JPH02180415A - Constant current device - Google Patents

Abstract

PURPOSE:To make the device highly accurate and to broaden the normal operating range of an output terminal by connecting plural NPN transistors(TR) while using the base in common so that (n) pieces of output sides may be provided for a single reference side, and connecting aluminum wiring to the emitter. CONSTITUTION:The emitter of a reference side TR 3, and the emitters of the (n) pieces of output side TRs 4 are grounded respectively through a resistance 5 and a resistance 6. An aluminum wiring pattern part 12 is formed on a wiring substrate A in a small width and a long dimension. Thus a fine resistance smaller than or equal to several OMEGA 10 can easily be formed in a small area. The above mentioned pattern part 13 functions as a resistance 6, and to its intermediate part, the pattern part 12 as a resistance 5 is integrally connected. Consequently by suitably contriving the form and dimension of the aluminum wiring pattern which can easily be worked by normal manufacture, the above- mentioned fine resistance with high accuracy can be prepared in a small area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a constant current device that mainly constitutes a one-sided current mirror constant current circuit with a large current output.

[Conventional technology]

Conventionally, a large current constant current output circuit as this type of constant current device has a non-inverting input terminal (21
) is connected to the output side of the operational amplifier (22) having an NPN transistor (23
) is connected to the base of the operational amplifier (22), and the emitter serves as the inverting terminal and output terminal of the operational amplifier (22), and a discrete resistor (24) with a small value is connected to this output terminal r. ) is the voltage V applied to the non-inverting input terminal (21) of
. It is known that the current value is determined by dividing by the resistance value RL of the discrete resistor (24).

[Problem to be solved by the invention]

However, in the conventional constant current device as described above, a voltage rise occurs due to the discrete resistor (24), and the voltage range on the low voltage side of the output terminal (25) that maintains normal constant current operation is reduced by the discrete resistor (24). There is an inconvenience that the width is narrowed by the voltage increase Vn caused by 24).

In addition, when using a current mirror one-type constant current circuit,
In order to improve current accuracy, it is common practice to connect a resistor to the reference side transistor and the output side transistor Niemi9 to compensate for variations in the performance of each transistor. In current mirror circuits, it is necessary to minimize the emitter resistance in order to expand the normal operating range on the low voltage side of the output terminal.
When a P-type diffused resistor used in a typical semiconductor integrated circuit is used, there is a problem in that a large-area resistor formation part is required in order to achieve the required accuracy.

The present invention has been made in view of these problems, and an object of the present invention is to provide a constant current device that is highly accurate and has a wide normal operating range of its output terminal.

[Means to solve the problem]

In order to achieve the above object, the constant current device of the present invention connects a plurality of NPN transistors with their bases in common, such that there is one on the reference side and n on the output side (n is any natural number). Further, the present invention is characterized in that a minute resistor formed by patterning aluminum wiring as a minute resistance component is connected to the emitter of each of the NPN transistors.

[For production]

The shape and dimensions of aluminum wiring patterns can be easily modified using normal manufacturing methods, so this
By functioning as a minute resistance component connected to the emitter of a PN transistor, it is possible to compensate for variations in transistor performance and realize a constant current output circuit with high accuracy and a wide normal operating range of the output terminal.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows the circuit configuration of an embodiment in which the present invention is applied to a current mirror one-type constant current device.
(1) is a power supply terminal, and a constant current power supply (2) serving as a reference for the current mirror circuit is connected to this power supply terminal (1). (3) is the base ring “side NPN transistor, (4
)... are n output side NPN transistors (n is a natural number), and the emitter of the base side transistor (3) is connected to each output side transistor (4) through a resistor (5). The emitters of . . . are each grounded via a resistor (8). In addition, the reference side transistor (3) and the output side transistor (4) which has a ratio of 1 to n.
... are connected so that the base is common,
The common base of these transistors (3), (4), etc. and the collector of the reference side transistor (3) are respectively connected to the constant current voltage IrA (2). Historically, the emitters of the output transistors (4) are commonly connected to the constant current output terminal (7).

FIG. 2 shows a wiring pattern in a semiconductor integrated circuit device having the above circuit configuration. In this figure, (
A) is a wiring board on which each pattern portion described below is formed. (8) is a pattern portion corresponding to the reference side transistor (3), and in this pattern portion (8), (8a) is the collector, (8b) is the base, (8c)
is the emitter. (9) is the output side transistor (4)
. . . In this common pattern portion (9), (9a) is the collector, (9b
) is the base, and (9c) is the emitter. Also, (10
) are the collector (8a) and base (8b) of the reference side transistor pattern section (8), the base (9b) of the output side transistor common pattern section (9), and the constant current power supply (
2) Aluminum wiring pattern part formed between (I
I) is an aluminum wiring pattern portion formed between the collector (9a) of the output side transistor common pattern portion (9) and an output pad (not shown) serving as a constant current output terminal (7).

Furthermore, (12) is the base side transistor pattern part (8
) The aluminum wiring pattern portion as the resistor (5) is drawn out from the emitter (8c) of the wiring board (A)l, and is formed in a narrow width and long dimension on the wiring board (A)l, and has such a configuration. Therefore, a microresistance of several tens of ohms or less can be easily formed in a small area, and a current mirror one-way constant current circuit that can handle large currents can be realized with high precision. (13) is the output side transistor common pattern part (9
) is an aluminum wiring pattern part drawn out from the emitter (9C), and functions as a resistor (G), and in the middle thereof, an aluminum wiring pattern part (12) serving as the resistor (5) is connected to the inside of the body. The drawer end is connected to a ground pad (not shown).

〔Effect of the invention〕

Salt 1 - When according to the invention as explained, the group is
A plurality of NPN transistors are connected with their bases in common so that there are n outputs (n is any natural number) for each transistor, and aluminum wiring is patterned as a minute resistance component at the emitter of each NPNI transistor. Because it is characterized by connecting microresistors formed by forming an aluminum wiring pattern, two people can create an NPN transistor by adjusting the shape and size of the aluminum wiring pattern, which can be easily processed using normal manufacturing methods. The microresistance connected to the emitter can be created in a small area and with high precision.
As a result, it is possible to achieve the excellent effect of realizing a constant current device with a large current output in which the normal operating range of the output terminal is wide.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an embodiment in which the present invention is applied to a current mirror one-type constant current device; FIG. 2 is a plan view showing a wiring pattern in a conductor integrated circuit device having the circuit configuration of FIG. 1; FIG. 3 is a circuit diagram showing a conventional constant current device. (3) (4) (8) (9)...NPN transistor, (8c) (9c)...emitter, (8b) (9b)
...Base, (5) (8) (12) (13)...Minute resistance.

Claims (1)

[Claims] A plurality of NPN transistors are connected with their bases in common so that there is one on the reference side and n on the output side (n is any natural number), and aluminum wiring is connected to the emitter of each NPN transistor with a minute resistance component. A constant current device characterized by connecting a microresistance formed by patterning.