Patent ID: 11965783
Assignee: REALTEK SEMICONDUCTOR CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A temperature sensing circuit, comprising:
a band gap voltage generating circuit generating a band gap voltage having a first temperature coefficient;
a current mirror branch mirroring an image current having a second temperature coefficient different from the first temperature coefficient from the band gap voltage generating circuit;
a variable resistor comprising a first end electrically coupled to the current mirror branch to receive the image current and generate a variable voltage at the first end;
a comparison circuit comparing the band gap voltage and the variable voltage to generate a comparison result;
a control circuit generating a control signal to continuously adjust a resistance value of the variable resistor according to the comparison result, and outputs a signal value when the signal value of the control signal forces the variable voltage to be substantially equal to the band gap voltage; and
a temperature determining circuit generating a temperature value according to the signal value,
wherein the band gap voltage generating circuit comprises:
a current source circuit having a first current output terminal and a second current output terminal;
a resistor comprising a first terminal electrically coupled to the first current output terminal and a second terminal, wherein the first terminal of the resistor generates the band gap voltage;
a pair of bipolar junction transistors, a first one of the pair of bipolar junction transistors is electrically coupled to the second terminal of the resistor, and a second one of the pair of bipolar junction transistors is electrically coupled to the second current output terminal; and
a voltage equalization circuit is electrically coupled to the first current output terminal and the second current output terminal, and control the current source circuit to make the first current output terminal and the second current output terminal having same voltage level.