A MOSFET AMPLIFIER AUTOTRACKING BIASING CIRCUIT
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Nov-30
Figure 1 shows a closed loop system for MOSFET biasing. It provides an automatic and precise temperature compensation to any MOSFET regardless of its electrical size and g,. No temperature sensing elements need to be coimected to the heat sink or to the device housing. In fact FETs with different gate threshold voltages can be changed in the amplifier without affecting the level of the idle current. The gate threshold voltage range is about *0.5V with a single initial setting of the idle current. This means that the gate threshold voltage can vary within these limits in short or long term for other reasons than temperature effects as well. These include such as moisture, atmospheric pressure, etc.