Patent Number: 7,612,614

Title: Device and method for biasing a transistor amplifier

Abstract: Provided is circuitry for biasing a transistor amplifier with a DC-voltage signal, the transistor amplifier having a first input terminal, a second input terminal, and an output terminal coupled to the second input terminal. The circuitry includes a sensor capacitor connected to the first input terminal and an impedance transistor arranged in parallel with said capacitor, the transistor and capacitor forming a low-pass filter. The circuitry also includes a biasing circuit configured to controllably vary a DC-voltage signal for operatively biasing the amplifier, the biasing circuit including a cascaded current arrangement configured to subdivide a reference current into smaller currents for selectively generating voltage potentials for biasing the impedance transistor to adjustably filter a noise component of the DC-voltage signal via the low-pass filter before the DC-voltage signal is provided to the first input terminal.

Inventors: Li; Ping Wai (Shatin, HK), Li; Cong Ke (Shatin, HK), Wang; Wei (Shatin, HK)

Assignee: Kontel Data System Ltd.

International Classification: H03F 3/04 (20060101)

Expiration Date: 1/03/02017