Voltage sampling circuit for internal power supply of power consuming device, sampling method and electric energy meter

Abstract

The invention discloses a voltage sampling circuit for an internal power supply of a power consuming device, a sampling method and an electric energy meter. The voltage sampling circuit comprises a control module, an internal power supply and an external power supply, wherein the internal power supply and the external power supply are both connected to the control module; the internal power supplyis provided with two sampled ends one of which is connected to the sampling end of the control module, and the other of which is connected to the control end of the control module through an artificial load. When the external power supply is turned on, the control end of the control module is set to a low level, the voltage of the artificial load is acquired by the sampling end of the control module, and the voltage value of the internal power supply in the power-off state of the power consuming device is obtained. After the sampling is completed, the control end is set to a high level. The voltage sampling circuit samples the internal supply voltage of the electric energy meter by simulating the electric energy consumption in the power-off state with the artificial load, not only does not consume a large amount of additional power consumption of the electric energy meter, but also achieves high sampling accuracy is high.

Description

technical field [0001] The invention relates to a voltage sampling circuit, in particular to a voltage sampling circuit, a sampling method and an electric energy meter of an internal power supply of a power consumption device. Background technique [0002] Many existing power consumption devices need to retain some functions in the power-off state, such as electric energy meters, sensors and fixed telephones, etc., and the parts that continue to work in the power-off state still need the necessary voltage to supply power to them, which will inevitably lead to Its internal power supply (such as: battery, etc.) is lost, which requires replacement of the internal power supply with too low voltage, and how to accurately measure the voltage value of the internal power supply in the power-off state so as to perform low voltage alarm in time is a problem in the prior art. Difficult technical barriers to break through. [0003] Taking the electric energy meter as an example, due to...

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Problems solved by technology

[0007] For method 1), the actual collected power consumption is not the power consumption when the meter is powered off, but the sum of the power consumption when the meter is powered off plus the power consumption after the control module sampling function is turned on. In fact, The power consumption of the energy meter itself is a few tenths or even a few hundredths of that when the control module turns on the sampling function, so the internal power supply voltage of this kind of downsampling is not the internal power supply voltage of the power meter when it is actually powered off. According to this It is also inaccurate to use the sampled internal power supply voltage to evaluate the actual voltage state of the internal power supply of the electric energy meter. In addition, the actual power consumption of the electric energy meter will increase because the sampling function of the control module is turned on, causing unnecessary power consumption to the internal power supply of the electric energy meter. , leading to abnormal attenuation of the life of the internal power supply of the electric energy meter;

[0008] For the second) method, the energy meter performs internal power supply voltage sampling after power-on. In order to ensure the continuity of the internal power supply life of the energy meter under power-off, it is generally required that the energy meter cannot be powered by a backup internal power supply after power-on. Therefore, when the internal power supply has no load, all the voltage of the internal power supply is consumed on the internal resistance. Therefore, the real value of the internal power supply voltage of the electric energy meter cannot be obtained by sampling the internal power supply voltage of the electric energy meter through the sampling function of the electric energy meter control module. , if the actual voltage state of the internal power supply of the energy meter is evaluated based on the sampled internal power supply voltage, it is also inaccurate

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