I'm more or less wanting to know if my thinking is right...

I'm trying to put together some protection for a 12 to 5 volt power converter that I'll be using to power some gadgets in my truck.

The converter I'm planning to use is a Murata Power Solutions converter that can be found at

http://www.digikey.com/product-search/en?keywords=811-2692-nd

I've never dealt with tvs diodes before so I picked one with a breakdown voltage of 22V and clamp at 32V. The particular one is at http://www.digikey.com/product-search/en?keywords=497-4998-1-nd

For R1 I have chosen a 5 ohm 30 watt resistor. I found on the datasheet for the converter that at it's lowest input voltage of 7 it will draw 1.16 amps at maximum output. I used 7 volts and 2 amps of drop across R1 to come up with 3.5 ohms... then converted to 14 watts. The second least costly resistor on digikey happened to be the 5 ohm 30 watt.

The capacitor I'm not too sure. I'm basing this design off of another thread that explained this set up, but didn't show it. I don't remember what was recommended for it. I was thinking around 22000 mF if I remember correctly.

My logic may be a bit off and I'm wondering if I'm over sizing things. The converter datasheet recommends a 2 amp fuse for protection on the input side so I'll have a 2 amp ATC fuse somewhere before all of this yet.

I also just remembered a Schottky diode was mentioned... so I was thinking 150V 3A like the one here http://www.digikey.com/product-detail/en/stmicroelectronics/STPS3150RL/497-3216-1-ND/654568. If I remember that should come first right?

Thanks for your thoughts!!

I'm trying to put together some protection for a 12 to 5 volt power converter that I'll be using to power some gadgets in my truck.

The converter I'm planning to use is a Murata Power Solutions converter that can be found at

http://www.digikey.com/product-search/en?keywords=811-2692-nd

I've never dealt with tvs diodes before so I picked one with a breakdown voltage of 22V and clamp at 32V. The particular one is at http://www.digikey.com/product-search/en?keywords=497-4998-1-nd

For R1 I have chosen a 5 ohm 30 watt resistor. I found on the datasheet for the converter that at it's lowest input voltage of 7 it will draw 1.16 amps at maximum output. I used 7 volts and 2 amps of drop across R1 to come up with 3.5 ohms... then converted to 14 watts. The second least costly resistor on digikey happened to be the 5 ohm 30 watt.

The capacitor I'm not too sure. I'm basing this design off of another thread that explained this set up, but didn't show it. I don't remember what was recommended for it. I was thinking around 22000 mF if I remember correctly.

My logic may be a bit off and I'm wondering if I'm over sizing things. The converter datasheet recommends a 2 amp fuse for protection on the input side so I'll have a 2 amp ATC fuse somewhere before all of this yet.

I also just remembered a Schottky diode was mentioned... so I was thinking 150V 3A like the one here http://www.digikey.com/product-detail/en/stmicroelectronics/STPS3150RL/497-3216-1-ND/654568. If I remember that should come first right?

Thanks for your thoughts!!

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