CN108089142B - Detection circuit and method for voltage dividing circuit parameters and electric energy metering chip - Google Patents
Detection circuit and method for voltage dividing circuit parameters and electric energy metering chip Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/04—Voltage dividers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention belongs to the technical field of voltage detection, and provides a detection circuit of a voltage dividing circuit parameter, which comprises a voltage dividing circuit coupled with a first signal source with a first frequency, wherein the voltage dividing circuit comprises a first voltage divider, a second voltage divider and a third voltage divider which are connected in series, a voltage measuring module is connected on the second voltage divider in parallel, and the detection circuit further comprises: the second signal source and the third signal source; the voltage measurement module is used for detecting a first signal component of the second frequency on the second voltage divider under the condition that only the first switch is connected, detecting a second signal component of the third frequency on the second voltage divider under the condition that only the second switch is connected, and determining whether circuit parameters of the voltage division circuit are abnormal according to the first signal component and the second signal component.
Description
Technical Field
The invention belongs to the technical field of voltage detection, and particularly relates to a detection circuit and method for parameters of a voltage dividing circuit and an electric energy metering chip.
Background
In a power supply system, voltage to be measured is generally attenuated to be within an input voltage safety range of an analog-to-digital converter (Analog to Digital Converter, ADC) through a sampling network, and digital output converted by the ADC enters a digital processing unit to process voltage amplitude and phase. In high-precision measurement (such as electric power facility monitoring and electricity utilization statistics), the precision of the metering instrument reaches +/-0.5%. This requires that the accuracy of the resistor divider and the voltage measurement path be sufficiently stable. Accurate voltage measurements require the selection of off-chip components with good temperature coefficients and high accuracy. The selection of unsuitable off-chip components may result in a change in the transfer function of the sampling network or in a change in the gain of the voltage measurement channel, which may lead to measurement errors in the voltage.
However, once the off-chip components (such as the resistor divider) in the sampling network are subjected to various external forces, such as static electricity, overvoltage, surge, etc., the transfer function of the voltage measurement channel may be changed, resulting in voltage measurement errors, and further, the errors of electric energy measurement are caused by combination with current measurement. In addition, with the development of intelligent electric meters, the intelligent electric meter is required to have functions of not only electric energy metering and accurate measurement, but also fault detection, fault positioning, reporting of abnormal conditions of the electric meter and the like.
Disclosure of Invention
The invention aims to provide a detection circuit and method for parameters of a voltage dividing circuit and an electric energy metering chip, and aims to solve the problems that an existing voltage measuring circuit cannot detect measurement errors and voltage measurement accuracy reduction caused by the change of the voltage dividing ratio of an off-chip component due to the influence of external force.
The invention provides a detection circuit of a voltage dividing circuit parameter, which comprises a voltage dividing circuit coupled with a first signal source with a first frequency, wherein the voltage dividing circuit comprises a first voltage divider, a second voltage divider and a third voltage divider which are connected in series, a voltage measuring module is connected on the second voltage divider in parallel, and the detection circuit further comprises:
a second signal source with a second frequency, which is input at the connecting end of the first voltage divider and the second voltage divider and is accessed by a first switch;
a third signal source with the third frequency, which is input at the connecting end of the second voltage divider and the third voltage divider and is accessed by a second switch;
the voltage measurement module is used for detecting a first signal component of the second frequency on the second voltage divider under the condition that only the first switch is connected, detecting a second signal component of the third frequency on the second voltage divider under the condition that only the second switch is connected, and determining whether circuit parameters of the voltage division circuit are abnormal according to the first signal component and the second signal component.
Further, the voltage measurement module is specifically configured to process the first signal component and the second signal component, respectively obtain an amplitude value and a phase value of the first signal component and an amplitude value and a phase value of the second signal component, and determine whether a circuit parameter of the voltage division circuit is abnormal according to at least one of a ratio of the amplitude value of the first signal component to the amplitude value of the second signal component, a phase change of the first signal component, and a phase change of the second signal component.
Further, the first voltage divider, the second voltage divider and the third voltage divider are circuits composed of at least one of resistors, inductors and capacitors.
Further, a feedback resistor used in the generating circuit of the second signal source or the third signal source is the same as a temperature coefficient of the first voltage divider.
Further, the second signal source and the third signal source are alternating current sources.
Further, the second signal source includes an operational amplifier, a first current mirror, a second current mirror, and the feedback resistor, wherein:
the inverting input end of the operational amplifier is connected with reference voltage, the output end of the operational amplifier is connected with the control ends of the first current mirror tube and the second current mirror tube, the non-inverting input end of the operational amplifier is connected with the low potential end of the first current mirror tube and is grounded through the feedback resistor, the high potential ends of the first current mirror tube and the second current mirror tube are connected with power supply voltage, and the low potential end of the second current mirror tube is used as the output end of the second signal source.
Further, the third signal source and the second signal source are the same signal source circuit.
Further, the second frequency and the third frequency are the same or different, and are each in a non-integer multiple relationship with the first frequency.
Further, the second voltage divider, the third voltage divider and the voltage measurement module are on-chip devices of the integrated circuit, and the feedback resistor used in the generating circuit of the first voltage divider and the second signal source or the third signal source is an off-chip device of the integrated circuit.
The invention also provides a method for detecting parameters of a voltage dividing circuit, which comprises the following steps:
loading a first signal source with a first frequency at two ends of the voltage dividing circuit; wherein the voltage dividing circuit comprises a first voltage divider, a second voltage divider and a third voltage divider which are connected in series
Accessing a second signal source with a second frequency by a first switch at a first end of the second voltage divider, and accessing a third signal source with a third frequency by the second switch at a second end of the second voltage divider;
detecting a first signal component of the second frequency on the second voltage divider when only the first switch is switched in, and detecting a second signal component of the third frequency on the second voltage divider when only the second switch is switched in, and determining whether a circuit parameter of the voltage dividing circuit is abnormal according to the first signal component and the second signal component.
Another object of the present invention is to provide an electric energy metering chip, which includes the above detection circuit; the voltage dividing circuit is arranged outside the electric energy metering chip.
The invention also provides an electric energy metering chip which comprises a voltage dividing circuit and the detection circuit.
The detection circuit and the method for the parameters of the voltage dividing circuit introduce an additional signal source into a conventional voltage measurement channel, and locate whether the off-chip component fails or not by means of the known information of the alternating current signal source and certain switch time sequence information so as to achieve the function of accurately locating the failure source. Further, by the detection circuit and the detection method, the off-chip resistors (feedback resistors used in the first voltage divider and the signal source generation circuit) with the same temperature coefficient are reasonably selected, so that the voltage measurement system has a temperature compensation effect, the voltage measurement precision can be further improved, and the influence of temperature drift on the voltage measurement result is reduced.
Drawings
FIG. 1 is a schematic diagram of a voltage divider circuit parameter detection circuit according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram of a voltage divider circuit parameter detection circuit according to a second embodiment of the present invention;
FIG. 3 is a schematic diagram of an example of a second current source in the voltage divider circuit parameter detection circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an exemplary voltage divider circuit in a voltage divider circuit parameter detection circuit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a voltage divider circuit parameter detection circuit according to an embodiment of the present invention when a first switch is in an on state and a second switch is in an off state;
fig. 6 is a schematic structural diagram of a voltage divider circuit parameter detection circuit according to an embodiment of the present invention when a first switch is in an open state and a second switch is in a closed state.
Fig. 7 is a schematic diagram of a voltage divider circuit parameter detection circuit according to an embodiment of the present invention when both a first switch and a second switch are in an off state.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1, a detection circuit for a voltage dividing circuit parameter provided in an embodiment of the invention includes a voltage dividing circuit 100 coupled to a first signal source 201 having a first frequency, the voltage dividing circuit 100 includes a first voltage divider 202, a second voltage divider 203, and a third voltage divider 204 connected in series, and a voltage measurement module 200 is connected in parallel to the second voltage divider 203. The detection circuit further includes a second signal source 208a and a third signal source 208b having a second frequency.
A second signal source 208a is input at the connection end of the first voltage divider 202 and the second voltage divider 203 and is connected to the first switch 206; a third signal source 208b is input at the connection end of the second voltage divider 203 and the third voltage divider 204, and is accessed by a second switch 207. The voltage measurement module 200 is configured to detect a first signal component of the second frequency on the second voltage divider 203 when only the first switch 206 is connected, and detect a second signal component of the second frequency on the second voltage divider 203 when only the second switch 207 is connected, and determine whether circuit parameters of the voltage division circuit 100 and the second signal source 208a are abnormal according to the first signal component and the second signal component; at the same time, it can be determined whether the circuit parameter of the second signal source 208a (the feedback resistance used in the signal source generating circuit) is abnormal.
In addition, referring to fig. 1, the frequencies of the second signal source 208a and the third signal source 208b may be the same or different, and the amplitudes may be the same or different; referring to fig. 2, the second signal source and the third signal source may be provided by the same signal source 208. The first voltage divider 202, the second voltage divider 203, and the third voltage divider 204 are all circuits composed of at least one of resistors, inductors, and capacitors.
Referring to fig. 2, in a more specific embodiment, a detection circuit of a voltage dividing circuit parameter includes a measured voltage Vm (a first signal source 201); the voltage dividing circuit 100 is a voltage sampling network, and comprises a first resistor R ext1 (first voltage divider 202), second resistor R int1 (second voltage divider 203), third resistor R int2 (third voltage divider 204) the presence of the sampling network is mainly to attenuate the signal to be detected within the safe inputtable range of the analog-to-digital conversion unit 205; the voltage measurement module 200 includes an analog-to-digital conversion unit 205 and digital signal processing units 209 and 210, and the voltage measurement module 200 serves as a measurement signal processing unit and a detection signal processing unit; the detection signal source 300 is composed of a time switch s 1 (first switch 206), s 2 (second switch 207) and an alternating current source V REF /R ext2 (second signal source 208), resistor R ext2 For the feedback resistor used in the signal source generating circuit of the second signal source 208, in the present invention, the detection signal generates a detection signal at the input end of the analog-digital unit through the voltage sampling network, and the detection signal generates a detection value through the signal processing unit.
In the present invention, the measured voltage V m Frequency of (a) and alternating current source V REF /R ext2 The second frequency and the third frequency are each a non-integer multiple of the first frequency. For example the measured voltage V m At a frequency of 50Hz, the AC current source V REF /R ext2 The frequency may be selected to be 432Hz. AC current source V REF /R ext2 The current source is mainly generated by combining a reference voltage source, an operational amplifier, a current mirror tube and a feedback resistor. Internal circuit of actual current sourceThe output waveform of the current source can be controlled to be an alternating current signal through a switch.
The first switch 206 and the second switch 207 are MOS transistors, and are mainly used to control an access point of an ac current source, and the first switch 206 and the second switch 207 are ensured not to be closed at the same time by reasonably controlling a time sequence of the switch signal generator. During normal measurement, the first switch 206 and the second switch 207 can be opened, and when it is required to detect whether the parameters of the sheet voltage division circuit have faults, the first switch 206 and the second switch 207 can be independently closed.
As a preferred embodiment, the feedback resistor R used in the signal source generating circuit of the second signal source 208 ext2 The internal resistance is the same as the temperature coefficient of the first voltage divider 202. At the same time by means of a feedback resistor R ext2 To cancel the temperature coefficient of the measurement channel first voltage divider 202. Thus, the feedback resistor R of the second signal source 208 ext2 Can be placed off-chip, mainly because an alternating current source with any temperature coefficient can be obtained by selecting an off-chip resistor with any temperature coefficient.
As a preferred embodiment, the voltage measurement module 200 is specifically configured to process the first signal component and the second signal component, obtain an amplitude value and a phase value of the first signal component and an amplitude value and a phase value of the second signal component, respectively, and determine whether a circuit parameter of the voltage division circuit 100 is abnormal according to at least one of a ratio of the amplitude value of the first signal component to the amplitude value of the second signal component, a phase change of the first signal component, and a phase change of the second signal component.
Referring to FIG. 3, as a preferred embodiment, the second signal source 208 comprises an operational amplifier Amp, a first current mirror Q1, a second current mirror Q1, and a feedback resistor R ext2 . Referring to fig. 1, the second signal source 208a and the third signal source 208b are the same signal source circuit, i.e. the same as the second signal source 208 in fig. 3.
The inverting input of the operational amplifier Amp is connected with the reference voltage V REF An output end connected with the first current mirror tube Q1 and the first current mirror tubeThe control end of the second current mirror tube Q1, the non-inverting input end of which is connected with the low potential end of the first current mirror tube Q1 and passes through the feedback resistor R ext2 The high potential ends of the first current mirror Q1 and the second current mirror Q1 are grounded and connected to a power supply voltage VCC, and the low potential end of the second current mirror Q1 is used as an output end of the second signal source 208. The introduction of an ac current source does not have any effect on normal voltage measurement, the current source needs to be a high-precision reference voltage divided by a resistor, and the presence of the analog-to-digital conversion unit 205 in the voltage measurement module 200 itself requires a high-precision voltage source, so that the complexity of the circuit design is greatly reduced, and only the high-precision voltage source needs to be shared. The current of the current source is moderate to ensure that the signal amplitude of the input port of the analog-to-digital conversion unit 205 is within the safe input range of the analog-to-digital conversion unit 205.
The second voltage divider 203, the third voltage divider 204 and the voltage measurement module 200 are on-chip devices of an integrated circuit, and the feedback resistors R of the first voltage divider 202 and the second signal source 208 ext2 Is an off-chip device of an integrated circuit. Selecting the feedback resistor R of the second signal source 208 ext2 The main reason for being placed off-chip is that a current source with any temperature coefficient can be obtained by selecting an off-chip resistor with any temperature coefficient. At the same time by means of a feedback resistor R ext2 To cancel the first resistance R of the measurement channel ext1 Is a temperature coefficient of (c) a.
Referring to fig. 4, the voltage dividing circuit 100 is not limited to the impedance types, and Z0, Z1, Z2 in the following figures may be resistors, capacitors, inductors, or combinations thereof, for example, resistors and capacitors connected in parallel. If the sampling network comprises components such as capacitance, inductance and the like, the fault source can be positioned by monitoring the amplitude and phase change amount of the detection signal at the same time.
The AC current source needs to use the high-precision band-gap reference voltage V REF And off-chip resistance R ext2 Realized by a high-precision band-gap reference voltage V REF And is also necessary for ADCs, the high precision bandgap reference voltage can be directly shared. The alternating current source circuit can control the current source circuit through the switchAnd the control signal of the switch is digitally controlled, so that an alternating current source can be conveniently generated.
On-chip resistor R int1 And R is R int2 The reason for selecting to place the chip is to reduce the off-chip components, and meanwhile, the chip resistor is stable and reliable, and is not easy to fail. Although the precision of the on-chip resistor is deviated by the manufacturing process, the resistance value can be calibrated when leaving the factory, so that the subsequent accurate calculation of the off-chip resistor value is facilitated.
The working process of the detection circuit of the voltage dividing circuit parameters comprises the following steps: for the sake of simplicity, it can be assumed that the resistances R of the second 203 and third 204 voltage dividers int1 ＝R int2 The working process can be actually based on the switch S 1 、S 2 Is divided into:
step1: referring to FIG. 5, switch S 1 Closing, S 2 Disconnection, at this point it is assumed that the second signal source 208 has a frequency f i Assume that the voltage signal to be measured V m Is an alternating current signal and has a frequency f u And f i ≠f u At the same time satisfy f i 、f u The two frequencies cannot have an integer multiple relationship, and the assumption here is mainly to ensure that the subsequent analog-to-digital conversion unit 205 and digital signal processing units 209, 210 processes can correctly distinguish between the signal amplitude and the phase of the unable frequency points.
Defining the voltage signal generated by the second signal source 208 at the input end of the analog-to-digital conversion unit 205 through the voltage dividing circuit 100 as U 0，fi_1 。
Separately calculating the voltage signal (first signal component) U generated by the second signal source 208 through the voltage dividing circuit 100 0，fi_1 ，
Step2: referring to FIG. 6, switch S 1 Open and close S 2 Closed, the second signal source 208 is still an ac signal and has a frequency f i The voltage signal generated by the high-precision alternating current source at the input end of the analog-to-digital conversion unit 205 through the voltage dividing circuit 100 is defined as U 0，fi_2 。
Separately calculating the voltage signal (second signal component) U generated by the second signal source 208 through the voltage divider circuit 100 0，fi_2 。
The switch S can be obtained by the operations of the formulas 1 and 2 1 、S 2 The measurement results of the alternating current source signals when being independently started respectively are divided by the two measurement results:
due to the second resistor R in the circuit design int1 Is a resistor with a known resistance value in the chip, the accurate resistance value can be known through factory calibration, and the first resistor R can be obtained through a formula 3 ext1 Is the exact value R of (2) ext1_real And whether the off-chip resistor is affected by various external forces can be easily obtained through comparison with the actual calibration value of the first resistor.
Will first resistance R ext1 Is the exact value R of (2) ext1_real Substituting equation 1 or equation 2 can determine the feedback resistance (feedback resistance R used in the second signal source generating circuit ext2 ) Is the exact value R of (2) ext2_real Therefore, the feedback resistor R can be judged ext2 Whether a fault has occurred. Thus, both off-chip devices can detect whether a fault occurs or not, and can accurately position the fault source.
And introducing an additional alternating current source into a conventional voltage measurement channel, and positioning whether the off-chip component fails or not by means of the known information of the alternating current source and certain switch time sequence information so as to achieve the function of accurately positioning the failure source. Meanwhile, by the voltage measuring device and the voltage measuring method, the off-chip resistors (R) with the same temperature coefficient are reasonably selected ext1 、R ext2 ) The voltage measurement system can have a temperature compensation effect, the voltage measurement precision can be further improved, and the voltage measurement result can be reducedIs affected by temperature drift.
The applied ac current source signal may be various periodic signals, such as a sine wave signal, a square wave signal, a triangular wave signal, and the like.
In addition, a detection method of the parameters of the voltage dividing circuit is disclosed, which comprises the following steps:
step one: loading a first signal source with a first frequency at two ends of the voltage dividing circuit; wherein the voltage dividing circuit comprises a first voltage divider, a second voltage divider and a third voltage divider which are connected in series
Step two: accessing a second signal source with a second frequency by a first switch at a first end of the second voltage divider, and accessing a third signal source with a third frequency by the second switch at a second end of the second voltage divider;
step three: detecting a first signal component of the second frequency on the second voltage divider with only the first switch being switched in, and detecting a second signal component of the third frequency on the second voltage divider with only the second switch being switched in;
step four: and determining whether the circuit parameters of the voltage dividing circuit are abnormal according to the first signal component and the second signal component.
In a preferred embodiment, the fourth step is specifically:
and processing the first signal component and the second signal component to obtain an amplitude value and a phase value of the first signal component and an amplitude value and a phase value of the second signal component respectively, and determining whether the circuit parameters of the voltage dividing circuit are abnormal according to at least one of the ratio of the amplitude value of the first signal component to the amplitude value of the second signal component, the phase change of the first signal component and the phase change of the second signal component.
Reference is made to fig. 5 and fig. 6 for a specific embodiment of a method for detecting parameters of a voltage dividing circuit.
In a preferred embodiment, further comprising:
detecting a third signal component of the first frequency on the second voltage divider with the first switch and the second switch disconnected;
and calibrating the voltage division circuit parameter according to the first signal component and the third signal component, in particular calibrating the voltage division circuit parameter according to the ratio of the first signal component to the third signal component.
Referring to FIG. 7, switch S 1 、S 2 All open, the ADC input voltage signal (third signal component) obtained through the voltage dividing circuit 100 is:
for switch S 1 、S 2 The on-off state of (2) does not change the signal V to be detected m The voltage signal obtained after the ac frequency point thereof passes through the voltage dividing circuit 100. This characteristic shows that the measurement of the signal to be measured is not disturbed when the off-chip component fault detection is carried out by means of an alternating current source.
The following equation is obtained by dividing equation 1 and equation 4:is a switch S 1 Closing, S 2 Voltage value of ADC quantized AC current signal frequency point when off, +.>And the voltage value of the voltage signal frequency point to be measured quantized by the ADC is obtained.
As can be seen from equation 5, the reference voltage V REF Can be considered as zero temperature coefficient if an off-chip resistor R having the same temperature coefficient is selected ext1 、R ext2 Thus, the following can be concluded from equation 5: i.e. the voltage V to be measured m Ratio of measurement results of (2) to measurement results of the incoming alternating current signalThe value is a temperature independent quantity. This means that the temperature coefficient of the voltage signal to be measured can be compensated by the ac current source signal measurement result. The voltage detection precision can be further improved, meanwhile, a high-precision resistor with an extremely low temperature coefficient is not needed, and only a resistor pair with the same temperature coefficient is needed. As can be seen from equation 5, the off-chip resistance (R ext1 、R ext2 ) The voltage measurement result of the whole voltage measurement device can have a temperature compensation effect. If the off-chip resistance R obtained by the previous solution is calculated ext1 、R ext2 Accurate value R ext1_real 、R ext2_real With equation 5, the divider circuit parameters can be calibrated according to Y.
The detection method not only can detect whether the off-chip component fails, but also can stably and reliably position a failure source, and the off-chip resistor (R ext1 、R ext2 ) Is the exact value R of (2) ext1_real 、R ext2_real The accurate detection signal (line voltage) V can be directly obtained by combining the formula (5) m Thus calibrating the voltage divider circuit parameters according to Y. At the same time, by selecting a suitable off-chip resistance (R ext1 、R ext2 ) (having the same temperature coefficient) the entire measurement system can be made to have a temperature compensation function.
The voltage measuring device is simple to implement, only two off-chip resistors are needed, and the alternating current source can be realized by means of a high-precision reference in the chip, so that the design complexity is greatly reduced.
The embodiment of the invention also provides an electric energy metering chip, which comprises the detection circuit. In the embodiment of the invention, the voltage dividing circuit is arranged outside the electric energy metering chip. Specifically, the detection circuit is integrated inside the chip, at this time, the detection circuit inside the chip is not influenced by external environment, and further, the switch states of the first switch and the second switch can be set in the voltage measurement module in advance to be switched after being started.
The embodiment of the invention also provides another electric energy metering chip which comprises a voltage dividing circuit and the detection circuit.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (11)
1. A detection circuit for a voltage divider circuit parameter, comprising a voltage divider circuit coupled to a first signal source having a first frequency, the voltage divider circuit comprising a first voltage divider, a second voltage divider, and a third voltage divider connected in series, the second voltage divider having a voltage measurement module connected in parallel thereto, the detection circuit further comprising:
a second signal source with a second frequency, which is input at the connecting end of the first voltage divider and the second voltage divider and is accessed by a first switch;
a third signal source with a third frequency, which is input at the connecting end of the second voltage divider and the third voltage divider and is accessed by a second switch;
the voltage measurement module is used for detecting a first signal component of the second frequency on the second voltage divider under the condition that only the first switch is connected and detecting a second signal component of the third frequency on the second voltage divider under the condition that only the second switch is connected, and determining whether circuit parameters of a first voltage divider of the voltage division circuit and a second signal source are abnormal according to the first signal component and the second signal component;
the voltage measurement module is specifically configured to process the first signal component and the second signal component to obtain an amplitude value and a phase value of the first signal component and an amplitude value and a phase value of the second signal component, respectively, and determine whether a circuit parameter of the voltage division circuit is abnormal according to a ratio of the amplitude value of the first signal component to the amplitude value of the second signal component;
the first voltage divider, the second voltage divider and the third voltage divider are circuits formed by at least one of resistors, inductors and capacitors.
2. The detection circuit of claim 1, wherein a feedback resistor used in the generation circuit of the second signal source or the third signal source is the same as a temperature coefficient of the first voltage divider.
3. The detection circuit according to claim 1 or 2, wherein the second signal source and the third signal source are alternating current sources.
4. The detection circuit of claim 1 or 2, wherein the second signal source comprises an operational amplifier, a first current mirror, a second current mirror, and the feedback resistor, wherein:
the inverting input end of the operational amplifier is connected with reference voltage, the output end of the operational amplifier is connected with the control ends of the first current mirror tube and the second current mirror tube, the non-inverting input end of the operational amplifier is connected with the low potential end of the first current mirror tube and is grounded through the feedback resistor, the high potential ends of the first current mirror tube and the second current mirror tube are connected with power supply voltage, and the low potential end of the second current mirror tube is used as the output end of the second signal source.
5. The detection circuit of claim 4, wherein the third signal source and the second signal source circuit are the same signal source circuit.
6. The detection circuit of claim 1, wherein the second frequency and the third frequency are the same or different and each is a non-integer multiple of the first frequency.
7. The detection circuit of claim 1 or 2, wherein the second voltage divider, the third voltage divider and the voltage measurement module are on-chip devices of an integrated circuit, and the feedback resistors used in the generation circuits of the first voltage divider, the second signal source and the third signal source are off-chip devices of the integrated circuit.
8. A method for detecting a voltage divider circuit parameter, comprising:
loading a first signal source with a first frequency at two ends of the voltage dividing circuit; the voltage dividing circuit comprises a first voltage divider, a second voltage divider and a third voltage divider which are connected in series;
accessing a second signal source with a second frequency by a first switch at a first end of the second voltage divider, and accessing a third signal source with a third frequency by the second switch at a second end of the second voltage divider;
detecting a first signal component of the second frequency on the second voltage divider with only the first switch being switched in, and detecting a second signal component of the third frequency on the second voltage divider with only the second switch being switched in;
determining whether circuit parameters of a first voltage divider of the voltage dividing circuit and the second signal source are abnormal according to the first signal component and the second signal component;
the determining whether the parameters of the voltage dividing circuit are abnormal according to the first signal component and the second signal component specifically comprises:
and processing the first signal component and the second signal component to respectively obtain an amplitude value and a phase value of the first signal component and an amplitude value and a phase value of the second signal component, and determining whether the circuit parameters of the voltage dividing circuit are abnormal according to the ratio of the amplitude value of the first signal component to the amplitude value of the second signal component.
9. The method of detecting as claimed in claim 8, further comprising:
detecting a third signal component of the first frequency on the second voltage divider with the first switch and the second switch disconnected;
and calibrating the voltage dividing circuit parameter according to the first signal component and the third signal component.
10. An electric energy metering chip, characterized in that it comprises a detection circuit according to any one of claims 1 to 7; the voltage dividing circuit is arranged outside the electric energy metering chip.
11. An electrical energy metering chip comprising a voltage dividing circuit, wherein the electrical energy metering chip further comprises a detection circuit as claimed in any one of claims 1 to 7.
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| CN110221238B (en) * | 2019-06-28 | 2025-04-18 | 深圳市锐能微科技有限公司 | Detection circuit and method of voltage divider circuit parameters and electric energy metering chip |
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| CN110221240B (en) * | 2019-06-28 | 2025-03-07 | 深圳市锐能微科技有限公司 | Voltage divider circuit parameter detection circuit and electric energy metering chip |
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