Monday, June 30, 2014

An Insider’s Look at High Voltage Fat Pack Rectifiers and Single Phase Bridges

In a previous post, we discussed VMI’s Slim Pack and Slim Pack Junior rectifier assemblies.  If you recall, these are axial-leaded assemblies containing one or more diodes in a string.  The diodes have been soldered or welded together, and then over potted. 

The advantages of high voltage sticks over discrete diodes are:

1) You can pack a lot of high voltage in one assembly

2) They can be configured in different ways such as building your own  single or three phrase bridge. 

3) Many of them can run in air without additional conformal coating or over encapsulation.

4) Reduced system component count.

5) Reduced system assembly time.  It’s faster to solder two leads than 22 leads.
Slim Packs (SP) are rated at 500mA and up to 20kV.

Slim Pack Juniors (SPJ) are rated at 50mA and up to 45kV.  Slim Pack Juniors are smaller and require conformal coating or encapsulation when operating at greater than 5kV.

Fat Pack High Voltage Stacks 

Okay, enough of the review already!  Continuing on in the line of rectifier assemblies, today’s topics include include VMI’s Fat Pack rectifier assemblies (FP) and our single phase bridges (SPB).  By the way, “Fat Packs” were called that by our manufacturing crew as a kind of verbal shorthand to distinguish them from “Slim Packs”.  The name stuck.  (To those Fat Packs who may take offense at being called a Fat Pack, no offense intended.  Perhaps you could slow down, look inward, and learn to love-thy-self.  You are perfect and beautiful just the way you are, and don’t let anyone tell you otherwise.  Plus, you can handle more than four times the current that a Slim Pack can).   

Fat Packs range from 2500V up to 25kV.  They can handle up to 2.2A of forward current, and are available in 100ns and 150ns reverse recovery times.  They measure 0.70” height, 0.400” width, and up to 7.9” in length.   They’re pretty heavy duty in comparison to most high voltage stacks.

Fat Pack Data Sheets
FP25F – 150ns

FP100F – 150ns

FP175UF – 100ns FP175F – 150ns
FP50F – 150ns

FP125F – 150ns

FP200UF – 100ns FP200F – 150ns
FP75F – 150ns
FP150F – 150ns
FP250U – 100ns

High Voltage Single Phase Bridges

Fat Packs, Slim Packs, and Slim Pack Juniors can all be configured to make a single-phase bridge.  It takes four of them to do so.  Or, you could go with a SPB assembly – VMI’s single phase bridges. 

These bridges come in a rectangular package ranging from 1.5” to 2.5” square and 0.6” tall (excluding terminations).  Terminal options include pins or four 4-40 inserts for mounting to a heat sink.

Each leg is made up of one or more diodes connected in series that have been tested for thermal response.  Thermal response testing verifies the internal integrity of the diode and makes sure the diode will dissipate internal heat in an efficient manner.  

Electrical properties range from 5kV to 20kV per leg.  All the bridges listed below are 70ns, 2A devices.,
5kV to 45kV High Voltage 1P Bridge with Inserts
"B" - 1P Bridge - Insert Terminals
High Voltage 1P Bridge with Pin Terminals - 5kV to 45kV per leg
"A" - 1P Bridge - Pin Terminals

The “A” suffix indicates pin terminals, as in SPB50UFA.
The “B” suffix indicates inserts are used, as in SPB50UFB. 

Data Sheets - Single Phase Bridges - 5kV to 20kV per leg 

So… summarize, VMI offers the following in high voltage stacks and single phase bridges - 

Type          Family     Voltage       Current        Trr
HV Stack   SP        2.5kV–25kV     500mA       70ns - 150ns
HV Stack   SPJ       10kV–45kV      50mA         70ns - 3000ns
HV Stack   FP        2.5kV–25kV      2.2A         100ns - 150ns
1P Bridge  SPB       5kV – 20kV       2.0A         70ns

If none of the above fits your needs, contact us.  Custom rectifier designs are welcome.

No comments:

Post a Comment