Deluga, Waldemar, and Iwona Zych in their article titled “Jewish Printed Amulets.” |(Print Quarterly 20, no. 4 (2003): 369-373.) claim that the Star of David appears on many Printed Amulets that once hung above a newborn’s bed. It appears under the opening text which is always from Psalm 20."The oldest known amulet was made as a single-leaf print in Prague in the 17th century. The woodcut illustrations have clearly been reused in this amulet; the original woodcuts were probably quite worn. Elements of the typographic decoration resemble those in Czech prints. It seems that the blocks used in some Jewish prints in Prague were exported to other European locales”.
CC picture from Jewish Encyclopedia