TRANSIMPEDANCE AMPLIFIER

• Main Author: SUGIMOTO YOSHIYUKI
• Format: Patent
• Language: English; Japanese
• Published: 22.10.2015
• Subjects: AMPLIFIERS; BASIC ELECTRONIC CIRCUITRY; CONTROL OF AMPLIFICATION; ELECTRICITY

PROBLEM TO BE SOLVED: To provide a transimpedance amplifier on which downsizing is implemented while appropriately adjusting a response time.SOLUTION: A TIA1 includes a TIA core section 11, a differential amplifier 12, a bypass circuit 13 which extracts a part of current, and a feedback control circuit 14 which controls the amount of the current to be extracted. The feedback control circuit 14 includes: a filter circuit 18 by which a low-frequency component of an output signal is filtered out; a current switched voltage shift circuit 19 which includes a voltage controlled current source IS1 and to which an output signal of the filter circuit 18 is inputted; a current switched voltage shift circuit 20 which includes a voltage controlled current source IS2 and to which a first threshold voltage is inputted; a voltage comparator 21 which outputs a control signal for controlling the bypass circuit on the basis of output signals from the current switched shift circuits 19 and 20; and a hysteresis voltage comparator 22 for controlling the voltage controlled current sources IS1 and IS2 on the basis of the control signal and a second threshold voltage. 【課題】応答時間を適切に調整しながら、小型化を実現したトランスインピーダンス増幅器を提供する。【解決手段】ＴＩＡ１は、ＴＩＡコア部１１と、差動増幅器１２と、電流の一部を引き抜くバイパス回路１３と、引き抜く電流の量を制御する帰還制御回路１４と、を備えたＴＩＡ１であって、帰還制御回路１４は、出力信号の低周波成分を透過させて出力するフィルタ回路１８と、電圧制御電流源ＩＳ１を含み、フィルタ回路１８の出力信号が入力される電流開閉型電圧シフト回路１９と、電圧制御電流源ＩＳ２を含み、第１の閾値電圧が入力される電流開閉型電圧シフト回路２０と、電流開閉型電圧シフト回路１９，２０の出力信号に基づいて、バイパス回路を制御する制御信号を出力する電圧比較器２１と、制御信号及び第２の閾値電圧に基づいて、電圧制御電流源ＩＳ１，ＩＳ２を制御するヒステリシス電圧比較器２２と、を有する。【選択図】図３