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Questions tagged [bootstrap]

A technique in systems design in which an initial result is fed back into the system to enhance its future operation. This could apply to anything from an analog amplifier to the process of getting software running on a computer.

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Mystery Diode in Schematic - MPQ8039 HALF BRIDGE DRIVER

The below image shows four example schematics for the the MPQ8039 Half Bridge Driver. Three of the four examples show a diode connected between the DRV pin (Gate Drive Supply Bypass) and the BS pin (...
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driving high side H bridge inverter

i still get confuse to understand the high side driving of H-bridge mosfet, it is said that to drive the high side, voltage at its gate have to be greater than the drain voltage, is it true? so when i ...
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55 views

Circuit protection problem driving high side MOSFET continuously

I need to drive a high side N-channel IGBT continuously. The circuit is essentially a passthrough, and the only thing I want to do is turn this pass through line on or off (usually if not always on) ...
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294 views

Bootstrap mosfet driver with ir2101

I am trying to build this circuit but I don't know how to test it. When I am measuring the voltage on the gate of high side mos is almost 12 volt like VCC. So to speak .. the boostrap circuit isn't ...
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124 views

What should be the voltage rating of bootstrap capacitor?

BST_1P is the bootstrap capacitor connection pin for high-side gate driver of TAS6422. In the datasheet it is suggested that, this capacitor should have minimum rated voltage of 16 V. What is the ...
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135 views

High Side MOSFET Driver

I am familiar with the bootstrap circuit and its design procedure. The steps involve: a) Figure out the Qg of the MOSFET at the Vgs you plan to operate (for instance Vgs=15V, Qg=150nC). Next, figure ...
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bootstrap capacitor with a lower lower voltage than vcc?

I want to drive a 300v IGBT half bridge that uses two n channel IGBT's. The problem is I need to a bootstrap when driving the IGBT that pulls the load to high, however the IGBT's max gate-emitter ...
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108 views

MOSFET bootstrap capacitor

I'm using a N channel gate driver with a bootstrap diode included, so I just need to add the capacitor. The FETs will be powered from a 3S lipo pack (12.6 to 9.0v) so I was wondering if I need 30v ...
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186 views

Select bootstrap capacitor value too high

What happen if we choose bootstrap capacitor value too high in high side gate driver applications? Can it be harmful for MOSFET/IGBT or it is just not important?
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329 views

Bootstrapped Transimpedance Amplifier (TIA) - High Frequency Instability

I have constructed transimpedance amplifier in the hopes to achieve both high-gain (5kΩ) and high-bandwidth (50MHz) performance using the FGA21 photodiode, the OPA657 Op-Amp and the 2N2369 Transistor. ...
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105 views

ARM chips that lack boot ROMs [closed]

This isn't anywhere near as true as it used to be, but I consider one difference between x86 platforms and ARM platforms to be whether or not booting involves the use of a mask ROM at reset to ...
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145 views

Transimpedance Amplifier (TIA) - How to shunt high current spikes?

I am working on the design of a high-bandwidth transimpedance amplifier (TIA) to detect a relatively weak optical signal (100μW) but also be able to withstand short pulse, high power optical signals (>...
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211 views

Boot process for ARM-Cortex-A series

STM32F2: Makefile, linker script and start-up file combination without commercial IDE is a simple but brilliant explanation of what happens when we start a system based on a Cortex-M series processor. ...
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491 views

Audio Amplifier with Bootstrap connection

I started to study more these days about Audio Amplifiers in class AB and I came across about something called bootstrap connection. As far as I know bootstrap is used to pull the signal higher than ...
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338 views

how to design circuit of high side MOSFET switching with bootstraping and mosfet driver ic?

Hey im starting to learn about MOSFETs at my university classes, but Im having trouble trying to design a circuit for a buck boost converter for a MPPT solar charge controller. The part pushing me ...
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134 views

Bootstrap drive for 2-transistor forward converter

I need a driver for the high side switch in a 2 transistor forward converter as follows: First, I thought a bootstrap circuit would be fine because during the freewheeling phase, the highside FET's ...
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462 views

How to determine the input resistance of a bootstrapped emitter follower

I've used bootstrapping several times, either to boost the input impedance of an amplifier or to increase its gain. However most of the times I can see the beneficial effects of bootstrapping without ...
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484 views

Does this high side n-ch mosfet bootstrap circuit work?

Edit: With the back to back mosfets i try to eliminate the blocking diode in a solar charger. So on the left side is a solar panel and on the right the battery. So lets say the battery is at 10v and ...
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196 views

Can I leave bootstrap pins floating? (Internal pull-up)

I have a microcontroller that uses 4 GPIO pins as "bootstrap pins". The state of these pins (high/low) at boot time will determine important features of the microcontroller, such as output voltage to ...
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222 views

Mosfet bootstrap voltages

I have a question regarding using an n-channel mosfet in the high side with a charge pump bootstrap. Lets assume the following: Vgs max is 15v Vgs(th) is 2v (logic level) voltage pressent at source ...
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320 views

Bootstrapping in discontinuous mode

I am designing a buck converter that would charge a battery and planning to use an N type MOSFET on high side and FAN7085_GF085 driver to go with it. Datasheet: (Can't post more than 2 links, sorry)....
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212 views

LDO to regulate bootstrap voltage

I am designing a BUCK converter 24V/12V, 80A, 300kHz switching freq. It will be used for stepping down battery voltage, so it can be expected for input voltage to vary from 22 to 30 volts. I am ...
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148 views

High-side driver IC use of diode in the npn transistor BE

I would like to know why is used a diode between the BE of the npn in this circuit. The npn is used to boost the current to deliver to M2 gate in this bootstrap circuit. Is it maybe needed to get rid ...
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515 views

High- and low-side MOSFET gate driver bootstrap circuit

I am trying to create a simple buck converter on a breadboard using this topology: I am familiar with the theory of this circuit and believe I have connected everything correctly. The gate driver I ...
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1answer
941 views

MOSFET's drain and source short out in high side driver circuit

The circuit above is used to drive a 48 Volt 1000 Watt motor "MY1020" using high side driver configuration. 48 Volts are achieved using 4 sealed lead acid batteries in series and the 12V battery is ...
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1k views

Choose Vcc for MOSFET driving a 48v Motor

The circuit above is used to drive a 48v motor as shown. I am using: IRF3205 MOSFETs (datasheet) IR2110 High and Low side driver (datasheet) 22uF bootstrap capacitor for PWM frequency of 30 KHz. I ...
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460 views

H-bridge using solid state relay instead bootstrap IC

experts! Good afternoon. I am working on a project using a H-bridge. It must work at 100V and, then, i first designed a bootstrap circuit with 2 IR7304S (attached picture). Then i was wondering if ...
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Effect of bootstrapping in amplifier circuit

I am trying to understand this "bootstrap bias" amplifier circuit. The picture below is adapted from the book "Transistor Techniques" by G. J. Ritchie: This circuit is a variation of the "voltage ...
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756 views

Half bridge galvonic gate drive with deadtime

I'm a Tesla enthusiast and build Tesla coils now and then. One thing I have always wondered, a lot of designs (some very popular) utilize a transformer to drive a N-MOS half bridge (see image below). ...
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423 views

help need in driving high side nmos without bootstrap circuit

I am currently planning to upgrade an existing circuit which charges a lead acid battery using a non-synchronous buck topology. The NMOS which i have used is IRFP4768PbF.Currently my driver is the ...
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1answer
2k views

mosfet bootstrap explained [closed]

I'm trying to get a hold on bootstraps for high side n-mosfets. as i currently understand it, it works somewhat like this: when pwm is high, mosfet is closed and capacitor is loaded to 12V. when PWM ...
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242 views

Boost capacitor sizing, gate driver LM5106 used with N-MOSFET IPP075N15N3 G

I am using a TI gate driver LM5106 and I wanted to size the bootstrap capacitor. The application regards a synchronous boost converter. According to pag. 13 I need the \$Qgs\$ charge of the MOSFET ...
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2k views

Bootstrap capacitor

I am new to electronics could any one explain to me what is the Bootstrap capacitor and what is used for I am doing research about buck convertor using MP1482 chip and I do not understand bootstrap ...
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230 views

Buck converter as a LED driver with NO LOAD

I am proceeding with a design of a LED driver using an LM3405. I don't read anything related to what happens when the load is not present, on the datasheet. As you may have already read, this is the ...
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199 views

Practical Bootstrapping

I have been looking up bootstrapping circuits. The concept makes sense, but I am afraid I just don't see the use. Can someone give a practical situation where one would be designing and decide this is ...
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442 views

Can the high current motor change the ground potential level in the H-Bridge?

I'm planning a half-bridge driver with bootstrap IC-s. My motor runs on 12V, with 50-60A. I linked the schematic. I supply the bootstrap from an other battery (7.2V). Due to the big current, can the ...
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70 views

What design considerations determine what kind of power supply I should use for a high-side FET?

I'm presently considering building a half-bridge converter, which means I have a transistor that's not tied to circuit common. To drive it, I'll need some voltage supply referenced to its source. This ...
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88 views

Buck not acting as designed

I have designed a synchronous buck converter to step down a 17.4V voltage source to 12V at the output. I have attached the schematic as shown. Problem: The Buck is not operating as expected at all. ...
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905 views

Calculation for the Boot Strap capacitor

For design of a synchronous buck converter (which would be used to charge the battery) which would be driven by Micro-controller's PWM output, i selected the IRLB8748 NMOS Power transistors (for both ...
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288 views

arduino boot up button and shutdown mode on regulator

We've a projet with an important autonomy concern. We use an homemade arduino (atmega328), and for the moment we're using interrupts on buttons to wake up the atmega. so we have: sleep ->(button ...
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2answers
1k views

Is it safe to “top up” bootstrap capacitors using a charge pump?

This document from TI describes a method to allow use of bootstrapped N-Channel MOSFETS at high duty-cycles, by keeping the bootstrap capacitor "topped up" with an external charge pump, separate from ...
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677 views

Z80 Binary Front Panel Design

Hello fellow engineers, I need some design design help with a Z80 based computer I am building. It will feature a binary Front Panel. The following functions may be performed via the front ...
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1answer
1k views

Buck converter Mosfet gate driver

How to turn on a buck transistor via a bootstrap circuit? In my circuit, I use a AVR microcontroller to turn on and off a buck switch. What circuit should I use here? Previously, I used optocoupler ...
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4k views

IR2110 getting really hot in this high-side gate driver configuration

I've constructed the following circuit: From this blog: Tahmid's Blog I put an LED in series with a 330 ohm resistor at the OUT terminal. I have the 5 V being supplied by an Arduino and the 12 V ...
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4k views

dc to ac inverter circuit

I want to design the following inverter circuit, I know the general working of it, but I need some details. in the gates of the FET transistors used in H Bridge there is a design contain 4 diodes 2 ...
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1answer
382 views

boost converter load problem

I am designing a boost converter for wind turbin, with load 12Vdc, 2A. Before I install my boost converter on my windturbin, I putt a test to make sure it work properly. So I use this circuit to ...
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2answers
3k views

Driving high side MOSFET problem

I designed a simple half bridge circuit using popular FET driver IR2101 (switching freq. around 500 Hz, drain current about 250 mA, supply voltage about 12 V): Of course I have resistive load ...
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490 views

Choosing bootstrap capacitor for MOSFET driver

I have IRS2011 high/low side MOSFET driver, for driving IFRZ44N MOSFETs configured in H-bridge. How would I calculate the bootstrap capacitor required by the IC for driving high-side? I am aware of ...
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1k views

Simulating IR2104

I have this simulation set up in Every Circuit. It can be viewed here: http://everycircuit.com/circuit/5875415639916544 For right now I have turned off M3 by jumpering M3's gate to the ground nearby. ...
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2k views

Is there a common name for this [voltage-boosting] circuit topology/idea?

In the OPA454 datasheet I found an interesting circuit idea that I'm not sure what is it usually called (if there is a common name for it). It involves using two opamps to shift the rails of a 3rd ...