"low-power" refers to components and circuits which are designed to have a lower power consumption than their common counterparts. This is most often a requirement because of limited available power, as in battery operated devices.

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Qualcomm and phone power comsumptions

There are some links about qualcomm and phone power consumptions: http://www.notebookcheck.net/Qualcomm-Snapdragon-800-MSM8974-SoC.103706.0.html ...
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Can I dynamically change STM32 voltage during runtime

I'm using an STM32L151 MCU for a battery powered wireless sensor node. I came across the TPS6274x series switching regulator, who's voltage can be reconfigured at runtime by flipping it's inputs. The ...
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68 views

Use GPIO to disable voltage divider

I'm using a voltage divider to read the battery level of a wireless sensor platform using STM32L151. I'm shooting to use 20k for R1 and 10k for R2, to be under the 50k limit of the MCU's ADC ...
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71 views

MSP430 waking up every millisecond, what power usage to expect?

I have an MSP430 waking up every millisecond from a timer interrupt (to do a tiny amount of work, ie increment a counter and check a couple of input pins). It is set up to run at 25MHz. What should ...
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12 views

How to send the RC522 RFID reader into sleep mode?

I'm trying to get the power consumption of a MFRC522 RFID module down, currently while running it consumes about 4mA. There should be a way to put it into sleep mode, I just can't find any ...
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25 views

LPRF design on 4 layers

Developing a new design on a 4-layer stack with reduced dimensions, there are some doubts I expect you can help me with. The board includes RF part, MCU, voltage regulator & battery charger. ...
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57 views

Measuring GameBoy power consumption

I am currently developing my own homebrew GameBoy game and I would like to try some tricks to reduce power consumption (for the sake of learning). The GameBoy has a HALT instruction that will stop ...
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2answers
79 views

Passive voltage drop from 6V DC to 5V DC for 3W circuit

I plan to put an Arduino onboard of my hub-generator powered bicycle circuitry. Currently, I have a circuit consisting of: 6V/3W AC hub generator (variable frequency and power); Rectifier bridge; ...
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36 views

low current buck converter

Just trying to find a suitable buck converter for my application, which is running off ~10-50V (12/24/48V battery banks) and supplying normally a very low load microcontroller (~1mA) but occasionally ...
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45 views

Loudest Piezo with low voltage and current?

I am making a board which will communicate wirelessly with a smart phone. When I send a specific command, I want it to sound an alarm to the user, making it able to be found when lost. I've got ...
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1answer
58 views

How do simple low power devices store setup when switched off?

I often come across battery powered items that store their state when switched off, particularly 'simple' items like LED bicycle lights (e.g. flash or solid light, changing each time it is switched ...
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45 views

Maintaining DC voltage with more batteries

I have a circuit which i am powering with two 1.5V AA batteries that dies at 2.6V volt as the battery discharges. Reading around, i realized that even though there is energy in the batteries, my ...
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28 views

Choose between Bluetooth Low Energy advertizing and connection for low-power small-data application

I have several sensors running on coin batteries, which are supposed to send data to a central device periodically. The data size is small: the meaningful data should be a few bytes excluding the BLE ...
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42 views

Low power design

I'm working on a project, it consist to collect data from sensor : HTU21D for humidity and Temp (digital I2C) LDR for light (Analog ADC) Potentiometer for adjustment (Analog ADC) communicate the ...
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45 views

MP3-25 flexible solar panel providing low current

I am working on a project where I need about 20 mA to come from a particular solar panel I am in possession of. The solar panel is an MP3-25 panel, I actually have 2 which I am trying to get to work. ...
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1answer
52 views

Role of Capacitors with additional power regulator

I have a a 7805 voltage regulator that has a capacitor on input and output. The 5v from that regulator is then elsewhere in the circuit stepped down to 3.3v with another regulator. I am wondering if ...
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47 views

Is it possible to produce 1 Hz flashes from a “joule thief?”

The joule thief circuit below produces a high-rate flashing LED. How can I slow the flash rate down to approximately 1 Hz? ...and will this be as efficient as a simple hex Schmitt inverter with a ...
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1answer
67 views

Power regulation and isolation for low current device

I'm looking for a solution to regulate power and provide isolation for a 3.3VDC system. I am using a 5VDC 500mA power supply that needs to be regulated to 3.3VDC with isolation to protect analog ...
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37 views

isolated voltage

I am looking to add an isolated 10-12V supply capable of producing ~200mA to an existing circuit which has 5V and 12V rails available on the board. I would prefer to use the latter (12V) as it can ...
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62 views

power supply and transfering data from smartphone via jack 3.5mm 4pin

In my Project, I was wondering if I can use the 3.5mm jack (4 pin) to transfer data and as power supply to my small circuit? So I'm just asking if it's possible? and if yes, can someone tell me how ...
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2answers
88 views

Help please! I need to give constant current to an LED from a Lipo battery

I'm trying to drive an LED from a Lipo battery. The useable voltage range of the Lipo goes from 4.2V down to 3.4V, and the forward voltage of the LED is 3.2V. With a resistor in series with the LED, ...
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2answers
82 views

Shut down regulator during sleep

I'm working on a wireless sensor network and would like to know what it would take to shut down the regulator during deep sleep. MCU: STM32L151C6T6 Regulator: TPS63001 Radio: RFM69HW LCD: some ...
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54 views

psIsolation Transformer DC 12 volts

I want to use 12 volts DC and step it up to 400 volts AC or higher at 100khz. I am buiding a signal generator that outputs a sine wave or square wave with an adjustable frequency of up to 100 kHz. I ...
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821 views

Simple, efficient “breathing” LED circuit

I'm currently working on a small circuit, which I intend on running off a CR2032. The intent is to have the circuit last at least 2 weeks (the longer the better), pulsing a green LED every 3 seconds, ...
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89 views

Dual redundant 1.5V battery power system?

I'm trying to build an efficient way to connect two 1.5V alkaline batteries in a redundant configuration for my circuit. I only want one battery to be supplying power to the circuit at any given time. ...
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73 views

Should I use a voltage regulator?

I'm powering an attiny45 from a single lithium ion battery; that when fully charged should have a maximum voltage of ~4volts and will be cutoff at 3volts. I was thinking I should be safe to just ...
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85 views

Low voltage cutoff circuit

I'm powering an attiny45 from a lithium ion battery; using these batteries the voltage cannot get below 3volts or it will damage the cell. How should I go about cutting the voltage out? Software, or ...
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2answers
96 views

How to regulate a 3.6 V battery to two power rails (3.3 V and 1.8 V)?

I have a 3.6 V battery from which I need two voltage rails, one that is 3.3 V and one that is 1.8 V. How should I design this circuit such that it is the most power efficient? Here is what I was ...
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87 views

Wide input voltage range buck converter/circuit to 3.3V 150mA

I am building an appliance that should work in very wide range input voltage: In some scenarios input is 5VAC, in other scenarios it can be 250VAC. It's not a problem to convert AC to DC, then ...
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31 views

safely cutting power to ICs and analog subsystems

I'm developing a wireless sensor node, which will be deployed in very remote locations. I'd like to be able to cut power entirely to some power-hungry ICs or subsystems using a power mosfet with low ...
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36 views

Low power, low duty cycle, full speed dc motor timer

I need to drive a 12v dc motor drawing 300ma under load. It only needs to run about 4-5 seconds per min. But the run and idle times need to be adjustable with some degree of accuracy. Once ...
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1answer
114 views

Why does the A8 have twice as many transistors than the Haswell processor yet runs on less power?

There's something I don't get - I am always under the impression that the more transistors we pack in, the more energy it consumes and the hotter it gets (assuming we haven't shrunk the die). However, ...
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133 views

Adafruit Trinket Solar Power

I'm curious if anyone has experience with getting a simple board like the Adafruit Trinket or DigiSpark or any of the other ATTiny based clone boards running on solar power. E.g. with a solar panel ...
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93 views

Minimising current consumption in a PIC

I'm using a PIC16LF1554 with a simple soil moisture sensor to remotely monitor houseplants. The sensor circuit will be powered by a coin cell and will spend most of its time asleep. It will wake ...
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69 views

Using a DC Power Analyser properly

In the context of an academic project, I designed a PCB which includes an MCU (EFM32), a GSM module and a GPS module. One of the main target was for the system to be low power. However, now that it is ...
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107 views

Power Efficient GSM modules

I am developing a Kit with GSM module which have to receive and send commands. I have gone through many GSM modules(SIM900). All of them consume around 1.5A at burst time. So I am in trouble to ...
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279 views

How does a smart phone measure the battery power?

A smartphone (assume Android) usually displays the battery percentage from 0 to 100%. I am assuming this is the usable power capacity of the battery. I have several questions: 1) How exactly does it ...
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103 views

Ultra low current pulse generator (for BLE module interrupt)

At the moment I'm working on a project with at BLE-module. This module is based on the CC2541 from TI. I want the BLE-module to permanently transmit a signal. This module has two modes: a level- and ...
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1answer
89 views

STM32F4xx - Can EXTI_GenerateSWInterrupt() Wake Up Processor from Stop Mode

As the title states, can the function EXTI_GenerateSWInterrupt() wake up the processor after it is put into a low-power mode using the PWR_EnterSTOPMode() function? The documentation says that an ...
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What is the maximum battery lifetime for a sleeping microprocessor? [closed]

I know it depends on the processor and the battery, I just want to know what's possible. [EDIT:] An example would be great!
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1answer
89 views

LED Mini Bulb Project wiring issue

OK, working on a project that would require the use of only one LED or mini bulb from a Christmas tree string of lights. I understand I can't use them direct from 110 volt or it will blow a circuit or ...
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103 views

STM32F4xx WFI unable to sleep due to SysTick Interrupt

I am trying to add some power conservation to our STM32F4xx powered device using its WFI sleep function. However, whenever I call the WFI function, the system is not being put to sleep (or rather, it ...
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57 views

Small system on a chip : Power consumption [closed]

This question is lying somewhere between electrical engineering and computer science, however I felt that this forum suited my question the best. I post this question because I feel that this kind of ...
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76 views

Low power Cmos Op-Amps

I recently designed a 2 stage micro-power op-amp in Cadence Virtuoso with an open-loop gain of 36dB. I checked the voltage swing in open-loop and got a full swing from 350mV to -350mv for a dual power ...
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2answers
103 views

How to start LED wirelessly in a very compact and cheap module?

I have been thinking and researching about this issue for a while with no success. I am hoping someone can solve this problem in the community. I want to have many small modules each with a small ...
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46 views

Low Accuracy GPS/Low Detection (e.g. detect country or state)

I'm making something to go with an electronic compass so I can always point to a certain (non-true north) location. To do this, I want to detect what state the user is in, and look up an approximate ...
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39 views

how many 74LS low-power Schottky inputs can an output of MC9S12DG128 drive?

I need to figure this out for a project and can't seem to find the answer. Does anyone know how I can figure this out? I think there is an equation to find this and can't seem to find the ...
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88 views

Prevent loss of Large Signal Voltage Gain at low Rload

Operational Amplifiers (opamps) have the tendency to drop their Large Signal Voltage Gain when the load is too low. This behaviour is usually described in the datasheet. Loads of 500 ohm and lower ...
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70 views

Is it detrimental to an SMPS to turn it on and off frequently?

I've got a 5V SMPS powering two separate servos: and The smps is a tps562200 The application is an autonomous sail boat (3 feet long). One's a winch, the other a rudder. I have code that scans ...
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123 views

Measuring power consumption of a design ranging uW to tenths of mW

I want to measure the power consumed by my design ranging from uW to tenths of mW. Power values I wish could be recorded digitally so that I can use them for analysis later. May be another form is ...