Skip to main content

Questions tagged [ldo]

A Low Drop-Out or LDO regulator is a DC linear voltage regulator which can operate with a very small input–output differential voltage.

Filter by
Sorted by
Tagged with
1 vote
2 answers
81 views

Voltage unexpected noise

I'm quite new to the electronic designs so might have made some horrible mistakes in the below circuit. It works as expected but it has a problem. The voltage at the output has some sort of noise ...
Marcin Pluta's user avatar
1 vote
2 answers
63 views

LDO vs voltage reference when input signal is noisy

I am designing an active EMI-filter (AEF) with an op amp (LTC6227). The AEF suppresses noise from a DC/DC converter. Ther op amp requires a supply voltage of 9V and a reference voltage of 4.5V at the ...
Schafa's user avatar
  • 11
2 votes
1 answer
86 views

Implementation of Circuit in AN104 for Load Transient Test

I have been testing the transient response of line regulator simply with a MOS and the resistor, this method, however, cannot generate arbitrary current and the current is not accurate. To improve the ...
cc Lau's user avatar
  • 23
0 votes
0 answers
22 views

How to stimulate PSRR of LT3060-2.5 and LT1761-2.5 in LTspice?

I tried following the steps on the analog devices website but it seems that with these components the results are not close to the datasheet while when I try this method with others it works. Do you ...
Phạm Sáng's user avatar
0 votes
2 answers
63 views

Inrush current: Additional capacitor or NTC to handle voltage spikes?

I will power an ESP32-S3 using a LDO (MCP1825S) which will require a 1 µF capacitor on the input and a 10 µF capacitor on the output. Both of them are ceramic ones, so typically have a low ESR: In a ...
Tintenfisch's user avatar
4 votes
3 answers
421 views

NCP1117 (3.3V LDO) with ceramic and aluminum electrolytic capacitors

For my ESP32 project I want to use a NCP1117 3.3V LDO and soon the question came, which capacitors are suitable if the LDO is driven either by USB or a 5V power supply while the cable length is about ...
Tintenfisch's user avatar
6 votes
5 answers
2k views

Best way to halve 12V battery voltage for 6V device, while still being able to measure the battery level?

I have a device that is powered by 4 AA (4x1.5V=6V) batteries, but I want to power it with a 12V battery. The device measures its input voltage to determine the battery level. I only need to know if ...
Juicer's user avatar
  • 377
0 votes
1 answer
58 views

Darlington NPN preregulator for LDO step down 42v to 12v ~ transistors keep blowing up

this is a follow-up from the original post about this circuit which can be found here. the purpose of this circuit is to reduce the voltage to a lower level that is more palatable for the LDO. and it ...
ManeGote's user avatar
1 vote
1 answer
91 views

DC-DC(Buck) shuts down when LDO enabled (intermitent)

I've encountered a problem on SOME of the boards in pre-production batch, when the boards main 5V rail generated by a buck dc-dc converter shuts down at the moment when one of the loads generated by ...
MMG's user avatar
  • 41
1 vote
1 answer
63 views

Analysing 42v to 3.3v DC converter circuit & component identification

I'm analysing a circuit responsible for generating 3.3v for a stm32f103c8t6 on a battery management system(10s). Its a completely proprietary battery management system with nothing online about it so ...
ManeGote's user avatar
-1 votes
1 answer
60 views

Power two microcontrollers with different voltages from one power supply [closed]

Background: We want to extend a Lasertag blaster with a Raspberry Pi Pico microcontroller (and more peripherals, e.g. LEDs, IR TX & RX, buttons). Goal: Use the existing 4xAA battery source (6-7V). ...
Felix S's user avatar
  • 99
0 votes
0 answers
41 views

When a typical fixed output voltage LDO is unpowered, is the output pulled to ground or is it floating/high impedance?

I am wondering since in a design the gate of a PMOS is pulled up by the output of a voltage regulator. Since the source of the PMOS still sees voltage on its source in that condition, I don't know if ...
TnF's user avatar
  • 151
0 votes
2 answers
53 views

Problem in powering up esp32 with MIC29302 IC regulator [closed]

I am trying to power the esp32 with the mic29302 regulator. I have used ams1117 for various applications but in this particular circuit I need more current (2 A) so I switched to mic29302 which can ...
pouya nosratkhah's user avatar
2 votes
0 answers
87 views

Help me optimize common collector transistor amplifier for two quadrant LDO

I need some help with a circuit I can’t find much information online. Basic function should be a LDO which can source and sink current. To make it a bit more challenging there are some further ...
huababua's user avatar
  • 115
0 votes
1 answer
68 views

Help needed in LDO design

I am trying to design a linear regulator. I started with a macro model for the error amplifier and added a pass stage. 50mA idc is the load. My desired output is 1.5V and Vin=1.8V. IBM180nm models. ...
desi_noob's user avatar
0 votes
1 answer
40 views

SMPS Controller Max Output Voltage

I am designing an SMPS circuit and I am using a ready SMPS controller. In the datasheet, the ADP2303 Datasheet input range is given (3-20V) ± 1.5% output accuracy over temperature Output voltage down ...
Electronx's user avatar
  • 756
0 votes
1 answer
77 views

What's the best way to make sure I have a known VCC on a battery powered device?

I'm making a portable device (well not really portable, but intended to be set up away from mains power) powered by AA batteries. I need a stable VCC as I have displays that I don't want the ...
Steam Ranger's user avatar
0 votes
2 answers
28 views

SGM2052 LDO Vbias pin connection

I am using SGM2052 LDO in my design. Using its fixed voltage version.In the datasheet you can see that it has a pin called Vbias. The description of Vbias is given below. Below is the typical ...
Confused's user avatar
  • 2,593
0 votes
0 answers
36 views

GPIO and LDO voltage slightly increases when other GPIO enables load

I have a circuit in that GPIO_1 (yellow trace) is generating repeating signals to control an NMOS and GPIO_2 (green trace) is controlling an LED driver (buck DC/DC) load via an NMOS switch. When a ...
Travis Su's user avatar
  • 245
0 votes
0 answers
76 views

Protecting negative power rail

I don't trust my power supply and want to protect my circuitry from over(under)-voltage, but cannot find a clear path of going forward with negative power rail. LDO which I use (LT3094) is rated for ...
Andrejs Cainikovs's user avatar
0 votes
1 answer
78 views

SPX3819 LDO output drops very low under small loads

I am troubleshooting a LDO that drops the output way down from 5V when put under very small loads. With a 100 Ohm load, it will typically drop below 4V, for example. Varies from board to board. In one ...
BobaJFET's user avatar
  • 1,012
0 votes
1 answer
189 views

Why is this LDO circuit not working?

I am trying to generate 5 V with this circuit for a load of 100 mA with a 2% tolerance in the output voltage. I don't want to use LDO ICs due to various reasons. My intention here is to enable/disable ...
Embedded Enthusiast's user avatar
0 votes
1 answer
76 views

Enabling power supply using microcontroller: schematic review

I am using two regulators in my design. They need to be enabled by a microcontroller. The microcontroller is working at 5 V. The regualtor P/N is a TPS62160QDSGRQ1 and the microcontroller is an ...
Confused's user avatar
  • 2,593
0 votes
1 answer
50 views

A stable very low-voltage reference generator (a very low-voltage LDO design idea) [closed]

Essentially, I have a voltage which varies between 0.15 VDC to 0.25 VDC, and this feeds into a system whose output is varying because of this variation at the input side. This is summarized in the ...
Debugger_Op's user avatar
0 votes
1 answer
86 views

Adjusting LDO voltage with a transistor

I'm designing an LDO power supply that is adjustable, I want to be able to switch between two output voltages using a MCU. I've designed the following circuit but can't test it as the parts are on ...
Ratti3's user avatar
  • 3
1 vote
1 answer
112 views

Single Ended to Differential Conversion with Opamp and Correct DC Biasing Method

First schematic below is the initial gain stage of the intermediate signal generated by mixer of radar. It is passed through sallen key high pass filter. Second schematic for differential to single ...
Cenk's user avatar
  • 75
6 votes
3 answers
452 views

Low LDO output capacitance (stability)

I need to replace the REG104 LDO (End of life) in a circuit where the max. allowed LDO output capacitance is 100 nF because of explosion proof intrinsic safety requirements. The REG104 LDO is stable ...
Stefan Wyss's user avatar
  • 7,653
1 vote
1 answer
47 views

Can I pull out 3.5W from an SOT223 LDO?

I'm building an LED array and I need to supply it with 12V. Each LED is in parallel, so I first want to drop out the voltage to 5V. The total intensity that would come out from the LDO would be 1A and ...
Gabriel Corrales's user avatar
0 votes
1 answer
82 views

Reverse current into DC/DC or LDO

Suppose we have a generic scheme like this in figure, in order to protect the inputs of a microcontroller or logic gates from overvoltage essentially. For instance now we're applying 10 V at the input,...
Gigapel's user avatar
  • 61
0 votes
2 answers
83 views

Current into DC/DC or LDO doubt

I need a circuit that regulate and invert the input signal 0-24V to 0-3.3V of output signal. Also a pullup that produce a low signal when the input is detached. I thought about a schematic like this. ...
Gigapel's user avatar
  • 61
0 votes
1 answer
64 views

How can I separate the switched-mode power supply from the RF PCB to avoid interference?

I want to construct an autonomous RF PCB module powered by a solar panel. To achieve this, I have obtained solar harvester and battery charger integrated circuits (ICs) designed to charge a Li-Po ...
Atrahasis's user avatar
  • 185
2 votes
0 answers
554 views

Powering loads with Milwaukee M18 power tool batteries

simulate this circuit – Schematic created using CircuitLab I'm trying to make a simple circuit to use a Milwaukee M18 18V power tool battery to power high-current loads. I want this circuit to ...
Tool_Scientist's user avatar
0 votes
0 answers
138 views

Choosing LDO to power ESP8266 on lithium battery

I want to power ESP8266 on lithium battery with a PIR sensor and have a small solar module to charge the battery, there is also weird looking 3pin transparent light sensor that by guess testing I ...
asim's user avatar
  • 600
1 vote
1 answer
92 views

Is the ouput of a given LDO high impedance when the LDO is shutdown

If a LDO is in shutdown, is the output of the LDO high or low impedance? Specifically for the LT3065.
GHE's user avatar
  • 11
0 votes
1 answer
167 views

How to create a power latching circuit without to exceed the GPIO specifications of an battery driven esp32 for a zero current power consumption

I want to operate an ESP32 with a 9V battery pack. In-between there is power latching circuit which is responsible for feeding a LDO voltage regulator with power for the micro controller module (ESP32)...
playmobox's user avatar
  • 105
0 votes
1 answer
89 views

LDO LM317HV Problem With Output Voltage

I am designed a power supply. In my design i need 12v and 5v for get this voltages i use 2 LDO LM317HV as i show on the picture. Vin is 48V. I need 0.3-0.2 A. I get a stable 12v on my board but i can'...
MSB's user avatar
  • 27
1 vote
3 answers
168 views

Input current in voltage regulators

I am watching a course on Udemy about hardware design. The lecturer has provided a tutorial on how to calculate the current consumption. I got quite confused when he started to talk about the input ...
Humphrey Appleby's user avatar
8 votes
5 answers
3k views

Is creating a voltage rail loop good or bad practice?

I am still new to PCB design but I often run into this. Say I have a USB connector on the bottom of a board, a SoC on the top, an LDO somewhere in the middle, and miscellaneous stuff on the sides. It'...
Kez's user avatar
  • 185
9 votes
4 answers
2k views

Connecting GPIOs on two boards with independent power supplies

I'm trying to design a board that will accept UART/8N1 input from another board at 3.3V. While the two boards share a common GND (obviously), they otherwise have totally independent power supplies: ...
jemalloc's user avatar
  • 720
1 vote
1 answer
87 views

1.5 V LDO regulator for lithium-ion cell conversion

TL:DR: I want to power a 1.2 V motor with a lithium-ion cell. I have a electric shaver and a trimmer that uses a 1.2 V NiCd battery cell. I'm surprised that, in 2022, I can still buy NiCd battery ...
jjrfadpammtpiagkjq's user avatar
1 vote
3 answers
203 views

Is this LDO instability a real problem or a model bug? [closed]

Here is an LTSPICE simulation for which I just have an LDO (ADP7118) in its recommended environment and some reasonable parasitics. It is unstable as you can see in the transient plot (showing the ...
bobuhito's user avatar
  • 554
0 votes
1 answer
65 views

Open drain input that switches additional circuitry on

I want to create a active cooling for power supply when charging a battery with BQ24610 IC. BQ24610 has open drain pin "STAT1" that switches on when battery is being charged. * I'd like to ...
Oxmaster's user avatar
  • 157
1 vote
0 answers
61 views

Could you provide feedback on my LTC2954 and TPS61090 Schematic?

I am a hobbyist diving a bit deeper into designing more complex PCBs. In the past, I have created basic ESP32 based 2 layer PCBs with basic LDOs for supplying power. I am currently working on a more ...
henryv3's user avatar
  • 23
1 vote
1 answer
53 views

Simplifying a complex power setup

I'm working on an STM32F407 PCB for a flight simulator that has the following conditions: Normally powered via 12V and an AMS1117-3.3 to power the MCU. Needs to provide 5V for certain peripherals ...
Maciej Swic's user avatar
3 votes
1 answer
80 views

LDO voltage regulator malfunctioning as passthrough after 24/7 usage

I have designed a custom pcb utilizing the ENC28J60 ethernet chip to be used with raspberry pi. The board has 5V in which powers both the ENC28J60 (through a AMS1117-3.3 LDO regulator) and the pi. ...
semiExcluder's user avatar
1 vote
1 answer
771 views

Powering ESP32-WROOM-32E using LM1117S-3.3 LDO voltage regulator

I want to power my ESP32-WROOM-32E module with an 3.7V Li-Po battery. To reduce the voltage to 3.3V I'd like to use LM1117S-3.3 LDO. As far as I know, the most ESP32 developing boards use AM1117 ...
Anton Tsvayer's user avatar
1 vote
2 answers
365 views

What is the general rule for LDO thermal considerations at various voltages?

This question isn't so much about my specific case, but rather, I'm looking for a general rule for estimating the max current that can be pulled from heatsink-less LDOs at some voltage difference. I ...
KJ7LNW's user avatar
  • 2,022
2 votes
2 answers
550 views

What is the best way to get 5V from USB?

If we need to make a board that use two voltage levels (3.3V and 5.0V) and the board can be powered both from the USB or from an external 5V power bus, then good practice is setting a diode on the USB ...
Arseniy's user avatar
  • 2,247
5 votes
7 answers
788 views

LDO stability with resistor in the feedback path

I am working on a circuit for measuring very low and very "fast" currents (think: measuring power consumption of an MCU). I found out that I can measure what I want with a sense amp and a ...
filo's user avatar
  • 9,046
0 votes
0 answers
33 views

Check of PDN for RF Amplifier - Revised

This is an update to my previous post. I was recommended to post it again. For optimal working conditions, HMC863ALC4TR needs Vdd = 5.5 V and Vgg = -0.75 V. I have tried to design such a network to ...
Humphrey Appleby's user avatar

1
2 3 4 5
12