Power Amplifier (Buffer) With Low Output Impedance and Current Measurement Capability
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
This article describes an amplifier which exhibits a low output impedance without inducing thermal runaway. The amplifier permits accurate output current measurement over several decades. Active current limiting and tristateable load disconnect are also achievable. (Image Omitted) The power amplifier 10 shown in Fig. 1 is represented by a five port device. The input and bias control ports draw negligible current. The current entering the amplifier is monitored with sense resistors (RS). The current monitoring circuit 12 separates the components of the amplifier output IO and bias currents IB. The bias current is compared with a reference and active feedback is employed to maintain this value. The actual configuration of the power amplifier is dependent on the particular circuit requirements.