JPH0651030A - Measuring device - Google Patents

Abstract

PURPOSE:To prevent deterioration of input signal by converting a voltage signal once into a current signal, transmitting it, inverting back into voltage signal, and feeding the resultant to a circuit to be measured. CONSTITUTION:To a current-voltage converting circuit part 34, constant current sources 31A-31C send current signals S15-S17 as a current waveform in accordance with control voltage signals S1-S3 given by an external control device 3. Using amplitude adjusting resistances R1-R3, this circuit part 34 converts into voltage signals S18-S20 the differences of the current signals S15-S17 from the offset voltage VOFF of a constant voltage value which is supplied from a voltage source 15, and feeds the result to the negative input end of a circuit to be measured IC2 and also feeds the voltage VOFF from the voltage source 15 to the positive input end. The circuit IC2 acquires voltage signals S7-S9 on the basis of the signals S18-S20 and gives the resultant to coils L1-L3 of the measuring circuit part. This prevents the signals from deterioration such as noise superposing over the signals S15-S17 during transmission or attenuation of the signal level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device, and is suitable for application to a measuring device for measuring an integrated circuit (IC) for driving a motor, for example.

[0002]

2. Description of the Related Art Conventionally, there is an IC measuring device as shown in FIG. 5, for example, as a device for inputting a voltage signal to a circuit block such as an IC.

That is, in FIG. 5, reference numeral 1 indicates an IC to be measured 2 for driving a brushless three-phase bidirectional motor as a whole.
The control voltage signals S1, S2 and S3 output from the external control device 3 are input to the constant voltage sources 5A, 5B and 5C provided corresponding to the respective phases at predetermined timings. .

The constant voltage sources 5A, 5B and 5C use the input control voltage signals S1, S2 and S3 as the voltage signals S4, S5 and S6 as they are, via the transmission lines 6A, 6B and 6C, and the input terminal U of the IC2 to be measured. Transmit to _IN , V _IN , W _IN . The IC to be measured inputs the offset voltage V _OFF to the input terminals U _IN , V _IN , and W _IN , and the offset voltage V _OFF
Also, the input waveform is obtained from the difference between the voltage signals S4, S5 and S6.

Here, the IC 2 to be measured is adapted to input the rotor position detection signal from the Hall element to the input terminals U _IN , V _IN and W _IN in actual use, and each phase based on the rotor position detection signal. A predetermined drive waveform is output from the output terminal for each.

Therefore, in the measuring apparatus 1, the IC to be measured is
Voltage signals S4 input to the input terminals U _IN , V _IN , and W _IN of 2
S5 and S6 are measurement signals that are pseudo-generated with respect to the rotor position detection signal input from the Hall element in actual use, and output terminals U _OUT , based on the voltage signals S4, S5, and S6. Coils L1 and L2 from V _OUT and W _OUT
And the drive signals S7, S8, and S9 output to L3 are measured.

[0007]

However, in the measuring apparatus 1 of this type, the voltage signal S input to the IC 2 to be measured is inputted.
4, S5 and S6 are transmitted as voltage waveforms through the transmission lines 6A, 6B and 6C, so that the transmission line 6
In A, 6B, and 6C, voltage drop and noise were superimposed, the waveform was deteriorated, and there was a problem that it was not correctly transmitted to the IC2 to be measured.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a measuring apparatus capable of preventing deterioration of a signal input to an IC to be measured.

[0009]

In order to solve such a problem, according to the present invention, a predetermined signal S1,
Signals S7, S8, S output from the circuit under test 2 by inputting S2, S3 via predetermined transmission lines 6A, 6B, 6C.
In the measuring device 20 for measuring the circuit under test 2 by detecting 9, the first conversion means 3 for converting the voltage signals S1, S2, S3 into the current signals S15, S16, S17.
4 and the current signals S15, S16, S17 transmitted via the transmission lines 6A, 6B, 6C to the voltage signals S18, S1.
9, second conversion means 34 for converting into S20 and inputting into the circuit under test 2 is provided.

Further, in the present invention, the transmission lines 6A, 6A
Current signals S15, S16 transmitted via B, 6C,
The second converting means 34 for converting S17 into voltage signals S18, S19, S20 and the offset voltage V _OFF obtained from the predetermined voltage source 15 and the voltage signals S18, S19, S2.
0 is input to the circuit under test 2.

Further, in the present invention, the measuring device 20 is
The plurality of current signals S15, S16, S17 are transmitted via the corresponding plurality of transmission lines 6A, 6B, 6C, and the current signals S15, S16, S17 are transmitted through the transmission lines 6A, 6B, 6
The plurality of second converting means 34 corresponding to C respectively convert the plurality of voltage signals S18, S19, S20 into a plurality of voltage signals S18, S19, S20, and the plurality of input terminals U _IN , V _{IN of the} circuit under test 2. , W _IN , and the specified voltage source 1
The offset voltage V _OFF obtained from 5 is input to the common input terminal COM of the circuit under test 2.

[0012]

By setting the signals transmitted via the transmission lines 6A, 6B and 6C as the current signals S15, S16 and S17, noise is superimposed on the current signals S15, S16 and S17 during transmission, It is possible to prevent deterioration of the signal, such as attenuation of the signal level.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 20 denotes a measuring device as a whole, which is controlled by a computer 21 through an interface 22. That is, a predetermined input command output from the computer 21 is input to the digital analog conversion unit (DA conversion unit) 23 via the interface 22.

The DA converter 23 sends an input signal to the IC under test 2 based on the input command from the computer 21. The IC 2 under measurement outputs a predetermined output signal to the measurement circuit section 24 based on the input signal.

The measuring circuit section 24 measures the output signal output from the IC 2 to be measured, sends it to the subsequent analog digital conversion section (AD conversion section) 25, and digitizes it. Then, the numerical data is sent to the computer 21 via the interface 22, and the computer 2
At 1, it is determined whether or not the output waveform of the IC 2 to be measured is a predetermined waveform.

The detailed structure of the measuring device 20 is shown in FIG. That is, in FIG. 2 in which parts corresponding to those in FIG. 5 are assigned the same reference numerals, the measurement circuit 20 sends the control voltage signals S1, S2 and S3 output from the external control device 3 to the constant current sources 31A, 31B and 31C. To do.

Based on the control voltage signals S1, S2 and S3, the constant current sources 31A, 31B and 31C output current signals S15, S16 and S17 having current waveforms corresponding to the control voltage signals S1, S2 and S3.
It is sent to the voltage conversion circuit unit 34.

The current-voltage conversion circuit section 34 includes a voltage source 15
OFFSET VOLTAGE V _OFF
And the respective current signals S15, S16 and S17 are converted into voltage signals S18, S19 and S20 at the amplitude adjusting resistors R1, R2 and R3, which are then input terminals U _IN , V _IN and V _{IN of the} IC2 to be measured. Input to W _IN .

The IC 2 to be measured is a current-voltage conversion circuit section 34.
The converted voltage signals S18, S19 and S20
Is input to the minus input end, the offset voltage V _OFF supplied from the voltage source 15 is input to the plus input end, and the voltage waveform is input to the IC 2 to be measured.

The IC2 to be measured has the voltage signals S18 and S1.
9 and S20 to obtain voltage signals S7, S8 and S9, which are output from output terminals U _OUT , V _OUT and W _OUT ,
This is output to the coils L1, L2 and L3 of the measurement circuit section 24 (FIG. 1).

In the case of this embodiment, since the IC to be measured 2 is an IC for driving the brushless three-phase bidirectional motor, the control voltage signals S1 corresponding to the three phases,
The external control device 3 outputs S2 and S3.

Here, the external control device 3 and the constant current source 31
The circuits corresponding to the respective phases of the signal generating unit composed of A, 31B and 31C are configured as shown in FIG. That is, FIG. 3 shows a first-phase (U-phase) signal generator, and the control voltage signal S1 output from the external control device 3 is input to the inverting input terminal of the operational amplifier A1 via the resistor R10. The operational amplifier A1 includes an inverting amplifier circuit 3 with a feedback resistor R11 and a capacitor C1 connected in parallel with the feedback resistor R11.
5, the control voltage signal S1 from the external control device 3 amplified by the inverting amplifier circuit 35 is converted into the current signal S15 by the subsequent sense resistor R12 and sent to the transmission line 6A.

The current signal S15 sent through the sense resistor R12 is fed back to the non-inverting input terminal of the operational amplifier A1 through the operational amplifier A2 and the resistor R13 to form a positive feedback loop. Thus, the current signal S15 output from the sense resistor R12 can be made constant.

In the above configuration, the measuring device 20 has the control voltage signal S output from the external control device 3.
1, S2 and S3 are once changed to current signals S15, S16 and S3.
17 is converted and transmitted through the transmission lines 6A, 6B and 6C, and then the current provided immediately before the IC to be measured −
By converting the voltage signals into the voltage signals S18, S19, and S20 in the voltage conversion circuit unit 34, it is possible to prevent signal deterioration such as signal attenuation in the transmission path or superposition of noise from the outside. be able to.

According to the above configuration, the voltage signal is once converted into the current signal, sent out to the transmission line, converted into the voltage signal again, and then input to the IC 2 to be measured.
It is possible to prevent deterioration of the signal input to the IC to be measured 2 in advance.

In the above embodiment, the IC to be measured is
As described above, the case where the voltage input signal input for each phase and the offset voltage are compared to measure a voltage waveform is measured, but the present invention is not limited to this, and the offset voltage is applied to the common input terminal. You may make it measure the to-be-measured IC which was made to input into.

That is, as shown in FIG. 4 in which parts corresponding to those in FIG. 2 are designated by the same reference numerals, the IC 42 to be measured has a common input terminal COM, and the input terminals U _IN , V _IN , W of each phase are provided. _IN
The input voltage waveform of each phase can be obtained by comparing the voltage signals S18, S19 and S20 input to the input terminal and the offset voltage of the common input terminal COM.

Further, in the above embodiment, the case where the present invention is applied to the measuring device for measuring the IC for driving the motor has been described, but the present invention is not limited to this, and various other I
It can be widely applied to measuring devices for measuring circuits such as C.

[0030]

As described above, according to the present invention, in a measuring device adapted to input a voltage signal to a circuit under test, the voltage signal is once converted into a current signal and transmitted, and then the voltage signal is again transmitted. By converting the input signal into the input signal and inputting it to the circuit under measurement, it is possible to realize a measuring device capable of preventing the deterioration of the input signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a measuring device according to the present invention.

FIG. 2 is a connection diagram showing an embodiment of a measuring device according to the present invention.

FIG. 3 is a block diagram showing a signal generator of the measuring device.

FIG. 4 is a block diagram showing another embodiment.

FIG. 5 is a connection diagram showing a conventional measuring apparatus.

[Explanation of symbols]

2, 42 ... IC to be measured, 3 ... External control device, 6A,
6B, 6C ... Transmission path, 31A, 31B, 31C ... Constant current source, 34 ... Current-voltage conversion circuit section, S15, S1
6, S17 ... Current signal.

Claims (3)

[Claims] 1. A measuring device for measuring a circuit under test by inputting a predetermined signal into the circuit under test through a predetermined transmission line and detecting a signal output from the circuit under test, It comprises a first converting means for converting a voltage signal into a current signal, and a second converting means for converting the current signal transmitted through the transmission path into a voltage signal and inputting it into the circuit under test. Measuring device. 2. The second conversion means for converting a current signal transmitted through the transmission line into a voltage signal, inputs the offset voltage obtained from a predetermined voltage source and the voltage signal to the circuit under test. The measuring device according to claim 1, wherein 3. The measuring device transmits a plurality of current signals via a plurality of corresponding transmission lines, and the current signals are respectively converted into voltage signals in a plurality of the second converting means corresponding to the transmission lines. And inputting the plurality of voltage signals to a plurality of input terminals of the circuit under test, and inputting an offset voltage obtained from a predetermined voltage source to a common input terminal of the circuit under test. The measuring device according to claim 1.