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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41 views

Power Circuit to Subtract a Voltage by a Known Amount

Using a charge-pump it's possible to add voltages together (i.e. source 10V + PWM 5V = 15V, ignoring diode drops) simulate this circuit – Schematic created using CircuitLab Surely there must ...
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37 views

Energy subtracted from a capacitor for a given voltage drop

I am trying to estimate, from a total energy of a capacitor (which is the output of a charge pump circuitry), how much energy do I have to power up an LED before the voltage goes below a certain ...
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31 views

Charge Injection in Charge Pumps

let's consider the following charge pump, which is used a lot in some PLL circuits (reference): Let's focus on the left part of the circuit (until the Loop Filter Network): its aim is simply that of ...
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58 views

Charge pump vs. boost converter for high current LED driver

I am designing a high current LED driver circuit to power a matrix of pulsed IR LEDs. The LEDs will operate at 5A; 4.6V; 0.1ms pulses (~10 pulses at this frequency, wait 300s, repeat.) The device is ...
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107 views

Charge Pump-Based Gate drive supply

I have heard many people talk about using a charge pump circuit instead of a bootstrap approach when supplying MOSFET gate drivers with a biasing level for the high side. I have yet to see anyone show ...
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74 views

Replace switching diode with MOSFET for lower voltage drop in charge pump?

I have seen reverse voltage protection circuits that use a pmos instead of a diode so that there is minimal power loss and voltage drop in that sector of the circuit. I want to make a charge pump for ...
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48 views

TI PCM51xx DAC Charge Pump Failure

I'm using a PCM5122 and previously a PCM5102 (this is the same part, but without the I2C/SPI interface) in my design and I've had a couple of prototypes end up with the 3.3v rail shorted to ground. A ...
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70 views

Two Different Charge Pump Circuit Variants. What Are Their Advantages?

While looking at the L6470 stepper driver datasheet I came across the following charge pump circuit suggestion (I will just name it Variant A). The charge pump is used to provide the "Bootstrap ...
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29 views

Conclusions about PFD/Charge pump simulation

I have built a Sequential NAND based phase detector with a charge pump that includes a differential amplifier and I want your help make some conclusions about the results I got running all the ...
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43 views

Bootstrapped charge pump design for phase frequency detector

I'm trying design a charge pump as it's showed in the following link: https://ibb.co/DDc6DsF (for some reason I couldn't upload it, I don't know why). what I don't understand is what is \$I_{ref}\$ (...
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63 views

capacitor selection for charge pump

In one of my project i need 12v logic level (for programming controller) and my circuit is running on 5v. So, instead of using 12v supply i am thinking to use charge pump circuit because i just need ...
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72 views

Increasing output current of the inverting voltage doubler charge pump circuit, implemented with MAX1720

I have a +3.3V voltage rail available. And I want to generate a pair of negative and positive symmetrical supplies out of it. The magnitude of the output voltages must be less than 7V and should be ...
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129 views

What is that component from the ADP5091 Schematic?

I am looking for an explanation what that component does inside of that circuit. It can be found on page 3 of the Datasheet of ADP5091: https://www.analog.com/media/en/technical-documentation/data-...
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71 views

How to 3x or 4x a DC voltage while minimizing board space with no microcontroller?

I have a 3.7V DC voltage source that I'd like to boost to at least 10 Volts. I've been using Microchip's TC7660 component as a voltage doubler. But it only comes in SOIC (rather large for SMT). And ...
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81 views

Can I share charge pumps between multiple L6206 H-Bridge drivers?

I'm building a board to drive 8 separate motors, and I'm planning to use four L6206 dual full H-Bridge drivers. The device uses N-channel MOSFETS all round and, from the datasheet: Using N-channel ...
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53 views

Charge pump from discrete parts

I need to build a 2 stage inverting charge pump in order to convert a 12v rail into -24V which is then regulated to -12V using a 7912 LDO. it is used for a audio amplifier design and I need about ...
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83 views

LM2776 gets damaged after some time

It is almost the reference design from the DS. The only differences are those quite large inductances I had to add to remove the noise. The neg voltage is used to power RR OPamps feeding the ADC the ...
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313 views

Why won't this charge pump supply more than a couple of milliamps?

I am trying to generate 12V from a 5V source, capable of supplying around 15mA with less than 0.5V of ripple. The circuit must use all through-hole components, and cost is an issue. Having ...
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61 views

TC962 not inverting

I have a PCB which uses a TC962 to convert +3 V to -3 V so that I can use a split supply for an op-amp; however, I see ~Vdd at Vout when I have the TC962 on the PCB but it works fine when I desolder ...
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55 views

Voltage Doubler - Charge Pump

The basic understanding of this that I have is that: Assume clock low is 0V, clock high is 3V and Vin is at a fixed 3V. Ignore diode drops Initially Clock is low (0V) and Vin is at 3V (always). ...
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260 views

Charge Injection Confusion

I'm having some trouble understanding the effect that charge injection has on capacitors - more specifically, when there is unequal charge on a capacitor. Consider the following circuit: My ...
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56 views

Supply current for dual supply

I have a circuit with 3 op amps who require dual +- 5 volt supplies. The datasheets mention their supply currents at 19 mA ,19 mA and ~5 mA. I intend to provide the -5 volts from a charge pump IC . ...
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144 views

Provide opAmp supply voltage using charge pump

I have low power (USB 5V, up to 500mA) available on a microcontroller board I am developing. Because the voltages I am going to measure (1.2-2.3V) using the MCU are not filling the ADC's range (0-3.3V)...
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57 views

Medium Power Charge Pumps

I'm working on an MRI research project where I need to power my device with a single BNC cable. Internally my device needs 15V, -8.5V, 5V, 3.3V and 1.2V supplies. The 15V, -8.5V and 1.2V only need ...
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70 views

LM2776 is it normal to have the oscillations in “bursts”

Is it normal LM2776 to oscillate in "bursts": The frequency of the oscillation is OK, but they come in the 8 oscillation bursts every ~9us. Is it normal? The board design and the schematic is ...
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73 views

How can we use the same charge-pumps circuit for varying input voltage?

As I understood it, a charge-pump increases the input voltage by stages Vout=Vin(N+1). In my example, the two stages of charge-pumps, I have Vout=3Vin. So in case of Vin=5.5V this leads to Vout=5.5*(3)...
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97 views

Why doesn't my charge pump work with 1.5v supply?

I have been trying to get the following circuit to work with 1.5V AA battery but it does not work, even though it works fine with a 3.3v supply. I built the multivibrator circuit by discrete ...
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141 views

power efficiency's definition

Power Efficiency is defined as output power/input power, right? And there are a little bit different definition of power efficiency ...output power/(output power+power loss). Is these mean same ...
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281 views

max232 charge pump problem

I have a problem with my MAX232 chip and can't find the solution. The schematic of the chip is in the attachment. The chip is soldered on to a PCB. I've checked all the connections, the supply ...
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96 views

Charge Pump - pre-existing ICs? [closed]

I would like to generate a biasing voltage of around ~300-500V. The load is small, less than 1mA (i.e., ~1W power transfer). Input is 30V DC, so I need a 10x voltage amplification. Normally, given I ...
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167 views

how does a charge pump boost works? [closed]

I have looked how charge pump works and I can understand for example the doubler voltage as it based on charge/discharge of the capacitor. as I have asked one of my student colleagues how it works, ...
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89 views

Input of boost converter or charge pump in the energy harvest [closed]

I read some paper about the energy harvest, and lots of paper said the induced voltage from, for example, the thermo-electric harvesting could be as low as tens of millivolts in a realistic case, so ...
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465 views

L6203 H-bridge output current rings in response to step input

I have an L6203 H-bridge connected to a brushed DC motor, and today I was testing the worst-case voltage drops across my 1Ω current sensing resistor with the motor stalled. My setup is as basic as it ...
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205 views

Why is the peak efficiency of most charge pump less than boost converter,but still can be published in IEEE [closed]

I read some paper about boost converter recently ,and find some author will compare the peak efficiency of their boost converter with charge pump,and the highest peak efficiency i saw is 33%,the ...
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154 views

Transfer function of a digital phase frequency detector

I'm confused about the transfer function of a digital phase frequency detector. Why can we say that the pfd output is proportional to the phase error? The pfd (with charge pump) generates current ...
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62 views

Pump Automatic Pressure Control Electronic Switch

What is the name of this small part?
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126 views

Use MAX680 charge pump positive side only?

I'm thinking of using a MAX680 charge pump IC to generate 10V from a 5V source, but I don't need the -10V output. The example here... ...shows four capacitors, presumably two for the +10V and two for ...
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222 views

LM2664 can I use the ceramic capacitors instead of the electrolytic ones?

I need the negative voltage for my OPAMP and I use the LM2664 inverter. I have a very limited space available on my PCB. Is it OK to replace the electrolytic capacitors with the ceramic ones?
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66 views

Charge pump to a specific potential somewhere else in the circuit

Just for context: The original problem I was originally trying to solve was measuring current through a shunt whose voltage potential may be outside the range of my control circuit's supply voltage. ...
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151 views

switched capacitor voltage doubler for strobe circuit

I am interested in making an LED blink fast with a low duty cycle. To make the LED bright again (despite the low duty cycle), I thought I'd try to use some sort of charge pump to overdrive the LED. I'...
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520 views

Noise of a charge pump in analog design

I am designing a DAC and have a Vin of 5V. For the analog stage I have a couple of options : Use an Op amp that has +5V in (low audio quality) Use an Opamp that has +-5V in (better audio quality) ...
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283 views

MOSFET Driving On The Cheap And Cheerful

I need (unless I'm XYing) to high side switch a FET pair from a (PIC16) microcontroller in the simplest way possible. They are switching an audio line with significant current (presently the output of ...
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405 views

Negative charge pump problem

I have an 18V 1.5A mains transformer (outputs around 30V peak with no load at 50Hz) followed by a full-bridge rectifier and a filter capacitor: (there would be a schematic here if SE allowed me more ...
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451 views

Charge pump design for pll

I am designing this charge pump for a pll. But the control voltage always stays between 1.7 and 1.8V. Because of this the VCO after this always oscillates at its higher end of frequency. What ...
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429 views

Op amp design for charge pump

This is the charge pump design from Razavi. I want to design the opamp for the circuit, a design for which is as given below. Is the op-amp architecture correct for this circuit, since it requires ...
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540 views

How to choose reference current in a charge pump circuit?

The figure shows a charge pump circuit using servo loop. The circuit is from Razavi RF Microelectronics text book. How to fix the Iref in the first branch?
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What are some ways to improve a voltage multiplier?

I am working on a Nixie power supply, but I would like to improve it. I have 4x9V batteries in series for a total of 36V to be switched across a multiplier. A (TTL) 555 timer is running astable from ...
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134 views

Voltage conversion +1V to -3V inside a new IC design

I am looking for a good integrated CMOS solution for creating -3V out of a 1V supply. The -3V are just used for biasing and hence do not load the supply. This means that the solution should be switch ...
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98 views

SIM card power supply design, from 3V/50mA into 2.7V/10..100mA

I am designing a SIM card with RF radio included. The radio with its CPU needs minimum 2.7V to run. The current consumption is my problem: - for a period of 50msec (during transmission), it requires ...
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196 views

Charge pump for stepping up 9V to 45V

I need to step up a 9V power supply (from a battery) to (at least) 45V, very small output current (less than 1mA, but it may be much less). My purpose is to drive a Russian rod vacuum tube, which ...