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    TURN-OFF CONTROL CIRCUIT
    1.
    发明专利
    TURN-OFF CONTROL CIRCUIT 失效

    公开(公告)号：JPH0637548A

    公开(公告)日：1994-02-10

    申请号：JP12003393

    申请日：1993-05-21

    Applicant: ST MICROELECTRONICS SRL

    Inventor： NEBULONI DANIELA ,  FASSINA ANDREA

    IPC: H03F1/00 ,  H03F1/30 ,  H03G3/34

    Abstract: PURPOSE: To provide a turn-off control circuit for removing noise produced when a sound amplifier is turned off. CONSTITUTION: A clock means constituted of a control means 13 connected to a power line 11, a filter 17 as a voltage source connected to the control means 13 and a transistor 10 where an emitter is connected to the output terminal of the sound amplifier 1, is grounded through a switch 15 and a base is connected to the control means is provided.

    ON-OFF CONTROL CIRCUIT AND AMPLIFICATION CIRCUIT FOR AUDIO AMPLIFIER AND ON-OFF METHOD OF AUDIO AMPLIFIER
    2.
    发明专利
    ON-OFF CONTROL CIRCUIT AND AMPLIFICATION CIRCUIT FOR AUDIO AMPLIFIER AND ON-OFF METHOD OF AUDIO AMPLIFIER 失效

    公开(公告)号：JPH0637560A

    公开(公告)日：1994-02-10

    申请号：JP12154793

    申请日：1993-05-24

    Applicant: ST MICROELECTRONICS SRL

    Inventor： NEBULONI DANIELA ,  FASSINA ANDREA

    IPC: H03F1/00 ,  H03F1/30 ,  H03G1/04 ,  H03G3/34

    Abstract: PURPOSE: To provide a circuit for controlling the on/off-switching of an audio amplifier with a method for preventing the steep fluctuation of output (V0 ) during switching, which is not suppressed, and preventing the production of noise (popping) that is not desirable in a loudspeaker. CONSTITUTION: The circuit for generating positive potential (V->V+) controlled by a negative input terminal against the positive input terminal of the audio amplifier 1 when the audio amplifier 1 is on/off-switched is provided. Particularly when on-switching, a potential difference is maintained while all the powers of the audio amplifier 1 are switched and it is removed for making output (V0 ) reach a standby state value at a slow and controlled mode. The potential difference in off-switching is gradually generated for gradually grounding the output of the audio amplifier 1 before the audio amplifier 1 itself is turned off.

    5.
    发明专利
    未知

    公开(公告)号：DE60030543D1

    公开(公告)日：2006-10-19

    申请号：DE60030543

    申请日：2000-06-13

    Applicant: ST MICROELECTRONICS SRL

    Inventor： BRAMBILLA DAVIDE ,  NEBULONI DANIELA ,  CLERIS MAURO

    IPC: H03F1/34 ,  H03F1/32

    Abstract: The amplifier (1, 2) has an input (2a); an output (2c) supplying an output signal (Vo), and a feedback network (5) connected between the input (2a) and the output (2c), and a distortion detection circuit (1). The feedback network (5; 55) includes a first and a second feedback element (6, 7) arranged in series and forming an intermediate node (10) supplying an intermediate signal (VB) in phase with the output signal (Vo) in absence of distortion, and in phase-opposition with the output signal in presence of distortion. The distortion detection circuit (1) includes a phase-comparating circuit (12, 15) which detects the phase of the output signal (Vo) and of the intermediate signal (VB), and generates a distortion-indicative signal (VCD), when the intermediate signal (VB) is in phase opposition with respect to the output signal (Vo).

    6.
    发明专利
    未知

    公开(公告)号：DE69533696D1

    公开(公告)日：2004-12-02

    申请号：DE69533696

    申请日：1995-08-31

    Applicant: ST MICROELECTRONICS SRL

    Inventor： BRAMBILLA DAVIDE ,  NEBULONI DANIELA ,  ROSSI GIORGIO ,  LECCE SERGIO

    IPC: G05F3/26 ,  H03F3/345

    Abstract: A current generator circuit with controllable frequency response is of a type which comprises at least one current mirror formed of MOS transistors, being powered through a terminal held at a constant voltage, having an input leg through which a reference current (I1) is driven by a first current generator (G1), and having an output leg for generating, on an output terminal (OUT) of the mirror, a mirrored current (Iout) which is proportional to the reference current (I1). The input leg includes at least a first transistor (M1) which is diode-connected and has a control terminal (Ga1) coupled to a corresponding terminal (Ga2) of a second transistor (M2) included in the output leg. In accordance with the invention, the mirror circuit further comprises an impedance matching means (3) connected across the control terminals (Ga1 and Ga2) of the first and second transistors and configured to hold the same voltage value at both terminals (Ga1 and Ga2). The impedance matching means (3) has an adjustable output impedance, specifically lower in value than the value to be had without this means. It functions to regulate the impedance on the control node (Ga2) of the second transistor (M2). The invention is equally applicable to N-channel and P-channel MOS transistors. Advantageously, the reference current can be varied by an external signal which is a function of the output signal, to provide feedback regulating features.

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