VOLTAGE-CURRENT CONVERTING CIRCUIT

摘要

PURPOSE:To improve the efficiency of a voltage-current conversion, by using enhancement type and depletion type electrodes to form a gate electrode of an insulated gate enhancement type MISFET which is used to a current mirror circuit. CONSTITUTION:Insulated gate enhancement type MISFET1 and 2 consist of a source region N<+>, a drain region N<+> and gate electrodes 6 provided via a channel region N<-> set between source and drain regions and a gate insulating layer. A gate electrode 6E is an enhancement type in which a p type impurity such as boron, etc. is introduced; while a gate electrode 6D is of depletion type in which an n type impurity such as phosphorus, etc. Therefore the mutual conductance is greatly high (with small ON resistance) when the gate voltage is approximate to the threshold voltage and is equivalent to the conventional value when the gate voltage is lower than the threshold voltage. This circuit improves the linearity of an output current to the input voltage.