Anyone Know Any SMPS Controller Chip Simpler Than TL494? - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2018, 01:10:54 pm
content: TL494 provides 2 alternating PWM through its E1 and E2 (pin #9 and #10) this is the main nice feature i want. but i dont need the extra pins such as error amplifiers, Vref, etc because the thing will run in full banana (no need Vout feedback, or is not a critical spec). also preferably the PWM power (C1 and C2 pin #8 #11) will tie directly to Vcc so its less 2 pins there. i only need some means of frequency control (Ct and Rt in TL494, preferably combined in 1 pin like other IC requiring Ct alone), dead time control and thats it. the 2nd feature is it should be small footprint so smd is preferable. output drive should not be critical, 20mA will do, more is better, this is for low power application somewhere 1-2W. so my dream would be a soic6 or 8 or sot6 or 8 package with Vcc, GND, (Ct, Rt), Deadtime, E1, E2 pins on it. all soic8 or dip8 smps controller IC that i can find in the net only provide single PWM output, not what i'm looking for (in fact i owned one of such IC already). anyone of you guys know such IC? waiting your reply, thanks.

author: ocset
author_rank: Super Contributor
timestamp: February 25, 2018, 02:35:35 pm
content: Sounds like you want something like an LLC converter driver?Infineon do some of those.But to be honest, you want variable frequency and variable dead time, so it sounds like you want a microcontroller with those facilities in it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 25, 2018, 03:16:37 pm
content: Presumably you want simplerand cheaper. You can get the former, but not both together. Keep that in mind.Besides dumb chips like the 555, that aren't specifically intended for SMPS anyway, I recall there's an IR2110 style gate driver with integrated oscillator, that may be of interest.I don't see how "simple" is a desirable goal, though. You at least want some protection features: UVLO, peak current limiting, or PWM foldback, or fault latching; maybe output over/under voltage protection and hiccup current limiting too. These functions require a lot of hardware tacked onto anything simple (like a gated oscillator). A purpose made controller, for whatever topology you're doing (LLC or otherwise), is almost always well worth the cost. TI and Power Integrations come to mind.Tim

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2018, 03:48:41 pm
content: Quote from: T3sl4co1l on February 25, 2018, 03:16:37 pmi thought simpler is cheaper.Quote from: treez on February 25, 2018, 02:35:35 pmi saw TL494 is used in most car audio amplfier to drive toroid transformer to produce dual rail output from 12V battery. this kinda neat idea i want to implement in my circuit. some of the audio board (smaller one iirc) dont utilize the error amplifier they just let the pins disconnected, usually its used for (overload? or short?) protection. since my circuit is low power, i dont need protection. only one audio board utilize it as feedback system ie PWM based on output voltage, but mostly run in full banana, which i dont see much problem with it. i like it because its simpler less component count and traces to route and much independent. my system will be 3.7 - 5V input, ±10-15V output if i cant find any off-the shelf dc-dc converter that meet this spec, i'm going to wind my own toroids.Quote from: treez on February 25, 2018, 02:35:35 pmi did it with pic10f206, work beautifully, but its 10X the price of TL494, and need programming on each board. i can end up using soic version of tl494, but i'm asking in advance if there is simpler out there that i can easily missed, so i dont have facepalm moment when i did the real prototype.edit: errr... TL494 doesnt work down to 3.7Vthis is another criteria to keep in mind...

author: danadak
author_rank: Super Contributor
timestamp: February 25, 2018, 04:29:45 pm
content: If you are looking for dead band PSOC Creator/PWM component implementsthis. See attached and -http://www.cypress.com/file/131736/downloadAnd phase shift -http://www.cypress.com/documentation/application-notes/an76439-psoc-3-and-psoc-5lp-phase-shift-full-bridge-modulation-andAnd its got onboard Vref, A/D, OpAmps, routability.......In the bigger parts you can put quite a few PWMs implemented on chip. In this example I instantiated 16PWMs inside the part.https://www.eevblog.com/forum/microcontrollers/best-way-to-add-external-dacs/25/Regards, Dana.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 26, 2018, 01:38:26 am
content: Quote from: Mechatrommer on February 25, 2018, 03:48:41 pmHigherquantityis cheaper.Example: compare the minimum price of an ARM Cortex M0 to an ATxmega. The latter is 1/4th the bus width, so it should be simpler, right?Or even just between ARMs; ATSAMs cost more than STM32F0s.Sure, it's unclear if the sale price is due to OEM costs (development, documentation, support, budgeting), but you can guarantee which one is selling more.Or compare to a PIC, or most 8051 cores, which are immensely popular. 8051 will probably outlast humanity, it's... the bacteria of CPUs.QuoteOh, there are hundreds, no problem there.The cheapest DC-DC converters are nothing more than two transistor "chopper" circuits, who needs an IC?Tim

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 26, 2018, 03:05:38 am
content: Quote from: T3sl4co1l on February 26, 2018, 01:38:26 amany circuit example there? i'm guessing one is boost converter and the other one is inverse voltage converter. i havent seen such dc-dc converter in only 2 transistors, at least diodes and inductors will also be needed, those can take up spaces and design complexity, parts and routing etc. furthermore, transformerless dc-dc doesnt provide galvanic isolation.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 26, 2018, 03:25:58 am
content: Quote from: Mechatrommer on February 26, 2018, 03:05:38 ame.g.https://electronics.stackexchange.com/questions/140125/how-does-this-circuit-give-dc-outputObviously there's a transformer, diodes, bias resistors and filter caps, the transistors are only whatactivecomponents are required.Tim

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 26, 2018, 09:07:29 am
content: Quote from: T3sl4co1l on February 26, 2018, 03:25:58 aminteresting. i simulated the simpler version..its nice in simulation (1.png) until i put it in real circuit (CH1 = collector1, CH2 = collector2, CH3 = transformer secondary). alot of ringing, 2 npn (C945) burnt for the cause and my psu went into current limit mode (set to 0.3A). i tried the transformer in my PIC10F206 as a 45KHz SMPS Controller its working fine so its not its fault. i'll try the second circuit later, thanks...

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 26, 2018, 10:38:07 am
content: i think i got it to work in Vinp = lower 3.7V - 5V (earlier i used 15V). nice but 200mA idle current (no load) for portable battery application is not a small figure, battery can flat in quick time. i think this circuit can be improved in term of dead time and probably transformer saturation point during idle. attached CH1 = collector 1, CH2 = collector 2, CH3 = secondary winding output, CH4 = current consumed from PSU (1V = 1A)