CN101988959B - Multi-functional measuring device capable of adjusting reference voltage and chip thereof - Google Patents
Multi-functional measuring device capable of adjusting reference voltage and chip thereof Download PDFInfo
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- CN101988959B CN101988959B CN 200910160245 CN200910160245A CN101988959B CN 101988959 B CN101988959 B CN 101988959B CN 200910160245 CN200910160245 CN 200910160245 CN 200910160245 A CN200910160245 A CN 200910160245A CN 101988959 B CN101988959 B CN 101988959B
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Abstract
The invention relates to a multi-functional measuring device capable of adjusting reference voltage, which comprises an analog front-end circuit, a measuring circuit, a reference voltage generating circuit, an access control circuit, a control circuit and a display device. The analog front-end circuit is used for converting a signal or an element to be measured to a proper signal so as to be measured by the measuring circuit and further output measurement result to the display device. The reference voltage generating circuit is electrically connected with the measuring circuit so as to output the reference voltage to the measuring circuit. The access control circuit is electrically connected with the reference voltage generating circuit and the control circuit, wherein the access control circuit is used for outputting a control signal to the reference voltage generating circuit according to measuring items selected by a user, thereby adjusting the reference voltage outputted by the reference voltage generating circuit.
Description
Technical field
The invention relates to a kind of digital multi ammeter (Digital Multi-Meter, DMM), particularly about a kind of digital multi ammeter that can adjust according to the measurement pattern reference voltage.
Background technology
General existing multifunction electric meter as shown in Figure 1, comprises an analog front circuit 10, a measurement circuit 11, a control circuit 12 and a display 13.Analog front circuit 10 is that measured signal (such as voltage, electric current, temperature etc.) or element under test (such as resistance, electric capacity, diode etc.) are changed into measurement circuit 11 acceptable signals, as: the voltage signal in the particular range.Then, measurement circuit 11 measures this signal again, and further measurement is exported to display 13.
Above-mentioned measuring equipment 11 except receiving input signal, also receives a reference voltage (reference voltage, Vr) when carry out measuring, make input signal with respect to the ratio of reference voltage as Output rusults.But different along with measured signal and element under test can be used different measurement patterns, therefore, also need provide many groups reference voltages (Vr-1, Vr-2 ..., Vr-n).And the selection of these reference voltages is determined according to the measurement pattern by control circuit 12.
As shown in Figure 2, its reference voltage of known multifunction electric meter (Vr) all is to be produced through electric resistance partial pressure by a reference voltage source (Vs).Reference voltage source (Vs) can use energy gap circuit (bandgapcircuit) or Zener diode (zener diode).And in order to allow the measurement of ammeter reach certain precision, be to utilize variable resistor, the error of reference voltage (Vr) can littlely be arrived within certain scope.Therefore, when ammeter production is finished, must use facility to adjust variable resistor and just can finish correction.And because each measurement pattern has reference voltage separately, so must all carry out variable-resistance adjustment for each measurement pattern; Therefore, correction is inconvenient, speed of production also is not easy to improve, and is subject to easily the external environment impact and the difficulty of increase correction in trimming process.In addition, some ammeter is that multiple measurement pattern is shared a reference voltage in order to save cost, such as: DC voltage/alternating voltage/DC current/alternating current/measurement patterns such as diode are shared a reference voltage.Although this mode can be saved cost, but because the analog front circuit of each measurement pattern using is different, to have different errors, sharing a reference voltage is all front-end circuit errors that measures pattern can't be proofreaied and correct in the lump, therefore may sacrifice the precision that some measures pattern.
Summary of the invention
In above-mentioned background of invention, in order to solve inconvenience that the multifunctional digital ammeter proofreaies and correct, time-consuming and sacrifice the problem of precision, the invention provides a kind of multi-functional measuring device that can automatically adjust according to the measurement pattern reference voltage, is to dispose can write/read memory and access-control scheme; Therefore, along with the user selects different measurement projects, generating circuit from reference voltage can be exported its corresponding reference voltage.
Therefore, a fundamental purpose of the present invention is to provide a kind of multi-functional measuring device that can automatically adjust according to the measurement pattern reference voltage, this measuring equipment can be selected different measurement projects along with the user, and generating circuit from reference voltage can be exported and meet the reference voltage that this measures project; Therefore, each measurement pattern has independently reference voltage, can proofread and correct in the lump the error of analog front circuit, makes measuring equipment have higher precision.
Another fundamental purpose of the present invention is to provide a kind of multi-functional measuring device that can automatically adjust according to the measurement pattern reference voltage, and this measuring equipment is to utilize original button on the operation-interface to finish the correction of reference voltage, does not need extra facility; Therefore, more convenient and quick in the correction.
According to above-mentioned purpose, the present invention at first proposes a kind of multi-functional measuring device of capable of adjusting reference voltage, is to comprise analog front circuit, measurement circuit, generating circuit from reference voltage, access-control scheme, control circuit and display.Analog front circuit is that measured signal or element under test are changed into suitable signal, measures also for measurement circuit and further exports measurement to display device.And generating circuit from reference voltage is to be electrically connected with measurement circuit, to export a reference voltage to measurement circuit.Access-control scheme, to be electrically connected with generating circuit from reference voltage and control circuit, wherein, when multi-functional measuring device is in the measurement pattern, access-control scheme is according to the selected measurement project of user, control signal to generating circuit from reference voltage and export one, the reference voltage of being exported to adjust generating circuit from reference voltage.
In addition, the present invention also comprises the chip that is disposed in the above-mentioned measuring equipment.Measuring chip comprises: an analog front circuit is to receive one first measured signal and export one second measured signal; One measurement circuit is to be electrically connected with analog front circuit, to measure the second measured signal and to export measuring value to a display; One generating circuit from reference voltage is to be electrically connected with measurement circuit, to export a reference voltage to measurement circuit; An and access-control scheme, to be electrically connected with generating circuit from reference voltage, when the measurement chip is in a measurement pattern, access-control scheme is according to the selected measurement project of user, control signal to generating circuit from reference voltage and export one, the reference voltage of being exported to adjust generating circuit from reference voltage.
Description of drawings
For being illustrated more clearly in the present invention, below enumerate preferred embodiment and cooperate accompanying drawing to be described in detail as follows, wherein:
Fig. 1 is existing a kind of multifunction electric meter;
Fig. 2 is known its reference voltage producing method of a kind of multifunction electric meter;
Fig. 3 is a kind of measuring equipment of the present invention;
Fig. 4 is the calcspar of a kind of measuring equipment of the present invention; And
Fig. 5 is the calcspar of a kind of its generating circuit from reference voltage of measuring equipment of the present invention.
Embodiment
At first, please refer to Fig. 3, is a kind of embodiment of the present invention, is a kind of measuring equipment of capable of adjusting reference voltage.This measuring equipment 20 is multifunction electric meters, has a shell 21, and be provided with a pair of test probe 22 in the bottom of shell 21,23, to measure a measured signal 24.In addition, have an operation-interface 25 and a display 26 on the shell 21, operation-interface 25 is provided with a knob 27, can be through rotation to select different measurement patterns, such as: measure magnitude of voltage, measure current value, measure diode etc., make the results are shown on the display 26 of measurement.And, have a button 28 on the operation-interface 25, be available for users to or the operator selects or the usefulness of setting.
And as shown in Figure 4, be the calcspar of above-mentioned measuring equipment 20.Measuring equipment 20 comprises a knob 27, a button 28, an analog front circuit 31, a measurement circuit 32, a generating circuit from reference voltage 33, an electricallyerasable ROM (EEROM) (EEPROM) 34, an electricallyerasable ROM (EEROM) (EEPROM) controller 35, a control circuit 36 and a display 37.Analog front circuit 31 mainly is comprised of institutes such as signal detection element, frequency detection circuit, amplifier or wave filters, can receive one first measured signal 30 and export one second measured signal, for example: the voltage signal in the particular range.Measurement circuit 32 is to be electrically connected with analog front circuit 31, to measure the second measured signal and to export measurement to display 37.Generating circuit from reference voltage 33 is to be electrically connected with measurement circuit 32, to export a reference voltage (Vr) to measurement circuit 32.Electricallyerasable ROM (EEROM) 34 is to store predefined a plurality of voltage parameter project.EEPROM controller 35, to be electrically connected with electricallyerasable ROM (EEROM) 34 and generating circuit from reference voltage 33, EEPROM controller 35 can read the data that is stored in the electricallyerasable ROM (EEROM) 34, and export one and control signal to generating circuit from reference voltage 33, the reference voltage of being exported to adjust generating circuit from reference voltage 33.36 of control circuits are and the electric connections such as knob 27, button 28, analog front circuit 31, measurement circuit 32, generating circuit from reference voltage 33 and EEPROM controller 35.Therefore, when the user is transferred to a certain measurement pattern with knob 27, for example: measure diode, control circuit 36 can further switch to analog front circuit 31 and measure the required circuit of diode, and order EEPROM controller 35 reads diode and measures corresponding voltage parameter project from electricallyerasable ROM (EEROM) 34.EEPROM controller 35 can further form this voltage parameter project one control signal and output to generating circuit from reference voltage 33, makes generating circuit from reference voltage 33 produce a diode and measures corresponding reference voltage.
Then, seeing also Fig. 5, is the calcspar of above-mentioned measuring equipment 20 its generating circuit from reference voltage 33.Generating circuit from reference voltage 33 is to comprise an energy rank circuit 331, a voltage amplifier 332, a digital analog converter (DAC) 333, an output multiplexer 334.Energy gap circuit 331, be output one energy gap reference voltage (Vref), voltage amplifier 332 is to be electrically connected with energy gap circuit 331, with reception energy gap reference voltage (Vref) and a gain control inputs, and export one first voltage (Va) and a second voltage (Vb).Digital analog converter (DAC) is and voltage amplifier 332 is electrically connected receiving above-mentioned second voltage (Vb) and a DAC input code, and further to export a tertiary voltage (Vc).And output multiplexer 334, to be electrically connected with voltage amplifier 332 and digital analog converter 333, to receive above-mentioned the first voltage (Va) and tertiary voltage (Vc), and output multiplexer 334 also receives an output and selects signal, to determine that the first voltage (Va) or tertiary voltage (Vc) are as output voltage; This output voltage is exactly the reference voltage (Vr) that generating circuit from reference voltage 33 is exported.
Above-mentioned gain control inputs, DAC input code and output select signal namely to form so-called voltage parameter project.The gain control inputs is to comprise one first gain and one second gain, wherein, the first gain is the first voltage (Va) with the product of energy gap reference voltage (Vref), and the product of the second gain and energy gap reference voltage (Vref) is second voltage (Vb).Above-mentioned the first gain or the second gain can be greater than, be less than or equal to one, so that voltage amplifier 332 can be that energy gap reference voltage (Vref) is made amplifications, decay or do not made voltage change.Certainly, the first gain also can be identical numerical value with the second gain.And tertiary voltage is second voltage and the product of its corresponding numerical value of DAC input code.
Therefore, when 20 productions of measurement device were finished, the producer must switch to measuring equipment 20 state or the pattern of correction, to obtain above-mentioned voltage parameter project.Under the state of proofreading and correct or pattern, the producer select a kind of measure pattern and change above-mentioned gain control inputs, DAC input code and output by the button 28 on the operation-interface 25 select signal, to adjust the output voltage of generating circuit from reference voltage 33.And the reference voltage of exporting when generating circuit from reference voltage 33 reaches when meeting the requiring of precision, the producer recycles gain control inputs, DAC input code and the output that button 28 will this moment and selects signal to be stored into electricallyerasable ROM (EEROM), will contain voltage parameter project that gain control inputs, DAC input code and output selects signal and deposit address to correspondence according to the measurement pattern.More than, just finish a kind of correction that measures its reference voltage of pattern.And the producer sets the corresponding gain control inputs of other its reference voltage of measurement pattern, DAC input code and output and selects signal and deposit electricallyerasable ROM (EEROM) again according to identical step.Therefore, above-mentioned correcting mode only need use the button 28 on the script operation-interface 25, is not need extra facility, and being to provide a more convenient and fast correction.And different measurement patterns have separately independently reference voltage, make measuring equipment 20 have better precision.
Claims (7)
1. measuring chip, comprise: an analog front circuit, in order to receive one first measured signal and to export one second measured signal, one measurement circuit, be electrically connected with this analog front circuit, to measure this second measured signal and to export measuring value to a display, one generating circuit from reference voltage, be electrically connected with this measurement circuit, to export a reference voltage to this measurement circuit, one control circuit is electrically connected with this analog front circuit, this measurement circuit and this generating circuit from reference voltage, and wherein this measuring chip is characterised in that:
This measuring chip further comprises an access-control scheme, this access-control scheme and this control circuit and this generating circuit from reference voltage are electrically connected, when this measuring chip is in a correction mode, a selected measurement project and a gain control inputs, a digital analog converter input code and an output that will should measure mutually project select signal to input to adjust a reference voltage that should measure mutually project, and should gain control inputs, this digital analog converter input code and this output selection signal of this control circuit is stored to this access-control scheme.
2. measuring chip as claimed in claim 1, wherein this generating circuit from reference voltage comprises:
One energy gap circuit is in order to export an energy gap reference voltage;
One voltage amplifier is electrically connected with this energy gap circuit, receiving this energy gap reference voltage and this gain control inputs, and exports one first voltage and a second voltage;
One digital analog converter is electrically connected with this voltage amplifier, receiving this second voltage and this digital analog converter input code, and exports a tertiary voltage; And
One output multiplexer is electrically connected with this voltage amplifier and this digital analog converter, receiving this first voltage and this tertiary voltage, and further receives this output selection signal, to determine that this first voltage or this tertiary voltage are as an output voltage.
3. measuring chip as claimed in claim 1, wherein this access-control scheme comprises a storer, and this storer and this access-control scheme are electrically connected.
4. measuring chip as claimed in claim 1, wherein this access-control scheme is an electricallyerasable ROM (EEROM) controller.
5. measuring chip, comprise: an analog front circuit, in order to receive one first measured signal and to export one second measured signal, one measurement circuit, be electrically connected with this analog front circuit, to measure this second measured signal and to export measuring value to a display, one generating circuit from reference voltage, be electrically connected with this measurement circuit, to export a reference voltage to this measurement circuit, one control circuit is electrically connected with this analog front circuit, this measurement circuit and this generating circuit from reference voltage, and wherein this measuring chip is characterised in that:
This measuring chip further comprises an access-control scheme, this access-control scheme and this control circuit and this generating circuit from reference voltage are electrically connected, when this measuring chip is in a measurement pattern, this access-control scheme is according to the selected measurement project of user, select signal to this generating circuit from reference voltage and export a gain control inputs, a digital analog converter input code and an output, this reference voltage of being exported to adjust this generating circuit from reference voltage.
6. measuring chip as claimed in claim 5, wherein this generating circuit from reference voltage comprises:
One energy gap circuit is in order to export an energy gap reference voltage;
One voltage amplifier is electrically connected with this energy gap circuit, receiving this energy gap reference voltage and this gain control inputs, and exports one first voltage and a second voltage;
One digital analog converter is electrically connected with this voltage amplifier, receiving this second voltage and this digital analog converter input code, and exports a tertiary voltage; And
One output multiplexer is electrically connected with this voltage amplifier and this digital analog converter, receiving this first voltage and this tertiary voltage, and further receives this output selection signal, to determine that this first voltage or this tertiary voltage are as an output voltage.
7. measuring chip as claimed in claim 5, wherein this access-control scheme is an electricallyerasable ROM (EEROM) controller.
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CN 200910160245 CN101988959B (en) | 2009-07-31 | 2009-07-31 | Multi-functional measuring device capable of adjusting reference voltage and chip thereof |
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CN 200910160245 CN101988959B (en) | 2009-07-31 | 2009-07-31 | Multi-functional measuring device capable of adjusting reference voltage and chip thereof |
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CN101988959A CN101988959A (en) | 2011-03-23 |
CN101988959B true CN101988959B (en) | 2013-04-24 |
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CN103163369B (en) * | 2011-12-19 | 2015-10-28 | 无锡华润矽科微电子有限公司 | Realize ic for energy metering structure and the method thereof of measuring accuracy pre-calibration function |
CN108226630B (en) * | 2016-12-22 | 2020-07-31 | 成都长城开发科技有限公司 | Switching method of reference voltage of intelligent electric meter |
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CN2354145Y (en) * | 1998-11-11 | 1999-12-15 | 张培 | Pocket digital multimeter |
CN1566968A (en) * | 2003-06-26 | 2005-01-19 | 上海华园微电子技术有限公司 | Pre-calibration electrical energy measuring chip |
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CN200997087Y (en) * | 2006-12-28 | 2007-12-26 | 东南大学 | CMOS reference voltage source with outputting voltage adjustment |
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JPS61202527A (en) * | 1985-03-06 | 1986-09-08 | Seiko Epson Corp | Video signal digital converting circuit |
JPS61228515A (en) * | 1985-04-02 | 1986-10-11 | Toshiba Corp | Controller for dc power supply |
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CN2354145Y (en) * | 1998-11-11 | 1999-12-15 | 张培 | Pocket digital multimeter |
CN1566968A (en) * | 2003-06-26 | 2005-01-19 | 上海华园微电子技术有限公司 | Pre-calibration electrical energy measuring chip |
CN1987488A (en) * | 2005-12-23 | 2007-06-27 | 深圳市芯海科技有限公司 | Electric energy metering chip |
CN200997087Y (en) * | 2006-12-28 | 2007-12-26 | 东南大学 | CMOS reference voltage source with outputting voltage adjustment |
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