Temperature sensing circuits are provided. The temperature sensing circuits may include a temperature sensing unit and a buffer unit. The temperature sensing unit may include a transistor that has a first pair of terminals having a first PN junction of the transistor therebetween and a second pair of terminals having a second PN junction of the transistor therebetween. The first pair of terminals are connected together. The temperature sensing unit may output a first temperature sensing voltage comprising a voltage between the second pair of terminals at a first node. The buffer unit may be connected to the first node. The buffer unit may have a cascode follower structure and may output a second temperature sensing voltage that has a magnitude proportional to a magnitude of the first temperature sensing voltage at a second node.