current mode and voltage mode dc to dc converter

[mess123]

dc to dc converter

Can anybody explain me what is the difference between current mode and voltage mode of a dc/dc coverter?
Also, I would like to know the difference between soft switching and hard switching in dc/dc converter.

 

[redfox750]

Me too, i really want to know about this two points and also about ZVS "Zero voltage switching" Is it the same as Dead time control?

 

[redfox750]

what? no one to answer? is it so hard quest?

 

[eem2am]

in each you have error amplifier with reference.

in current mode, this then feeds into PWM COmparator with the current sense voltage ramp.

in voltage mode, its exactly the same as that,,,,,BUT................THE error amp output goes into the PWM comparator with a fixed triangle wave into the other input of the pwm comparator


so the only difference is where you get the ramp from.

in current mode, you get it (ramp) from the current sense resistor, in volt mode, you get it from a triangle oscillator.

that is only difference.

nobody tell you this, as it is an industrial secret, and in recession, nobody want you or anyone else to know

 

[redfox750]

current mode seems more simple so why some use voltage mode?, and please if you know about ZVS or dead time control tell me,

thanks

 

[eem2am]

switchingpowermagazine.com amd powerint.com have articles on curr mode vs volt mode

In brief, voltage mode is the old fashioned way.

however, think of a transformer isolated forward converter where there is hardly any current ramp.......this would not be easy to do current mode.

also, imagine a one transistor forward converter...current mode......how does your primary current sense resistor tell the difference between the magnetising current and the referred secondary current.......not a showstopper but inconvenient at least

 

[mess123]

My source of power is Fuel cell. which control (voltage or current control) is suitable? Also there is a dual loop (inner current loop and outer voltage loop)?