"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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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
76 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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0answers
29 views

Questions on RC Truck/Arduino/Endurance [closed]

I've googled, and searched - nothing too related to my question. I appreciate any help. I want to get an RC Truck (1/18 scale) or something to use as a Chassis - and control via Arduino/Bluetooth. My ...
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2answers
68 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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0answers
48 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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3answers
728 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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0answers
73 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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1answer
67 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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2answers
48 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
74 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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1answer
52 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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29 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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26 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
99 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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1answer
85 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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1answer
67 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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2answers
62 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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2answers
85 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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1answer
159 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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1answer
79 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 ...
0
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1answer
71 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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3answers
71 views

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
79 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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0answers
65 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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1answer
54 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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0answers
75 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
101 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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0answers
45 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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2answers
33 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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2answers
74 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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3answers
66 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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2answers
105 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 ...
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2answers
119 views

Capacitor leakage and design for low energy battery powered devices

For the design of a portable battery operated device, I have some power circuitry which requires a DC-DC converter and some other regulators, battery charger IC etc. While in the process of ...
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2answers
161 views

Operating an ATmega328P-PU at 2.5V

For my job, I was tasked with creating a board to interface with a 2.5V device we've made. So, to keep things simple, I decided to interface it with an ATmega328P-PU running the Arduino firmware at ...
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2answers
173 views

Looking for efficient battery supply to power 3.3V circuit

I have been searching everywhere for the best way to power my circuit and I can't find straight forward information. My circuit needs 3.3V and the maximum current it draws is 50mA. It will run at ...
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4answers
63 views

Options for semi-permanent memory in a low-energy setting

(Hopefully this will be broad enough to be on-topic.) I'm looking for options to store several megabytes of data over the period of a few weeks in a coin-cell powered application. The data doesn't ...
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1answer
72 views

Prevent EPROM powering from IO pin

I consider using a cheap Microchip 3-pin EPROM with single bidirectional data line as ID storage on various daughter boards. Since I don't want to waste daughter board connector pins on a device ...
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2answers
127 views

Opening MOSFET's gate with low voltage PWM

I have PWM of very low frequency and very low duty cycle. And max voltage comes out are 3.3. But thats not enough to open the MOSFET's gate(IRFP250N). Now I want to amplify the voltage. I do not have ...
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2answers
70 views

Low power ripple pulse counter

I'm trying to find a ripple/pulse/edge counter chip that can record rising edges from a wind anemometer while my AVR sleeps. The signal is typically 0-50 Hz. I want to read it every 10 minutes, so it ...
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0answers
47 views

Why would a buck regulator continue to draw current when EN was off?

I've got a board with two regulators on it a TPS62125 (to power the whole board) an LM2734 (to power servos) For the purpose of this test, the EN pin of the LM2734 is pulled down to ground with a ...
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0answers
316 views

STM32F030 RTC wakeup from stop mode

I'm writing an app, that most of its time will spend in STOP or STANDBY mode (battery powered microsystem). I'd like the internal RTC to wakeup my STM32 every 5 minutes, enter the ISR, do its tasks in ...
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10answers
3k views

Avoiding DC voltage drop over long distances

I am trying to power my IP camera over a long distance from the power socket (about 10m). The included power adapter, rated for 5V 2A is about 1.5m long. I cut the cable and extended it using a ...
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3answers
619 views

ATtiny85 power consumption double expected

I'm trying to get an ATTiny85 to run off a battery. I have it clocked from a 16.384 MHz crystal, with the divide-by-8 fuse set. Vcc is 3.3 volts. Figure 22-7 in the datasheet says that at idle ( ...
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1answer
117 views

Shutdown mode in si4010 microcontroller

I'm working on a project with si4010 microcontroller plus a battery and I want to save power, so I have to enable the shutdown mode. I need to wake up every 1s and do the process and then go back to ...
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4answers
125 views

Very low-quiescent (<2mA), 5V, simple “speaker” driver

How can I drive a 30ohm speaker from a 5V microprocessor in a simple, very low quiescent-current (<2mA) manner? The "speaker" is actually a coil, not a speaker - and I'm trying to induce a ...
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4answers
418 views

What are some of the segmented displays with the lowest power consumption?

I have to select a low-power display for a solar-powered digital clock. I have looked into numerous technologies, including e-ink. However, I was still unable to compare between them due to the lack ...
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1answer
327 views

PIC32 sleep mode with watchdog wakeup failing

I am in the process of trying to get a PIC32MX795F512L to run with lower power consumption. I'm trying to get it to enter sleep mode and then be woken by the watchdog timer. All pretty standard ...
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80 views

powering a micro in sleep mode

I've got a setup that will spend 1/3 of its time running a few servos (figure up to 1A @ 5V), 1/3 running sensors / other (<300mA @ 3.3V), and 1/3 of its time sleeping with just the watchdog ...
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2answers
83 views

Is it safe to not power this USB to I2C chip when USB isn't plugged in?

I am working with someone on a data logger based on an MSP430. Since it operates on battery power, we want the device to use as little power as possible. We are planning to use this chip (FT201X) to ...
2
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2answers
560 views

ATmega328P running on CR2032 has issues with timing/sleep code as voltage depreciates over time

I have an ATmega328P running at 16 Mhz on CR2032 with a few sensors and radio for about a week now. It started out at 3+ Volts and is currently measuring at 2.96 Volts. At present, I am not using ...