JPS6247221U

JPS6247221U -

Info

Publication number: JPS6247221U
Application number: JP13775685U
Authority: JP
Priority date: 1985-09-09
Filing date: 1985-09-09
Publication date: 1987-03-23

Description

[Brief explanation of the drawing]

第１図は本考案の可変減衰器の実施例を示す回
路図である。第２図、第３図、第４図及び第５図
は本考案の互いに異なる他の実施例の要部を示す
回路図である。第６図は従来例の回路図であり、
第７図はその要部等価回路図である。第８図は他
の従来例の回路図である。Ｑ_１，Ｑ_２…差動対トランジスタ、Ｒ_１，Ｒ_２…負荷抵抗、Ｄ_１，Ｄ_２，Ｄ_３，Ｄ_４…ダイオー
ド、Ｑ_７，Ｑ_７ａ，Ｑ_７ｂ…制御トランジスタ、
７…供給手段、Ｑ_８…第１トランジスタ、Ｑ_９…
第２トランジスタ、Ｑ_１０，Ｑ_１１，Ｑ_１２，Ｑ
_１３…第３〜第６トランジスタ。 FIG. 1 is a circuit diagram showing an embodiment of the variable attenuator of the present invention. FIGS. 2, 3, 4, and 5 are circuit diagrams showing main parts of other different embodiments of the present invention. FIG. 6 is a circuit diagram of a conventional example,
FIG. 7 is an equivalent circuit diagram of the main part. FIG. 8 is a circuit diagram of another conventional example. Q ₁ , Q ₂ ... Differential pair transistor, R ₁ , R ₂ ...Load resistance, _D1 , _D2 , _D3 , _D4 ...Diode, _Q7 , _Q7a , _Q7b ...Control transistor,
7... Supply means, Q ₈ ... First transistor, Q ₉ ...
Second transistor, Q ₁₀ , Q ₁₁ , Q ₁₂ , Q
₁₃ ...Third to sixth transistors.

Claims

[Claims for Utility Model Registration] (1) A load resistor connected to an output electrode of a transistor, a diode connected between the load resistor and a reference potential point, and a control transistor that controls the conduction current of the diode. wherein the variable attenuator changes the amount of attenuation by changing the ratio of conduction resistance of the diode to the load resistance by the control means, wherein a control signal of the control transistor is applied and a predetermined relationship is established with the amount of current flowing through the control transistor. a first transistor through which an amount of current flows, and supply means for supplying the same amount of current to the diode as the amount of current flowing through the control transistor driven by the current of the first transistor. variable attenuator. (2) Utility model registration claim 1, characterized in that the load resistor consists of a pair of resistors connected to the output electrodes of each of two differential pair transistors.
Variable attenuator as described in section. (3) Registration of a utility model characterized in that the diodes are comprised of a pair of diodes, one end of which is individually connected to the pair of resistors, and the other ends of the pair of diodes are commonly connected to the control transistor. A variable attenuator according to claim 2. (4) The supply means includes a second transistor that supplies the current of the first transistor, and a third transistor that forms a current mirror circuit together with the second transistor.
, and a fourth transistor, the output electrodes of the third and fourth transistors are respectively connected to one end of the pair of diodes, and the current ratio of the control transistor and the first transistor is 2:1.
The variable attenuator according to claim 3, which is provided with means for setting the attenuator so that (5) The control transistor includes first and second control transistors whose control electrodes are connected in common, and the diode has one end connected individually to the pair of resistors and the other end connected to the first control transistor. first and second diodes, one end of which is individually connected to the pair of resistors and the other end of which is connected to the second resistor.
The supply means includes a second transistor that supplies the current of the first transistor, and third and fourth diodes that form a current mirror circuit together with the second transistor. , fifth and sixth transistors, and the output electrodes of the third, fourth, fifth and sixth transistors are connected to the first, second, third and fourth diodes, respectively. A variable attenuator according to claim 2 of the utility model registration claim. (6) The supply means includes a second transistor that supplies the electrode of the first transistor, and a third transistor that constitutes a current mirror circuit together with the second transistor.
a third transistor, the diode having one end connected to each of the pair of resistors and the other end commonly connected to the electrode of the third transistor;
a fourth diode, and the current from the third transistor flows through the third diode and the first diode to the control transistor;
The variable attenuator according to claim 2, which is a registered utility model, and divides the current into a diode and a current flowing to the control transistor through the second diode. (7) The diode is characterized in that one end is connected to the load resistor and the other end is connected to a reference potential point via a control transistor, and the control transistor operates near a saturation region. A variable attenuator according to claim 1 of the utility model registration claim.