CONSTANT VOLTAGE GENERATION CIRCUIT

• Main Authors: YOSHII KOJI, MITSUI KENJI
• Format: Patent
• Language: English; Japanese
• Published: 03.04.2024
• Subjects: CONTROLLING; PHYSICS; REGULATING; SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES

To prevent malfunction in which a plurality of modes are continuously transited, by suppressing accuracy deterioration of an output voltage.SOLUTION: A constant voltage generation circuit includes: a first amplifier circuit that drives a transistor configured to control an output current, based on a reference voltage; a second amplifier circuit that operates at a higher speed than the first amplifier circuit and drives the transistor based on a reference voltage; a protection circuit that limits an output current flowing from the transistor to a load; and a control circuit that controls the operation of the second amplifier circuit. The control circuit executes control as follows: the second amplifier circuit is not operated until the output current increases to a second threshold current while the second amplifier circuit is operated when the output current becomes equal to or larger than the second threshold current; the second amplifier circuit is operated until the output current decreases to a first threshold current smaller than the second threshold current; and the second amplifier circuit is not operated when the output current becomes equal to or smaller than the first threshold current. The second amplifier circuit includes an operating potential fixing circuit for fixing an operating potential of an internal node during non-operation.SELECTED DRAWING: Figure 1 【課題】出力電圧の精度劣化を抑制し複数のモードを遷移し続ける誤動作を防止する。【解決手段】定電圧発生回路は、基準電圧に基づいて出力電流を制御するトランジスタを駆動する第１の増幅回路と、第１の増幅回路に比較して高速で動作し、基準電圧に基づいてトランジスタを駆動する第２の増幅回路と、トランジスタから負荷に流れる出力電流を制限する保護回路と、第２の増幅回路の動作を制御する制御回路を含む。制御回路は、出力電流が増大し、第２のしきい値電流までは、第２の増幅回路を動作させず、第２のしきい値電流以上となったときに、第２の増幅回路を動作させる一方、出力電流が減少し、第２のしきい値電流よりも小さい第１のしきい値電流までは、第２の増幅回路を動作させ、第１のしきい値電流以下となったときに、第２の増幅回路を動作させないように制御する。第２の増幅回路は非動作時に内部ノードの動作電位を固定する動作電位固定回路を含む。【選択図】図１