Digi-Key TechXchange Communities: Message List

Voltage Detector

noreply@digikey.com — Sat, 02 Mar 2013 14:31:45 GMT

I asked around and here's what I found out:

Supervisors with a push-pull output have a CMOS output (VDD-PMOS-NMOS-GND) where RESET is center tapped. This allows for less component count for a supervisory solution. Its drawbacks are that they can’t do as shown below for an open drain output.

Supervisors with a open-drain output have (depending on /RESET or RESET) a MOSFET at its output where an external resistor can be chosen to pull-up to a specific voltage. This allows more flexibility in your VoH value for whatever the output is driving (possibly an enable pin) and allows for ORing logic where the open drain outputs can be connected together.

Hope this helps

MOSFET Driver

noreply@digikey.com — Tue, 29 Jan 2013 21:08:54 GMT

You are not required to use a MOSFET driver - but most companies will tell you that it is recommended to ensure the gate driver requirements are met. For an N-channel MOSFET to turn-on properly you need to provide at least 10-V on the gate with reference to the source. That ensures that the device is fully saturated to take advantage of the RDS(on) of the MOSFET. IR says that gate drivers are recommended to provide this necessary voltage. Here's a link to an application note providing the details on how gate drivers work:

http://www.irf.com/technical-info/appnotes/an-978.pdf

Hope that helps.

Do we need more testing for Li-ion batteries?

noreply@digikey.com — Thu, 24 Jan 2013 18:37:48 GMT

Recent news (http://tinyurl.com/ahv2vgx ) indicated that li-ion battery below the cockpit of the Boeing 787 that caught fire - while on the ground - may have been subjected to voltage exceeding the design limit. Some say it's the protection circuitry and other think it is the battery. It's important because Airbus and the International Space Station intend to use the same technology. Do we look for another battery technology or beef up the protection circuitry?

Going digital - good or bad?

noreply@digikey.com — Mon, 17 Dec 2012 12:21:47 GMT

When deciding whether to use a linear supply or a digital supply what pushes your decision to either direction? Do customers ask for the better control offered by digital control in power?

When to use a light pipe and diffuser?

noreply@digikey.com — Thu, 25 Oct 2012 11:34:13 GMT

For LCD backlighting, when is it best to use a light pipe?

When is it best to use a diffuser?

When and how do you use them together?

What types of each have you found to work best?

How worthwhile are webinars, virtual tradeshows?

noreply@digikey.com — Fri, 05 Oct 2012 11:50:41 GMT

The Internet offers us numerous ways to get information and one unique way is to virtually attend events such as trade shows, company product introductions, and even technical classes such as webinars.

Have you attended any of these virtual events? What do you think - do they provide what you expected/want? Would you like to see any changes?

Do you use twitter to get or ask technical information?

noreply@digikey.com — Mon, 10 Sep 2012 13:14:41 GMT

If you do follow twitter threads, which ones do you find the most helpful to get or stay current with your engineering discipline?

Do you tweet?

How to prevent reverse transients

noreply@digikey.com — Mon, 27 Aug 2012 11:02:36 GMT

Improperly installed batteries, hot-plug transients, faulty connections, and reversible third party USB chargers can all generate dangerous reverse bias or reverse transient situation as well as over-voltage spikes. Are there circuit designs that can minimize or prevent these transients or voltage spikes?

What type capacitors do you use in your LED lighting power supply?

noreply@digikey.com — Fri, 17 Aug 2012 20:27:30 GMT

The longevity of an LED lighting system is said to be significantly longer (about 5X longer) than the power supply for the lighting design. Some think that getting rid of the electrolytic capacitors in the power supply and replacing them with ceramic capacitors will improve the life span of the system. What is your experience?

2. When you are trouble shooting your design – where do you go first for help with power related problems?

noreply@digikey.com — Fri, 27 Jul 2012 14:31:56 GMT

The Internet, colleagues, manufacturer, somewhere else.