Bias current generation circuit

• Main Authors: Kuo, Chun-I, Min, Shawn, Ho, Chun-Ta
• Format: Patent
• Language: English
• Published: 27.09.2022
• Subjects: CONTROLLING; PHYSICS; REGULATING; SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES

The present invention discloses a bias current generation circuit. An operation amplifier compares an input voltage having a zero-temperature coefficient and a feedback voltage to generate a driving voltage. An output transistor generates a bias current according to the driving voltage. A variable resistive circuit is electrically coupled to the output transistor through a feedback node to generate the feedback voltage according to the bias current and includes series-coupled resistors and switch transistors. Each of the resistors has a resistance having a positive temperature coefficient and includes a current input terminal and a current output terminal. Each of the switch transistors is electrically coupled between the current output terminal of one of the resistors and a ground terminal. One of the switch transistors turns on according to a control voltage variable according to the temperature variation to enable resistors to generate the resistance having a negative temperature coefficient.