Signal generating device, bandgap reference device and method of generating temperature-dependent signal

A signal generating device including a first circuit coupled between a first reference voltage and a second reference voltage and arranged to generate a first current to a first BJT; a first control circuit connected to the first BJT and arranged to adjust the first current. The first circuit outputs a part of a temperature-dependent signal on an output terminal, and includes: a first active device having a first and a second connecting terminal coupled to the first BJT; a second active device having a first connecting terminal coupled to the first BJT, and a second connecting terminal coupled to a second reference voltage; a first amplifier having an input terminal coupled to the first BJT, and an output terminal coupled to the control terminal of the first active device; and a second control circuit coupled to the first circuit for controlling the temperature-dependent signal according to the first current.