OVERCURRENT DETECTION CIRCUIT

• Main Author: MATSUDA KUNIHIKO
• Format: Patent
• Language: English; Japanese
• Published: 01.02.2018
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; PULSE TECHNIQUE; TESTING

PROBLEM TO BE SOLVED: To provide an overcurrent detection circuit capable of eliminating a possibility of a wrong detection on an overcurrent as much as possible.SOLUTION: A current circuit 12 draws a current through between the collector and emitter of a transistor Tr1 according to a constant reference voltage applied from a reference voltage generating circuit 10. A current circuit 13 outputs a bias at an electrification terminal of a transistor Tr3 from an input node Ni of a battery voltage BAT by a bias circuit B. The third transistor Tr3 inputs the bias to a control terminal and also feeds electricity to between the collector and emitter from an output node No. Further, second and third transistors Tr2 and Tr3 are so connected as to reduce variation of a fed current between the collector and emitter against temperature variation.SELECTED DRAWING: Figure 1 【課題】過電流を誤検出する可能性を極力なくすことができるようにした過電流検出回路を提供する。【解決手段】電流回路１２が、基準電圧生成回路１０から与えられる一定の基準電圧に応じてトランジスタＴｒ１のコレクタエミッタ間を通じて電流を引く。電流回路１３は、バイアス回路Ｂによりバッテリ電圧ＢＡＴの入力ノードＮｉからトランジスタＴｒ３の通電端子のバイアスを出力する。第３のトランジスタＴｒ３はバイアスを制御端子に入力すると共に出力ノードＮｏからコレクタエミッタ間に通電する。また、第２及び第３のトランジスタＴｒ２及びＴｒ３は温度変化に対するコレクタエミッタ間の通電電流の変化を低減するように接続されている。【選択図】図１