4 ms·

I mention power supplies in both the colloquial sense, but also the power supply circuitry - I know things like the ESP chips themselves don't use much power.

I mention power supplies in both the colloquial sense, but also the power supply circuitry - I know things like the ESP chips themselves don't use much power. As for my Google TV: the PSU is integrated, so I can't tell.

mordae 4y ago
You have it right. Many cheap always-connected smart devices use Low-dropout regulator (LDO). What does wiki say about these? > The advantages of an LDO regulator over other DC-to-DC voltage regulators include the absence of switching noise (as no switching takes place), smaller device size (as neither large inductors nor transformers are needed), and greater design simplicity (usually consists of a reference, an amplifier, and a pass element). The disadvantage is that, unlike switching regulators, linear DC regulators must dissipate power, and thus heat, across the regulation device in order to regulate the output voltage. See for example: https://templates.blakadder.com/athom_PG01EU16A.html https://templates.blakadder.com/athom_PG01EU16A.html You can clearly see an AMS1117 (a super popular LDO), right next to the ESP board on lower right. Most LDOs have a chunk of metal tinned to the board so that the copper layer can help with heat dissipation. You can quickly identify them by this design. Here is another one on a dev board: https://hallroad.org/images/watermarked/thumbnails/465/465/detailed/24/Espressif_ESP32_WROOM_32D_Development_Board.jpg https://hallroad.org/images/watermarked/thumbnails/465/465/d... More on the topic: https://www.digikey.com/en/articles/use-adjustable-low-leakage-ldos-to-extend-battery-life-in-wearable-designs https://www.digikey.com/en/articles/use-adjustable-low-leaka...
PaulHoule 4y ago
A device that's designed to handle 200W power peak might have a power supply which is 95% efficient, but it might be that you're paying that 5% all the time. (If, for instance, there is a big-ass transformer with a lot of iron in it you are making magnetic domains flip back and forth whenever the device is plugged in.) The standby mode might use 0.2W but the device burns 10W in the power supply. Old power supplies used ideas from analog electronics: if the voltage regulator was reducing the voltage from 10V to 9V then you are directing that extra volt (10% of the energy) into a resistor. More modern power supplies use digital ideas such that transistors are fully on or fully off. Because they waste less energy they have an easier time getting rid of heat, so they can be dramatically lighter and smaller... but more expensive. Other answers would be to add a second smaller power supply for the standby mode or run the standby mode off a battery or super-capacitor that charges intermittently. The cost of those improvements would definitely be noticed by the manufacturer and the consumer at the time of purchase. The consumer might not notice a small increase in the electric bill, even if it adds up to a lot over time, because it is against a high and noisy background.

mordae 4y ago

You have it right. Many cheap always-connected smart devices use Low-dropout regulator (LDO). What does wiki say about these? > The advantages of an LDO regulator over other DC-to-DC voltage regulators include the absence of switching noise (as no switching takes place), smaller device size (as neither large inductors nor transformers are needed), and greater design simplicity (usually consists of a reference, an amplifier, and a pass element). The disadvantage is that, unlike switching regulators, linear DC regulators must dissipate power, and thus heat, across the regulation device in order to regulate the output voltage. See for example: https://templates.blakadder.com/athom_PG01EU16A.html https://templates.blakadder.com/athom_PG01EU16A.html You can clearly see an AMS1117 (a super popular LDO), right next to the ESP board on lower right. Most LDOs have a chunk of metal tinned to the board so that the copper layer can help with heat dissipation. You can quickly identify them by this design. Here is another one on a dev board: https://hallroad.org/images/watermarked/thumbnails/465/465/detailed/24/Espressif_ESP32_WROOM_32D_Development_Board.jpg https://hallroad.org/images/watermarked/thumbnails/465/465/d... More on the topic: https://www.digikey.com/en/articles/use-adjustable-low-leakage-ldos-to-extend-battery-life-in-wearable-designs https://www.digikey.com/en/articles/use-adjustable-low-leaka...

PaulHoule 4y ago

A device that's designed to handle 200W power peak might have a power supply which is 95% efficient, but it might be that you're paying that 5% all the time. (If, for instance, there is a big-ass transformer with a lot of iron in it you are making magnetic domains flip back and forth whenever the device is plugged in.) The standby mode might use 0.2W but the device burns 10W in the power supply. Old power supplies used ideas from analog electronics: if the voltage regulator was reducing the voltage from 10V to 9V then you are directing that extra volt (10% of the energy) into a resistor. More modern power supplies use digital ideas such that transistors are fully on or fully off. Because they waste less energy they have an easier time getting rid of heat, so they can be dramatically lighter and smaller... but more expensive. Other answers would be to add a second smaller power supply for the standby mode or run the standby mode off a battery or super-capacitor that charges intermittently. The cost of those improvements would definitely be noticed by the manufacturer and the consumer at the time of purchase. The consumer might not notice a small increase in the electric bill, even if it adds up to a lot over time, because it is against a high and noisy background.