CURRENT/VOLTAGE CONVERSION CIRCUIT

PROBLEM TO BE SOLVED: To make a band to be side and to improve conversion efficiency by providing a base ground-type transistor where a collector is connected to resistance and an emitter is connected to a current signal source between a current signal source and resistance. SOLUTION: An NPN-type transistor 10 where the collector is connected to resistance 2, the emitter is connected to a connection terminal 5 and reference voltage Vref is applied to a base is provided between resistance 2 and a connection terminal 5. Capacity CCB between the collector and the base of the transistor 10 is considerably small compared with parasitic capacity CPD having considerably large capacity in general. Thus, a passage frequency band characteristic considerably improves. Even when the resistance value of resistance 2 is enlarged for improving conversion efficiency , the passage frequency band characteristic can be kept to be considerably high. When the passage frequency band characteristic is not required to be set so high, conversion efficiency can considerably be improved.