Crowbar Circuits for the Caen Bias High Voltage supplies.

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• Caen High Voltage output diagram, PDF format, courtesy of Nicolla B.
• Document discussing the circuit design and safety considerations that was given to the CDF safety committee. Word Format. PDF Format.
• That document evolved into the specification document that applies to both designs below. Specifications - Word, Specifications - PDF

Two designs are proposed to accommodate the two versions of power supplies and their outputs.

Layer 00 Supplies. The output is capable of >500 volts and it is never split.

• Circuit Diagram for Layer 00 bias supplies, PDF format.
• Bill of Materials including costs for the Layer 00 crowbar module. PDF Format

SVX/ISL Split Bias Supplies. The outputs are sometimes split and the maximum voltage is <300 volts.

• Document discussing the issues complicating crowbar use on split power supplies. Word Format. PDF Format.
• Circuit Diagram for SVX/ISL split bias supplies, PDF format. Includes series diodes and shared voltage sensing.
• Second cut at the estimated Bill of Materials and costs for the SVX/ISL double crowbar module. PDF Format. This still has the expensive fuses.

 Fun with fuses

• The low amperage fuses are from Littlefuse. Here is the Data sheet in PDF.
• The fuses come in two cases with two lead variations. Our initial examination of the metal can version showed it to be ruggedly made but quite expensive. This X-ray shows the fuse wires coming in from the left with the fusible link between them, pointing off to the right. The circular shadow is an epoxy ball that supports the assembly. Only a small portion of the link is exposed. This happened to be a two amp fuse because a dash accidently replaced a period in the sample order.
• For cost reasons we purchased the plastic case versions at the correct amperage and found that our X-ray machine could not resolve the fusible link. We broke out the microscope and were impressed. This is a picture of a 2 milliamp fuse and this is a 5 milliamp version. Just for the fun of it we got a hair (straight, not curly) to compare. The hair is above the link.

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Last edited 8 March 2002, by Vince Pavlicek