offline SMPS with low "standby" power consumption
offline SMPS with low "standby" power consumption
(OP)
Hello,
Please can you tell me, I wish to do an isolated , offline SMPS (85 to 265VAC) , Power output = 34W.
It has one isolated output of 36V (+/-5%), 32W and one isolated output of 5V (+/- 4%) , 2W.
When the SMPS is in "standby" (i.e., its minimum load condition) the 36V rail is completely unloaded, and will be "shut down" completely, to save power.
However, the 5V rail , when the SMPS is in "standby", will have a load on it of 200mW.
I have to design this SMPS so that it draws no more than 500mW from the mains when in standby.
If you know of a PWM controller which is suitable for this, please can you tell of it....i believe this is a very low requirement for power draw in standby
Please can you tell me, I wish to do an isolated , offline SMPS (85 to 265VAC) , Power output = 34W.
It has one isolated output of 36V (+/-5%), 32W and one isolated output of 5V (+/- 4%) , 2W.
When the SMPS is in "standby" (i.e., its minimum load condition) the 36V rail is completely unloaded, and will be "shut down" completely, to save power.
However, the 5V rail , when the SMPS is in "standby", will have a load on it of 200mW.
I have to design this SMPS so that it draws no more than 500mW from the mains when in standby.
If you know of a PWM controller which is suitable for this, please can you tell of it....i believe this is a very low requirement for power draw in standby





RE: offline SMPS with low "standby" power consumption
The 500 mW standby is part of the EU-2013 and future Energy Star requirements.
RE: offline SMPS with low "standby" power consumption
I guess if you have no SMPS design experience then I can see it being difficult.
TI sells a lot of interesting SWPS IC's and has a fair number of design notes. But then, look at a few of the main SMPS device players since they all have design notes and reference designs to give you starter ideas.
RE: offline SMPS with low "standby" power consumption
i appreciate that it doesnt sound difficult, but it really is very hard..........because the controller's bias power draw becomes of the same order as the load power.
RE: offline SMPS with low "standby" power consumption
John D
RE: offline SMPS with low "standby" power consumption
This sounds like what you might need for your 85-265VAC 34W.