This is an assignment question:

A system is operating at 325 VDC input, what is the required static leakage current during sleep mode in order to achieve Zero power?

I know there may be a lot of values for the leakage current which satisfy the requirement but I do not know a good or typical value for this. Although I saw that mostly the value will be in terms of micro amperes, I am still not sure about a value for this. Can I get help on this?

  • \$\begingroup\$ Slight improvement of your question will make it a better information source for others latterly. Is this 230 VAC + recification. What is the application? Why do you want zero power/ who said/why do you care? \$\endgroup\$
    – Russell McMahon
    Oct 14, 2014 at 6:05
  • \$\begingroup\$ It's a good idea NOT to accept an answer until a few people at least have answered or a few days have past with no further action. Some people will avoid accepted questions and/or be discouraged. Sometims later answers show that initial answers arte less good than thought (or wrong). Sometimes better or much better answers come along. While my answer may address your needs somebody may (or might have) come along with a tor de force tutorial on standby power with diagrams and graphs and. Such happens. \$\endgroup\$
    – Russell McMahon
    Oct 14, 2014 at 6:08
  • \$\begingroup\$ well, the question did not include anything except what I stated. If there was more info I would have wrote it in my question on it. \$\endgroup\$
    – mj1261829
    Oct 14, 2014 at 6:14
  • \$\begingroup\$ If questions are assignment questions you MUST say so. You will still get answers - and sometimes people will spend MORE time to help you BUT the aim is to help you thing, not just to fill in the boxes for you. We want to help you learn, not turm you into a vegetable :-). So DO ask asshnment questions but ask Gogle first and tell us what you have done and what you know. See answer additions about to happen. \$\endgroup\$
    – Russell McMahon
    Oct 14, 2014 at 6:15
  • \$\begingroup\$ sorry for not stating that this was an assignment question. Anyhow, If I have a problem I do always first search the problem, Try to look for possible solutions and read more about the context of the problem before posting it on a Q/A site/forum. Thank you for stating this, I may also have more questions related to the assignment questions so I'll try to articulate more next time. \$\endgroup\$
    – mj1261829
    Oct 14, 2014 at 6:27

1 Answer 1


"Zero Power" is usually a buzz-word / marketing term.
Zero power genuine occurs at zero current. This is not what you really want to know.

The IEC 62301 standard for measuring standby power in household electrical appliances rounds power usage of 5 mW or less to zero. So, 13 uA or less in your case - see below.

What matters depends on the source the energy and why you care.
325 VDC sounds like 230 VAC rectified - is that the source?

As a guide to costs - at 25 cents per unit, over a year (8765 hours) a Watt of power drawn continuously will cost you about $2.20. Adjust that figure for your power charges per unit.

1 Watt = P/V A = 1/375 = 2.7 milliamps 1 mW = 2.7 microamps

It is reasonably possible to achieve startup detection with ~= 3 mA available.
It's a lot harder with 3 uA.

One approach is storing energy in a capacitor with the detection circuit drawing extremely low current, with the capacitor giving an energy pool while waking up.

If uA level currents are needed and if sleep mode requires operation of an LED or similar then time multiplexing will be required to get useful drive levels. So 3uA with a 1:1000 duty cycle would allow a mA pulse once per second.

If you want more information please refine the question.


"The IEC 62301 standard for measuring standby power in household electrical appliances rounds power usage of 5 mW or less to zero." http://iwatt.com/press-release/industrys-first-digital-zero-power-acdc-pwm-controller-cuts-wasted-power-costs-in-offline-chargers-adapters/#sthash.sfdFUw29.dpuf

Example IC:

iW1700 zero power controller IC

They say:

  • The iW1700 zero-power ac/dc digital PWM controller enables low-cost, energy-efficient 120/230V-ac offline adapters and chargers requiring as much as 5W, which consume zero no-load power for cell phones; audio players; digital cameras; and other lowpower, portable devices.

    The device uses patented adaptive digital PWM/PFM technology that sends the controller into sleep mode when you disconnect the load, cutting no-load power consumption to less than 4 mW—effectively zero because the IEC 62301 standard for measuring standby power in household electrical appliances rounds power usage of 5 mW or less to zero.

    Digital techniques enable the iW1700 to support primary-side control, eliminating the need for an optocoupler. It also features quasiresonant switching for low EMI, cycle-by-cycle waveform analysis, and a switching frequency as high as 72 kHz to achieve no-load charger performance, meet manufacturers’ power- supply requirements, and still enable a low BOM cost. The iW1700 comes in a low-cost, standard six-pin SOT-23 package and sells for 25 cents (10,000).

Good technical description

enter image description here Manufacturer: www.iwatt.com
Acquired 2013 by: http://www.dialog-semiconductor.com/

  • \$\begingroup\$ well, This was just an assignment question. I asked only because just picking a value which can make the power go near zero may not be the answer that is expected form us. Also I am not sure about a practical value for this. Maybe its harder to get to less leakage current but if you should try to lower the power as much as possible while considering other factors (ex. costs as you said) even during sleep mode shouldn't you try to lower the leakage current as much as possible? Thanks anyways for the answer. \$\endgroup\$
    – mj1261829
    Oct 14, 2014 at 6:06

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