CN106646241A - Voltage detection circuit and voltage measurement method - Google Patents

Abstract

The embodiment of the invention discloses a voltage detection circuit and a voltage measurement method, wherein the voltage detection circuit comprises: a reference voltage generating circuit and a single chip microcomputer; the output end of the reference voltage generating circuit is connected with a reference voltage input pin of the singlechip, and the power supply end of the reference voltage generating circuit is connected with a working voltage, wherein the reference voltage generating circuit is used for providing a reference voltage for the singlechip and outputting the reference voltage to the singlechip through the output end; and a power supply pin of the single chip microcomputer is connected with power supply voltage, and the single chip microcomputer is used for calculating the power supply voltage by detecting the band gap voltage of the single chip microcomputer and utilizing a relational expression between the band gap voltage and the power supply voltage. The invention can reduce the additional power supply voltage detection circuit and the power consumption brought by the additional power supply voltage detection circuit, is convenient to detect and saves resources.

Description

A voltage detection circuit and voltage measurement method

technical field

The invention relates to the field of circuits, in particular to a voltage detection circuit and a voltage measurement method.

Background technique

A single-cell lithium battery can directly supply power to the microcontroller. When the user uses a single-cell lithium battery for power supply, in order to observe the remaining power of the lithium battery in time and take corresponding measures, it is necessary to detect the voltage of the lithium battery. For example, in some portable light emitting diode (Light Emitting Diode, referred to as LED) lamps, the voltage of the lithium battery can be detected, so that the lithium battery can be replaced in time when the remaining power of the lithium battery is insufficient.

At present, the detection of the lithium battery voltage is mainly to sample the voltage of the lithium battery through two voltage divider resistors, thereby calculating the voltage of the lithium battery and estimating the remaining power. However, when using this method to detect the voltage of the lithium battery, it is necessary Connect two voltage divider resistors in the original circuit to calculate, and the voltage divider resistors are directly connected to the battery, there is no shutdown measure, so even when the LED lamp is not working, there is still current flowing through the two A voltage dividing resistor causes a large standby current and wastes resources, thus requiring a more convenient method for detecting the voltage of a lithium battery.

Contents of the invention

Embodiments of the present invention provide a voltage detection circuit and a voltage measurement method in order to detect the voltage of a lithium battery more easily.

The first aspect of the embodiments of the present invention provides a voltage detection circuit, including:

Reference voltage generating circuit and single-chip microcomputer;

The output end of the reference voltage generating circuit is connected to the reference voltage input pin of the single-chip microcomputer, and the power supply terminal of the reference voltage generating circuit is connected to an operating voltage, wherein the reference voltage generating circuit is used to provide a reference for the single-chip microcomputer voltage, and output the reference voltage to the single-chip microcomputer through the output terminal;

The power supply pin of the single-chip microcomputer is connected to the power supply voltage, and the single-chip microcomputer is used to calculate the power supply voltage by detecting the bandgap voltage of the single-chip microcomputer and using a relational expression between the bandgap voltage and the power supply voltage.

Wherein, the reference voltage generating circuit includes a resistor and a voltage stabilizing source, the control terminal of the stabilizing voltage source is connected to the sampling terminal of the stabilizing voltage source, and is connected to one end of the resistor, and the ground of the stabilizing voltage source is The pin is grounded, the other end of the resistor is connected to the input voltage, and the sampling end of the voltage stabilizing source is the output end of the reference voltage generating circuit.

Wherein, the model of the single-chip microcomputer is HT66F006, the reference voltage input pin of the single-chip microcomputer is connected to the sampling terminal of the voltage stabilizing source, the power supply pin of the single-chip microcomputer is connected to the power supply voltage, and the ground pin of the single-chip microcomputer is grounded.

Wherein, the fifth input and output pin of the single-chip microcomputer is connected to the voltage input terminal of the reference voltage generating circuit, and is used to provide the working voltage for the reference voltage generating circuit by using the fifth input and output pin of the single-chip microcomputer.

Wherein, the voltage input terminal of the reference voltage generating circuit is connected to the power supply voltage.

Wherein, the model of the voltage stabilizing source is TL431.

The first aspect of the embodiments of the present invention provides a voltage measurement method, which is applied to the voltage detection circuit provided in the first aspect of the embodiments of the present invention, including:

Detecting the internal bandgap voltage of the single-chip microcomputer;

The power supply voltage is calculated according to a relationship expression between the internal bandgap voltage and the power supply voltage.

Wherein, the relationship expression between the internal bandgap voltage and the power supply voltage is a linear expression y=kx+b.

Wherein, before the detection of the internal bandgap voltage of the single-chip microcomputer, the method also includes:

A linear expression y=kx+b of the internal bandgap voltage and the supply voltage is determined.

Wherein, the linear expression y=kx+b for determining the internal bandgap voltage and the power supply voltage includes:

Respectively collect two different reference power supply voltages and reference internal bandgap voltages respectively corresponding to the two different reference power supply voltages;

A linear expression y=kx+b of the internal bandgap voltage and the power supply voltage is determined by using the two different reference power supply voltages and the reference internal bandgap voltage. The present invention detects the internal bandgap voltage of the singlechip through the singlechip, and then based on the reference voltage, and calculates the power supply voltage according to the linear relationship between the internal bandgap voltage and the power supply voltage, since the power supply voltage is calculated through the internal bandgap voltage of the singlechip, Therefore, when the LED lamp is not working, the microcontroller is in a dormant state. Therefore, the additional power supply voltage detection circuit and the power consumption caused by it can be reduced, the detection is convenient, and the resources are saved.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a first embodiment of a voltage detection circuit provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a second embodiment of a voltage detection circuit provided by an embodiment of the present invention;

3 is a schematic structural diagram of a third embodiment of a voltage detection circuit provided by an embodiment of the present invention;

FIG. 4 is a schematic flowchart of a first embodiment of a voltage measurement method provided by an embodiment of the present invention;

Fig. 5 is a schematic flow chart of the second embodiment of the voltage measurement method provided by the embodiment of the present invention.

detailed description

Embodiments of the present invention provide a voltage detection circuit and a voltage measurement method in order to detect the voltage of a lithium battery more easily.

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

The terms "first", "second" and "third" in the specification and claims of the present invention and the above drawings are used to distinguish different objects, rather than to describe a specific order. Furthermore, the term "comprise", as well as any variations thereof, is intended to cover a non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally further includes For other steps or units inherent in these processes, methods, products or apparatuses.

Referring first to FIG. 1 , FIG. 1 is a schematic structural diagram of a first embodiment of a voltage detection circuit provided by an embodiment of the present invention. Wherein, as shown in FIG. 1, the voltage detection circuit provided by the first embodiment of the present invention may include:

Reference voltage generating circuit 1 and single-chip microcomputer 2;

Wherein, the output end of the reference voltage generating circuit 1 is connected to the reference voltage input pin of the single-chip microcomputer 2, and the power supply terminal of the reference voltage generating circuit 1 is connected to an operating voltage, wherein the reference voltage generating circuit 1 is used for Providing a reference voltage to the single-chip microcomputer 2, and outputting the reference voltage to the single-chip microcomputer 2 through the output terminal;

The power supply pin of the single-chip microcomputer 2 is connected to the power supply voltage, and the single-chip microcomputer 2 is used to calculate the power supply voltage by detecting the bandgap voltage of the single-chip microcomputer 2 and utilizing the relational expression between the bandgap voltage and the power supply voltage .

Wherein, the reference voltage generating circuit 1 can generate a standard voltage, which is connected to the reference voltage input pin of the single-chip microcomputer 2, and is used to provide the reference voltage to the single-chip microcomputer 2, so that the voltage detection of the entire voltage detection circuit is more accurate.

Wherein, the bandgap voltage is an internal voltage that can be detected after the single-chip microcomputer 2 works, and there is a linear relationship between the bandgap voltage and the power supply voltage of the single-chip microcomputer 2, so in the embodiment of the present invention, when the single-chip microcomputer 2 is working, The voltage of a single-cell lithium battery is detected according to the approximately linear characteristic of the bandgap voltage and the power supply voltage of the single-chip microcomputer at the general ambient temperature (-20°C ~ +40°C).

In the embodiment of the present invention, the power supply terminal of the single-chip microcomputer 2 is connected to the working voltage, that is, the power supply voltage to be measured.

Optionally, in some possible implementations of the present invention, one end of the capacitor is connected to the common node between the power supply terminal of the single-chip microcomputer 2 and the power supply voltage access pin, and the other end of the capacitor is grounded, so as to provide stable voltage for the single-chip microcomputer 2. Input voltage.

Preferably, in some possible implementation manners of the present invention, the value of the above capacitance may be 147 microfarads.

In the embodiment of the present invention, when the circuit is connected, the circuit starts to work, the single chip microcomputer 2 detects the internal bandgap voltage, and standardizes the bandgap voltage based on the reference voltage provided by the reference voltage generating circuit 1, and then according to the bandgap voltage and The linear relationship between the power supply voltages, two sets of bandgap voltages and power supply voltages can be detected, and the prepared linear expressions of the bandgap voltage and power supply voltage can be calculated, so that the expression can be used to pass the detection band at any time. The gap voltage is calculated to obtain the power supply voltage at this moment. Using this method, the bandgap voltage can be directly detected inside the single-chip microcomputer to calculate the power supply voltage, so that the power supply voltage of the single-chip microcomputer can be obtained without connecting an additional power supply voltage detection circuit. Since the power supply voltage is calculated through the bandgap voltage inside the single-chip microcomputer, the single-chip microcomputer is in a dormant state when the LED lamp is not working, which reduces the power consumption caused by the additional voltage detection circuit, facilitates detection, and saves resources.

The present invention detects the internal bandgap voltage of the singlechip through the singlechip, and then based on the reference voltage, and calculates the power supply voltage according to the linear relationship between the internal bandgap voltage and the power supply voltage, since the power supply voltage is calculated through the internal bandgap voltage of the singlechip, Therefore, when the LED lamp is not working, the microcontroller is in a dormant state. Therefore, the additional power supply voltage detection circuit and the power consumption caused by it can be reduced, the detection is convenient, and the resources are saved.

Referring to FIG. 2 , FIG. 2 is a schematic structural diagram of a second embodiment of a voltage detection circuit provided by an embodiment of the present invention. Among them, as shown in Figure 2, Figure 2 is a more specific description of the voltage detection circuit shown in Figure 1, as shown in Figure 2:

The reference voltage generating circuit 1 includes a resistor 11 and a voltage stabilizing source 12, the control end of the voltage stabilizing source 12 is connected to the sampling end of the voltage stabilizing source 12, and is connected to one end of the resistor 11, the stabilizing voltage source 12 The ground pin of the voltage source 12 is grounded, the other end of the resistor 11 is connected to the input voltage, and the sampling end of the voltage stabilizing source 12 is the output end of the reference voltage generating circuit 1 .

Optionally, in some possible implementations of the present invention, one end of the resistor 11 for providing voltage input to the reference voltage generating circuit 1 may be connected to a battery.

Preferably, in some other possible implementations of the present invention, one end of the resistor 11 for providing voltage input to the reference voltage generating circuit 1 can also be provided by a pin of the single-chip microcomputer, thereby saving additional power input.

Preferably, in some possible implementations of the present invention, the resistance value of the resistor 11 is 1 kohm.

In the embodiment of the present invention, the function of the reference voltage generating circuit 1 is realized by using the voltage stabilizing source 12 , so as to provide the single chip microcomputer 2 with a standard voltage.

Referring to FIG. 3 , FIG. 3 is a schematic structural diagram of a third embodiment of a voltage detection circuit provided by an embodiment of the present invention. Wherein, as shown in Figure 3, Figure 3 is a more specific description of the voltage detection circuit shown in Figure 2, as shown in Figure 3:

The model of the single-chip microcomputer 2 is HT66F006, and the reference voltage input pin of the single-chip microcomputer 2 is connected with the sampling terminal of the voltage stabilizing source, the power supply pin of the single-chip microcomputer 2 is connected to the power supply voltage, and the ground pin of the single-chip microcomputer 2 grounded.

The fifth input and output pin of the single-chip microcomputer 2 is connected to the voltage input terminal of the reference voltage generating circuit 1, and is used to provide an operating voltage for the reference voltage generating circuit 1 by using the fifth input and output pin of the single-chip microcomputer 2 .

The model of the voltage stabilizing source 12 is TL431.

In the embodiment of the present invention, the fifth input and output pin of the single chip microcomputer 2 is used to provide a stable voltage to the reference voltage generating circuit 1, thereby eliminating the need to connect an additional power supply to the reference voltage generating circuit 1.

The embodiment of the present invention utilizes the TL431 stabilized voltage source to provide the reference voltage to the reference voltage input pin of the HT66F006 single-chip microcomputer, and uses the fifth input and output pin of the HT66F006 single-chip microcomputer to provide the working voltage to the reference voltage generation circuit 1, so that the HT66F006 single-chip microcomputer can be based on the The reference voltage is used for voltage detection, and the single-chip microcomputer can be used to provide working voltage to the reference voltage generating circuit 1, so that the voltage detection circuit can perform voltage detection under this connection.

Referring to FIG. 4 , FIG. 4 is a schematic flowchart of a first embodiment of a voltage measurement method provided by an embodiment of the present invention. Wherein, the voltage measurement method shown in Figure 4 is applied to the voltage detection circuit shown in Figures 1 to 3, specifically, implemented in the single-chip microcomputer of the voltage detection circuit shown in Figures 1 to 3, as shown in Figure 4, The voltage measurement method provided by the embodiment of the present invention may include:

S401. Detect the internal bandgap voltage of the single-chip microcomputer.

In the embodiment of the present invention, based on the above-mentioned voltage detection circuit, the single-chip microcomputer can detect its internal bandgap voltage.

Specifically, after detecting the internal bandgap voltage of the single-chip microcomputer, a standard internal bandgap voltage value is obtained based on the reference voltage, and the value is converted into a digital value through an ADC (analog-to-digital conversion).

S402. Calculate the power supply voltage according to the relationship expression between the internal bandgap voltage and the power supply voltage.

In the embodiment of the present invention, the relationship expression between the internal bandgap voltage and the power supply voltage is a linear expression y=kx+b, so it can be understood that, for the linear expression, two sets of bandgap voltage and power supply voltage can be used The value can be used to calculate the parameters in the expression, that is, to determine the exact expression, so that the determined expression can be used to calculate the value of the power supply voltage after calculating the internal bandgap voltage.

It can be seen that in the solution of this embodiment, by detecting the internal bandgap voltage of the single-chip microcomputer, and then calculating the power supply voltage according to the relationship expression between the internal bandgap voltage and voltage voltage, the circuit can be realized without additional voltage detection circuit The detection of the power supply voltage can reduce the extra power supply voltage detection circuit and the power consumption caused by it, the detection is convenient, and the resources are saved.

Optionally, in some possible implementations of the present invention, before the detection of the internal bandgap voltage of the single-chip microcomputer, the method further includes:

A linear expression y=kx+b of the internal bandgap voltage and the supply voltage is determined.

It can be understood that it is necessary to determine the linear expression of the internal bandgap voltage and the power supply voltage to calculate the power supply voltage through the detected internal bandgap voltage of the microcontroller.

Optionally, in some possible implementation manners of the present invention, the determining the relationship expression y=kx+b between the internal bandgap voltage and the power supply voltage includes:

Collecting two different values of the internal bandgap voltage and the power supply voltage respectively;

A linear expression of the internal bandgap voltage and the power supply voltage is determined by using the twice different values of the internal bandgap voltage and the power supply voltage and the linear expression y=kx+b.

It can be understood that, for a linear expression, the expression can be determined by two sets of values of the internal bandgap voltage and the voltage voltage, so that the power supply voltage can be calculated using the expression after the expression is determined.

Optionally, in some possible implementations of the present invention, the collected internal bandgap voltage and power supply voltage need to be converted according to a standard voltage, and a value obtained through ADC conversion is used for calculation.

Referring to FIG. 5 , FIG. 5 is a schematic flowchart of a second embodiment of a voltage measurement method provided by an embodiment of the present invention. Wherein, the voltage measurement method shown in FIG. 5 is applied to the voltage detection circuit shown in FIG. 1 to FIG. 3, specifically, implemented in the single-chip microcomputer of the voltage detection circuit shown in FIG. 1 to FIG. 3, as shown in FIG. 5, The voltage measurement method provided by the embodiment of the present invention may include:

S501. Collect respectively two different reference power supply voltages and reference internal bandgap voltages respectively corresponding to the reference power supply voltages.

Specifically, in the embodiment of the present invention, TL431 is used as a reference voltage for AD sampling. Because if the commonly used battery voltage sampling circuit is used, the standby current will be increased, the minimum standby current will be increased: I=(3.0V/200K)=15uA, and the maximum standby current will be increased: I=(4.2V/200K)=21uA, resulting in a single cell The standby current of the circuit board powered by lithium battery will increase by 15uA-20uA.

S502. Determine the linear expression y=kx+b of the internal bandgap voltage and the power supply voltage by using two different reference power supply voltages and the reference internal bandgap voltage.

Specifically, in the embodiment of the present invention, the TL431 in Figure 3 is used as the reference voltage for AD sampling, and a high-precision DC voltage stabilizer is used as the power supply voltage of the single-chip microcomputer, and the bandgap voltage is measured twice under different VCC values. ADC conversion value, the linear expression between the power supply voltage of the microcontroller and the bandgap voltage of the microcontroller can be calculated through two measurements.

For example, if a precise DC voltage source is used to supply 2.7V to the microcontroller, the bandgap voltage obtained by AD sampling of the microcontroller is 1.241V, and a precise DC voltage source is used to supply power to the microcontroller with 5.5V, and the bandgap voltage obtained by AD sampling of the microcontroller is 1.255V. According to y=kx+b, two equations can be obtained:

1.241k+b=2.7;

1.255k+b=5.5.

According to these two equations, k=200, b=-245.5 can be obtained, thus the linear expression of the internal bandgap voltage of the single chip microcomputer and the power supply voltage can be determined as y=200x-245.5.

S503. Detect the internal bandgap voltage of the single-chip microcomputer.

Specifically, after determining the linear expression y=200x-245.5 between the internal bandgap voltage of the single-chip microcomputer and the power supply voltage, a single lithium battery is connected to directly supply power to the single-chip microcomputer, and the internal bandgap voltage of the single-chip microcomputer is detected at this time after conversion value.

S504. Calculate the power supply voltage according to the relationship expression y=kx+b between the internal bandgap voltage and the power supply voltage.

Specifically, as an example, after determining the linear expression y=200x-245.5 between the internal bandgap voltage of the single-chip microcomputer and the power supply voltage, the single-chip microcomputer re-sampled to obtain a bandgap voltage of 1.248V, then the voltage of the single-cell lithium battery can be calculated as 4.1V.

It can be seen that in the solution of this embodiment, by detecting the internal bandgap voltage of the single-chip microcomputer, and then calculating the power supply voltage according to the relationship expression between the internal bandgap voltage and voltage voltage, the circuit can be realized without additional voltage detection circuit The detection of the power supply voltage can reduce the extra power supply voltage detection circuit and the power consumption caused by it, the detection is convenient, and the resources are saved.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware, and the programs can be stored in a computer-readable storage medium. During execution, it may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM) and the like.

What is disclosed above is only a preferred embodiment of the present invention, and of course it cannot limit the scope of rights of the present invention. Those of ordinary skill in the art can understand all or part of the process for realizing the above embodiments, and according to the rights of the present invention The equivalent changes required still belong to the scope covered by the invention.

Claims (10)

1. a kind of voltage detecting circuit, it is characterised in that the voltage detecting circuit includes：

Reference voltage generating circuit and single-chip microcomputer；

The output end of the reference voltage generating circuit is connected with the reference voltage input pin of the single-chip microcomputer, The power supply termination operating voltage of the reference voltage generating circuit, wherein, the reference voltage generating circuit is used In to the single-chip microcomputer provide reference voltage, and by the reference voltage by the output end output arrive it is described Single-chip microcomputer；

The power pins of the single-chip microcomputer connect supply voltage, and the single-chip microcomputer is used for by the detection single-chip microcomputer Band gap voltage, and calculate the power supply using the relational expression between the band gap voltage and supply voltage Voltage.

2. voltage detecting circuit according to claim 1, it is characterised in that the reference voltage occurs Circuit includes the sampling end connection of resistance and source of stable pressure, the control end of the source of stable pressure and the source of stable pressure, and It is connected with one end of the resistance, the ground pin ground connection of the source of stable pressure, another termination input of the resistance Voltage, the sampling end of the source of stable pressure is the output end of the reference voltage generating circuit.

3. voltage detecting circuit according to claim 1, it is characterised in that the model of the single-chip microcomputer For HT66F006, the reference voltage input pin of the single-chip microcomputer is connected with the sampling end of the source of stable pressure, institute The power pins for stating single-chip microcomputer connect supply voltage, the ground pin ground connection of the single-chip microcomputer.

4. voltage detecting circuit according to claim 3, it is characterised in that the 5th of the single-chip microcomputer Input and output pin is connected with the voltage input end of the reference voltage generating circuit, for using the monolithic 5th input and output pin of machine provides operating voltage for the reference voltage generating circuit.

5. voltage detecting circuit according to claim 2, it is characterised in that the reference voltage occurs The control source termination supply voltage of circuit.

6. the voltage detecting circuit according to claim 4 or 5, it is characterised in that the source of stable pressure Model TL431.

7. a kind of voltage measurement method, the voltage detecting circuit being applied to described in claim 1 to 6, it is special Levy and be, methods described includes：

Detect the described internal band gap voltage of the single-chip microcomputer；

The supply voltage is calculated with the relational expression of the supply voltage according to the internal band gap voltage.

8. method according to claim 7, it is characterised in that the internal band gap voltage and the electricity The relational expression of source voltage is linear representation y=kx+b.

9. method according to claim 8, it is characterised in that the detection single-chip microcomputer inside band gap electricity Before pressure, methods described also includes：

Determine the linear representation y=kx+b of the internal band gap voltage and the supply voltage.

10. method according to claim 9, it is characterised in that the determination internal band gap electricity The linear representation y=kx+b with the supply voltage is pressed, including：

Different twice reference voltage and the reference voltage difference different twice are gathered respectively Corresponding reference inside band gap voltage；

Determine the inside with reference to internal band gap voltage with described using the reference voltage different twice The linear representation y=kx+b of band gap voltage and the supply voltage.