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# Ccm Mode

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68 Threads found on edaboard.com: Ccm Mode

## Transfer function of PSFB converter

As far as continuous conducting mode (ccm) is considered, the switching stage can be modeled as a controlled voltage source in equivalent circuit. Thus there's no difference between singled ended buck or bridge converter. Relevant parameters for the transfer function are modulator dead time and output LC filter.

## Small signal open loop transfer function for dual interleaved bucks.

Hello, The LTspice simulation of a 28vin to 1V5 out, 20A out, Dual Buck converter (each buck switches at 200khz and is in ccm, current mode) shows a crossover frequency of 14000 Hertz and phase margin of 63 degrees. The excel calculation of this circuit (also attached), gives it as 9600Hz for crossover, and 53 degrees for phase margin. ?So slig

## DC-DC converters in DCM

Let us assume that we have built a particular PID for a buck DC-DC converter considering the continuous conduction mode(ccm) of operation. In this case, the combined response of switch and the filter of the buck is a second order system and thus we need PID. Consider a situation where the load current drastically reduces and take a case where bu

## Feedback loop calculation for eight bucks in parallel

Hello The attached is a power supply involving eight current mode (ccm) bucks all in parallel, driving into the same load. Its easy to get the Feedback loop bode plots (& calculate gain and phase margin and crossover) for one buck supplying into one load, but how is it done for eight in parallel? Vin=28v vout = 1v5 iout = 136.8A total Eac

## Inductor current in the buck converter

As previously mentioned, the presumptions are unclear, for a buck converter in ccm you get the behavior described Easy peasy. It can be easily derived with pencil and paper method, similarly you should be able to determine why your simulation gives different results when you compare with theoretical behavior.

## Buck Converter voltage mode control

Please calculate power stage gain of continuous time equivalent circuit and realize that it will increase and be current dependent in DCM. Respectively a voltage controller that is stable in ccm can become unstable in DCM with insufficient gain margin.

## Flyback in voltage mode or current mode, and CCM to DCM

If one is designing a Current mode ccm flyback, then when the load gets lighter, such that it goes into DCM, then this DCM is always stable in current mode. (as long as it had been stable in ccm) In a ccm Voltage mode Flyback, lightening the load such that it goes into DCM can actually (...)

## Voltage mode CCM flyback cannot be done with type 2 compensator?

type 3 is best for volt mode as you need to counteract the inherent pole formed by the transformer and the o/p capacitors in volt mode... I agree, but I would go further than you and say that not only is type 3 better, but it is essential for a voltage mode flyback in ccm, -type 2 just isn?t good enough here?so I am (...)

## Compensator design for Boost pfc recifiers

yes, just see the opamp circuit shown in the lt1248 datasheet.. I appreciate you use average current mode control, because with current mode control , ccm pfc circuit would need very large amount of slope compensation for when voltage is near zero average current mode control is c

## DCM Full Bridge is best because no shoot through current (cf CCM Full Bridge)

Hello, We are doing a Current mode, DCM Full Bridge SMPS, VIN=390VDC (PFC output) ; VOUT=400VDC max; Pout=100W max ; Application=100W LED lamp (V(LED) = 340-400VDC at 250mA); F(sw) = 100KHz Dimmable down to 10W. Mains isolation We have chosen to do the Full Bridge as a DCM Full Bridge. The reason for DCM is

## Power stage small sighnal transfer function for current mode CCM synchronous Buck?

Hello, We are calculating the feedback loop (gain & phase margins) for a Current mode, Synchronous Buck Converter which is in ccm at full load. When on no load, the Sync Buck still has ?continuous? inductor current, ..so, for evaluating the Power Stage transfer function when on no_load, do we use the equation for a ?discontinuous? current (...)

## Flyback converter common mode filter impact on stability

Hi all, I recently to take over the design of a colleague who has left our company and and have difficulties with it. It is a current mode Flyback converter operated in DCM. The circuit is very similar to that described in Plexim "Design of a TL431-Based Controller for a Flyback Converter". The input side consists of a common mode choke and a c

## Low Load on a DC/DC buck controller

It's usually impossible to keep continuous conduction mode (ccm) of a buck converter at low loads. Percent ripple current specifications are for rated load. As the absolute ripple current amount doesn't increase at low loads, there shouldn't be a problem of related output voltage ripple with usual output filters. But changing from ccm to (...)

## PIC16F73 Buck converter design problem

Show your circuit. Do you know that the output voltage will be proportional to duty cycle only in continuous conduction mode (ccm) of the buck converter, in other words with sufficient load current?

## Continuous conduction mode PFC inductor does not need Litz winding?

Hello, Would you agree that the inductor of the PFC stage with the current shown below in it, does not need to be litz wound, since the ccm waveform has too-insignificant harmonics? Ie, one strand of ECW wire should be enough?

## [Moved]: Buck converter stability

Depends on DCM or ccm operation. No effect in ccm (continuous mode), but duty cycle is changing the loop gain in DCM, calculate yourself.

## Type II and type III compensation

Hi guys, I have one question: I have read around some technical white papers and in some books that the type II is suitable for a phase boost of 90? and for converter operating in current-mode and ccm. However, there is two white papers from two manufacturers that says that this compensator can be used to compensate converters that have a large

## Are there unbreakable rules regarding type 2 feedback compensation of flyback SMPS?

Do you agree with the following ?rules? (A to D) on the checking of type 2 compensator pole and zero positions? This is with regard to a ccm, Current mode flyback with a type 2 feedback compensation network..That is, making sure it is not going to be unstable.. ?The Type 2 compensator zero MUST BE at (or very near) the same freq

## Type 2 error amplifier for flyback cannot be done without knowledge of RHPZ?

Hello, On pages 212 to 217 of ?Power supply cookbook? by Brown, it goes through a type 2 error amplifier feedback compensation scheme for a ccm flyback in current mode. It discusses the placement of the error amplifier's poles and zero, but does not do this with respect to the power stage RHPZ. Why is no mention made of the RHPZ? Surely an error

## CCM Voltage mode flyback output capacitor size?

On page 6 of AN57 by powerint.com, it states that the resonant frequency of the Power stage LC should be greater than 500Hz... Why is this?...I could not find out from the forum.

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