Frequently Asked Questions - Energy

What is standby power waste?
When appliances such as VCRs, DVDs and cell phone chargers are plugged into the wall, they consume energy even when the product is not in use. Consumers often believe that their appliance is off, when in fact it is standing by and still consuming power.

For example, when you turn off a VCR with a remote control, it continues to consume energy in the standby or sleep mode because the power supply inside the VCR is still on, powering the remote control receiver. Even though the remote control receiver consumes very little power (approximately 0.1 W), power supplies that use inefficient technology such as linears, are not smart enough to reduce consumption during the standby state and end up wasting several watts of power. This is what we refer to as standby power waste.
What is no-load power waste?
No-load power waste is a subset of standby power waste. No-load power is the energy used by a device when it is disconnected from it's load and performing no function. For example, a mobile phone charger that is plugged into the wall, but not connected to the phone will still consume power. Linear chargers can consume between 0.8 W to 2 W even when they are disconnected from the phone.
Which devices use standby power?
Any device with an external power supply or (wallpack), remote control, or clock display requires standby power. Literally every electronic product that plugs into the wall such as TVs, VCRs, DVDs, washing machines, cell phone chargers, night lights, cordless and feature phones, refrigerators, cable TV decoders, satellite TV decoders, radios, computers, printers, monitors, fax machines, copiers, modems, audio amplifiers, industrial control units, motor controls, etc. etc. It is estimated that there are approximately 3 to 4 billion AC to DC power supplies world wide every year. The Lawrence Berkeley Lab Standby Power website has a chart on Standby Power Use By Device.
Why are standby power losses a problem?
While individual device standby losses may seem insignificant, when you multiply the number of households, by the number of devices in a household and the amount of time each spends in standby, the problem adds up quickly. It is estimated by International Energy Agency that 5 to 15% of household electricity consumption worldwide is wasted in standby mode. In the US, each watt of energy costs approximately $1 to $1.5 per year. The Lawrence Berkeley National Lab estimates that standby waste costs US households over $5 Billion in electricity a year. According to the Department of Energy, the amount of standby energy used per year in the US is equivalent to 26 average sized power stations!

As the popularity of home electronics and number of new appliances with electronic controls and features increase, this problem will continue to grow.
How can standby power consumption be reduced?
Up to 90% of standby power is wasted energy consumed by inefficient power supply designs and unnecessarily energized components. The Lawrence Berkeley National Lab estimates that a 75% reduction is possible in new equipment and that nearly all standby functions can be performed with a total appliance standby power of one watt or less. This can be achieved by using improved power supply technologies and designs, namely, by replacing inefficient linear power supplies with smarter switch-mode power supplies.
What’s wrong with the current technology -- linear power supplies?
Linear power supplies, also referred to as "energy vampires" because of their energy-sucking nature, work off of old technology from the 1800's, which hasn't kept pace with current innovation. Linear transformers use large iron cores and require many turns of copper wire in order to convert regular 50/60 cycle AC house current to the safer low-voltage DC needed to power our appliances and electronic devices. As a result, they are extremely large and bulky, often times covering two outlets on your wall plate or power strip. Moreover, linears do not have the smarts to recognize the standby or sleep mode of the appliance and cut back the consumption accordingly. As a result they consume many more watts than necessary. As a test, go feel one of the bulky linears plugged into the wall. It will be warm to the touch...those are wasted watts!
How are switch-mode power supplies better?
The second-generation power supply, called the switch-mode power supply or "switcher" for short, arrived in the late 1960s. By increasing the AC frequency from 50 or 60 cycles-per-second to several thousand cycles-per-second, engineers discovered they could reduce the size and weight of the transformer and significantly improve its efficiency (reduce the amount of energy wasted in the form of heat dissipation).
Why do inefficient linears still exist?
Despite being bulky and inefficient at converting power, linears are popular because they have become very cheap to manufacture. Until recently, under 5 W switch-mode power supplies haven't been competitive in cost and since product manufacturers don't have to pay the electric bill, there hasn't been an incentive to prioritize energy efficient designs. It's only been in recent years that governments and environmental agencies have started to develop standby energy policies that reward, or in some cases, mandate energy efficient designs.
Are there cost-competitive AND energy efficient power supply alternatives?
In 1998, Power Integrations introduced a revolutionary energy efficient power supply technology called, "EcoSmart®". EcoSmart enables a switch-mode power supply design to operate with much higher efficiency when in standby or when the load is not connected. Moreover, by using innovative integrated circuit (IC) technology, it finally allowed switcher designs to be cost-competitive with the linear transformer under 5 W. Through integration, external components are eliminated, lowering system cost and improving reliability considerably.
How does EcoSmart work?

ICs with Power Integrations' EcoSmart technology include extra circuitry on the chip (using no additional-cost external components) that senses when a power supply is in a low-power state (no-load or standby). The "smarts" in EcoSmart then takes one or more steps to improve the efficiency of the power supply in this state:

  • It lowers the "duty cycle", that is it limits the supply of power to the load, drawing less current from the electric utility
  • It "cycle skips", supplying short bursts of power to the load, waiting for the device to "wake-up," using electric energy only during each short burst
  • It lowers the frequency of the power supply, reducing the "switching losses," thus improving efficiency while in low-power operation


The above measures significantly improve the overall power supply efficiency because of two simple facts: power adapters, battery chargers and appliances are always plugged in; and the devices they power are typically in a low power state as much as 22 or more hours per day, every day. Since its introduction, manufacturers worldwide have adapted their designs to use Power Integrations' ICs in over one billion power supplies.

What power ranges are covered by EcoSmart?

Currently, Power Integrations produces EcoSmart products that cover the power range of over 90% of all AC to DC power supplies built worldwide using the following device families:

Device FamilyOuput Power Range (W)
0 to 5.5
TinySwitch-III 5 to 28
PeakSwitch9 to 45 (86 W Peak)
TOPSwitch-GX7 to 210
TOPSwitch-HX11 to 150