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Analog Switch question

Looking for some advice on how to make this.

I need to make a DTDP analog switch work with a few second delay after receiving input.

I was thinking about a 555 and some kind of analog switch like an AD7512 or something like that.

For example, I have a usb cable I will plug into a tablet. It needs to short the D+ and D- pins (on the cable going to the tablet) together for a couple of seconds then connect the the D+ and D- (from a usb hub).

You can read my description below or look at the circuit I drew here.

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The hub will provide power to charge the tablet, but to put the tablet into charge mode you need to short the pins first. After that you can disconnect the short and it will continue charging. Switch in the USB hub's data lines and everything is working. Charging and connected to a hub all on one USB port.

Reply to
Michael Kennedy
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By the way, sorry if you see my message twice. I tried posting from a google account to see if anyone would read it.

I just got a real Usenet provider again for the first time in years.

Reply to
Michael Kennedy

Do you need it automatic, or can you just put a DPDT momentary switch on it and be done? Mikek

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Reply to
amdx

Well, I have it with a switch now and it works just fine. That's how I know this works and made that circuit diagram.

A switch is a simple solution but I guess I was wanting to turn this into a project I can learn something from. This seems like it should be a fairly simple circuit to build. but when it comes to designing circuits I have almost no experience so I figured I'd ask around since I don't know what kind of devices are out there.

Maybe I should post this over on s.e.design.

Reply to
Michael Kennedy

What are you planing on using as the trigger for the 555? Just the power from when the USB is plugged into the tablet. hmm I think there is already voltage on the power pins What are the other uses of the USB. If you put the circuit internal to the tablet will this affect those other devices. You could switch a small DPDT relay with the 555. Mikek

Reply to
amdx

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