A method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor.

Abstract

This invention provides a method for transmitting analog signals and achieving analog signal isolation using a dual-winding inductor, belonging to the field of analog signal transmission and isolation technology. The method includes: transmitting a voltage value to a V / D converter for V / D conversion to obtain a duty cycle; then processing the duty cycle through a flyback circuit to obtain the output analog signal. This solves the analog signal isolation problem by converting voltage (analog signal) to duty cycle using the V / D converter, followed by using a flyback circuit to convert the duty cycle into the output analog signal. This achieves analog signal isolation through a transformer, and the output analog signal is proportional to the input analog signal. Through V / D conversion and flyback circuit processing, it can adapt to different input voltage values ​​and obtain corresponding analog signal outputs. A complete processing procedure from voltage input (analog signal) to voltage output (analog signal) is implemented in a single circuit system. The circuit is simple, has high accuracy, and helps simplify circuit design and reduce costs.

Description

Technical Field

[0001] This invention relates to the field of analog signal transmission technology, and in particular to a method for transmitting analog signals and achieving analog signal isolation using a dual-winding inductor. Background Technology

[0002] Generally, transformers are used to change voltage or current values, to transmit energy, or to transmit digital signals while ensuring electrical isolation. "Electrical isolation" refers to preventing the flow of charge between the primary and secondary sides. Figure 6 A linear power supply is a method of transferring energy using a transformer. Similarly, a switching power supply is a method of transferring energy using a switch. Figure 7 and Figure 8 Both methods involve transmitting digital signals through transformers, thereby indirectly transmitting analog quantities. Figure 7 This method indirectly transmits analog signals by performing a V / f conversion (electrical-to-frequency conversion), followed by transformer isolation and then another V / f conversion (frequency-to-voltage conversion). This indirect method has the following drawbacks: Signal distortion: Signal distortion may be introduced during the V / f and f / V conversion processes, leading to a decrease in signal accuracy. Frequency response limitation: The system's frequency response range is limited, making it unable to transmit high-frequency signals. Transformer limitation: The bandwidth and linearity of the transformer are limited, which may cause signal distortion. Cost and complexity: The system requires additional circuitry and components, increasing cost and complexity.

[0003] Figure 8 This method involves A / D (analog-to-digital conversion), followed by transformer isolation, and then D / A (digital-to-analog conversion) to finally achieve an analog signal. The main drawbacks of this method are: the A / D and D / A conversion processes introduce quantization and conversion errors, affecting signal accuracy; transformer isolation can lead to signal attenuation, distortion, and bandwidth limitations; and the overall system cost is high, with complex circuitry and significant design and debugging difficulties.

[0004] This invention utilizes a transformer that neither transmits digital signals nor energy (or is not intended to transmit energy), but rather transmits analog quantities by transmitting energy. A specific schematic diagram is shown below. Figure 9 As shown.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for transferring analog quantities and isolating analog quantities using a dual-winding inductor.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] A method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor includes:

[0009] The input analog signal is transmitted to a signal converter (V / D converter) for signal conversion processing, resulting in a series of pulse signals. The duty cycle of the pulse signals is proportional to the magnitude of the input analog signal.

[0010] The pulse signal controls at least one switch S, similar to a flyback circuit in a switching power supply. p (like Figure 2 As shown), this makes the magnetizing inductance L of the "transformer" (that is, the inductance of the primary winding measured when the secondary winding is open) (the equivalent model of the "transformer" is as follows). Figure 3 (As shown) Connecting or disconnecting a fixed voltage V d When the pulse signal is high, it controls the primary winding of the flyback circuit, causing at least one switch S to... p "Conduction" means the magnetizing inductance of the primary winding of the "transformer" is connected to V. d And it begins to store energy. Since at least one switch S0 on the secondary side of the "transformer" is open, the voltage generated on the secondary side is blocked by the switch and no current flows through the capacitor C and resistor R0. The above-mentioned "transformer" cannot play the role of a transformer. At this time, the so-called "transformer" is just a two-winding inductor composed of a primary winding and a secondary winding.

[0011] When the pulse disappears (low level state), at least one switch S in the primary section is controlled. p When disconnected, the winding circuit of the primary inductor of the transformer is cut off, and the energy stored in the magnetic field is released through the secondary side by connecting the switch S0 of the transformer.

[0012] By using a flyback circuit similar to a switching power supply, an analog output proportional to the input analog quantity is obtained; the key is that the input and output analog quantities are isolated through the aforementioned transformer or the aforementioned dual-winding inductor.

[0013] The duty cycle refers to a series of pulse signals with a fixed frequency used to control the switching on or off of a switch. D Equal to the high level time T on Except for high level time T on Add low level time T off The sum is:

[0014] D = T on / ( Ton + T off );

[0015] The relationship between the signal parameters and the input analog quantity is as follows:

[0016] D =a V (1)

[0017] in, D Here are the signal parameters; 'a' is a constant. V To input an analog signal, based on the working principle of the flyback circuit:

[0018] 0≤ D <1;

[0019] That is: 0 V <1;

[0020] That is: 0 <a<1 / V (1).

[0021] Optionally, the value range of 'a' in the processing circuit must ensure that the energy stored in the form of a magnetic field within one switching cycle is completely released. Assuming analog quantity... V The maximum value is 10V, and a can be 0.05 to ensure that there is enough time for the magnetic energy to be fully released on the secondary side of the "transformer".

[0022] Optionally, the value range of 'a' in the processing circuit must ensure that the energy stored in the form of a magnetic field within one switching cycle is completely released. In other words, the flyback circuit must operate in intermittent mode.

[0023] Optionally, the primary circuit includes at least one or more switches S; when the on-time of the switch S is... T on At that time, the switching frequency is f The switching period is T s , V 1 represents the input voltage value, then the signal parameters D The expression is:

[0024] (2)

[0025] The energy stored in inductor L during the single conduction time of the field-effect transistor Q is:

[0026] (3)

[0027] in I m For the peak current across the inductor, according to the differential equation of the inductor: ​

[0028] (4)

[0029] Among them, V d V is the supply voltage. d And L is a constant. It is also constant, the current value i It increases linearly with time, from which we can deduce:

[0030] (5)

[0031] Based on formula (4):

[0032] (6)

[0033] Substituting formula (6) into formula (3), we get:

[0034] (7)

[0035] set up Then formula (7) becomes:

[0036] (8)

[0037] When the field-effect transistor Q is turned off, energy is released from the secondary side, then:

[0038] (9)

[0039] We obtain the following from formulas (8) and (9):

[0040] (10)

[0041] Continuing the derivation from formula (10):

[0042] (11)

[0043] Where k, R, T s Both are constant; the output voltage changes with the conduction time of the field-effect transistor Q. T on The change is linear; combining formulas (2) and (11), we can further obtain:

[0044] (12)

[0045] set up ,get V o =K V 1;

[0046] and ,Will Substituting, we get:

[0047] (13)

[0048] If K=1, then we get:

[0049] V o = V 1(14)

[0050] Output voltage V o and input voltage V 1. Proportional and following relationship.

[0051] Optionally, the V o =K V When K is 1 in 1, V o = V 1. That is, the output analog quantity is exactly the same as the input analog quantity, and the analog quantity is current, voltage or other physical quantity.

[0052] Optionally, the dual-winding inductor may include an air inductor.

[0053] Optionally, the dual-winding inductor includes one or more magnetic cores.

[0054] Optionally, the flyback circuit can be a single-transistor flyback circuit or a dual-transistor flyback circuit. In the dual-transistor flyback circuit, D1 and D2 can be replaced by other switches with diodes. In the dual-transistor flyback circuit, D1 and D2 can be replaced by other controllable switches. In this case, the switching logic of D1 and D2 is opposite to that of Sp1 and Sp2. When Sp1 and Sp2 are on, D1 and D2 should be off; when Sp1 and Sp2 are off, D1 and D2 should be on.

[0055] Optionally, the primary switch includes: field-effect transistors, bipolar transistors, analog and optocoupler switches, IGBTs, and other solid-state switches.

[0056] Optionally, the secondary switch of the flyback circuit includes a diode.

[0057] Optionally, the secondary switch of the flyback circuit is an analog switch, whose switching control is completely synchronized with the primary switch.

[0058] Optionally, an air gap can be opened in the core of the dual-winding inductor to make the magnetizing inductance more linear.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] This invention provides a method for transferring analog signals and isolating analog signals using a dual-winding inductor. First, it solves the problem of converting voltage values ​​to duty cycles by using a V / D converter. This helps convert the analog voltage signal into a digital signal form suitable for subsequent circuit processing. Then, a flyback circuit processes the duty cycle to obtain the output analog signal, thus converting the converted digital signal back to an analog output, fulfilling specific analog output requirements. This method can flexibly handle voltage input signals; through V / D conversion and flyback circuit processing, it can adapt to different voltage input values ​​and obtain the required analog output. It achieves complete processing from voltage input to analog output within a single circuit system, with high integration, which helps simplify circuit design and reduce costs. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a conceptual block diagram of the present invention, in which the "transformer" is included in a flyback circuit.

[0063] Figure 2 The conceptual block diagram, which includes a partially enlarged view of the flyback circuit, further illustrates the electrical isolation function of the "transformer" in one embodiment.

[0064] Figure 3 This is a simplified model of a "transformer" consisting of an ideal transformer and a magnetizing inductor.

[0065] Figure 4 For the simplified single-transistor flyback circuit diagram, the V / D converter section has been omitted.

[0066] Figure 5 For the simplified schematic diagram of the two-transistor flyback circuit, the V / D converter section is omitted. Sp1 and Sp2 are simultaneously turned on and off, while So is turned off when Sp1 and Sp2 are on, and turned on when Sp1 and Sp2 are off.

[0067] Figure 6 This is a schematic diagram of an existing linear power supply circuit.

[0068] Figure 7 This is a schematic diagram of an existing circuit that indirectly transmits analog signals through V / f conversion (voltage-to-frequency conversion), followed by transformer isolation and then f / V conversion (frequency-to-voltage conversion).

[0069] Figure 8 This is a schematic diagram of the existing analog signal transmission process, which involves A / D (analog-to-digital conversion), followed by transformer isolation, and then D / A (digital-to-analog conversion) to finally achieve analog signal transmission.

[0070] Figure 9 This invention provides a method for transmitting analog quantities by means of energy transfer. Detailed Implementation

[0071] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] The purpose of this invention is to provide a method for transferring analog quantities and isolating analog quantities using a dual-winding inductor.

[0073] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0074] Example 1:

[0075] This embodiment provides a method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor, such as... Figure 1-5 and Figure 9 As shown, it includes:

[0076] A method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor includes:

[0077] The input analog signal is transmitted to a signal converter for signal conversion processing, resulting in a series of pulse signals. The duty cycle of the pulse signals is proportional to the magnitude of the input analog signal, such as... Figure 9 As shown.

[0078] The pulse signal controls a MOSFET switch Q (such as...) similar to a flyback circuit in a switching power supply. Figure 9 As shown), a fixed voltage source V d Connect the transformer T, whose magnetizing inductance is L. m (The equivalent model of a "transformer" is as follows) Figure 3 (As shown). When the pulse signal is high, it controls the primary of the flyback circuit to turn on Q, and the magnetizing inductance V of the primary of the "transformer" is activated. dUnder the influence of the current, the current begins to increase and stores energy in the form of a magnetic field. Since the diode of the "transformer" is reverse biased, no current flows through the secondary winding of the "transformer". The "transformer" mentioned above cannot play the role of a transformer. At this time, the so-called "transformer" is just a two-winding inductor composed of a primary winding and a secondary winding.

[0079] When the pulse disappears (low level state), at least one switch Q of the primary control section is opened, the winding circuit of the primary inductor of the "transformer" is cut off, and the energy stored in the magnetic field is released through C2 and R by the diode D of the secondary side of the "transformer".

[0080] By using a flyback circuit similar to a switching power supply, an analog output proportional to the input analog quantity is obtained; most importantly, the isolation between the input and output analog quantities is achieved through the aforementioned "transformer" or the aforementioned dual-winding inductor.

[0081] in Figure 2 and Figure 3 To further explain Figure 1 Some circuit diagrams and schematic diagrams are merely special cases of certain implementations and do not represent a limitation on the claims.

[0082] The duty cycle refers to a series of pulse signals with a fixed frequency used to control the switching on or off of a switch. D Equal to the high level time T on Except for high level time T on Add low level time T off The sum is:

[0083] D = T on / ( T on + T off );

[0084] The relationship between the signal parameters and the input analog quantity is as follows:

[0085] D =a V (1)

[0086] in, D Here are the signal parameters; 'a' is a constant. V To input an analog signal, based on the working principle of the flyback circuit:

[0087] 0≤ D <1;

[0088] That is: 0 <aV <1;

[0089] That is: 0 <a<1 / V ;

[0090] The value of 'a' here is just a special case; it can have other values ​​as well.

[0091] Furthermore, the value range of 'a' in the processing circuit must ensure that the energy stored in the form of a magnetic field within one switching cycle is completely released.

[0092] Furthermore, the primary circuit includes one or more switches S; when the on-time of the switch S is... T on At that time, the switching frequency is f The switching period is T s , V 1 represents the input voltage value, then the signal parameters D The expression is:

[0093] (2)

[0094] The energy stored in inductor L during the single conduction time of the field-effect transistor Q is:

[0095] (3)

[0096] in I m For the peak current across the inductor, according to the differential equation of the inductor:

[0097] (4)

[0098] Among them, V d V is the supply voltage. d And L is a constant. It is also constant, the current value i It increases linearly with time, from which we can deduce:

[0099] (5)

[0100] Based on formula (4):

[0101] (6)

[0102] Substituting formula (6) into formula (3), we get:

[0103] (7)

[0104] set up Then formula (7) becomes:

[0105] (8)

[0106] When the field-effect transistor Q is turned off, energy is released from the secondary side, then:

[0107] (9)

[0108] We obtain the following from formulas (8) and (9):

[0109] (10)

[0110] Continuing the derivation from formula (10):

[0111] (11)

[0112] Where k, R, T s Both are constant; the output voltage changes with the conduction time of the field-effect transistor Q. T on The change is linear; combining formulas (2) and (11), we can further obtain:

[0113] (12)

[0114] set up ,get V o =K V 1;

[0115] and ,Will Substituting, we get:

[0116] (13)

[0117] If K=1, then we get:

[0118] V o = V 1(14)

[0119] Output voltage V o and input voltage V 1. Proportional and following relationship.

[0120] Furthermore, the aforementioned V o =K V 1. K can be set to 1, thus V o = V1 means that the output analog quantity is exactly the same as the input analog quantity, and the analog quantity is current, voltage or other physical quantity.

[0121] Furthermore, the analog quantity can be current, voltage, or other physical quantities.

[0122] Furthermore, the dual-winding inductor includes an air inductor.

[0123] Furthermore, the dual-winding inductor includes one or more magnetic cores.

[0124] Furthermore, the flyback circuit adopts a single-transistor flyback circuit or a dual-transistor flyback circuit.

[0125] Furthermore, the primary switch includes: a field-effect transistor, a bipolar transistor, or an analog switch.

[0126] Furthermore, the secondary switch of the flyback circuit is an analog switch, and its switching control is completely synchronized with the primary switch.

[0127] Furthermore, an air gap is opened in the magnetic core of the dual-winding inductor to make the excitation inductance more linear.

[0128] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0129] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor, characterized in that, Comprising: Transmitting an input analog quantity to a signal converter for signal conversion processing to obtain a string of pulse signals, where the duty cycle of the pulse signals is proportional to the magnitude of the input analog quantity; The pulse signal controls at least one switch S in the flyback circuit of the switching power supply. p This causes the transformer's magnetizing inductance L to be switched on or off by a fixed voltage V. d When the pulse signal is high, the primary winding of the flyback circuit is controlled to cause at least one switch S to... p When the transformer is turned on, the magnetizing inductance of the primary winding is connected to V. d And begin to store energy. Since at least one switch S0 on the secondary side of the transformer is open, the voltage generated on the secondary side is blocked by the switch and no current flows through the capacitor C and resistor R0. The above transformer cannot play the role of a transformer. At this time, the transformer is just a two-winding inductor composed of a primary winding and a secondary winding. When the pulse disappears, controlling at least one switch Sp in the primary part to disconnect, then the winding circuit of the primary inductor of the transformer is cut off, and the energy stored in the magnetic field is released through the secondary by turning on the switch S0 in the secondary of the transformer; Through the output of the flyback circuit of the switching power supply, an analog quantity output proportional to the input analog quantity is obtained; the isolation of the input and output analog quantities is achieved through the above-mentioned transformer or the above-mentioned dual-winding inductor; The duty cycle refers to a series of pulse signals with a fixed frequency used to control the switching on or off of a switch. The duty cycle D is equal to the high-level time T. on Except for the high-level time T on Add low level time T off The sum is: D=T on / (T on +T off ); The relationship between the duty cycle D and the input analog quantity is: D = aV; Where, D is the duty cycle; a is a constant, and V is the input analog quantity. According to the working principle of the flyback circuit: 0 ≤ D < 1, that is: 0 < aV < 1, that is: 0 < a < 1 / V (1) If the maximum value of the analog quantity V is 10V and a takes 0.05, ensure that T off has sufficient time to fully release the magnetic energy in the secondary of the transformer.

2. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 1, characterized in that, The flyback circuit must operate in the discontinuous operation mode.

3. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 1, characterized in that, The primary circuit includes one or more switches S. p When the switch S p The conduction time is T on At that time, the switching frequency is f and the switching period is T. s If V1 is the input voltage value, then the expression for the duty cycle D is: Then switch S p The energy stored in inductor L during a single conduction time is: Among them I m For the peak current across the inductor, according to the differential equation of the inductor: Among them, V d V is the supply voltage. d And L is a constant. Since the current value i is constant and increases linearly with time, it can be deduced that: Derived from formula (4): Substituting formula (6) into formula (3), we get: set up Then formula (7) becomes: When switch S p After shutdown, energy is released from the secondary stage, then: Obtained through formula (8) and formula (9): Continuing to derive from formula (10): Where k, R, T s Both are constant, the output voltage changes with the switch S. p On-time T on The change is linear; combining formulas (2) and (11), we can further obtain: set up Get V o =KV1; and Will Substituting, we get:

4. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 3, characterized in that: When the V o =When K is 1 in KV1, V o =V1, meaning the output analog quantity is exactly the same as the input analog quantity.

5. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 1, characterized in that: The transformer or dual-winding inductor includes one or more magnetic cores.

6. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 5, characterized in that: The magnetic core of the transformer or dual-winding inductor can have an air gap opened, making its magnetizing inductance L more linear.

7. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to any one of claims 1-6, characterized in that: The analog quantity is current or voltage or other physical quantities.

8. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to any one of claims 1-6, characterized in that: The flyback circuit includes a single-switch flyback circuit or a dual-switch flyback circuit.

9. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to claim 8, characterized in that, The diodes D1 and D2 in the dual-switch flyback circuit are replaced with switches with diodes or controllable switches. At this time, the switching logic of the switches with diodes or controllable switches is opposite to that of the switches Sp1 and Sp2. When the switches Sp1 and Sp2 are turned on, the switches with diodes or controllable switches should be turned off; when the switches Sp1 and Sp2 are turned off, the switches with diodes or controllable switches should be turned on.

10. The method for transferring analog quantities and achieving analog quantity isolation using a dual-winding inductor according to any one of claims 1-6, characterized in that: The primary switch includes a field-effect transistor, a bipolar transistor, and an analog switch, an opto-coupler switch, an IGBT, and other solid-state switches; The secondary switch of the flyback circuit uses a diode or an analog switch, and its switch control is completely synchronized with the control of the primary switch.

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