JPH0423352A - Trimming method for function of hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To regulate the offset of an operational amplifier without providing another offset regulating resistor by providing a probing section at input and output sides of the amplifier, interposing a function trimming resistor between probes in contact with the section so as to be parallel with a capacity element, and trimming the offset regulating resistor connected to the amplifier while sensing input and output voltages of the amplifier. CONSTITUTION:The offset voltage of an operational amplifier 25 can be regulated by triming offset regulating resistors R5, R6 provided at the offset regulating terminals 30a, 30b of an operational amplifier 25. Accordingly, probes 33a, 33b provided at a laser trimming apparatus 34 having a laser light emitting unit are brought into contact with probing terminals 32a, 32b provided at the input and output sides of the amplifier 25, and the resistors R5, R6 are laser- trimmed while measuring the input and output voltages.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a method for trimming functions of a hybrid integrated circuit, which adjusts the circuit functions of the hybrid integrated circuit by putting the hybrid integrated circuit together with its peripheral circuits into an operating state. In more detail,
The hybrid integrated circuit performs offset adjustment of the operational amplifier that controls the main function of the integrating circuit provided in the hybrid integrated circuit by trimming an offset adjustment resistor attached to the operational amplifier, and further trims the function of the hybrid integrated circuit. The present invention relates to a method for trimming functions of integrated circuits.

(Prior Art) Generally, a hybrid integrated circuit consists of passive elements such as resistors, capacitors, or coils, and analog or digital ICs.
Since the hybrid integrated circuit is a functional module that combines active elements such as, when adjusting the circuit function of the hybrid integrated circuit, it is required to comprehensively inspect and confirm the functions and characteristics.

The functional adjustment of the hybrid integrated circuit is performed by functional trimming in which the hybrid integrated circuit and its peripheral circuits are brought into operation, and the resistance values and the like are trimmed while measuring the signals of each part.

A typical example of an analog IC incorporated into the hybrid integrated circuit is an operational amplifier (hereinafter referred to as an operational amplifier) that has a differential amplification function, and this operational amplifier has feedback applied from the output side to the input side. By this,
It performs various circuit functions and has stable characteristics.

As a circuit using the operational amplifier, for example, an integrating circuit for extracting a vertical synchronization signal of video equipment is known.

An integrating circuit that integrates input and obtains an output using an operational amplifier incorporated in the hybrid integrated circuit will be described with reference to FIG.

The operational amplifier 5 having an inverting input terminal 6 and a non-inverting input terminal 7 has a negative bias terminal 8 and a positive bias terminal 9 connected to a negative bias voltage -Vee and a positive bias voltage +Vcc, respectively.
Power is supplied by being connected to the

The inverting input terminal 6 of the operational amplifier 5 is connected to the input terminal 3 provided on the hybrid integrated circuit l via an input resistor R1, and the non-inverting input terminal 7 is connected via an offset compensation resistor R2. and is connected to a common potential terminal 11 that forms a reference potential in the hybrid integrated circuit 1.

Furthermore, the output side of the operational amplifier 5 is connected to the output terminal 4.

The output side of the operational amplifier 5 connected to the output terminal 4 is
The feedback capacitor C1 is connected to one end of the feedback capacitor C1 which is used for integration together with the operational amplifier 5.
1 is connected to the inverting input terminal 6 of the operational amplifier 5 to form a negative feedback loop.

In the negative feedback loop, when the operational amplifier 5 is in operation, negative feedback is applied from the output side of the operational amplifier 5 to the inverting input terminal 6 via the feedback capacitor C1.

The feedback capacitor CI includes a low frequency gain control resistor R4.
A series circuit consisting of a phase compensation capacitor C2 and a phase compensation capacitor C2 are connected in parallel.

Further, both ends of an offset adjustment resistor R3 are connected to offset adjustment terminals 10a and 10b provided for offset adjustment of the operational amplifier 5.

The offset adjustment resistor R3 is a separate component having a slider, and the slider is connected to the positive bias terminal 9 biased to the positive bias potential Vcc.

As mentioned above, the operational amplifier 5 incorporated in the hybrid integrated circuit 1
An integrating circuit 2 is constituted by a feedback capacitor 01 and a feedback capacitor 01.

Next, the circuit operation of the integrating circuit 2 will be explained.

When an input voltage is input to the input terminal 3 with the common potential terminal 11 as a reference potential, an input current determined by the input resistor R1 flows.

The input current flows into the feedback capacitor CI and charges the feedback capacitor C1 because the input impedance of the inverting input terminal 6 of the operational amplifier 5 is very large.

By charging the feedback capacitor C1 with the input current, an output voltage obtained by integrating the input voltage is outputted to the output terminal 4 connected to the output side of the operational amplifier 5.

At this time, the low frequency gain control resistor R4 is set to limit the closed loop gain in the low frequency range, and the phase compensation capacitor C2 is set to prevent self-oscillation in the high frequency range. ing.

In the operational amplifier 5 in the above-mentioned integrating circuit 2, an offset voltage is generated due to unbalance of the transistors, FETs, etc. that are the components of the operational amplifier 5.

In order to adjust the offset voltage, for example, an individual offset adjustment resistor R3 (a variable resistor, also referred to as a trimmer resistor) is attached to the operational amplifier 5 to adjust the offset voltage.

Further, in functional trimming of the hybrid integrated circuit 1,
When performing offset adjustment, since the capacitive feedback capacitor C1 is connected to the negative feedback loop of the operational amplifier 5, the AC input voltage (
The offset adjustment resistor R3 is adjusted while measuring the AC output voltage output to the output terminal 4, thereby adjusting the offset of the operational amplifier 5.

At this time, the offset adjustment resistor R3 is a separate component, and the adjustment is performed by inserting a driver into an adjustment groove or the like provided in the offset adjustment resistor R3 and rotating the adjustment groove.

Note that the offset adjustment resistor R3 may be formed by a screen printing baking method, and trimmed by inputting an AC input voltage to the operational amplifier 5 using a laser or an abrasion trimming device.

(Problem to be Solved by the Invention) However, according to the conventional function trimming method for a hybrid integrated circuit, when performing offset adjustment of an operational amplifier in an integrating circuit consisting of an operational amplifier, a feedback capacitor, etc. Since a feedback capacitor is connected to the feedback loop of the operational amplifier and the feedback loop is AC-coupled, an AC input voltage must be input to the inverting input terminal and the non-inverting input terminal of the operational amplifier. There is a problem in that an AC signal source or the like is required depending on the situation.

Further, the offset adjustment of the operational amplifier is performed by rotating and adjusting individual offset adjustment resistors connected to the offset adjustment terminals of the operational amplifier using a driver or the like, which requires time and effort. There were problems in that the process was complicated and individual errors by the adjustment workers also occurred.

Furthermore, when the offset adjustment resistor of the operational amplifier is formed by screen printing and baking and trimmed by a trimming device, the output voltage to be measured has an alternating current value, so the alternating current output required by the trimming device is There was a problem in that the time required to read the voltage was longer than that for the DC output voltage, and a dedicated measuring instrument was required.

The present invention has been made in view of the above circumstances, and provides offset adjustment of an operational amplifier provided in a hybrid integrated circuit.
The present invention provides a method for functionally trimming a hybrid integrated circuit, which requires the provision of individual offset adjustment resistors (and which can be performed by trimming thick film resistors formed by screen printing and firing).

(Means for Solving the Problems) In order to achieve the above object, the present invention provides feedback by applying feedback from the output side to the input side of the operational amplifier via capacitive elements on the input side and the output side. , in the function trimming method of a hybrid integrated circuit having an integrating circuit in which the integral operation of the input voltage becomes the output voltage, a probing section is provided on the input side and the output side of the operational amplifier, and a probing section is provided between the probes in contact with the probing section. By interposing a functional trimming resistor in parallel with the capacitive element and trimming the offset adjustment resistor connected to the operational amplifier while detecting the input voltage and output voltage of the operational amplifier, the hybrid It performs functional trimming of integrated circuits.

(Function) In the present invention, in an integrating circuit configured by applying feedback from the output side to the input side of an operational amplifier provided in a hybrid integrated circuit by a feedback loop via a feedback capacitor, the operational amplifier By providing probing terminals on the input side and the output side, and bringing the probe of the trimming device into contact with the probing terminal, the functional trimming resistor provided between the probes is connected in parallel with the feedback capacitor. It can be connected to a feedback loop to change the feedback loop from capacitive AC coupling to DC coupling via a resistor.

Therefore, when performing offset adjustment of the operational amplifier of the integrating circuit, the DC input voltage can be input to the operational amplifier instead of the AC input voltage, and the measurement of the output voltage by the trimming device can be facilitated.

However, the offset adjustment resistor of the operational amplifier is formed by a thick film screen printing method, and then laser or
Offset adjustment of the operational amplifier can be performed by trimming using an abrasive trimming device.

(Example) Embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a method for trimming functions of a hybrid integrated circuit according to the present invention.

The operational amplifier 25 having an inverting input terminal 26 and a non-inverting input terminal 27 is supplied with power by connecting a negative bias terminal 28 and a positive bias terminal 29 to a negative bias voltage - ee and a positive bias voltage +Vcc, respectively. has been done.

The inverting input terminal 26 of the operational amplifier 25 has an input resistance R
1 to the input terminal 23 provided on the hybrid integrated circuit 21, and the non-inverting input terminal 27 is connected to a common potential terminal forming a reference potential in the hybrid integrated circuit 21 via an offset compensation resistor R2. 31 , and the output of the operational amplifier 25 is further connected to the output terminal 24 .

The output side of the operational amplifier 5 is connected to one end of a feedback capacitor CI, which is used for integration together with the operational amplifier 5, and the other end of the feedback capacitor C1 is connected to the inverting input terminal 6 of the operational amplifier 5. , a negative feedback loop is formed.

The negative feedback loop, when the operational amplifier 25 is in operation,
Negative feedback is applied from the output side of the operational amplifier 25 to the inverting input terminal 26 via the feedback capacitor C1.

The feedback capacitor C1 includes a low frequency gain control resistor R4.
A series circuit consisting of a phase compensation capacitor C2 and a phase compensation capacitor C2 are connected in parallel.

Further, offset adjustment terminals 30a and 30b provided for offset adjustment of the operational amplifier 25 are connected to one ends of offset adjustment resistors R5 and R6, respectively, and the other ends of the offset adjustment resistors R5 and R6 are connected to the offset adjustment terminals 30a and 30b, respectively. connected in common.

A commonly connected connection point of the offset adjustment resistors R5 and R6 is connected to the positive bias terminal 29 and biased to a positive bias voltage +Vcc.

The offset adjustment resistors R5 and R6 are thick film resistors formed by a thick film screen printing method or the like.

Operational amplifier 2 incorporated in hybrid integrated circuit 21 as described above
5, a feedback capacitor 01, and the like constitute an integrating circuit 22.

Next, the circuit operation of the integrating circuit 22 will be explained.

When an input voltage is input to the input terminal 23 with the common potential terminal 31 as a reference potential, an input current determined by the input resistor R1 flows.

The input current flows into the feedback capacitor C1 and charges the feedback capacitor C1 because the input impedance of the inverting input terminal 26 of the operational amplifier 25 is very large.

By charging the feedback capacitor C1 with the input current, an output voltage obtained by integrating the input voltage is outputted to the output terminal 24 connected to the output side of the operational amplifier 25.

At this time, the low frequency gain control resistor R4 is provided to limit the closed loop gain in the low frequency region, and the phase compensation capacitor C2 is provided to prevent self-oscillation in the high frequency region. .

The operational amplifier 25 in the above-mentioned integrating circuit 22 includes transistors and FETs that are the constituent elements of the operational amplifier 25.
An offset voltage may be generated on the output side due to an unbalance such as the above, which may interfere with the integration function of the operational amplifier 25, the feedback capacitor 01, etc., so it is necessary to adjust the offset voltage.

Offset voltage adjustment of the operational amplifier 25 can be performed by trimming offset adjustment resistors R5 and R6 provided at the offset adjustment terminals 30a and 30b of the operational amplifier 25.

Therefore, the laser trimming device 34 has a laser beam irradiation section (not shown) on the probing terminals 32a and 32b provided on the input side and output side of the operational amplifier 25.
The offset adjustment resistors R5 and R6 are laser trimmed while the probes 33a and 33b provided on the offset adjustment resistors R5 and R6 are brought into contact with each other and the input voltage and output voltage are measured.

At this time, the probe 33a of the laser trimming device 34,
Since a functional trimming resistor R7 is provided between 33b and 33b, AC coupling with negative feedback applied from the output side of the operational amplifier 25 to the inverting input terminal 26 via the feedback capacitor C1 is connected to the feedback capacitor C1. By connecting the function trimming resistor R7 in parallel to C1, the feedback loop becomes DC coupled.

However, the common potential terminal 31 provided in the integrating circuit 22
A DC input voltage is input to the input terminal 23 of the operational amplifier 25 with reference to , and the DC output voltage output to the output terminal 24 of the operational amplifier 25 is set to
4, and offset adjustment resistor R5.
, R6, the offset of the operational amplifier 25 can be adjusted.

As described above, according to this embodiment, the offset adjustment of the operational amplifier 25 that controls the main function of the integrating circuit 22 is performed by inputting a DC input voltage to the input terminal 23 of the operational amplifier 25, and inputting the DC input voltage to the output terminal of the operational amplifier 25. The offset adjustment of the operational amplifier 25 is performed by laser trimming the offset adjustment resistors R5 and R6 provided in the operational amplifier 25 while measuring the DC output voltage output to the operational amplifier 24. This eliminates the need for complicated measurement means for measuring AC signals.

Further, offset adjustment terminals 30a, 3 of the operational amplifier 25
The offset adjustment resistors R5 and R6 provided at 0b are
By being formed of thick film resistors, the offset adjustment resistors R5 and R6 can be functionally trimmed together with other thick film resistors in the hybrid integrated circuit 21, thereby eliminating the need for separate variable resistance components. , the complicated adjustment of the variable resistor can be eliminated.

Note that the use of the laser trimming device 34 is not limited to trimming the offset adjustment resistors R5 and R6, and it is also possible to trim the resistance values of the offset adjustment resistors R5 and R6 by spraying fine glass particles or the like. A ledge trimming device may also be used.

(Effects of the Invention) Since the hybrid integrated circuit function/rimming method according to the present invention is configured as described above, it has the following effects.

(The offset adjustment of the A+ operational amplifier is performed using a probe of a trimming device, which has a probing terminal on each of the input side and output side of the operational amplifier, and a resistor for functional trimming between the probes on the probing terminal. A feedback loop from the output side to the input side of the operational amplifier is brought into contact with DC coupling, and an offset adjustment resistor made of a thick film attached to the operational amplifier is functionally trimmed to adjust the offset of the operational amplifier. This eliminates the need to input an AC input voltage during offset adjustment, and has the excellent effect of eliminating the need for an AC signal source.

(B+ Also, since the offset adjustment resistor used for offset adjustment of the operational amplifier is formed by a thick film screen printing method or the like, a separate offset adjustment resistor is not required, which reduces component costs. Since the offset adjustment is durable together with the functional trimming process of other thick film resistors installed in the hybrid integrated circuit, the efficiency of the functional trimming process can be improved, and it is also possible to prevent individual errors caused by the adjustment operator. It has a great effect.

(C1 Furthermore, since functional trimming of the offset adjustment resistor of the operational amplifier can be performed using a DC input voltage without requiring an AC input voltage, the reading time for measuring the DC input voltage with a trimming device is shortened. , which has the excellent effect of eliminating the need for a dedicated measuring instrument.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a method for trimming functions of a hybrid integrated circuit according to the present invention, and FIG. 2 is a circuit diagram showing a conventional method for trimming functions of a hybrid integrated circuit. 21... Hybrid integrated circuit, 22... Integrating circuit, 25... Operational amplifier, 26... Inverting input terminal, 27... Non-inverting input terminal, 30a, 30b... Offset adjustment terminal, 32a ,3
2b: Blobbing terminal, 33a, 33b: Probe, R5, R6: Offset adjustment resistor, R7: Function trimming resistor, C1: Feedback capacitor. Fig. 21... Hybrid S product circuit 26... Inverting input terminal 22... Integrating circuit 27... Non-inverting input terminal 25... Operational amplifiers 30a, 30b... Offset adjustment terminals 32a, 32
b...Probing terminals 33a, 33b...Probe R5, Re...Offset adjustment resistor R7...Function trimming resistor C...Feedback capacitor No.

Claims (1)

[Claims] (1) A hybrid integrated circuit having an integrating circuit in which the integral operation of the input voltage becomes the output voltage by applying feedback from the output side to the input side via a capacitive element on the input side and output side of the operational amplifier. In the function trimming method, a probing section is provided on the input side and the output side of the operational amplifier,
A functional trimming resistor is interposed between the probes in contact with the probing section in parallel with the capacitive element, and an offset adjustment device connected to the operational amplifier is connected to the operational amplifier while sensing the input voltage and output voltage of the operational amplifier. A method for trimming functions of a hybrid integrated circuit, characterized in that the functions of the hybrid integrated circuit are trimmed by trimming a resistor.