A linear voltage regulator circuit and transformer

Abstract

The application discloses a linear voltage regulating circuit and a transformer, and relates to the technical field of voltage regulating circuits, and in particular relates to a linear voltage regulating circuit and a transformer. The linear voltage regulating circuit comprises a square wave signal generating module, a current input module, a current mirror module and a voltage regulating module; the square wave signal output end of the square wave signal generating module is connected with the current input module; the output end of the current input module is connected with the first current branch of the current mirror module; the power supply end is connected with the voltage regulating module; the reference voltage node of the voltage regulating module is connected with the second current branch of the current mirror module; the square wave signal output end is used for outputting a square wave signal; the current input module is used for converting the square wave signal into a direct current signal; the voltage regulating module is configured to change the voltage of the power supply end when the voltage of the reference voltage node changes; when the duty cycle of the square wave signal changes, the current of the second current branch changes, and the voltage of the reference voltage node changes.

Description

Technical Field

[0001] The embodiments of the present invention relate to electronic circuit technology, and more particularly to a linear voltage regulating circuit and a transformer. Background Technology

[0002] The working process of the main circuit of the linear power supply is as follows: the input power is first initially regulated by the pre-regulator circuit, then converted into DC power by the isolation rectifier of the main working transformer, and then finely adjusted by the linear adjustment element under the intelligent control of the control circuit and the single-chip microprocessor controller, so that it outputs a high-precision DC voltage source.

[0003] In existing technologies, linear (switching) power supplies have the following problems: ordinary microcontrollers can only achieve a fixed voltage output by controlling the pull-down resistor through high and low levels of I / O, and cannot achieve linear voltage regulation output. Using chips with built-in DAC functions is expensive. Summary of the Invention

[0004] This invention provides a linear voltage regulation circuit and transformer to achieve linear voltage regulation through a square wave signal.

[0005] In a first aspect, embodiments of the present invention provide a linear voltage regulation circuit, comprising:

[0006] Square wave signal generation module, current input module, current mirror module, and voltage regulation module;

[0007] The square wave signal output terminal of the square wave signal generation module is connected to the current input module;

[0008] The output terminal of the current input module is connected to the first current branch of the current mirror module;

[0009] The power supply terminal is connected to the voltage regulation module;

[0010] The reference voltage node of the voltage regulation module is connected to the second current branch of the current mirror module;

[0011] The square wave signal output terminal is used to output a square wave signal;

[0012] The current input module is used to convert the square wave signal into a DC signal;

[0013] The voltage regulation module is configured such that when the voltage of the reference voltage node changes, the voltage at the power supply terminal changes accordingly.

[0014] When the duty cycle of the square wave signal changes, the current in the second current branch changes, and the voltage of the reference voltage node changes accordingly.

[0015] Optionally, the current input module includes a first resistor, a first capacitor, and a second capacitor;

[0016] The square wave signal output terminal is grounded through the first capacitor;

[0017] The first resistor and the second capacitor constitute a filter circuit, and the square wave signal output terminal is connected to the first current branch through the first resistor.

[0018] Optionally, the current mirror module includes a first switching transistor and a second switching transistor;

[0019] The control terminals of the first switch and the second switch are connected;

[0020] The first switching transistor is disposed in the first current branch, the output terminal of the current input module is connected to the first terminal of the first switching transistor, and the second terminal of the first switching transistor is grounded.

[0021] The second switch is located in the second current branch, the reference voltage node is connected to the first terminal of the second switch, and the second terminal of the second switch is grounded.

[0022] Optionally, the voltage regulation module includes a second resistor, a third resistor, and a fourth resistor;

[0023] The second resistor, the third resistor, and the fourth resistor are connected in series, and the connection point of the third resistor and the fourth resistor serves as the reference voltage node.

[0024] Optionally, the voltage regulation module further includes a feedback device;

[0025] The power supply terminal is connected to the first terminal of the feedback device, the second terminal of the feedback device is grounded, and the reference voltage node is connected to the control terminal of the feedback device.

[0026] Optionally, the voltage regulation module further includes a buck / boost module;

[0027] The power supply terminal is connected to the power output terminal of the buck / boost module, and the reference voltage node is connected to the feedback terminal of the buck / boost module.

[0028] Optionally, the first and second switching transistors are MOSFETs.

[0029] Optionally, the duty cycle of the square wave signal is 0 to 100%.

[0030] Secondly, embodiments of the present invention also provide a transformer, including any of the linear voltage regulating circuits described in the embodiments of the present invention.

[0031] Optionally, it may also include a voltage conversion module, which is used to boost or buck the input voltage.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a linear voltage regulation circuit, which includes a square wave signal generation module, a current input module, a current mirror module, and a voltage regulation module. The current input module is used to convert the square wave signal output by the square wave signal generation module into a DC current. By adjusting the duty cycle of the square wave signal output by the square wave signal generation module, the DC current output by the current input module changes linearly. The current output by the current input module passes through the current mirror module and is copied to the power supply branch where the voltage regulation module is located. Then, when it passes through a specified resistor, it forms a feedback voltage or reference voltage, so that the voltage at the power supply terminal changes linearly with the change of the duty cycle of the square wave signal. Attached Figure Description

[0033] Figure 1 This is a block diagram of the linear voltage regulation circuit in the embodiment;

[0034] Figure 2 This is a schematic diagram of the linear voltage regulation circuit in the embodiment;

[0035] Figure 3 This is a schematic diagram of another linear voltage regulation circuit in the embodiment;

[0036] Figure 4 This is another linear voltage regulation circuit schematic diagram in the embodiment. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] Example 1

[0039] Figure 1 This is a block diagram of the linear voltage regulation circuit in the embodiment, for reference. Figure 1 The linear voltage regulation circuit includes:

[0040] Square wave signal generation module 100, current input module 200, current mirror module 300, and voltage regulation module 400;

[0041] The square wave signal output terminal of the square wave signal generation module 100 is connected to the current input module 200;

[0042] The output terminal of the current input module 200 is connected to the first current branch of the current mirror module 300;

[0043] The power supply terminal VOUT is connected to the voltage regulation module 400;

[0044] The reference voltage node of the voltage regulation module 400 is connected to the second current branch of the current mirror module.

[0045] For example, in this solution, the square wave signal output terminal is used to output a square wave signal, wherein the duty cycle of the square wave signal is adjustable, and the square wave signal generation module 100 can be configured to output a square wave signal with any duty cycle.

[0046] For example, in this solution, the current input module 200 is used to convert a square wave signal into a DC signal;

[0047] The current input module 200 can be a circuit module (such as a filter circuit) or a digital-to-analog converter chip.

[0048] The voltage regulation module 400 is configured such that when the voltage of the reference voltage node changes, the voltage at the power supply terminal VOUT changes accordingly.

[0049] The voltage regulation module 400 may include a voltage regulation circuit (e.g., a voltage regulation circuit based on TL431), or the voltage regulation module 400 may be a voltage conversion chip, etc.

[0050] For example, in this scheme, when the duty cycle of the square wave signal changes, the current in the second current branch changes, and the voltage of the reference voltage node changes accordingly.

[0051] Specifically, when the duty cycle of the square wave signal changes, the current output by the current input module 200 changes, which in turn changes the current in the first current branch. The current in the second current branch is equal to that in the first current branch, and the current in the second current branch changes.

[0052] When the current in the second current branch passes through the specified resistor, the voltage at the reference voltage node changes accordingly.

[0053] This embodiment proposes a linear voltage regulation circuit, which includes a square wave signal generation module, a current input module, a current mirror module, and a voltage regulation module. The current input module converts the square wave signal output by the square wave signal generation module into a DC current. By adjusting the duty cycle of the square wave signal output by the square wave signal generation module, the DC current output by the current input module changes linearly. The current output by the current input module passes through the current mirror module and is copied to the power supply branch where the voltage regulation module is located. Then, when it passes through a specified resistor, it forms a feedback voltage or reference voltage, so that the voltage at the power supply terminal changes linearly with the change of the duty cycle of the square wave signal.

[0054] Figure 2This is a schematic diagram of the linear voltage regulation circuit in the embodiment, for reference. Figure 2 In one possible implementation, the current input module includes a first resistor R8, a first capacitor C6, and a second capacitor C7;

[0055] The square wave signal output terminal (PWM) is grounded through the first capacitor C6;

[0056] The first resistor R8 and the second capacitor C7 form a filter circuit, and the square wave signal output terminal is connected to the first current branch through the first resistor R8.

[0057] For example, in this solution, the first resistor R8 and the second capacitor C7 are used to convert the square wave signal into a DC signal, and the first capacitor C6 is used to stabilize the voltage at the output of the square wave signal.

[0058] refer to Figure 2 In one possible implementation, the current mirror module includes a first switch Q2A and a second switch Q2B;

[0059] The control terminals of the first switch Q2A and the second switch Q2B are connected;

[0060] The first switch Q2A is located in the first current branch, the output terminal of the current input module is connected to the first terminal of the first switch Q2A, and the second terminal of the first switch Q2A is grounded.

[0061] The second switch Q2B is located in the second current branch. The reference voltage node VREF is connected to the first terminal of the second switch Q2B, and the second terminal of the second switch Q2B is grounded.

[0062] refer to Figure 2 For example, in this solution, taking the first switching transistor Q2A and the second switching transistor Q2B as NPN transistors, the bases of transistors Q2A and Q2B are connected together, the base of Q2A is connected to the collector, and the common emitter is grounded;

[0063] If the current output of the current input module is set to Ir, then Ir = Ic1 + Ib. Since the BE terminals of transistors Q2A and Q2B are grounded and transistors with the same specifications are used, their voltages are equal. Therefore, Ib = Ib1 + Ib2, and Ib1 = Ib2, Ic1 = Ic2.

[0064] The collector current Ic of the transistor is controlled by Ib. Assume that the correlation coefficient between Ic and Ib is β = 100.

[0065] Then Ir = Ic1 + Ib1, Ic1 = 100 * Ib1, Ir = 101 * Ib1. Therefore, Ir is approximately equal to Ic1. That is, by controlling the value of R8, Ic2 can be controlled, thereby making the voltage of the reference voltage node VREF follow the change.

[0066] For example, in this solution, the first switch Q2A and the second switch Q2B can also be MOSFETs.

[0067] refer to Figure 2 In one possible implementation, the voltage regulation module includes a second resistor R5, a third resistor R7, and a fourth resistor R9;

[0068] The second resistor R5, the third resistor R7, and the fourth resistor R9 are connected in series, and the connection point of the third resistor R7 and the fourth resistor R9 is used as the reference voltage node VREF.

[0069] For example, in this scheme, the second resistor R5, the third resistor R7 and the fourth resistor R9 constitute a voltage divider circuit. The current in the voltage divider circuit flows through resistors R5 and R7 and forms the reference voltage node VREF.

[0070] refer to Figure 2 In one possible implementation, the voltage regulation module further includes a feedback device U2, based on the voltage regulation module including a second resistor R5, a third resistor R7 and a fourth resistor R9.

[0071] The power supply terminal VOUT is connected to the first terminal of the feedback device U2, the second terminal of the feedback device U2 is grounded, and the reference voltage node VREF is connected to the control terminal of the feedback device U2.

[0072] Specifically, in this scheme, the feedback device U2 can be a TL431, and the feedback device U2 is also equipped with a diode U4A, a fifth resistor R6, a sixth resistor R4, and a third capacitor C5;

[0073] The power supply terminal VOUT is connected to the feedback device U2 via the sixth resistor R4 and the diode U4A. The fifth resistor R6 is connected in parallel with the diode U4A. One end of the third capacitor C5 is connected to the control terminal of the feedback device U2, and the other end is connected to the negative terminal of the diode U4A.

[0074] For example, in this scheme, the sixth resistor R4 is used for current limiting, and the fifth resistor R6 and the third capacitor C5 are conventional peripheral circuit devices of the feedback device U2, and their specific functions will not be described in detail.

[0075] Figure 3 This is a schematic diagram of another linear voltage regulation circuit in the embodiment, for reference. Figure 3In one possible embodiment, the voltage regulation module further includes a buck / boost module U5, based on the second resistor R5, the third resistor R7 and the fourth resistor R9.

[0076] The power supply terminal VOUT is connected to the power output terminal Vout of the buck / boost module U5, and the reference voltage node VREF is connected to the feedback terminal FB of the buck / boost module.

[0077] For example, in this solution, the buck / boost module U5 uses a Buck / Boost chip. When the voltage value of the feedback terminal FB of the buck / boost module U5 changes, the voltage output of the power output terminal Vout of the buck / boost module U5 (i.e., the power supply terminal VOUT voltage) changes accordingly.

[0078] Based on any of the aforementioned schemes, in one possible implementation scheme, the duty cycle of the square wave signal is set to 0-100%.

[0079] refer to Figure 2 Based on the aforementioned scheme, in one possible implementation scheme, the linear voltage regulation circuit includes: a square wave signal generation module, a current input module, a current mirror module, and a voltage regulation module;

[0080] The square wave signal generation module uses an MCU, which is configured to output PWM signals.

[0081] The current input module includes a first resistor R8, a first capacitor C6, and a second capacitor C7;

[0082] The current mirror module includes a first switch Q2A and a second switch Q2B;

[0083] The voltage regulation module includes a second resistor R5, a third resistor R7 and a fourth resistor R9, a feedback device U2, the feedback device U2 is also equipped with a diode U4A, a fifth resistor R6, a sixth resistor R4, and a third capacitor C5;

[0084] The square wave signal output terminal (PWM) is grounded through the first capacitor C6, and the first resistor R8 and the second capacitor C7 form a filter circuit;

[0085] The first switch Q2A is located in the first current branch. The square wave signal output terminal is connected to the first terminal of the first switch Q2A through the first resistor R8. The control terminals of the first switch Q2A and the second switch Q2B are connected. The second terminal of the first switch Q2A is grounded.

[0086] The second switch Q2B is located in the second current branch. The reference voltage node VREF is connected to the first terminal of the second switch Q2B, and the second terminal of the second switch Q2B is grounded.

[0087] The second resistor R5, the third resistor R7, and the fourth resistor R9 are connected in series, and the connection point of the third resistor R7 and the fourth resistor R9 is used as the reference voltage node VREF.

[0088] The power supply terminal VOUT is connected to the feedback device U2 via the sixth resistor R4 and the diode U4A. The fifth resistor R6 is connected in parallel with the diode U4A. One end of the third capacitor C5 is connected to the control terminal of the feedback device U2, and the other end is connected to the negative terminal of the diode U4A.

[0089] If the current output of the current input module is set to Ir, then Ir = Ic1 + Ib. Since the BE terminals of transistors Q2A and Q2B are grounded and transistors with the same specifications are used, their voltages are equal. Therefore, Ib = Ib1 + Ib2, and Ib1 = Ib2, Ic1 = Ic2.

[0090] The collector current Ic of the transistor is controlled by Ib. Assume that the correlation coefficient between Ic and Ib is β = 100.

[0091] Then Ir = Ic1 + Ib1, Ic1 = 100 * Ib1, Ir = 101 * Ib1, from which we can conclude that Ir is approximately equal to Ic1.

[0092] In this scheme, by controlling the duty cycle of the PWM signal and the resistance value of R8, Ic2 (i.e., the current through resistors R5+R7) can be controlled, thereby causing the voltage at the reference voltage node VREF to follow the change, and ultimately causing the voltage at the power supply terminal VOUT to change linearly.

[0093] In this scheme, the maximum upper limit voltage of VOUT output can be limited by controlling the current flowing through (R5+R7).

[0094] In this scheme, the minimum output start-up voltage can be limited by adjusting the parameters R5+R7 and R9. The calculation formula is as follows: VOUT=VREF*[1+(R5+R7) / R9].

[0095] Figure 4 This is another linear voltage regulation circuit schematic diagram in the embodiment, see reference. Figure 4 ,exist Figure 2 Based on the scheme shown, the current mirror module can be replaced with a comparator module;

[0096] Specifically, the comparator module includes an operational amplifier U6. The square wave signal output terminal is connected to the first terminal of the operational amplifier U6 through the first resistor R8, and the second terminal of the operational amplifier U6 is connected to its output terminal.

[0097] The output of operational amplifier U6 is connected to the reference voltage node VREF through the tenth resistor R10;

[0098] In this scheme, the PWM signal is filtered by the first resistor R8 and the second capacitor C7 and then input to the operational amplifier U6. The operational amplifier U6 realizes the linear transmission of the above current, thereby realizing the linear voltage regulation of the reference voltage node VREF and the power supply terminal VOUT.

[0099] Example 2

[0100] This embodiment proposes a transformer, including any of the linear voltage regulating circuits described in Embodiment 1. The implementation method and beneficial effects of the linear voltage regulating circuit are the same as the corresponding content described in Embodiment 1, and the specific details will not be repeated.

[0101] refer to Figure 2 In one possible implementation, the transformer further includes a voltage conversion module T1, which is used to boost or buck the input voltage (AC input).

[0102] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A linear voltage regulating circuit, characterized in that, include: Square wave signal generation module, current input module, current mirror module, and voltage regulation module; The square wave signal output terminal of the square wave signal generation module is connected to the current input module; The output terminal of the current input module is connected to the first current branch of the current mirror module; The power supply terminal is connected to the voltage regulation module; The reference voltage node of the voltage regulation module is connected to the second current branch of the current mirror module; The square wave signal output terminal is used to output a square wave signal; The current input module is used to convert the square wave signal into a DC signal; The voltage regulation module is configured such that when the voltage of the reference voltage node changes, the voltage at the power supply terminal changes accordingly. When the duty cycle of the square wave signal changes, the current in the second current branch changes, and the voltage of the reference voltage node changes accordingly. The current input module includes a first resistor, a first capacitor, and a second capacitor. The square wave signal output terminal is grounded through the first capacitor; The first resistor and the second capacitor constitute a filter circuit, and the square wave signal output terminal is connected to the first current branch through the first resistor; The current mirror module includes a first switching transistor and a second switching transistor; The control terminals of the first switch and the second switch are connected; The first switching transistor is disposed in the first current branch, the output terminal of the current input module is connected to the first terminal of the first switching transistor, and the second terminal of the first switching transistor is grounded. The second switch is located in the second current branch, the reference voltage node is connected to the first terminal of the second switch, and the second terminal of the second switch is grounded. The current in the second current branch is adjusted by adjusting the duty cycle of the square wave signal and the resistance value of the first resistor.

2. The linear voltage regulation circuit as described in claim 1, characterized in that, The voltage regulation module includes a second resistor, a third resistor, and a fourth resistor; The second resistor, the third resistor, and the fourth resistor are connected in series, and the connection point of the third resistor and the fourth resistor serves as the reference voltage node.

3. The linear voltage regulation circuit as described in claim 2, characterized in that, The voltage regulation module also includes a feedback device; The power supply terminal is connected to the first terminal of the feedback device, the second terminal of the feedback device is grounded, and the reference voltage node is connected to the control terminal of the feedback device.

4. The linear voltage regulation circuit as described in claim 2, characterized in that, The voltage regulation module also includes a buck / boost module; The power supply terminal is connected to the power output terminal of the buck / boost module, and the reference voltage node is connected to the feedback terminal of the buck / boost module.

5. The linear voltage regulation circuit as described in claim 1, characterized in that, The first and second switching transistors are MOSFETs.

6. The linear voltage regulating circuit as described in claim 1, characterized in that, The duty cycle of the square wave signal is 0~100%.

7. A transformer, characterized in that, Includes the linear voltage regulating circuit as described in any one of claims 1 to 6.

8. The transformer as described in claim 7, characterized in that, It also includes a voltage conversion module, which is used to boost or buck the input voltage.

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