Yep. The charger that it was purchased with should have been 5W ( approximately 2.5 amps at 2 volts). The charger you have is not meant for the iPad Mini. It might be an iPhone charger. The iPhone chargers look identical to the iPad Mini charger, but don’t produce enough current to properly charge an iPad Mini.
Cheap knockoffs usually supple the right ammount of current for the devices they are meant for, but have other safety and reliability issues. Best to buy from Apple, or an Apple certified manufacturer like Belkin or Griffin.
Good luck with the new charger.