Electronic circuit device

Details Electronic circuit device Electronic circuit device

1990-04-12

1991-11-26

Larkins, William D.

Amplifiers

Signal feedback

Combined with control of bias voltage of signal amplifier

357 51, 330298, H01L 2983, H03F 152, H03K 1708

Patent

active

050687034

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention is directed to an electronic circuit device having a monolithic integrated power transistor having a plurality of individual partial transistors connected in parallel.
An electronic circuit device having a monolithic integrated power transistor of this type is disclosed in U.S. Pat. No. 4,656,496. The total required emitter surface of the power transistor is split up into a large number of partial emitters, each having a resistor in the line to the partial emitter. The current distribution in the overall layout of the power transistor can be effectively stabilized by this means when sufficiently large voltage drop is provided at maximum current. An additional measurement resistor and, accordingly, an additional voltage drop would be required for circuit devices having current regulation or current limiting (compare the circuit arrangements according to U.S. Pat. No. 4,567,537), which would mean an increase in the saturation voltage of the power transistor in operation.


SUMMARY OF THE INVENTION

An electronic circuit device in accordance with the present invention comprises a plurality of independent partial transistors connected in parallel. The transistors have resistors in their emitter lines for stabilizing the distribution of the sum current to the individual partial transistors in the power transistor. The device has at least one measurement resistor in an emitter line of one of said partial transistors for providing a signal voltage proportional to the current in said line, thereby providing a device suitable for use in electronic circuits requiring current regulation or current limiting.
In contrast to the previously known devices, the electronic circuit device according to the present invention has the advantage that a measurement resistor for achieving a signal voltage proportional to the current for a regulating circuit in which the monolithic integrated power transistor is incorporated is provided without the saturation voltage of the power transistor being increased. Another advantage is that no additional chip surface is required for the measurement resistor, since the resistors in the emitter lines can be accommodated on the total surface required by the power transistor so as to be neutral with respect to surface, the total surface required by the power transistor being decisively determined by the desired power loss characteristic of the power transistor.


BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in more detail with the aid of the drawing wherein:
FIG. 1 shows an electronic circuit device, according to the prior art, with an electric motor in the collector circuit of the power transistor. In a known manner, the transistor comprises a plurality of individual transistors connected in parallel and comprising resistors in the emitter lines;
FIG. 2 shows a circuit, according to the invention, in which the resistors in the emitter lines of the individual transistors are utilized, according to the invention, as measurement resistors for achieving a signal voltage proportional to the current, wherein additional resistors are provided for decoupling the signal voltage;
FIG. 3 shows the connections of a section of a layout of a cell of the power transistor;
FIG. 4 shows the interconnection of the individual cells to form a layout of the power transistor.
FIGS. 5 to 8 show sections from the layout:
FIG. 5a shows the structure of the circuit device in cross section;
FIG. 5b shows a plan view of the structure of the circuit device;
FIG. 6 shows the layout section of the circuit, according to FIG. 3, with a Zener diode element as additional component of a cell of the power transistor;
FIG. 7 shows the interconnection of the components mentioned in FIG. 6 forming the bond of the power transistor with the driver stages assigned to the cells, in section; and
FIG. 8 shows the formation of a power transistor, according to FIG. 7, with a double-row arrangement of the cells.


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, the indi

REFERENCES:
patent: 3740621 (1973-06-01), Carley
patent: 4567537 (1986-01-01), Kalkhof et al.
patent: 4656496 (1987-04-01), Widler
patent: 4783690 (1988-11-01), Walden

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