# Questions tagged [low-power]

Low-power refers to electronics that are designed to use less power than their common counterparts. This is often a requirement because of limited available power, as in battery operated devices, or in cases with limited cooling capabilities, as in notebooks.

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### Help with voltage doubler in a WPT application

I need some help with this schematic to have higher voltage at Vrect. This is for charging a receiver at 25 mm in a WPT application. I was expecting a voltage of 2Vin at the output of the voltage ...
110 views

### Ultra low power 1 digit LCD [closed]

I have a very weak power supply (Fuel cell) and I would like to connect it to power a 7 segment LCD. The reason I am connecting the LCD is to use it as an indicator to see the increase and decrease in ...
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### Is it possible to increase the current of an Arduino Nano 3V3 pin without altering the voltage?

I am trying to use an ESP8266 with an Arduino Nano but I see that the NANO can not enough current for supplying ESP8266 from 3V3 pin. I think it is limited from the faactory. If I use the 3V3 pin RX ...
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### What are the names of screens used in "Basic calculators"?

I was trying to power a basic calculator that day with a power source and I started from 0V going up to 1.5 v I noticed the calculator screen turning out to show a "0", but I could not do ...
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### Bodyheat powered microcontroller

Old Post and even older Post I came across before posting this question. The answers by McMahon and Alexeev are pretty much what I was thinking: human energy source: ~100 W skin surface: ~1.75 m2 ⇒ ~...
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### Low power way to extend a short pulse [closed]

How would I extend a short active high digital pulse (around 1 us) to about a couple of ms with few uA of current consumption? The exact time of extension isn't important. I am working in the 3.3V ...
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### For a mathematical operation in CPU, could power consumption depend on the operands?

Obviously, the number of operations affect a CPU's power consumption, but does it solely depend on the operations themselves? For example, adding 0 and 1 involves setting one single bit, but adding ...
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92 views

### STM32 Low Quescient Current Power Supply

I want to find the most efficient way to power an STM32 microcontroller from a lipo (3.7V nominal). I have calculated that @ 3.3V, the current consumption is approximately: in run mode:1.75mA in idle ...
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### Is dynamic power in a chip independent of power characteristics (typical vs. maximum)?

The Intel FPGA Quartus Power Analyzer (QPA) tool can estimate the dynamic and static power dissipation, depending on setup of the device characteristics, including toggle rate to estimate dynamic ...
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### Low Power Consumption with Ultrasonic Sensor (US-100, HC-SR04)

I have designed a Zigbee sensor to measure the water level in the cistern. It should be operated with batteries, so the ultrasonic sensor should only be activated for measurement. With the current ...
45 views

### USB Data Line Current Value

I am designing USB2.0 hardware input but i don't have enough space on my PCB area. I searched many site but I cant find any information about D+ D- data lines power consumption. I am using 15R ...
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63 views

### Power 5V and 3.3V components from li-ion battery

I want to make a portable device that runs of a rechargeable li-ion (4.2-2.7V) batteries. I have components that run on 3.3V (ATmega328P ,GPS) and some LEDs (5V.) There are multiple ways I can think ...
73 views

### Buck-boost converter (LTC3442) not producing output until excited

EDIT: Added datasheet for the inductor and some oscilloscope measurements. I'm using a LTC3442 buck-boost converter from Linear Technology / Analog Devices (datasheet) in my design to produce a 3.3V ...
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### STM32F030 High current in stop mode

I would like to put STM32F030K6T6 into STOP mode (low power mode), in which there should be current consumption around 5 μA. But whatever I do the current consumption is around 450 μA in stop mode. ...
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### Why does modulo operation consume more power?

I mainly use Cortex-M4F or Cortex-M0/0+ devices such as: STM32L4, G4 STM32L0, G0 I sometimes see blogs like this one saying "Avoid Modulo" for lower power consumption. Comparing these two ...
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### LiPo cell as RTC backup battery

I am wondering what is the sensible way of using the LiPo cell that powers a handheld device to also act as the RTC backup battery for the MCU. There is charging circuitry for the LiPo cell on-board ...
• 136
944 views

### Why does lower frequency require a lower voltage to drive a logic value?

Dynamic frequency scaling almost always appear in conjunction with dynamic voltage scaling, since lower frequencies require lower voltages for the digital circuit to yield correct results. The ...
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### Interfacing a microcontroller to a PDM microphone via DMA and low power

I need to interface a low power PDM microphone (Vesper VM1010) to a low power microcontroller with ZigBee support. For the latter, I've settled on Silicon Labs EFM32 Gecko, primarily due to its ...
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93 views

### Dropping voltage from battery supply for low current application

My battery might supply 3.7 V, while absolute maximum for an IC it is supplying is 3.55 V and lowest operating voltage is 2.65 V. The IC is at sleep most of the time, consuming 10 nA. Every now and ...
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### Am I calculating/considering linear regulator voltage ripple correctly?

I need a clean and power efficient -1.22V supply for a ADC driver fully-differential op-amp, the main power source will be a Lipo battery cell. I'm considering ADM8828 followed by a LT1964. The LT1964 ...
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### Low current, +- 20V supply from 5V [closed]

For my application I need +20V and -20V, at a low current, 10mA but probably 1mA might be good enough - difficult to say until I try. I start with 5V provided by a common USB power supply. I have read ...
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### Chip for power management [closed]

I am working on a project which is powered by a 24VDC power supply. My plan is to replace the 24VDC power with a battery. To make the battery last long, I am planning to auto shutdown when ...
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### Switching Polarity from 12V Voltage Regulator Pair with MOSFETs

I'm trying to make a low-power (<30 uA) voltage boost board to boost a 3.7 V battery to 12V, that includes the capability to reverse polarity at a very low frequency (alternating every ~10 min), ...
49 views

### Achieving low power with Seeeduino Cortex-M0+ powered from 12V battery

I hope it's OK to cross-post this question: https://arduino.stackexchange.com/questions/88618/achieving-low-power-with-arduino-zero-clone-seeeduino-cortex-m0. I'm getting a bit desperate. I have ...
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1 vote
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### Ultra Low-Power H-Bridge (micro Amp)

I'm working on a project to drive a pair of electrodes, one at 12 V and one at 0 V, with a very low-frequency polarity change (every 10 minutes). The current draw across the electrodes peaks at 200 uA,...
1 vote
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### Power input management help?

I'm working on a power supply management circuit for a small 30 mW device powered by alkaline batteries for months in remote locations, used by both skilled and unskilled users. The device will have ...
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### Understanding shutdown mode in STM32L47

I am using an STM32L476 for my application and want to use shutdown mode to conserve the battery life of the device. I was going through the reference manual and found the following: Shutdown mode: ...
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### Detecting cut wire (tampering) for low power project

I'm trying to develop a cut wire detector that will be used in order to detect if a specific wire is broken or not (a.k.a fake bomb). I'm using an ATMEGA328P running on batteries (3V) at the internal ...
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### UPF: UPF_SCOPE_NOT_FOUND_ERROR

I am trying to write a upf for the ARM architecture. My test bench and rtl are pretty straight forward. ...
1 vote
161 views

### SIM7020 current consumption way too high

For a project I'm using the SIM7020 Narrowband-IoT (NB-IoT) module to send data to the cloud. The SIM7020 is controlled by an Arduino Pro Micro (ATmega32U4). Because the sensor is running on a ...
1 vote
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### ESP32-WROVER-E low-power custom board validation

I recently finished my degree in Electronics Engineering. My experience with that degree is that you learn a lot of things, but you don't go really deep into any subject. So I'm trying to solve that ...
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1 vote
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### How can I get different voltage inputs from a high voltage power supply?

I want to use a 5 kV DC supply to power a low-current (0.5-3.5 mA) circuit in a microfluidic device. I would like to create two input voltages from this power supply to have a 300 V drop from 4.3 kV ...
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I was wondering if the following is possible: I was hoping to be able to do the above with my USB 2.0 10m active extension cable as I cannot find a Y version of the same cable, to simply cut the male ...
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### Fudan FM33LG048 microcontroller draws too much current in deep sleep mode

I am working with Fudan FM33LG048 low power microcontrollers. Despite turning off all clocks except low frequency external oscillator, disabling all peripherals, and entering to the deep sleep mode ...
1 vote
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### Converting a range on high side to a range on low side for very precise voltage sensing in ultra low power application

I have an ultra low power design running on CR2032 where it is critical to monitor precisely the current usage and the primary cell voltage during dev. So I added a second MCU dedicated to ...
44 views

### Automatic LDR switching circuit

I would like to create an energy efficient LDR evaluation circuit. The circuit should provide the possibility to connect an external LDR (R8) or use an internal, permanently installed LDR (R25). When ...
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### LPDDR on separate replaceable modules / boards - possible? drawbacks?

I've read that LPDDR is more efficient in active states and times more energy efficient than DDR in inactive states, e.g. in Performance vs power in off-chip DDR SDRAM, there is a mentioning of ...
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### How to make an A.C. voltage source (low voltage) with desired frequency from a D.C. source?

I want to make an A.C. source with desired voltage and frequency (adjustable) from D.C. sources like batteries. I tried to search circuits on the internet, but as I am relatively new in the field (...
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### Which circuit to maximize power at regulated 3V3 DC from low power 6VAC/20mA source?

The power output of provides a guaranteed 6VAC/20mA/50kHz minimum output into a resistive load with fluctations possible up to 12VAC. Other loads are not specified. The output impedance is not ...
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### How does a doorbell work?

I'm trying to make my own smart doorbell with the same wiring of our current doorbell. So I'm investigating how the bell does work now. So part of the bell gong I know how it works but how does the ...
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59 views

### Standard equation for delivered power from synchronous generator wrong for fractional kW machines?

When synchronous machines get to a certain size (in the $MW\hspace{-0.8mm}s$) the armature resistance is a lot smaller than the synchronous reactance, $R_A << X_s$, because of this $R_A$ ...
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232 views

### Can I control IRFZ44N Mosfet directly from 5V microcontroller?

I know that IRFZ44N is not a logic level Mosfet, but I need it to control only 12v 1.2A (14.4W). Can I control it by applying only 5V on gate from an atmega microcontroller? I checked the datasheet ...
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### Isolating low-current, low-voltage digital signals

I'm working with a battery-powered sensor that allows reading its measurements using two digital signals - a clock and a data line. The clock speed is abount 3kHz. In addition to those two signals, ...
128 views

### Decoupling Capacitor on GPIO instead of connected directly to battery

I am building a device that is for most of the time in sleep mode. When woken up, I am sending some BLE signals and use a LED. To support the battery I have a 2u2F capacitor. But because my battery is ...
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### Can I split my positive supply voltage into a positive and negative voltage for better energy-efficiency?

I have a question about an idea of mine, concerning the split up of a 5 V supply voltage into a 3.3 V and a -1.7 V voltage. My circuit has to be as efficient as possible and therefore I don't want to ...
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### Why is my measured leakage current of the capacitors much lower than my calculated value?

This is more a theoretical question. I have a DC circuit with multiple capacitors with different voltages. Because I need to know how much current my circuit needs over a longer time, I calculated all ...
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337 views

### Use a MOSFET to switch on/off power supply for a low power microcontroller

I am trying to develop a circuit that can switch on and off the power supply for a microcontroller. I have around 0.2 - 0.7 V which I can generate to control the electronic switch. My idea was to use ...
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### How to make force sensitive resistor energy efficient?

I'm trying to sense when pressure stops being applied between two surfaces with a small embedded device connected to a coin battery smaller than 50mAh. All I care about is if they're separated or not (...
172 views

### Using a MOSFET to power LED for low power applications

I'm creating a low-power IoT sensor node and I wanted to place some LEDs on my PCB. The chosen LED has a forward current of 2mA, which my MCU can easily supply, however I was wondering, as saving ...
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