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Paul Illegems

Can You Easily Build Integrated Power Switches? Part 2

Paul Illegems
JAYARAMAN KIRUTHI VASAN
JAYARAMAN KIRUTHI VASAN
12/9/2013 1:30:08 AM
User Rank
Master
Re: AC switch
Paul,

I understand the anti-parallel combination of an SCR makes a triac.

Having an in-built switch inside a mixed signal device provides host of benefits. For example, an already available feature has been the provision for switching ADC/DAC voltage references on/off through firmware.

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Paul Illegems
Paul Illegems
12/2/2013 11:29:35 AM
User Rank
Newbie
Re: AC switch

Jayaraman, A triac is a discrete component, with a dedicated production process. It is a variation on an SCR device (pnpn structure) to make it bidirectional. In the article I'm writing about a switch on a mixed signal chip with many other circuits. Such switches often have other circuits on the same die, like current limiters and other features. One example is a USB port power controller & charger chip. Such a device has many circuits beside the power switch. The challenge is to create a very low impedance switch in a standard process that was developed for regular (low power) analog and digital circuits. 

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JAYARAMAN KIRUTHI VASAN
JAYARAMAN KIRUTHI VASAN
11/25/2013 4:18:22 AM
User Rank
Master
AC switch
Paul,

Much of the information in this post is new to me. 

The information is related to DC switches. Is designing an AC switch like a triac easier than a DC switch? 

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RedDerek
RedDerek
11/19/2013 7:52:36 PM
User Rank
Master
Low MOSFET switch method
When driving towards a low Rds switch, two methods were approached.

First was the topology of the MOSFET. This is where the industry went from a planar topology to a vertical topology. And for the vertical, it was then increasing cell density to pack more and more MOSFETs in the same area.

Second is packaging, the bondwires were tossed out years ago in favor of bumps and clips. Vishay and IR both led the market in this type of technology and licensed out to the other folks - Renesas, Fairchild, IXYS, NXP, Infineon, STMicro.

The end result was the lowest Rds back around 2003 was sub 0.5 milliOhm. The problem after this is the measurment method since a lot of current is required to get a high enough voltage drop to make sense of reading.

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