PROBLEM TO BE SOLVED: To provide a current detection circuit capable of detecting the current with respect to power supply voltage of 0 V.SOLUTION: The current detection circuit includes: a transmission power source 131 a floating power source 210 connected to the transmission power source a constant current source 220 connected to the floating power source an operational amplifier 234 with a power terminal connected to the floating power source a first resistance 231 connected across the transmission power source and a first input terminal of the operational amplifier a detection resistance 232 connected across the transmission power source and a second input terminal of the operational amplifier a variable current source 240 connected to the output terminals of the first resistance, the first input terminal and the operational amplifier and an output current voltage converting section 250 connected to the variable current source. The constant current source and the output current voltage converting section are connected to a power source of other than 0 V having inverse polarity of the transmission power source.COPYRIGHT: (C)2014,JPO&INPIT【課題】0Vの電源電圧に対して電流検出が可能となる電流検出回路を提供することを目的とする。【解決手段】送信部電源131と、送信部電源に接続されるフローティング電源210と、フローティング電源に接続される定電流源220と、フローティング電源に電源端子が接続されるオペアンプ234と、送信部電源とオペアンプの第1の入力端子の間に接続される第1の抵抗231と、送信部電源とオペアンプの第2の入力端子の間に接続される検出抵抗232と、第1の抵抗と第1の入力端子とオペアンプの出力端子に接続される可変電流源240と、可変電流源に接続される出力電流電圧変換部250とを備え、定電流源と出力電流電圧変換部は0V以外であって送信部電源と逆の極性をもつ電源に接続される。【選択図】図2
