8205A PDF

A are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for A. 28 Apr This manual contains new product information. Fortune Semiconductor Corporation reserves the rights to modify the product specification. A Transistor Datasheet, A Equivalent, PDF Data Sheets. MOSFET. Parameters and Characteristics. Electronic Component Catalog.

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Even if both MOSFETs were turned off, there is still 82055a current path and the battery would continue discharging well past its safe discharge voltage. The reason we use two back-to-back MOSFETs in this situation is because we want to make sure that we can completely block power from flowing in either direction when necessary which is a bit tricky with those pesky body diodes.

Dual mosfet A – lithium battery protection circuit Ask Question. Here’s the example where M1 is reversed over-discharge protection fails. In this we may get wrong results. Power MOSFETs have body diodes present within 8250a structure, this is a by-product of how they bare designed and it not always a desired feature this being one of those times.

protection ic a – EasyEDA

To answer your question about what the drain voltage will be relative to ground the battery’s negative terminalthere are a few cases: Because both source terminals of the two back-to-back MOSFETs are connected together, it’s really easy to put a positive bias on the gates as we can tie both gates together and drive them as one.

Alex 3 6. Hope this at least clears up how MOSFETs work and why someone would even want to put two back-to-back like in that battery protection circuit.

Atmega 1 8 Sign up using Email and Password. So the voltage at the combined drains will be a resistor-divider’s-worth above ground, say perhaps 0.

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Dual mosfet A – lithium battery protection circuit – Electrical Engineering Stack Exchange

Home Questions Tags Users Unanswered. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. I have read but not comprehend that wiki page many times.

With an increasing Vgs the mosfet turns on and as it turns on Vds decreases. When Vgs gets high enough Vds 82055a drop below Vgs-Vth and the mosfet will go into the linear region. Now that we’ve gotten some background info out of the way we can get to answering your question. Sam 2, 5 I still don’t understand it.

This is assuming you measure in a “forward” direction from the BATT- terminal to the drains.

Any more in either direction and one of the diodes would start conducting. Suggested to correct the circuit for simulation.

Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. Normally, the drain of a mosfet is connected to the positive. This is a basic lithium battery protection circuit, but looking at the dual mos-fet part of the circuit, It doesn’t make sense to me.

As a few others have mentioned, the drains of that dual MOSFET will be pretty close to the same potential as the negative 82005a terminal. The circuit given by Alex to simulate appears to be wrong as it connects drain to source, while the device A under discussion has both drains shorted. Post as a guest Name.

Another thing 8250a understand is that when Vgs rises Vds falls. In this case, the protection circuit would detect the battery reaching its cutoff voltage, and would bring OD to ground, thus turning off M1. To ensure that the battery can be completely isolated i.

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The drain voltage is only important when either.

protection ic 8205a

Note that M2 cannot disconnect the battery during normal operation due to it’s internal parasitic body diode, and this is the reason why M1 is required in this orientation to block “forward” flow when off. If you flipped M2, a similar situation exists where the protection circuit loses its ability to protect against over-charging. And seeing as MOSFETs don’t care which way power’s flowing when they’re fully ON, this arrangement basically makes something which looks just like a relay.

It’s a A dual mos-fet, with its drain connected together and each of its source connected to the negative of the input and output. You need to read the datasheet of DWP: To answer your question about what the drain voltage will be relative to ground the battery’s negative terminalthere are a few cases:. You can also read the two questions I asked about the same circuitry: Atmega i think you confusion is that the active and saturation regions for a mosfet and bjt are opposite.

Sign up using Facebook. Over current protection for a 1-cell battery and Remove over-current protection of battery protection circuit. Sign up or log in Sign up using Google.

However, M1’s intrinsic diode would still be conducting! By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

This turned into a much longer ramble than I expected and I may have missed a few things or used a few B-grade analogies.