ABNORMALITY DETECTION CIRCUIT

To provide an abnormality detection circuit capable of detecting the abnormality of a protection element.SOLUTION: An abnormality detection circuit is equipped with a first switching element 31, a second switching element 42, a detecting portion 55 that detects the voltage of a capacitor 44, a protection element 32 that has a first terminal 321 connected to a power supply terminal 21 of a load 2 and a second terminal 322 connected to the capacitor 44, and prohibits a current flow from the second terminal 322 to the first terminal 321, excluding in a case where the voltage of the second terminal 322 is higher than that of the first terminal 321 and voltage between the terminals exceeds a predetermined pressure, and a control portion 6. The control portion 6 brings the second switching element 42 into a non-energization state after charging the capacitor 44, executes switching processing for bringing the first switching element 31 into the energization state and then switching it to a non-energization state, and determining whether or not a protection element 32 is abnormal on the basis of a detection value of the detecting portion 55 after the switching processing is completed.SELECTED DRAWING: Figure 1 【課題】保護素子の異常を検出することができる異常検出回路を提供する。【解決手段】本発明は、第１スイッチング素子３１と、第２スイッチング素子４２と、コンデンサ４４の電圧を検出する検出部５５と、負荷２の電源端子２１に接続された第１端子３２１、及びコンデンサ４４に接続された第２端子３２２を有し、第２端子３２２の電圧が第１端子３２１の電圧より高く且つ端子間電圧が所定圧を超えた場合を除いて、第２端子３２２から第１端子３２１への電流の流れを禁止する保護素子３２と、制御部６と、を備え、制御部６は、コンデンサ４４が充電された後に第２スイッチング素子４２を非通電状態にし、続いて第１スイッチング素子３１を通電状態にしてから非通電状態に切り替える切替処理を実行し、切替処理完了後の検出部５５の検出値に基づいて保護素子３２が異常であるか否かを判定する。【選択図】図１