I can't speak for Canada, but in the US if a court issues a search warrant for data stored on one of your devices you are obligated to take whatever steps are necessary to turn over the data, including decrypting the data if applicable. This power is provided to the government by the 4th Amendment. What you are likely referring to is the 5th Amendment right that protects a person from being compelled to testify against themselves, which protects a person from being compelled to turn over a password if doing so would incriminate them, but this is only applicable in circumstances where
turning over the password would incriminate you, not where the decryption of the data would incriminate you. This is applicable only in circumstances where it is uncertain whether you have access to the device in question, since compelling you to produce the password amounts to compelling you to admit that it is your device. Once a court is satisfied that it is beyond doubt that the device is yours and you know the password, a judge is free to compel you to provide the password.
There's a further consideration of whether you can refuse if the literal string of the password itself would incriminate you, but I don't believe that has been conclusively litigated.