eem2am
Banned
hello,
I apologise for long posT...though if you are a little knowledgable about SMPS's , then this will be straightfroward, just a spec sheet of an SMPS.........
i wish to design an isolated, offline SMPS and i am wondering if i have missed hearing about any new "low standby power" SMPS controllers?
V(in) = 85 to 265VAC
V(out)_1 = 36V +/- 10%
V(out)_2 = 5V +/- 4%
V(out)_1 and V(out)_2 must be isolated SELV outputs.
The 5V rail has maximum power of 2W
The 36V rail has a maximum "running" power of 10W.
(-but see below for its peak power of 36W)
Both 36V and 5V rails could have power levels anywhere from 200mW to their maximum, at any given moment.
In "standby", the 5V rail will have a load of 170mW.
In "standby", the 36V rail is not needed at all, and could be shut down in some way.
In "standby", the SMPS must draw no more than 500mW from the mains (yes, just 500mW).
The 36V rail is interesting.....it has a 30mF (yes, 30mF)capacitor across it.......when the SMPS is switched on at the mains, this 30mF capacitor must be charged up to 36V. -This 30mF capacitor must attain 36V within 1 second of the SMPS being switched on at the mains.
-When this 30mF capacitor is charged up to 36V, then the load on the 36V rail is 10W maximum
-This 30mF capacitor exists to provide some power to both the 36V rail and the 5V rail in the event of a mains failure.
-When the 30mF capacitor is being charged up, there is no other load on the 36V rail other than this charging capacitor.
-The big challenge with this is 1) the peak load of 38W while the 30mF capacitor is charging.....2) Even bigger challenge is the 500mW maximum power drawn from the mains when in "standby" mode............as you know, in "standby" mode, the secondary (specifically the 5V rail) has a 170mW load on it.......assuming 80% efficiency, this means a 213mW load seen at the primary........meaning that that we only have 287mW of margin before we violate the 500mW power consumption.
-Do you know of a controller thats good for this?
I apologise for long posT...though if you are a little knowledgable about SMPS's , then this will be straightfroward, just a spec sheet of an SMPS.........
i wish to design an isolated, offline SMPS and i am wondering if i have missed hearing about any new "low standby power" SMPS controllers?
V(in) = 85 to 265VAC
V(out)_1 = 36V +/- 10%
V(out)_2 = 5V +/- 4%
V(out)_1 and V(out)_2 must be isolated SELV outputs.
The 5V rail has maximum power of 2W
The 36V rail has a maximum "running" power of 10W.
(-but see below for its peak power of 36W)
Both 36V and 5V rails could have power levels anywhere from 200mW to their maximum, at any given moment.
In "standby", the 5V rail will have a load of 170mW.
In "standby", the 36V rail is not needed at all, and could be shut down in some way.
In "standby", the SMPS must draw no more than 500mW from the mains (yes, just 500mW).
The 36V rail is interesting.....it has a 30mF (yes, 30mF)capacitor across it.......when the SMPS is switched on at the mains, this 30mF capacitor must be charged up to 36V. -This 30mF capacitor must attain 36V within 1 second of the SMPS being switched on at the mains.
-When this 30mF capacitor is charged up to 36V, then the load on the 36V rail is 10W maximum
-This 30mF capacitor exists to provide some power to both the 36V rail and the 5V rail in the event of a mains failure.
-When the 30mF capacitor is being charged up, there is no other load on the 36V rail other than this charging capacitor.
-The big challenge with this is 1) the peak load of 38W while the 30mF capacitor is charging.....2) Even bigger challenge is the 500mW maximum power drawn from the mains when in "standby" mode............as you know, in "standby" mode, the secondary (specifically the 5V rail) has a 170mW load on it.......assuming 80% efficiency, this means a 213mW load seen at the primary........meaning that that we only have 287mW of margin before we violate the 500mW power consumption.
-Do you know of a controller thats good for this?