公开(公告)号：EP0570655A1

公开(公告)日：1993-11-24

申请号：EP92830254.6

申请日：1992-05-22

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Nebuloni, Daniela ,  Fassina, Andrea

IPC: H03G3/34 ,  H03F1/30

CPC classification number: H03G3/348 ,  H03F1/305

Abstract: A circuit (15) for controlling on-off switching of an audio amplifier (1) in such a manner as to prevent sharp uncontrolled variations of the output (V o ) during switching from resulting in undesired noise (popping) on the loudspeakers. For so doing, the circuit provides for generating a controlled positive potential at the negative input in relation to the positive input of the amplifier (V- > V+) when this is switched on or off. More specifically, when switching on, the potential difference is maintained pending switching of all the sources on the amplifier, after which, it is gradually eliminated for enabling the output (V o ) to reach the steady-state value slowly and in controlled manner; whereas, when switching off, the potential difference is generated gradually for enabling the output of the amplifier to be grounded slowly prior to turning off the amplifier (1) itself.

Abstract translation: 一种用于控制音频放大器（1）的开关切换的电路（15），以防止在切换期间输出（Vo）的急剧不受控制的变化，从而导致扬声器上的不期望的噪声（弹出）。 为此，该电路提供了在负极输入时相对于放大器的正输入（V→V +）产生一个受控的正电位，当这被打开或关闭时。 更具体地，当接通时，在放大器的所有源的切换之前，电位差保持不变，之后逐渐消除，使得输出（Vo）能够缓慢地并以受控的方式达到稳态值; 而当关断时，电位差逐渐产生，以使放大器的输出在放大器（1）本身关断之前缓慢接地。

公开(公告)号：EP0760555A1

公开(公告)日：1997-03-05

申请号：EP95830369.5

申请日：1995-08-31

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Brambilla, Davide ,  Nebuloni, Daniela ,  Rossi, Giorgio ,  Lecce, Sergio

IPC: H03F3/345 ,  G05F3/26

CPC classification number: H03F3/345 ,  G05F3/267

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 (I out ) 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.

Abstract translation: 具有可控频率响应的电流发生器电路是一种类型，其包括由MOS晶体管形成的至少一个电流镜，通过保持在恒定电压的端子供电，具有输入支路，参考电流（I1）通过该输入支路由 第一电流发生器（G1），并且具有用于在所述反射镜的输出端子（OUT）上产生与所述参考电流（I1）成比例的镜像电流（Iout）的输出支路。 输入支路至少包括二极管连接的第一晶体管（M1），并且具有耦合到包括在输出支路中的第二晶体管（M2）的相应端子（Ga2）的控制端子（Ga1）。 根据本发明，镜电路还包括连接在第一和第二晶体管的控制端（Ga1和Ga2）两端的阻抗匹配装置（3），并被配置为在两端（Ga1和Ga2）处保持相同的电压值， 。 阻抗匹配装置（3）具有可调节的输出阻抗，具体值低于没有这种方法的值。 它用于调节第二晶体管（M2）的控制节点（Ga2）上的阻抗。 本发明同样适用于N沟道和P沟道MOS晶体管。 有利地，参考电流可以通过作为输出信号的函数的外部信号来改变，以提供反馈调节特征。

公开(公告)号：EP0427135B1

公开(公告)日：1996-09-11

申请号：EP90121025.2

申请日：1990-11-02

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Botti, Edoardo ,  Stefani, Fabrizio ,  Nebuloni, Daniela

IPC: H03F1/32 ,  H03F1/34

CPC classification number: H03F1/34 ,  H03F1/3217

公开(公告)号：EP0427135A3

公开(公告)日：1991-09-11

申请号：EP90121025.2

申请日：1990-11-02

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Botti, Edoardo ,  Stefani, Fabrizio ,  Nebuloni, Daniela

IPC: H03F1/32 ,  H03F1/34

CPC classification number: H03F1/34 ,  H03F1/3217

Abstract: A circuit for sensing the output distortion of amplifier stages (3) of the type which has a first input which receives a voltage signal (V IN ) to be amplified, a second input connected to a feedback network (R₁,R₂) and an output which generates an amplified output signal (V OUT ). The circuit comprises at least one comparator (5,6,8), which receives in input a first signal (V REF ) which is correlated to the voltage signal (V IN ) and a second signal (V-) which is correlated to the output signal (V OUT ) of the amplifier stage (3), and is enabled so as to generate a distortion signal (ΔV) in output when the second signal (V-) exceeds the first one (V REF ) in terms of absolute value, i.e. in the presence of distortion.

公开(公告)号：EP0576770A1

公开(公告)日：1994-01-05

申请号：EP92830253.8

申请日：1992-05-22

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Nebuloni, Daniela ,  Fassina, Andrea

IPC: H03F1/30 ,  H03G3/34

CPC classification number: H03F1/305 ,  H03G3/348

Abstract: A circuit comprising a transistor (10) which, when supply (V S ) is turned off, locks the output (9) of the audio amplifier (1) to the supply line (11), the potential of which is reduced gradually by a filter capacitor (25), so that the output voltage (V o ) follows the supply voltage (V S ) with the same slope, and is so controlled by the filter capacitor (25), thus eliminating undesired noise ("popping") at the output (9) caused by electric transients in the audio amplifier.

Abstract translation: 一种电路，包括晶体管（10），当电源（VS）截止时，所述晶体管（10）将所述音频放大器（1）的输出（9）锁定到所述电源线（11），其电位通过滤波器逐渐减小 电容器（25），使得输出电压（Vo）以相同的斜率跟随电源电压（VS），并且被滤波电容器（25）控制，从而消除输出端的不期望的噪声（“弹出”）（ 9）由音频放大器中的电瞬变引起。

公开(公告)号：EP0427135A2

公开(公告)日：1991-05-15

申请号：EP90121025.2

申请日：1990-11-02

Applicant: SGS-THOMSON MICROELECTRONICS S.r.l.

Inventor： Botti, Edoardo ,  Stefani, Fabrizio ,  Nebuloni, Daniela

IPC: H03F1/32 ,  H03F1/34

CPC classification number: H03F1/34 ,  H03F1/3217

Abstract: A circuit for sensing the output distortion of amplifier stages (3) of the type which has a first input which receives a voltage signal (V IN ) to be amplified, a second input connected to a feedback network (R₁,R₂) and an output which generates an amplified output signal (V OUT ). The circuit comprises at least one comparator (5,6,8), which receives in input a first signal (V REF ) which is correlated to the voltage signal (V IN ) and a second signal (V-) which is correlated to the output signal (V OUT ) of the amplifier stage (3), and is enabled so as to generate a distortion signal (ΔV) in output when the second signal (V-) exceeds the first one (V REF ) in terms of absolute value, i.e. in the presence of distortion.

Abstract translation: 用于感测具有接收要放大的电压信号（VIN）的第一输入的类型的放大器级（3）的输出失真的电路，连接到反馈网络（R1，R2）的第二输入和输出， 产生放大的输出信号（VOUT）。 电路包括至少一个比较器（5,6,8），其在输入端接收与电压信号（VIN）相关的第一信号（V REF）和与输出信号相关的第二信号（V-） （VOUT），并且当第二信号（V-）以绝对值表示超过第一信号（VEF）时，使得能够在输出中产生失真信号（DELTA V），即在 存在失真。