I develop products that are sold all over the world. The line voltage may be one of (100, 120, 220, 240). I am currently considering options for handling this requirement. We typically have a 5V rail that needs a couple amps, and 15V rails that need under an amp. Perhaps another tap with a higher voltage.
Transformer and Linear Regulators: This is what we presently do. We have a power entry module like this where the user can install the fuse differently to select the correct voltage.
- Pros: Clean Supply (we measure extremely small signals with these devices), Simple to achieve Galvanic isolation with multiple secondaries, With undervoltage and overvoltage accounted for, the device is not damaged even if the fuse is installed incorrectly.
- Cons: Bulky Transformer, We have to change the fuse drawer based on destination address which adds a manufacturing step. Also, we occasionally sell to OEMs who then resell their system to unknown addresses.
Switched Mode Power Supply:
- Pros: Can handle variable input voltage.
- Cons: The switching introduces noise which will impact the performance of some of our products.
I am not asking for a decision from the above options, but rather wondering if there are any other options to put on the list. What do you guys do?