JPH0228913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a function trimming device that uses an integrated circuit or the like as a circuit to be adjusted. The present invention relates to a method for setting an adjustment target voltage for accurate trimming.

In general, a functional trimming device uses an A/D converter or a data-readable voltmeter (for example, a digital voltmeter) using an A/D converter to measure the voltage of a portion of a circuit to be adjusted.

However, since these measurement circuits have nonlinearity and drift, there is a limit to measurement accuracy, which has been a cause of hindering improvement in adjustment accuracy. Furthermore, the above-mentioned voltmeter takes a long time to measure, and it is difficult to improve adjustment efficiency.

An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, obtain the difference between the voltage of the target part of the circuit to be adjusted and the adjustment target voltage with high precision, and accurately and efficiently perform trimming of the function according to that value. An object of the present invention is to provide a method for setting an adjusted target voltage that can be performed.

The configuration of the adjustment target voltage setting method according to the present invention is as follows:
Measure the voltage of the target part of the circuit to be adjusted, calculate the required adjustment amount according to the difference between the digital value and the digital value of the adjustment target voltage, and adjust the voltage of the target part of the circuit to be adjusted according to the adjustment amount. In a functional trimming device that has the function of controlling and processing to change circuit constants, the adjustment target voltage can be set at a desired digital value corresponding to each target part of the circuit to be adjusted, and the The number of bits is made sufficiently larger than the number of bits for A/D conversion of the voltage measurement result of the target portion.

In short, by allowing the target adjustment voltage to be set as a digital value, programmability is facilitated, and the number of bits is sufficiently greater than the number of bits for A/D conversion of the voltage measurement result. By doing so, it is possible to absorb errors, nonlinearity, etc. in the A/D conversion, and to improve the accuracy of voltage measurement.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a system configuration diagram of an embodiment of the adjustment target voltage setting method according to the present invention, and FIG. 2 is a processing flowchart thereof.

Here, 1 is a processing device, 2 is an adjustment drive unit, 3 is a D/A conversion circuit (D/A), and 4 is
an amplifier circuit, 5 a switching circuit, 6 an attenuation circuit, 7
is an A/D conversion circuit (A/D).

First, the functions and operations of each of the above parts will be explained.

The D/A conversion circuit 3 can receive digital data from the processing device 1 and output various analog voltages according to the data. Furthermore, the amplifier circuit 4 amplifies the output of the D/A conversion circuit 3 and generates an adjustment target voltage for the circuit to be adjusted IC.

That is, the D/A conversion circuit 3 and the amplifier circuit 4 are configured to obtain an arbitrary reference voltage equal to the adjustment target voltage according to the digital data output from the processing device 1, and to adjust the adjustment target voltages of various adjusted circuit ICs. It is designed to be applicable to

D/A conversion circuit 3 and amplifier circuit 4 used here
are selected and used, respectively, with accuracy sufficiently higher than the accuracy of the A/D conversion circuit 7 used in the measurement circuit. For example, when using a 12-bit precision circuit for the A/D conversion circuit 7, the D/A conversion circuit 3 has 16
In addition to using a bit-accurate circuit, the amplifier circuit 4 also uses a circuit with small errors.

Next, the switching circuit 5 is controlled by the processing device 1, and the measurement signal voltage of the circuit to be adjusted IC and the D/A
Either one of the reference voltages output by the conversion circuit 3 and the amplifier circuit 4 is selected and inputted to the attenuation circuit 6 at the next stage.

The attenuation circuit 6 transmits the input signal to the next stage A/
Attenuate it to within the allowable input voltage of the D conversion circuit 7,
The signal is input to the A/D conversion circuit 7.

Upon receiving the conversion start signal from the processing device 1 , the A/D conversion circuit 7 converts the analog input signal voltage into a digital signal and outputs the digital signal to the processing device 1 .

The processing device 1 can be composed of, for example, a microcomputer, a minicomputer, etc., and controls the D/A conversion circuit 3, the switching circuit 5, and the A/D conversion circuit 7, and outputs the output data of the A/D conversion circuit 7. and executes a predetermined processing program to control the adjustment drive unit 2. The operation is as shown in the processing flowchart of FIG. 2, which will be described later.

The adjustment drive unit 2 is, for example, a laser trimming device, which inputs a trimming amount from the processing device 1 and adjusts a thick film resistor formed on a circuit IC to be adjusted (for example, a thick film module) according to the trimming amount. , trimming the capacitor, etc., and changing the circuit constants so that the related voltage becomes the adjustment target voltage. If the components to be adjusted in the circuit IC to be adjusted are variable resistors, capacitors, coils, etc., the adjustment drive unit 2 is also equipped with a jig (for example, a rotary driver) for changing the constants of those components. be.

Next, the overall operation will be explained based on FIGS. 1 and 2.

First, before measuring the voltage of the circuit IC to be adjusted and trimming the target portion, the processing device 1 performs the switching circuit 5
After setting the voltage on the D/A conversion circuit 3 and amplifier circuit 4 side, the adjustment target voltage S ₀ of the target part of the circuit IC to be adjusted is set.
The digital data _C0 corresponding to is sent to the D/A conversion circuit 3.

The D/A conversion circuit 3 converts its output C ₁ into an amplification factor α
The amplifier circuit 4 inputs its output α·C ₁ to the switching circuit 5. Here, α・
The value of the digital data C ₀ is determined in advance by actual measurement or the like so that C ₁ =S ₀ .

The output α・C ₁ =S ₀ is inputted through the switching circuit 5 to the attenuation circuit 6 with an attenuation rate of 1/β (β≧1),
The output S ₀ /β is input to the A/D conversion circuit 7.

The A/D conversion circuit 7 converts the A/D from the processing position 1
The conversion start signal converts the above input S ₀ /β to A/
The D-converted digital value _S1 is read by the processing device 1.

The processing device 1 temporarily stores the data _S1 , then switches the switching circuit 5 to the adjusted circuit IC side, and takes in the measurement signal voltage _X0i through the same path as described above.

That is, the measurement signal voltage X _0i is
The output X _0i /β is input to the A/D conversion circuit 7, and the value X _i obtained by A/D converting this is read and stored in the processing device 1.

The processing device 1 calculates the difference (S ₁ −X _i ) between the data X _i imported here and the data S ₁ previously temporarily stored, and determines the adjustment target for the target portion that has been set in the processing device 1 in advance. Range tolerance T ₁ and above difference (S ₁
−X _i ).

When the difference (S ₁ −X _i ) is larger than the tolerance T ₁ , the value of the difference [(S ₁ −X _i )−T ₁ ] and the adjustment constant R set in advance in the processing device 1 are further calculated. The product (S ₁ −X _i −T ₁ )×R=D _i is calculated, and the adjustment drive unit 2 is controlled using the value D _i as the adjustment amount, and the measurement signal voltage from the target part of the circuit IC to be adjusted is Trimming is performed so that X _0i approaches the adjustment target voltage S ₀ .

Here, the adjustment constant R is a constant corresponding to the adjustment drive unit 2, such as the cutting length for a laser type or sandblasting type trimmer, or the volume rotation angle for a screwdriver type trimmer. be.

Thereafter, while maintaining the switching circuit 5 as it is, the measurement signal voltage X _0i of the circuit to be adjusted IC is taken into the processing device 1 again through the same route, and the same processing as described above is performed.

In this way, the adjustment is repeated a plurality of times so that the measurement signal voltage X _0i of the target portion of the circuit IC to be adjusted falls within the adjustment target range S ₀ ±T ₀ . Tolerance T ₀ ,
The relationship between T ₁ is T ₀ /β=T ₁ .

Here, the adjustment amount D _i decreases as the circuit constant approaches the adjustment target range, but the adjustment constant R is determined in advance through experiments or the like so as not to deviate from the tolerance near the target value.

By repeating the adjustment in this way, when the difference from the target value is large, the adjustment amount is large, and as you get closer to the target, the adjustment amount is smaller, trying to adjust to the target voltage with high precision and high speed. It is something.

According to this embodiment, even if the A/D conversion circuit 7 that measures the voltage has errors due to nonlinearity or drift, the highly accurate adjustment target voltage can be passed through the same measurement system to the processing device in advance. 1 and offset the error when measuring the characteristics of the circuit IC to be adjusted, it is possible to salvage the relatively inaccurate characteristics of the measurement system and obtain high adjustment accuracy.

That is, since the measurement system of the circuit to be adjusted IC and the measurement system of the highly accurate adjustment target voltage are the same including the A/D conversion circuit 7, the A/D conversion circuit 7
The indirectness of
Since the time until IC measurement is sufficiently shorter than the above-mentioned drift caused by changes in ambient temperature, etc., this drift is also canceled out.

As described above in detail, according to the present invention, the adjustment of the circuit to be adjusted can be performed with high precision and at high speed using a general voltage measuring circuit. Significant effects can be obtained in improving reliability, efficiency, and economy.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the adjustment target voltage setting method according to the present invention, and FIG. 2 is a processing flowchart thereof. 1...processing device, 2...adjustment drive unit, 3
...D/A conversion circuit, 4...Amplification circuit, 5...Switching circuit, 6...Attenuation circuit, 7...A/D conversion circuit.

Claims (1)

[Claims] 1. Measure the voltage of the target part of the circuit to be adjusted, calculate the required adjustment amount according to the difference between the digital value and the digital value of the adjustment target voltage, and adjust the voltage of the target part of the circuit to be adjusted according to the adjustment amount. In a functional trimming device that has the function of controlling and processing so as to change the circuit constants of the circuit, each of the above-mentioned values is The desired adjustment target voltage corresponding to the target part is set using a digital value, and in order to set the adjustment target voltage with higher accuracy than the A/D conversion accuracy of the voltage measurement of each target part, the desired adjustment target voltage is set as a digital value. An adjustment target voltage setting method characterized in that the number of bits of the digital value is greater than the number of bits of the A/D conversion.