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Anonymous Poster

Solid State Equivalent of 60 SP3T Switches

09/29/2006 2:12 AM

I'm working on a (power) matrix switcher as part of a larger project and I have no experience with these. I need help choosing components that:

Take a single PWM signal as input

Have a small amount of processor power, 4 free registers

Triggers 60 solid state switches, this is what I need help with.

Each switch input needs 3 output states Out1 Out2 NotConnected

Future, prototypes may require the NC state to disconnect the input but short the outputs together

Switches must operate min 14kHz

V to each switch input 1V-60V

I to each switch input 50mA-40A future units up to 80A briefly

Dissipate less than 12% of input power through switch junctions, the lower the better as there is a size and weight target that limits heat sink size.

I thought a FPGA would be good for the logic but the power side has me stumped. MOSFET? Do I need to resort to relays?

slo
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#1

Re: Solid State Equivalent of 60 SP3T Switches

09/29/2006 8:31 AM

Start with a half bridge (half of an H-bridge) and driver which has the capability to control each gate output independently, thereby giving you the three states: ON 1, ON 2, OFF; also SHORT (but be careful -- transistors CAN blow up with significant explosive power)!

I would recommend either an IGBT or MOSFET designed for motor (inductive load) drivers. Multiple drivers can be controlled by adding buffers to digital outputs, but propagation delay times should be kept as close to the same as possible.

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Anonymous Poster
#2
In reply to #1

Re: Solid State Equivalent of 60 SP3T Switches

09/29/2006 6:47 PM

60 half bridges? I suppose that would work. Or emulate the half bridges within the FPGA by doubling the number of gates and linking pairs exclusive OR. I wonder If I could get this done with only 2 chips? Probably impractical to expect 120 40A IGBT devices in 1 package though. Any recommendations? My eyes aren't focusing very well today and too much coffee has given me a headache. Any help narrowing down the number of catalog pages I need to look at would be appreciated. slo
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