Reference voltage generating circuit and air conditioner

Abstract

The embodiment of the utility model provides a reference voltage generation circuit and an air conditioner, and the reference voltage generation circuit comprises a voltage division circuit, the input end of which is used for accessing a DC power supply, and the ground end of which is grounded; the input end of the voltage regulation circuit is connected with the voltage division point of the voltage division circuit, the controlled end of the voltage regulation circuit is used for accessing a control signal with an adjustable duty ratio, the ground end of the voltage regulation circuit is grounded, and the voltage regulation circuit is used for controlling the voltage division circuit to process the voltage division of the direct-current power supply into a divided voltage with a corresponding waveform according to the duty ratio of the control signal; and the input end of the filter circuit is connected with the voltage division point of the voltage division circuit, and the filter circuit is used for filtering the accessed divided voltage and outputting the filtered voltage as reference voltage. By means of the voltage adjusting circuit, dynamic adjustment of the reference voltage is achieved by changing the duty ratio of a control signal so as to adapt to compressors of different models, and the use scene of the sampling current circuit can be widened.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of air conditioners, and particularly relates to a reference voltage generation circuit and an air conditioner. BACKGROUND

[0002] With the increasing popularity of variable frequency air conditioners, users have higher and higher requirements for the use quality of air conditioners. Among them, the compressor sampling current circuit of the variable frequency drive board has a reference voltage, which can obtain a wide range of current sampling values. However, this reference voltage cannot adapt to different types of compressors, limiting the use scenarios of the sampling current circuit. CONTENT OF THE INVENTION

[0003] The application provides a reference voltage generation circuit and an air conditioner, which can dynamically adjust the reference voltage to adapt to different types of compressors and can widen the use scenarios of the sampling current circuit.

[0004] In a first aspect, an embodiment of the application provides a reference voltage generation circuit, comprising:

[0005] a voltage dividing circuit, an input end of which is used to access a direct current power supply, and a ground end of which is grounded;

[0006] a voltage regulating circuit, an input end of which is connected to a voltage dividing point of the voltage dividing circuit, a controlled end of which is used to access a duty cycle adjustable control signal, and a ground end of which is grounded, the voltage regulating circuit being used to control the voltage dividing circuit to divide and process the direct current power supply into a voltage divided voltage of a corresponding waveform according to a duty cycle of the control signal;

[0007] a filter circuit, an input end of which is connected to the voltage dividing point of the voltage dividing circuit, the filter circuit being used to filter the voltage divided voltage accessed and output the voltage divided voltage as a reference voltage.

[0008] Optionally, the voltage regulating circuit comprises:

[0009] a switch tube, a first end of which is used to access the control signal, a second end of which is grounded, and a third end of which is connected to the voltage dividing point of the voltage dividing circuit.

[0010] Optionally, the voltage regulating circuit further comprises:

[0011] a first resistor, one end of which is connected to the third end of the switch tube, and the other end of which is connected to the voltage dividing point of the voltage dividing circuit.

[0012] Optionally, the voltage regulating circuit further comprises:

[0013] a second resistor, one end of which is the input end of the voltage regulating circuit, and the other end of which is connected to the first end of the switch tube.

[0014] a third resistor, one end of which is connected to the first end of the switch tube, and the other end of which is grounded;

[0015] a first capacitor, one end of which is connected to the first end of the switch tube, and the other end of which is grounded.

[0016] Optionally, the voltage dividing circuit comprises:

[0017] a first voltage dividing resistor, one end of which is used for connecting to a direct current power supply, and the other end of which is a voltage dividing point of the voltage dividing circuit;

[0018] a second voltage dividing resistor, one end of which is connected to the other end of the first voltage dividing resistor, and the other end of which is grounded.

[0019] Optionally, the filter circuit comprises:

[0020] a fourth resistor, one end of which is connected to the voltage dividing point of the voltage dividing circuit;

[0021] a second capacitor, one end of which is connected to the other end of the fourth resistor, and the other end of which is grounded.

[0022] Optionally, the reference voltage generating circuit further comprises:

[0023] an isolation circuit, an input end of which is connected to an output end of the filter circuit, and the isolation circuit is used for outputting the reference voltage after isolation processing.

[0024] Optionally, the isolation circuit comprises:

[0025] a voltage follower, a first input end of which is the input end of the isolation circuit, and a second input end of which is connected to an output end thereof.

[0026] In a second aspect, the embodiments of the present application further provide an air conditioner, comprising a current detection circuit and the reference voltage generating circuit according to any one of the above, an input end of the reference voltage generating circuit being used for inputting a control signal with adjustable duty cycle, and an output end of the reference voltage generating circuit being connected to a reference voltage input end of the current detection circuit.

[0027] In the reference voltage generating circuit and the air conditioner of the embodiments of the present application, the voltage regulating circuit is used to realize dynamic adjustment of the reference voltage by changing the duty cycle of the control signal, so as to adapt to different types of compressors, and the use scenarios of the sampling current circuit can be widened. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] For a more complete understanding of the present application and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like parts throughout the several figures.

[0030] Figure 1 A structural block diagram of the reference voltage generating circuit provided by an embodiment of the present application.

[0031] Figure 2 A circuit diagram of the reference voltage generating circuit provided by an embodiment of the present application.

[0032] Figure 3 Another structural block diagram of the reference voltage generating circuit provided by an embodiment of the present application.

[0033] Figure 4 Another circuit diagram of the reference voltage generating circuit provided by an embodiment of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] With the increasing popularity of household variable frequency air conditioners, users have higher and higher requirements for the use quality of air conditioners. The compressor sampling current circuit of the variable frequency drive board has a reference voltage, which can obtain a wide range of current sampling values: I = (AD-Ub) / (G*Rs), wherein I is the compressor sampling current, AD is a reference voltage such as 3.3V, Ub is the reference voltage, G is the amplification factor, and Rs is the sampling resistance. However, the reference voltage Ub is usually obtained by fixed resistance voltage division, that is, the reference voltage Ub is single and unchangeable, which cannot provide a wide range of current reference voltage for different types of compressor current sampling values, thereby limiting the use scenarios of the sampling current circuit.

[0036] To reduce the occurrence of the above problems, an embodiment of the present application provides a reference voltage generating circuit and an air conditioner, which will be described below in conjunction with the drawings.

[0037] As Figure 1 , Figure 1 A structural block diagram of the reference voltage generating circuit provided by an embodiment of the present application. Illustratively, the reference voltage generating circuit 100 includes a voltage division circuit 110, a voltage regulation circuit 120, and a filter circuit 130.

[0038] The input end of the voltage dividing circuit 110 is used to connect a direct current power supply, such as 3.3V, and the ground end of the voltage dividing circuit 110 is connected to the ground GND.

[0039] The input end of the voltage regulating circuit 120 is connected to the voltage dividing point of the voltage dividing circuit 110, the controlled end of the voltage regulating circuit 120 is used to connect a duty cycle adjustable control signal, such as a pulse width modulation signal PWM, and the ground end of the voltage regulating circuit 120 is connected to the ground GND. The voltage regulating circuit 120 is used to control the voltage dividing circuit 110 to divide the direct current power supply into a corresponding waveform voltage dividing voltage according to the duty cycle of the control signal.

[0040] The input end of the filter circuit 130 is connected to the voltage dividing point of the voltage dividing circuit 110, and the filter circuit 130 is used to filter the connected voltage dividing voltage and output it as a reference voltage.

[0041] The reference voltage generating circuit 100 provided by the embodiment of the present application uses the voltage regulating circuit 120 to realize dynamic adjustment of the reference voltage by changing the duty cycle of the control signal, so as to adapt to different types of compressors and can widen the use scene of the sampling current circuit.

[0042] Please refer to Figure 2 , Figure 2 The circuit diagram of the reference voltage generating circuit provided by the embodiment of the present application is shown. For example, the voltage dividing circuit 110 includes a first voltage dividing resistor R11 and a second voltage dividing resistor R22. One end of the first voltage dividing resistor R11 is used to connect a direct current power supply, and the other end of the first voltage dividing resistor R11 is the voltage dividing point of the voltage dividing circuit 110. One end of the second voltage dividing resistor R22 is connected to the other end of the first voltage dividing resistor R11, and the other end of the second voltage dividing resistor R22 is connected to the ground GND.

[0043] For example, the voltage regulating circuit 120 includes a switch tube Q1. The first end of the switch tube Q1 is used to connect a control signal, the second end of the switch tube Q1 is connected to the ground GND, and the third end of the switch tube Q1 is connected to the voltage dividing point of the voltage dividing circuit 110.

[0044] For example, the switch tube Q1 includes a MOS tube, and the first end, the second end and the third end of the switch tube Q1 correspond to the gate, the source and the drain of the MOS tube respectively.

[0045] When the voltage regulating circuit 120 only includes the switch tube Q1, the switch tube Q1 is controlled by the control signal, and the duty cycle of the control signal affects the conduction state of the switch tube Q1. When the switch tube Q1 is disconnected, the voltage dividing circuit 110 divides the voltage according to the original voltage dividing circuit 110. When the switch tube Q1 is turned on, the voltage dividing circuit 110 changes the size of the voltage dividing voltage under the control of the control signal, so that dynamic adjustment of the voltage dividing voltage can be realized.

[0046] Of course, the voltage regulating circuit 120 can further comprise a first resistor R1, one end of the first resistor R1 being connected to the third end of the switch tube Q1, and the other end of the first resistor R1 being connected to the voltage dividing point of the voltage dividing circuit 110. The switch tube Q1 can be turned on or turned off according to the control signal, and the on or off duration of the switch tube Q1 can be adjusted according to the duty cycle of the control signal, so that the voltage at the voltage dividing point can be dynamically adjusted, and the effect of dynamically adjustable reference voltage can be realized.

[0047] For example, the voltage regulating circuit 120 further comprises a second resistor R2, a third resistor R3 and a first capacitor C1. One end of the second resistor R2 is the input end of the voltage regulating circuit 120, and the other end of the second resistor R2 is connected to the first end of the switch tube Q1. One end of the third resistor R3 is connected to the first end of the switch tube Q1, and the other end of the third resistor R3 is connected to the ground GND. One end of the first capacitor C1 is connected to the first end of the switch tube Q1, and the other end of the first capacitor C1 is connected to the ground GND. Among them, the second resistor R2 and the first capacitor C1 are used for filtering the control signal.

[0048] It should be noted that the filtering circuit 130 is used for low-pass filtering the voltage dividing voltage, so that the voltage dividing voltage can be linearly dynamically output as a steady voltage. Since the voltage dividing voltage has a waveform, and the voltage dividing voltage is dynamically switched, it needs to be filtered, which can be understood as taking the average value of the voltage dividing voltage waveform, and taking the average value as the reference voltage.

[0049] For example, the filtering circuit 130 comprises a fourth resistor R4 and a second capacitor C2. One end of the fourth resistor R4 is connected to the voltage dividing point of the voltage dividing circuit 110. One end of the second capacitor C2 is connected to the other end of the fourth resistor R4, and the other end of the second capacitor C2 is connected to the ground GND.

[0050] It should be noted that the fourth resistor R4 and the second capacitor C2 constitute a low-pass filter, and the cut-off frequency of the low-pass filter is f = 1 / (2π×R4×C2). When the frequency of the pulse width modulation signal is greater than 10 times the cut-off frequency, the output voltage of the filtering circuit 130 is a steady constant. The low-pass filter composed of the fourth resistor R4 and the second capacitor C2 is also an important part of the linear dynamic change output of the reference voltage.

[0051] The process of adjusting the voltage dividing voltage or the reference voltage according to the duty cycle of the control signal PWM is as follows:

[0052] When the PWM signal is continuously high, that is, the duty cycle of the PWM signal is 100%, the switch tube Q1 is turned on, the first resistor R1 and the second voltage dividing resistor R22 are connected in parallel and then connected in series with the first voltage dividing resistor R11, that is, when the PWM signal is continuously 1, the reference voltage output by the reference voltage generating circuit 100 is Ub=3.3V×(R1 / / R22) / (R11+(R1 / / R22)), R1 / / R22 indicates the equivalent resistance of the first resistor R1 and the second voltage dividing resistor R22 in parallel, and the reference voltage at this time is the minimum value.

[0053] When the PWM signal is continuously low, that is, the duty cycle of the PWM signal is 0, the switch tube Q1 is not turned on, that is, the switch tube Q1 is disconnected, at this time the reference voltage is only divided by the first voltage dividing resistor R11 and the second voltage dividing resistor R22, and the reference voltage output by the reference voltage generating circuit 100 is Ub=3.3V×R22 / (R11+R22), at this time the reference voltage is the maximum value.

[0054] When the duty cycle a of the PWM signal is in the range of 0 to 100%, the reference voltage output by the reference voltage generating circuit 100 is Ub=a×3.3V×R22 / (R11+R22)+(1-a)×3.3V×(R1 / / R22) / (R11+(R1 / / R22), wherein the above formula is rationalized to obtain a first-order equation about the PWM duty cycle a.

[0055] It should be noted that the control signal input by the voltage regulating circuit 120 is the PWM signal, which repeatedly switches the voltage dividing voltage of the voltage dividing circuit 110 from the minimum reference voltage to the maximum reference voltage according to the duty cycle of the PWM signal, that is, the output of the voltage dividing circuit 110 is also a waveform-adjustable voltage dividing voltage.

[0056] Please refer to Figure 3 and Figure 4 , Figure 3 a further structural block diagram of the reference voltage generating circuit provided by the embodiment of the present application, Figure 4 a further circuit diagram of the reference voltage generating circuit provided by the embodiment of the present application. Illustratively, the reference voltage generating circuit 100 further comprises an isolation circuit 140. The input end of the isolation circuit 140 is connected to the output end of the filtering circuit 130, such as the other end of the fourth resistor R4, and the isolation circuit 140 is used to output the reference voltage after isolation processing.

[0057] Illustratively, the isolation circuit 140 comprises a voltage follower, the first input end of the voltage follower is the input end of the isolation circuit 140, and the second input end of the voltage follower is connected to the output end thereof.

[0058] For example, the voltage follower includes an operational amplifier IC1B, the non-inverting input of the operational amplifier IC1B is connected to the output of the filter circuit 130, the inverting input of the operational amplifier IC1B is connected to the output of the operational amplifier IC1B, and the power supply end of the operational amplifier IC1B is connected to the DC power supply, and the ground end is grounded.

[0059] It should be noted that the voltage value of the non-inverting input of the operational amplifier IC1B is the same as the voltage value of the output thereof, and the operational amplifier IC1B functions as an isolation and buffering device, which needs to maintain the signal amplitude unchanged and improve the driving capability.

[0060] It should be noted that the current value is different due to different types of compressors, and the sampling current value range of the frequency conversion driving board is different. In order to avoid frequent replacement of the sampling resistor to obtain a fixed voltage division value, a single voltage, and a fixed sampling current range value, the reference voltage generating circuit 100 of the embodiment of the present application is designed by combining a hardware MOS tube with a resistor, and has the advantages of high efficiency and cost maximization.

[0061] The embodiment of the present application also provides an air conditioner, which comprises a current detection circuit and the above-mentioned reference voltage generating circuit. The current detection circuit can be used for current detection of a compressor, the input end of the reference voltage generating circuit is used for inputting a duty cycle adjustable control signal, and the output end of the reference voltage generating circuit is connected to the reference voltage input end of the current detection circuit. The specific structure of the reference voltage generating circuit is referred to the above-mentioned embodiments. Since the air conditioner adopts all the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0062] In the above-mentioned embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0063] In the description of the present application, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more features.

[0064] The reference voltage generating circuit and the air conditioner provided by the embodiments of the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples in this paper. The above-mentioned embodiment is only used to help understand the method and core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range will be changed, and the above-mentioned description should not be understood as limiting the present application.

Claims

1. A reference voltage generating circuit characterized by comprising: include: A voltage divider circuit, whose input terminal is connected to a DC power supply and whose ground terminal is grounded; A voltage regulation circuit has its input terminal connected to the voltage dividing point of the voltage divider circuit, its controlled terminal used to receive a control signal with an adjustable duty cycle, and its ground terminal grounded. The voltage regulation circuit is used to control the voltage divider circuit to divide the DC power supply into a voltage divider of the corresponding waveform according to the duty cycle of the control signal. A filter circuit, the input of which is connected to the voltage divider point of the voltage divider circuit, is used to filter the input voltage divider voltage and output it as a reference voltage.

2. The reference voltage generating circuit according to claim 1, wherein The voltage regulation circuit includes: The switching transistor has its first terminal used to receive the control signal, its second terminal grounded, and its third terminal connected to the voltage divider point of the voltage divider circuit.

3. The reference voltage generating circuit according to claim 2, wherein The voltage regulation circuit further includes: The first resistor has one end connected to the third terminal of the switching transistor and the other end connected to the voltage divider point of the voltage divider circuit.

4. The reference voltage generating circuit according to claim 2, wherein The voltage regulation circuit further includes: The second resistor has one end connected to the input terminal of the voltage regulation circuit and the other end connected to the first terminal of the switching transistor. The third resistor has one end connected to the first terminal of the switching transistor and the other end grounded. The first capacitor has one end connected to the first terminal of the switching transistor and the other end grounded.

5. The reference voltage generating circuit according to claim 1, wherein The voltage divider circuit includes: The first voltage divider resistor has one end connected to a DC power supply and the other end being the voltage divider point of the voltage divider circuit. The second voltage divider resistor has one end connected to the other end of the first voltage divider resistor, and the other end grounded.

6. The reference voltage generating circuit according to claim 1, wherein The filtering circuit includes: The fourth resistor has one end connected to the voltage divider point of the voltage divider circuit; The second capacitor has one end connected to the other end of the fourth resistor, and the other end grounded.

7. The reference voltage generating circuit according to claim 1, wherein The reference voltage generating circuit further includes: An isolation circuit, the input of which is connected to the output of the filter circuit, is used to isolate the reference voltage before outputting it.

8. The reference voltage generating circuit according to claim 7, wherein The isolation circuit includes: A voltage follower, the first input of which is the input of the isolation circuit, and the second input of which is connected to its output.

9. The reference voltage generating circuit according to claim 8, wherein The voltage follower includes: An operational amplifier includes a non-inverting input terminal, an inverting input terminal, a power supply terminal, a ground terminal, and an output terminal. Its non-inverting input terminal is connected to the output terminal of the filter circuit, its inverting input terminal is connected to its output terminal, its power supply terminal is connected to a DC power supply, and its ground terminal is grounded.

10. An air conditioner characterized by comprising: The device includes a current detection circuit and a reference voltage generation circuit as described in any one of claims 1 to 9, wherein the input terminal of the reference voltage generation circuit is used to input a control signal with an adjustable duty cycle, and the output terminal of the reference voltage generation circuit is connected to the reference voltage input terminal of the current detection circuit.

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