Sorry for the long and dull post...please by all means just skim read and hit back with anything you suspect may be remotely relevant.....
We are providing 1V5, 173A to a processor load by way of a 28V input.
This means using a cascaded network of Off-the-shelf Power modules by Vicor.com as in the JPEG attached here.
So, the 28Vin goes into a Vicor P024T048T12AL Power module, and this then feeds into a Vicor VTM48ET020T080A00 Power module which outputs the 173A at 1.5V (as in the attached JPEG)
(the power modules are actually paralleled to manage the large current throughput.)
The ‘upstream’ power module has a regulated Vout but the ‘downstream’ module is just a converter with a fixed Vout/Vin ratio (unregulated).
However, the ‘upstream’ power module purports to be able to do “Adaptive loop” control which means that the Load does not experience (much) droop of its supply voltage as it draws more current. (the upstream module adaptively increases its Vout as it supplies more current, and this is done in conjunction with user-set control resistors).
Question 1:
Do you know if this adaptive control actually still works when these power modules are paralleled?
..the following application note claims to offer advice on such adaptive vout control for systems with up to two VTM modules in series……why only two?....does adaptive vout control not work for more than 2 modules in parallel…
Application note on Adaptive vout regulation:
http://cdn.vicorpower.com/documents/application_notes/vichip_appnote24.pdf
Question 2:
Why is the MVTM36BT015M080A00 power module (datasheet immediately below) more expensive than the VTM48ET020T080A00 power module?...
..After all, the latter has a much lower output resistance.
MVTM36BT015M080A00 power module datasheet……
http://www.vicorpower.com/products?productType=cfg&productKey=MVTM36BT015M080A00
Question 3:
If we use the adaptive loop regulation with the P024T048T12AL/ VTM48ET020T080A00 Power modules, then given our load requirement, and supposing we have a 6 milliohm of trace resistance to the load from the output of the VTM48ET020T080A00 Power module, then what sort of load regulation could we expect? There is actually an application note which purports to offer a calculation for this (linked immediately below), however, this excel calculation spreadsheet will not allow me to adjust the cell contents…it asks for a password to do so, and I do not have this.)
App Note on Adaptive loop feedback…
http://cdn.vicorpower.com/documents/application_notes/vichip_appnote24.pdf
Question 4:
The bottom left of page 8 of the Vicor P024T048T12AL Power module datasheet states that…..
“Please consult Vicor Applications Engineering regarding additional considerations when paralleling more than two PRMs.”
..Why is this?...what’s the problem when connecting more than two P024T048T12AL Power module datasheets in parallel.?
Vicor P024T048T12AL Power module datasheet:
http://www.vicorpower.com/products?productType=cfg&productKey=P024T048T12AL
Vicor VTM48ET020T080A00 Power module datasheet:
http://www.vicorpower.com/products?productType=cfg&productKey=VTM48ET020T080A00
We are providing 1V5, 173A to a processor load by way of a 28V input.
This means using a cascaded network of Off-the-shelf Power modules by Vicor.com as in the JPEG attached here.
So, the 28Vin goes into a Vicor P024T048T12AL Power module, and this then feeds into a Vicor VTM48ET020T080A00 Power module which outputs the 173A at 1.5V (as in the attached JPEG)
(the power modules are actually paralleled to manage the large current throughput.)
The ‘upstream’ power module has a regulated Vout but the ‘downstream’ module is just a converter with a fixed Vout/Vin ratio (unregulated).
However, the ‘upstream’ power module purports to be able to do “Adaptive loop” control which means that the Load does not experience (much) droop of its supply voltage as it draws more current. (the upstream module adaptively increases its Vout as it supplies more current, and this is done in conjunction with user-set control resistors).
Question 1:
Do you know if this adaptive control actually still works when these power modules are paralleled?
..the following application note claims to offer advice on such adaptive vout control for systems with up to two VTM modules in series……why only two?....does adaptive vout control not work for more than 2 modules in parallel…
Application note on Adaptive vout regulation:
http://cdn.vicorpower.com/documents/application_notes/vichip_appnote24.pdf
Question 2:
Why is the MVTM36BT015M080A00 power module (datasheet immediately below) more expensive than the VTM48ET020T080A00 power module?...
..After all, the latter has a much lower output resistance.
MVTM36BT015M080A00 power module datasheet……
http://www.vicorpower.com/products?productType=cfg&productKey=MVTM36BT015M080A00
Question 3:
If we use the adaptive loop regulation with the P024T048T12AL/ VTM48ET020T080A00 Power modules, then given our load requirement, and supposing we have a 6 milliohm of trace resistance to the load from the output of the VTM48ET020T080A00 Power module, then what sort of load regulation could we expect? There is actually an application note which purports to offer a calculation for this (linked immediately below), however, this excel calculation spreadsheet will not allow me to adjust the cell contents…it asks for a password to do so, and I do not have this.)
App Note on Adaptive loop feedback…
http://cdn.vicorpower.com/documents/application_notes/vichip_appnote24.pdf
Question 4:
The bottom left of page 8 of the Vicor P024T048T12AL Power module datasheet states that…..
“Please consult Vicor Applications Engineering regarding additional considerations when paralleling more than two PRMs.”
..Why is this?...what’s the problem when connecting more than two P024T048T12AL Power module datasheets in parallel.?
Vicor P024T048T12AL Power module datasheet:
http://www.vicorpower.com/products?productType=cfg&productKey=P024T048T12AL
Vicor VTM48ET020T080A00 Power module datasheet:
http://www.vicorpower.com/products?productType=cfg&productKey=VTM48ET020T080A00
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