Oblon, Spivak, McClelland, Maier & Neustadt
Variable current source for variably controlling an output current in accordance with a control voltage
 In addition to a Gilbert amplifier 101 which includes transistors 1 to 4, a current mirror circuit 102 is disposed. The internal structure of a current supply block 103 is modified. The current supply block 103 linearly converts an externally supplied control voltage Vcont by linear voltage/current conversion and determines a collector current (of a current amount IB) of a transistor 47. The same amount (=IB) of current as this collector current is developed as a collector current of a transistor 42 of the current mirror circuit 102. A collector of the transistor 42 is connected to a current source 45 of the current supply block 103 and an emitter of the transistor 3. Hence, assuming that a current value of the current source 45 is Io, an emitter current IA flowing through the transistor 3 is determined as IA=Io-IB. As a result, an output current I1 of the transistor 1 which has its base connected to the emitter of the transistor 3 changes in proportion to the control voltage Vcont. 
Mitsubishi Denki Kabushiki Kaisha
G
G05F
inventional
Hiromitsu
Yamashita