Compensation network for pinch off voltage sensitive circuits

摘要

A control circuit is provided that can be used to compensate for pinch off voltage sensitive circuits. The control circuit comprises a control FET (26) having a gate (27), a drain (29), and a source (28). The control FET source (28) is connected to a tracking potential (23) through control FET source resistor (31) in series with a constant voltage drop element (32). A control voltage input (22) is applied to the control FET drain (29). A current flow through the control FET (26) results in a transfer function that is substantially linear for linear changes in control voltage input below a voltage pinch off value of the control FET (26). As the voltage control output (23) approaches the pinch off voltage value of the control FET (26), smaller changes in control voltage output (23) are realized for the same change in control voltage input (22).