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Questions tagged [charge-pump]

Charge pumps are a form of DC-DC converter that use a capacitor as the storage element. They often have a higher efficiency and lower cost than inductor based designs when current requirements are low.

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Charge pump understanding question regarding PWM duty cycle and PWM voltage level

I am playing around with charge pumps / voltage doublers for the first time and have some questions that I can't find anything online to. First, I have a standard charge pump, in an ideal world the ...
Spider999's user avatar
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2 answers
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Are unregulated charge pumps used in some applications?

As we see in SMPS converters that feedback is necessary to regulate the output. Here charge pumps are both regulated and unregulated converters. I am curious to understand in which applications ...
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Quadruple MOSFET charge pump simulation does not work as expected

Background Source claims that this MOSFET-based charge pump circuit should work. The schematic looks logical and I was able to reason my way through its expected behaviour. I tried simulating the ...
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Regulated charge pump design

I am working with an IC that uses a partially intergrated regulated charge pump. The circuit looks like this: It behaves like a voltage doubler. However, when looking at other regulated charge pumps ...
Mu3's user avatar
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How to correctly switch between two analog signals before op-amp

I have two sources to generate a ramp signal to drive a voltage controlled oscillator. Source one is DAC of the STM32H743 and the second one is RF Synthesizer ADF4158's charge pump output. RF ...
Cenk's user avatar
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Modified astable multivibrator with sharp edges

I am designing an astable multivibrator that would avoid rounded output edges and also has a totem pole output, so it is able to drive a small charge pump. So I decided to replace a collector ...
Michal Podmanický's user avatar
2 votes
3 answers
245 views

Why does this 2-stage PWM charge pump have a very low efficiency?

I designed this 2-stage charge pump to get about 9V and 3mA (tolerances accepted) from a lithium-ion battery. The output works well and provides the requested voltage and current. I thought it is a ...
Tirdad Sadri Nejad's user avatar
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Simple charge pump - what’s advantage?

Consider simple charge pump. If the output voltage is close to 11V there is no swing across Cfly. To get some swing on Cfly the output voltage has to be 8V or so. But 2V boost is for nothing. So what ...
Michal Podmanický's user avatar
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Increasing basic charge pump's output current

I am trying to increase the output current of this charge pump circuit but I am out of ideas Once C1 (10mF) is charged up to roughly 3V the mosfet will open up at random intervals for 400ms thus ...
crispus's user avatar
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Wireless charger reverse engineering

I am trying to figure out how to design an H-bridge for a wireless charger. And I thought that reverse engineering an off-the-shelf one might give me some clues. I might have made numerous mistakes ...
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7 votes
3 answers
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What technical progress enabled high-efficiency charge pumps?

I found a lot of information on the internet, most of which told me that charge pumps are only suitable for low-power scenarios and they are not very efficient. Charging ICs based on the charge pump ...
Bruce's user avatar
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Bootstrapping circuit vs. charge pump for high side switching

I am designing a circuit where I need to do some high side switching to turn on/off the power to a circuit (part of some protection circuitry). This switching is actually very slow and only occurs ...
Samuel Snerden's user avatar
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Substitute for MAX865EUA-T [closed]

It's been few weeks I'm searching for a substitute for my MAX865EUA-T (datasheet). I need a component able to do a +10V/-10V output with a +5V input, this component was perfect for me since it's ...
Bibibou's user avatar
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1 answer
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How to tune a safety charge pump

I am designing a charge pump that will enable a relay when the charge pump is energized (inspired from this answer). The relay is part of an emergency stop system and the charge pump is used to check ...
Sam's user avatar
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3 votes
4 answers
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MAX3232 capacitors voltage rating

I'm having a doubt about the voltage rating of the capacitors of the RS3232 (a UART to RS232 transceiver). For C3 and C4 (storing the +- voltage rails for the transceiver), the never exceed voltages ...
Sandro's user avatar
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Reason for VM Pin in S-882Z Series Charge Pump?

I was wondering if anyone has any idea why this S-882Z Series charge pump uses a VM (voltage monitor) pin instead of the Vout pin that most charge pumps use? And in general, why is the pinout so ...
jocadomi's user avatar
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wGate driver working-Parallel NFET

Reference With context to the following image. From the input pin, which can be interfaced with CMOS logic. The highlighted enhancement type PMOS & NMOS pair acts as an inverter pair, right? (...
Harkirat's user avatar
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Why use a different circuit to create a positive voltage with the ICL7660, rather than running it “upside-down”?

The primary use of the ICL7660 (and it’s many clones/alternatives) is to create a “negative voltage” equal to its input voltage, which it does with minimal external components. However, in my ...
Harry Brooke's user avatar
2 votes
1 answer
166 views

How can switched capacitor converter be useful when its output is not regulated?

The charge-pump converter also known as switched capacitor converter and flying capacitor converter is a type of inductorless switching voltage source i.e SMPS. It can generate a voltage higher than ...
quantum231's user avatar
2 votes
3 answers
183 views

Charge pump as a solenoid driver

I have a solenoid valve, and the datasheet claims response times as low as 165 µs. I have driven the valve at its rated voltage (28 V) and am only able to get response times of ~3 ms. The company that ...
Shaken_U's user avatar
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Having trouble understanding textbook explanation of "hot chassis" in full-wave voltage doubler vs half-wave

The textbook explanation is not doing it for me. The half-wave voltage doubler shown in Fig. 4-27(a) offers some improvement in safety over the full-wave voltage doubler. Compare Figs. 4-24(a) and 4-...
Al T's user avatar
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4 answers
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Meaning of "three-stating" a PLL charge pump

I am designing a phase lock circuit using an Analog Devices ADF4107 PLL Frequency synthesizer (https://www.analog.com/en/products/adf4107.html). The PLL is programmed manually and one of the settings ...
ultravioletcatastrophe's user avatar
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69 views

What can I use to drive charge and discharge high-side N-channel MOSFETs?

I want to control the charge and discharge MOSFETs of the series cells balancing circuit. There is a charge pump to do that but I do not know how to design such a charge pump. Is there any source ...
Shamurov's user avatar
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Powering a small pump from a Raspberry Pico microcontroller

I'm trying to power a small 5 V pump from a Pico Raspberry board power PIN (Vsys) that also powers an OLED display. When the pump is activated it causes the microcontroler to reset. I think this is ...
mulan's user avatar
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3 votes
1 answer
219 views

Will this charge pump work?

I am trying to make a charge pump for a project of mine. I'll be using some spare transistors I salvaged from an old tube TV and I intend to use the increased voltage for a high-side gate driver for ...
kale hops's user avatar
1 vote
1 answer
998 views

Self-boost charge pump for high-side driving: how to drive the high-side driver itself?

This is the circuit: My question is: how can I send signals to the high-side MOSFET driver? I thought about this way: But "B" may be 0 V when the MOSFET is on, resulting in a negative ...
lidorov19's user avatar
5 votes
1 answer
393 views

TC962 Voltage Doubler - Why the slightly lower output?

I am prototyping this voltage doubler circuit based off the datasheet of the TC962. Capacitors are GRM21BZ71E106KE15L. When applying 9V at the input, the output is 17.96V at no load. When drawing ...
Luke Galea's user avatar
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1 answer
185 views

Turn off high side switch

I am trying to turn off my N-channel MOSFET which is driven by a charge pump. It takes too long to discharge the pump through the gate-resistor to ground, therefore the power dissipation is very high....
Martin's user avatar
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2 votes
2 answers
180 views

How do I achieve well-formed pulses in a Dickson charge pump?

A picture is worth a thousand words, and I tend to make a lot of mistakes in my words, so, first picture, the circuit in question: I know the Dickson charge pump looks a little different but it is ...
RobMcN's user avatar
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272 views

555 timer charge pump with feedback

In the circuit I am working on there is a requirement to create 30V DC source for a very light load (couple of mA max). I am aware that there a specialized ICs that can do that but I would like to ...
Ivan Demyachenko's user avatar
2 votes
2 answers
703 views

Impedance calculation of a four stage Dickson voltage multiplier

I built a four stage Dickson voltage multiplier for RF energy harvesting at 2.45 GHz. This is the circuit which I built. My components are BAT54S as diode and 100uF capacitor. I need to calculate the ...
Bowman's user avatar
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3 votes
4 answers
3k views

Why does MOSFET N back to back switch work?

Please consider an exemplary back-to-back MOSFET N driver IC (drew the body diodes of M1 and M2 for clarity): I understand how is it possible to turn off the M1/M2 transistors from the gate voltage ...
Łukasz Przeniosło's user avatar
3 votes
4 answers
400 views

What is the relation between NE555 voltage doubler output voltage vs load?

Considering this circuit (NE555 voltage doubler), how can I find the formula for the relation between the value of the load resistor and the output voltage? You can see below two examples of this ...
JeanMi's user avatar
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2 votes
1 answer
85 views

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 ...
davegravy's user avatar
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0 votes
3 answers
226 views

LM27762: 200 mV difference between positive and negative

I'm trying to figure out why there is 200 mV difference between positive and negative voltage on LM27762 (measured these values at op-amp pins). I used a schematic from their datasheet and everything ...
user1258202's user avatar
1 vote
1 answer
331 views

How does a PLL PFD produce a high frequency?

I am going to work with a PLL and a VCO. I have read and understood the basic procedure in which the charge pump works. I understood that say, when the reference signal (or the divided signal) is up ...
shafik's user avatar
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1 vote
1 answer
135 views

Charge pump with adjustable frequency: what frequency to pick and why?

I decided need a charge pump IC that I intend to use to get -3.3V from 3.3V to supply my op amps and diff amps to avoid running into output voltage swing limitations of those ICs (For true near zero ...
Ilya's user avatar
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1 vote
2 answers
145 views

Charge pump circuit- What is the need for caps near CLK pin?

Below is a charge pump circuit in NB680 IC Datasheet I was trying to understand the charge pump functionality by comparing it with the standard circuitry shown below: https://www.edn.com/capacitive-...
Dynamic_equilibrium's user avatar
1 vote
3 answers
1k views

How to design a boost converter? (1.5V to 4V)

I want to build a circuit that powers 2 standard red LEDs (forward voltage of 2V each) from 1 AA battery. I would like to learn how to design and build a boost converter that can take 1.5V in and ...
Adam's user avatar
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13 votes
13 answers
4k views

What is physically happening when there is a square wave input on the left plate of a capacitor and open circuit on right plate of a capacitor?

Mathematically I understand that through KVL that the output in the first image will match the input square wave. I am trying to understand physically what is happening. How is the voltage ...
maldingRookie's user avatar
-3 votes
2 answers
160 views

Absolute cheapest/simplest voltage booster? (for High side Mosfet Switch) [closed]

what is the absolute cheapest solution to provide gate voltage for a high side switch? I will have to use NFETs due to 20A+ cont. with low losses. There is no switching happening (think of a load ...
Attenbach's user avatar
0 votes
1 answer
178 views

How can I simplify this charge pump?

In thinking about an answer to a different question, I came up with a likely-not-ideal solution to the following: Given a square-wave input of 125 Hz whose minimum is 0V and maximum is somewhere ...
Reinderien's user avatar
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2 votes
1 answer
252 views

Can I use negative voltage generator TC7660 as voltage doubler to drive LED of MAXIM30101 oximeter IC?

I am trying to use two AAA battery to generate two power supplies, 1.8V(via regulator AM1117) 5-6V to drive LED (using voltage doubler TC7660). Both these voltage is requirement of Oximeter sensor ...
Xinus's user avatar
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5 votes
2 answers
880 views

Charge pump has an unexpected voltage drop with a 1K load

I have been reading this tutorial about how to design a charge pump with BJTs. I have built my own one, that aims to produce ~-6V instead of the above's -5V. I'm able to reach -6V when no load is ...
Martel's user avatar
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1 vote
0 answers
159 views

charge pump - failure analysis

I have a strange behavior on a custom powerstep01 board I designed. This is the Schematic of the CP / BOOT section: simulate this circuit – Schematic created using CircuitLab The values for ...
KarlKarlsom's user avatar
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2 votes
3 answers
160 views

Offsetting Op-Amp output offset in combination with charge pump

I want to have a +-12.0V square wave output from an opamp fed from a 3.3 and 5V power supply. The signal is 2.5kHz with a low duty cycle of 3-10% generated by an MCU. Peak voltage at both ends need to ...
JeromeBu1982's user avatar
0 votes
1 answer
574 views

Charge Pump PWM to GND connection necessary?

Hey there, first post from an avid forum reader: This is the schematic for a simple Charge Pump circuit from circuitdigest.com* (great website). I am trying to build a charge pump with 12V VCC and 5V ...
Attenbach's user avatar
1 vote
2 answers
321 views

How can I use an AC capacitance voltage divider through diodes to charge a DC capacitor?

What I need help designing is a circuit that will be a capacitor voltage divider that will be fed by a high AC input voltage, but be able to discharge each capacitor through diodes at a set lower ...
Fernando Gigliotti's user avatar
2 votes
1 answer
177 views

How to analytically find node voltages in a voltage doubler?

Given a voltage doubler circuit: simulate this circuit – Schematic created using CircuitLab You can figure out what should happen in stead state if \$R_L=\infty\$ and \$R_s=0\$. In that case, \$...
KD9PDP's user avatar
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2 votes
1 answer
202 views

High voltage Dickson charge pump switching

I am working on a circuit based on the LT1930 (DC634A) to boost input voltage between 30 and 90V. I would like to take this boosted voltage and double it via a Dickson charge pump to the required ~...
dtk's user avatar
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