's meant for old 24V halogen transformers and detects triac dimming ... could probably be hacked for PWM dimming, but it's a bit awkward. ZXLD1371 maybe? Bit more expensive, but doesn't matter for a one off.

author: Wolfram
author_rank: Frequent Contributor
timestamp: October 08, 2022, 12:13:32 pm
content: The fully charged voltage of a 7S 4.2 V/cell pack is pretty close to the nominal LED voltage. Make sure that the LED Vf at nominal current is never significantly below this across production variation and temperature range. Boost converters can not control the current if Vout is smaller than Vin (in practice you have a diode drop of margin in a non-synchronous boost, but not in a synchronous one).

author: Marco
author_rank: Super Contributor
timestamp: October 08, 2022, 01:02:39 pm
content: Quote from: Wolfram on October 08, 2022, 12:13:32 pmOops, I didn't even think about how a boost converter behaves near Vi=Vo, even without outright conduction through the diode the duty cycle gets extreme.Going to need either buck boost or a four switch converter. ZXLD137 would still work.
Boost Converter in CCM?  - Page 1
Forum section: electronics / projects

author: Dmeads
author_rank: Regular Contributor
timestamp: October 22, 2019, 01:12:18 am
content: Whats up! trying to learn Switching converters with LTspice and I was wondering if this one is operating in continuous conduction mode?The picture is of the current in the inductor (blue) and the current in the diode (green) IMPORTANT NOTE: I offset the diode (green) waveform by -5 Amps so you can see what is going on otherwise they over lap.I am assuming that this converter is in CCM because the current in the inductor doesn't go down to zero before the diode starts conducting because of the switch turning on.Is this correct?I calculated my duty cycle and stuff from this link:http://www.ti.com/lit/an/slva372c/slva372c.pdfwhich was helpful but i needed to adjust a little bit. I increased my inductor size by 4 times to reduce initial current spikes in the inductor.switching frequency is 400kHz and I gave a random ESR to the inductor of 0.2 Ohms cuz in reality it will have thick wire.picture and file are attatched.Thanks!

author: TimNJ
author_rank: Super Contributor
timestamp: October 22, 2019, 02:36:39 am
content: You can easily distinguish CCM from DCM by checking if the inductor current ever reaches 0. If it reaches 0 during the switching cycle, it is discontinuous (DCM). In your case, IL1is continuous, so I'd say its CCM.The positive slop of the current wave should be equal to Vin/L, and the negative slope should be equal to -Vout/L. Your slopes are fairly close to that.On a practical note, notice that your inductor ripple current is extremely low at less than 2%. This might sound like a good thing, but in reality it means your inductor will have to be physically very large to not saturate at 15A and 240uH. Most designs will shoot for 10 to 30% ripple current as a trade off. That is, drop the inductance, increase core gap (if there is one), and so on.

author: jmw
author_rank: Frequent Contributor
timestamp: October 22, 2019, 02:37:19 am
content: Yes that's CCM. Zoom in on I(L1) and you'll see the expected sawtooth waveform. The boundary condition for DCM operation is: \$K < K_{\mathrm{crit}} = D(1-D)^2\$ where \$K = \frac{2 L f_s}{R_L}\$.Ferrite core inductors saturate and 14.5 A is going to require something substantial. Winding loss alone at 200 mohm is going to be almost 40 W. Also, I assume you'll eventually want to operate closed-loop and 84% duty cycle is close to the limit of what a lot of controllers will support.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 22, 2019, 10:07:50 am
content: Zero rise and fall time is rather unrealistic, especially with a zero(?) ohm source. 20ns and 5 ohms would be pretty typical for a gate driver.I think that will address the huge fast spikes.Tim

author: FalkMusick
author_rank: Newbie
timestamp: October 25, 2019, 08:25:50 pm
content: To reduce the simulation time, you m might consider using the spice initial condition command. For example .ic V(Vout)=160 I(L1)=12
Boost Converter Suggestion 3.6 to 12V - Page 1
Forum section: electronics / projects

author: LabSpokane
author_rank: Super Contributor
timestamp: October 18, 2016, 04:18:39 am
content: I'm looking for suggestions for a boost converter to step 3.6-4.2VDC up to 12VDC @ 0.5 to 1A. I'm only looking to power some motors for a brief period of time, so I don't need super-clean output necessarily. Power source is a hefty LiPo.Ideas?

author: raptor1956
author_rank: Frequent Contributor
timestamp: October 18, 2016, 04:51:15 am
content: Something like this should do the job with plenty of headroom.https://www.amazon.com/DROK-Converter-1-2-30V-Charging-Regulator/dp/B00C93SF1M/ref=sr_1_62?ie=UTF8&qid=1476766138&sr=8-62&keywords=boost+converterBrian

author: Skimask
author_rank: Super Contributor
timestamp: October 18, 2016, 04:51:30 am
content: A couple TPS65131 would probably do it (paralleled).I don't even remember my own numbers, but I was hitting real near datasheet specs when I was playing with my TPS65131 boards. A single TPS65131 wouldn't get you a solid amp, but a couple would surely do the business.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: October 18, 2016, 05:15:18 am
content: As shown in thefull schematic over here, I've had good results with the TPS61088 (the '89 is very similar but with a smaller switch). It's a good chip but hardly cheap; an excellent choice when engineering time is more dear than parts cost.

author: LabSpokane
author_rank: Super Contributor
timestamp: October 18, 2016, 10:23:09 pm
content: Anyone know why the LM2587 is so crazy expensive? I'm assuming that the Chinese have cloned the design and are faking the labels on all these $3-4 LM2577/87 prefab boost converters.

author: mariush
author_rank: Super Contributor
timestamp: October 19, 2016, 05:23:40 am
content: You could check out TI's Webbench wizard (you need a free account with them to see designs) , which will recommend various designs based on their chips.You could go with chips on the expensive side like TPS61088 for example, and use very few smd components and overall take little space on pcb:or you could use cheaper and simpler to solder chips like LM3478 for exaple, but lose efficiency and take more footprint on pcb :

author: LabSpokane
author_rank: Super Contributor
timestamp: October 19, 2016, 05:55:28 am
content: Thanks all. I think I'm running with the TPS61088. Expensive and overkill, but she'll get the job done with minimal fuss.
Boost converter TPS40210 problem please help....!!!! - Page 1
Forum section: electronics / projects

author: manjunath
author_rank: Contributor
timestamp: September 15, 2014, 05:13:51 pm
content: Hi, i have design a voltage booster circuit using TI web bench(circuit is in attachment) using TPS40210 IC and its working fine but when i try to interface my booster circuit with application circuit (Transformer circuit shown in attachment) the 48v voltage drop to input voltage of 20V. i am not getting where the problem is in please can anyone help me.

author: manjunath
author_rank: Contributor
timestamp: September 15, 2014, 05:19:30 pm
content: Transformer circuit is in this circuit....!!!!

author: rx8pilot
author_rank: Super Contributor
timestamp: September 16, 2014, 09:54:49 pm
content: I have not seriously analyzed anything, but what stands out to me is that the TPS converter circuit may not be capable of dealing with that huge capacitor on the front-end of your application circuit. There is a .03 ohm sense resistor measuring current, which probably is set up for a low output current. The inrush on the an 8200uf cap is pretty huge which would have the TPS going into fault and skipping PWM pulses to protect itself.
Boost converter voltage drop - Page 1
Forum section: electronics / projects

author: fedimakni
author_rank: Regular Contributor
timestamp: January 27, 2020, 08:44:28 am
content: HelloI used both the TPS610986 and TPS61291 boost converter in order to power a load that consume around 200mA in both situation (TPS610986 powering the load then use the TPS61291 to power the same load) the boost converter voltage drop down to around 0.45V. Both of them work correctly with load that consume 10-20mA but with higher load the voltage drop down i didn't understand the reason as the datasheet mention that both could work fine by supplying 200mA. ( I also tried a load that consume 100mA but i faced the same problem)Input voltage: 3VOutput voltage: 3.3VCould you please tell me how to fix it.ThanksPS: attached the schematic of both boost converter that I used

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: January 27, 2020, 08:49:28 am
content: for the TPS610986 , the recommended cap from VSUB to GND is 10uF whereas your schematic uses 1uF.Can you also check with lowering the input voltage. Some boost converters behave strange when the output voltage is close to input.

author: fedimakni
author_rank: Regular Contributor
timestamp: January 27, 2020, 08:58:18 am
content: I am not using the Vsub as the mode pin is tied to ground. so it's deactivated. and the same problem occur with the second boost converter.Even with 2V input voltage i still face the same problem

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: January 27, 2020, 09:21:19 am
content: can you tell the part number for the inductors used?

author: fedimakni
author_rank: Regular Contributor
timestamp: January 27, 2020, 09:41:08 am
content: VLS252010HBX-4R7M-1 for the TPS610986MDMK2020T3R3MM for the TPS61291

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: January 27, 2020, 09:50:42 am
content: How bad is the voltage drop?can you share the layout layers. Some of the TI DCDC converters are very sensitive to layout.

author: fedimakni
author_rank: Regular Contributor
timestamp: January 27, 2020, 10:01:56 am
content: the layout is good, it's almost identical to the recommended layout in the datasheetThe voltage drop to 0.75V

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: January 27, 2020, 10:17:00 am
content: The output traces seem way too thin and can drop a bit, but not to 0.75V.Did you probe at the cap at the output of the DCDC?Looks like the DCDC is not able to get into PWM mode. Can you check the waveform at the inductor to check if it is in PWM mode with high current.compare with the datasheet curves.Can you force PWM operation?

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: January 27, 2020, 10:28:06 am
content: can you make the MODE pin high and check?

author: fedimakni
author_rank: Regular Contributor
timestamp: January 27, 2020, 10:39:15 am
content: the traces are 10mil i think they are enough for 200mA.you mean checking the waveform between both pin of the inductor? or one pin and the other oscilloscope probe pin to the ground?For the TPS61291 there's no mention of pwm :/
Boost converter with MC34063A only outputting 7.5V instead of 36V - Page 1
Forum section: electronics / projects

author: WarFreak131
author_rank: Contributor
timestamp: October 31, 2022, 02:07:06 am
content: Hello,I recently got the parts in to create a boost converter that takes 5V and boosts it to 36V based on the MC34063A IC.I followed the method of calculation for the values prescribed by the datasheet. I can't find my original calculations, so the Rscvalue of 1 OHM might be a little high (should probably be closer to 0.3 OHM), but under no-load conditions should that matter?Anyway, I have attached a picture of the schematic I created as well as my breadboard layout. For some reason, I cannot get 36V out of it. It will only go up to about 7.6V as measured across the 33uF capacitor. Everything is seated correctly, and I have tried swapping IC's in case the first one was broken.Can someone find an issue with the schematic or with the placement of the components on the breadboard? On the schematic, the labels on the SIP header should be Vin, GND, Vout.

author: Salome2
author_rank: Regular Contributor
timestamp: October 31, 2022, 02:44:47 am
content: you've connected the 56uH choke wrong

author: WarFreak131
author_rank: Contributor
timestamp: October 31, 2022, 03:11:19 am
content: Good catch! One end should be connected to pin 7 instead of 8, correct?EDIT: Yep, 36.0 V on the dot! Thank you.
Boost PFC:  Mode of control - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: November 17, 2017, 09:34:22 am
content: Hello,We want power factor correction for our offline, 230VAC, color changing, flashing led light. The power level is from 25W to 150W.We want a boost PFC followed by two 75W Buck converters. These lamps will sometimes flash on and off at 2Hz (150W to zero watts)We must tolerate the slow feedback loop of the boost PFC. However, we want the feedback loop to be as fast as possible and yet still achieve PFC. There is no hold-up requirement, and we wish to use the very smallest film output capacitance that we can get away with. The LED strings are 200V.Also, we must be PFC’d from 25W load to 150W load.As such, we cannot use Critical mode pfc for the boost...because its operating frequency goes too high when we are at lighter load....... We can mitigate this by using a very large inductor, but thats not wanted.Also, getting PFC from 25W to 150W, and having the PFC be as high in bandwidth as possible, means that Fixed frequency CCM PFC is not so convenient for us, since tuning the voltage and current loops, for the maximum possible bandwidth of the voltage loop, requires considerable care, and the exercise must be repeated whenever the output capacitance is changed or the boost inductor value changes.Therefore, we will use the L6562 Boost PFC controller in Fixed off time control.Do you agree that this makes the most sense for our application?L6562 DATASHEET:http://www.st.com/content/ccc/resource/technical/document/datasheet/ba/de/2e/d0/3a/ca/4a/e6/CD00151385.pdf/files/CD00151385.pdf/jcr:content/translations/en.CD00151385.pdfL6562 in Fixed off time controlhttp://www.st.com/content/ccc/resource/technical/document/application_note/cc/e2/9f/39/ad/27/4d/7e/CD00004484.pdf/files/CD00004484.pdf/jcr:content/translations/en.CD00004484.pdf
Boosted rail push pull output for driving high impedance headphones with low B+ - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: September 07, 2023, 06:53:52 pm
content: What do you think, would it work?The 2 capacitors would be charged close to the power rail potential, then when the voltage swing would go high enough, the fets would start raising the "negative side" of the cap to the B+ potential, this way you can triple the voltage swing. Since the ground side would also be "sunk" down to 0 - B+; So if the B+ is 10V and we talking in ideals, the positive swing would go to 20V, and the ground side would go to -10V, so 30V ptp swing from a 10V supply.Theoretically you could boost the "booster" voltage too, sort of like an audio charge pump.

author: magic
author_rank: Super Contributor
timestamp: September 07, 2023, 07:03:08 pm
content: I think this arrangement was called "class H".It can work, usual class G/H caveats apply: collector voltage boosting causes some minor change in output stage gain (which is never exactly unity), and switching may couple glitches into the output if not done carefully.If the amp is mains powered, higher rails can be easily generated by line frequency charge pump (Cockcroft-Walton voltage doubler).

author: langwadt
author_rank: Super Contributor
timestamp: September 07, 2023, 09:23:10 pm
content: https://www.tubecad.com/2020/11/blog0521.htm
Bootstrap capacitor issue for gate drive. - Page 1
Forum section: electronics / projects

author: Kokoriantz
author_rank: Frequent Contributor
timestamp: December 04, 2024, 02:05:20 am
content: I will drive a TAS5631b digital input by a TPA3110. The TAS DS gives 352khz to 500khz while the TPA may run from 250khz.The bootstrap capacitor of 33nF, the DS of TAS states that it is suitable for 300khz-400khz range. The simple conclusion is to increase the capacitor that I would like to be 100nF, the TPA has 220nF.A question was asked about this matter on TI's e2e forum and bellow is the answer.Hello Kato-san,I apologize for the delay. I was out for holiday.Generally it is not recommended to change the bootstrap capacitor value. The TAS5624A was designed and tested with 33nF capacitors. This is standard for our devices. Channing this value may cause the part to not function properly at very high and very low PWM modulation levels.Also, the bootstrap capacitor will have little impact on audio quality. Typically the loop filter, loop gain, and architecture of the amplifier determines overall performance level.If your customer is looking fro better performance, I would recommend the TPA32xx family of device.Best Regards,MattIs this reasoning correct?If the capacitor is higher, it will discharge less and it will need not more time to recharge.I learned to calculate the bootstrap capacitor value from DS of LM5108 which is the following.
Bootstrap protection diodes - Page 1
Forum section: electronics / projects

author: moffy
author_rank: Super Contributor
timestamp: January 13, 2016, 12:14:44 am
content: Bootstraping protection diodes for sensitive circuits.I was looking through an excellent book on low leakage input amp in which the author spent a lot of time analyzing the op amp and then placed a couple of 1N914 diodes to the +/- 15v supplies without any analysis. He had an error budget of 10pA which can easily be swamped by the diodes especially at higher temps.Also there is the common case of oscilloscope probe amplifiers, the protection diodes have to be taken into account especially their non linear capacitance with voltage. So I thought I would use a simple LTSpice circuit to illustrate.In one circuit the protection diodes are boostraped by and NPN and PNP voltage follower. In the other case they aren't. A single 5k resistor is in series.A 1Mhz 10vp-p tone is applied in both cases.Bootstrapped:1.Current: 240na p-p2.Harmonic distortion: 97 db downNon Bootstrapped:1.Current: 110ua p-p2.Harmonic distortion: 70db downWith some matching between the diodes it would be possible to get say a 10 to 1 improvement in leakage current.
Bootstrap / startup switch circuit for 3.3V from 9V ? - Page 1
Forum section: electronics / projects

author: smoothVTer
author_rank: Regular Contributor
timestamp: December 04, 2017, 08:52:27 pm
content: My system has a 9V battery as the main power supply. There is a 4-position switch as well; in the system off state, position 0, the switch poles are open. Positions 1, 2, and 3 short the switch's poles to ground individually. This allows me to interface the switch with GPIOs on my uC for function selection, by virtue of external pull-up resistors on the uC GPIO pins.The LDO has an enable pin which must be driven logic high.I want this enable pin driven high when the switch pulls any of the GPIO lines to ground.The problem is, I cannot think of a circuit which will allow me to use the 9V (always-on) supply and interface with the 3.3V side of the uC without drawing current into the uC while in shutdown.Here's an illustration. Only a single switch pole is shown, but the idea is the same between all the GPIO lines. I've modeled the 3 GPIOs as typical ESD rail to rail diodes & 50p / 1meg input impedance:What circuitry can I use to achieve this function? In the off state, the VDD supply is sitting at 0V, so I cannot rely on VDD to power any logic gates. I could power logic gates from the 9V supply, but then I have 2 problems: a level mismatch between the GPIO expectation of 3.3V nominal logic levels, and the 3.3V and 9V supplies fighting for dominance. There must be a way to bridge the 9V supply leg with the GPIO lines, perhaps by sensing current from the 9V rail to ground, but I cannot come up with a circuit to do this safely for the GPIO lines.
Bootstrapped BF998 Unity buffer 1GHz - Page 1
Forum section: electronics / projects

author: moffy
author_rank: Super Contributor
timestamp: May 24, 2015, 04:08:20 am
content: Please find attached a simulation file for LTSpice for a bootstrapped unity(0.985) gain buffer. It's not original as noted in the readme.txt, but comes from a great source Steve Roach/Jim Williams and is worth noting.

author: moffy
author_rank: Super Contributor
timestamp: May 25, 2015, 12:15:04 am
content: I should have mentioned that linearity appears good also, for a 6vp-p sine wave at 10MHz the next highest harmonic is -74db from the fundamental.
Bosch Charger AL 1130 and portable power supply - Page 1
Forum section: electronics / projects

author: goris
author_rank: Newbie
timestamp: April 29, 2017, 08:07:33 am
content: Hello!I Could use some help, guides and/or similar. I want to be able to charge my power tool batteries off grid. I have been searching and all I could find is that people applied balance charging on the tool batteries.I have a portable power supply made of 3S 18650 cells (expandable to 4s) and I'd like to use it to recharge my power tool batteries. All of my power tools are based on 12V (old 10.8V) LiOn battery packs. I've got a couple of Bosch tools, drill, jigsaw and angle grinder among others. I've got chargers for these as well (AL 1130 and AL 1115). I need only one so i'd gladly sacrifice one of the chargers for the cause.My question is if it is possible to bypass the mains on this charger and power it with my 15 Ah power pack?!Thank you in advance.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 29, 2017, 09:19:12 am
content: AFAIK the Bosch chargers use a switched mode circuit and directly use it control the current. So it won't work easy to bypass an input section and than start from 12 V. Likely it uses a kind of flyback circuit - so a different supply would need to rewind the transformer and a new drive side circuit. So it might work in principle, but can be difficult.Many of the Bosch chargers also use quite some conformal coating - so already replacing the fuse is not so easy.

author: jeroen79
author_rank: Frequent Contributor
timestamp: April 29, 2017, 11:00:48 am
content: I would start by looking in the Bosch charger where the high voltage mains is turned to a low voltage DC.Then you can see if you could wire inbyour own low voltage supply.Or modify the Bosch batteries to expose each cell's + and - so you can connect a different charger.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 29, 2017, 03:38:53 pm
content: The small Bosch battery packs are not that expensive any more. So there is a limited use of using a power pack made of the same size cells to recharge them. It would be something different if charging from something like a car battery. So I would consider just getting a few more of the 10.8/12 V packs if needed.They also have larger ones (with a internal 3s2p configuration) with 4 and 5 Ah, that might be useful for the more power hungry machines like the jigsaw and angle grinder.
Bosch Integral TH13 LCD dislpay - Page 1
Forum section: electronics / projects

author: tomeo.gonzales
author_rank: Regular Contributor
timestamp: March 22, 2019, 12:38:29 pm
content: Hi all,I've got three LCD displays used in Bosch Integral TH13 phones.6 inch size, B/W.The model is SII 4141, controller chip is LZ93A76 also made by SIII don't know how to use it and I don't find anything about it on GooglePlease see the attached picture.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 22, 2019, 02:25:15 pm
content: the lz93a76 is a timing generator, the controllers display drivers are the two rectangles blob in the flex cablesdo you have other markings on the lcd ?

author: tomeo.gonzales
author_rank: Regular Contributor
timestamp: March 22, 2019, 03:49:37 pm
content: No. The PCB in the picture contains all the markings and integrated circuits. (except the blobs for the columns driver)

author: tomeo.gonzales
author_rank: Regular Contributor
timestamp: March 24, 2019, 09:02:15 pm
content: Thank you Coromonadalix for the informationI manage to obtain the mainboard of the Bosch Integral TH13 phone.The controller chip is SED1330F.The datasheet is available online.The datasheet for the rest of the chips was easy to find.The only unknown chip is CG24942 made by Fujitsu. (it looks like a character generator ROM)

author: coromonadalix
author_rank: Super Contributor
timestamp: March 24, 2019, 10:40:49 pm
content: Niice an SED1330f is relatively easy to work withLots of code in the arduinos forums ... if you could trace the signal paths with the th13 boards youll have your 15 pins connectors schematicsNot sure it seems to be an hirose connector ?

author: tomeo.gonzales
author_rank: Regular Contributor
timestamp: March 26, 2019, 04:33:21 pm
content: I'm not sure about the connector. It has 15 pins. Next I'll try to map the connector pins to SED1330F chip pins. Then I try to use the RAM and character generation chip on board TH13 with some Arduino code.
Bosch Worcester gas boiler EMS bus specification - Page 1
Forum section: electronics / projects

author: j.a.mcguire
author_rank: Contributor
timestamp: March 18, 2016, 12:39:17 pm
content: Does anyone know if it's possible to obtain documentation detailing the specification of the EMS communications bus on a Bosch Worcester gas boiler range?I would like to design my own thermostat and integrate it with this unit but I can't find any information on the EMS bus protocol? Is this a universal standard or specific to Bosch?Many thanks for any info.

author: kaz911
author_rank: Super Contributor
timestamp: March 18, 2016, 12:58:36 pm
content: non standard no docs...to the best of my knowledge.Change the WB for an OpenTherm compatible boiler. WB's are overrated.

author: davefiddes
author_rank: Newbie
timestamp: December 14, 2020, 06:11:14 pm
content: I know this is an old thread but seems to be the only one on the topic. The Worcester Bosch EMS protocol is now very well documented:https://emsesp.github.io/docs/#/How-the-EMS-bus-worksThere is a range of ESP8266/ESP32 based firmware to control EMS based devices:https://github.com/proddy/EMS-ESP

author: kaz911
author_rank: Super Contributor
timestamp: December 16, 2020, 10:29:16 am
content: Quote from: davefiddes on December 14, 2020, 06:11:14 pmIt still does not make it a quality product... Too much plastic and too many moving parts.
Bose Wave Radio input blown - Page 1
Forum section: electronics / projects

author: BikeisDusty
author_rank: Newbie
timestamp: August 04, 2013, 04:17:07 pm
content: I am trying to repair a Bose Wave radio. One of the input caps was a total short, so that was replaced. However, it still was not working. I am thinking the radio took a surge that it self protected itself from.The AC input has two paths. One that goes to a large transformer and the other to a rectifier. The rectifier side is where the large cap had gone south. The transformer side also had damage that I did not see originally.The path to the transformer has one side with a small inductor. The other side has a thermistor and inductor. The inductors are the same from Toko. I cannot find the exact item as the part number does not show up. It looks like this though:http://www.toko.co.jp/products/pdf/inductors/8rhb2.pdfI believe the inductors are small as there are not many turns in the coil.The inductor with the Thermistor is blown. For testing purposes, is it safe to try the circuit a jumper its place? This is just feeding a transformer that has multiple taps. The transformer then services 3 separate rectifier circuits. All of these appear to be working according to the diode tester on my multi-meter.Is there anything else I should look for in the circuit that could have caused the inductor to let the smoke out?ThanksBill

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 04, 2013, 05:32:34 pm
content: Quote from: BikeisDusty on August 04, 2013, 04:17:07 pmThat's the part that worries me, are you saying that the AC input goes directly to a rectifier?Look at the attachment, is this what you are talking about?

author: BikeisDusty
author_rank: Newbie
timestamp: August 04, 2013, 07:27:00 pm
content: Sorry, I should have been more clear. It goes to the ground plane that starts over at the rectifier. Your diagram helped, even though it is not the same. I believe that a diode in the bridge has gone bang as it is a short. The other 3 check out in the circuit.I just jumped the inductor and then tapped the leads to the board as similar to what is shown in your diagram. The 12VDC lead arched. The others did not, so that lead me to re-check everything in its path. I hope it is just the diode as the rest is crammed around the big heat sink and shielded box.If you think I should check other things let me know.Bill

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 05, 2013, 08:36:43 am
content: Quote from: BikeisDusty on August 04, 2013, 07:27:00 pmThat would even be worse, you don't want the AC input on your ground is it?Anyway, if you think one of the diodes is shorted replace all 4 of them and try again.
Bought an MCU-333 board (INA333 clone), gain barely changes - Page 1
Forum section: electronics / projects

author: fabricioandd
author_rank: Newbie
timestamp: May 08, 2025, 11:57:28 pm
content: Hey everyone,I recently bought a board labeled MCU-333, which is basically a 3.3V regulator + an INA333 clone amplifier + a potentiometer for setting RG (the gain resistor). I’m using it to amplify a small differential signal, and feeding it a clean 3.3V VREF.In theory, by adjusting the potentiometer, the gain should vary from 1 to 1000 (as per the INA333 datasheet: Gain = 1 + 50kΩ / RG). However, no matter how I tweak the potentiometer, the gain only changes slightly, roughly from 1x to 2x — measured by checking Vout relative to Vref.I suspected the potentiometer might be the issue, so I desoldered it and confirmed it works fine — its resistance changes smoothly across the expected range.So now I’m wondering:What could I be doing wrong?The only hypothesis I have left is that the INA333 clone on this board just doesn't behave like the real one. But if that's true... why is this board sold so widely?Has anyone else used this board? Is this a known limitation of these clones?Thanks in advance for any insight!Here are the circuit diagrams:https://ae01.alicdn.com/kf/HTB17pfFywTqK1RjSZPhq6xfOFXai.jpghttps://ae01.alicdn.com/kf/HTB1MrTCyzDpK1RjSZFrq6y78VXag.jpghttps://ae01.alicdn.com/kf/S61cc076c43dd46c8aaa23f8dd0d2e43cx.jpg
Boundary conduction mode flyback converter not working - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: October 11, 2017, 07:27:41 pm
content: Hello,We had some 230VAC, 30W T8 LED tubes made for us in China. A number of them have started flashing on and off.A quick flash, then 800ms delay, repeated.When I took one apart, I found what was obviously an isolated Boundary conduction mode flyback driver. It was obviously BCM because there was an 18k resistor connected from the AC side of the auxiliary coil diode, to a pin on the controller.. (obviously the ZCD pin)When I removed this 18k resistor, the LEDs stopped flashing and lit continuously, however, with no ZCD pin input, the controller is a bit “Lost”. In fact, it severely overpowers the LEDs, and gives out 45W at just 70VAC input. –Goodness knows how much power it would try and give out if I turned the VAC input any higher than 70VAC.The Boundary conduction mode flyback controller is an 8 pin SOIC, with the number “AGB2ZA” on it.I cannot find the datasheet anywhere on the web, -do you know where is the datasheet?