Bias circuit for supplying a bias current to a RF power amplifier

• Main Author: WU CHIH-WEN
• Format: Patent
• Language: Chinese; English
• Published: 12.02.2019
• Subjects: AMPLIFIERS; BASIC ELECTRONIC CIRCUITRY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TELEPHONIC COMMUNICATION

The invention discloses a bias circuit for providing a bias current to a radio frequency power amplifier and a circuit for amplifying a radio frequency signal received in a mobile device. The bias circuit uses a plurality of voltage reference circuits coupled between a base terminal of a bipolar transistor and a voltage source for generating a bias current to a radio frequency power amplifier to provide a bias current to the RF power amplifier. Each of the plurality of voltage reference circuits has a node clamped to a reference voltage, the node being coupled to a conductive path from the voltage source to a base terminal of the bipolar transistor. When the current flowing from the voltage source increases, the current flowing through each of the plurality of voltage reference circuits also increases, so that compared to the range of variation of the current flowing out of the voltage source the variation range of current flowing into the base terminal of the bipolar transistor remains within a small range.