CN117318496A

CN117318496A - Resonant converter and control method thereof

Info

Publication number: CN117318496A
Application number: CN202311248246.6A
Authority: CN
Inventors: 熊伟; 李飞; 韦创炜; 徐福斌; 宋云庆; 余作霸; 刘文军; 彭涛; 刘菲
Original assignee: Shenzhen Xianyang New Energy Technology Co ltd
Current assignee: Shenzhen Xianyang New Energy Technology Co ltd
Priority date: 2023-09-25
Filing date: 2023-09-25
Publication date: 2023-12-29

Abstract

The application discloses a resonant converter and control method of resonant converter, resonant converter includes: a transformer including a primary coil and a secondary coil coupled to the primary coil; the resonance circuit is electrically connected with the primary coil and is used for generating resonance current and outputting the resonance current to the primary coil, and the secondary coil generates coupling current based on the resonance current of the primary coil; the rectifying circuit is electrically connected with the secondary coil and is used for rectifying the coupling current and outputting the rectified coupling current; and the control circuit is coupled with the secondary coil and is used for collecting the current direction of the coupling current and controlling the rectifying circuit according to the current direction of the coupling current so as to enable the current direction of the coupling current to be matched with the current direction of the resonance current. The application can reduce the consumption of manpower, reduce the manpower cost and save time.

Description

Resonant converter and control method thereof

Technical Field

The present disclosure relates to the field of resonant converters, and in particular, to a resonant converter and a control method of a resonant converter.

Background

LLC resonant converters are widely used in charging piles, battery detection techniques and energy storage directions. In the technical principle, the secondary side usually uses a diode or a MOS tube for rectification. In the development process, the same name end of the transformer is reversed due to engineering file design problems or sampling errors of suppliers, so that components are damaged in the power-on process.

Judging the same name end of the transformer, the existing processing method comprises the following two steps:

1. before the transformer is not welded on the PCB (Printed Circuit Board) plate, an LCR (L: inductance, C: capacitance, R: resistance) bridge is used for measuring the inductance of the transformer winding, any two ends of the two windings are short-circuited, the inductance of the other two ends is measured, and the same-name ends of the transformer are judged through the increase and decrease of the inductance.

2. After the transformer is welded on the PCB, the secondary side MOS tube driver PWM (Pulse Width Modulation) is forbidden to be output through software code change. Or changing hardware, and disconnecting the secondary side MOS tube to drive PWM. And measuring the relation between the conduction of the secondary side diode and the conduction of the primary side MOS tube during operation.

However, the first mode needs an engineer to detect the transformer through the LCR device, and the second mode needs an engineer to change the software or the hardware, which both needs to consume a lot of manpower, consume a lot of time, and increase the manpower cost.

Disclosure of Invention

The embodiment of the application provides a resonant converter and a control method of the resonant converter, which can reduce the consumption of manpower, reduce the manpower cost and save time.

An embodiment of the present application provides a resonant converter, including:

a transformer including a primary coil and a secondary coil coupled to the primary coil;

the resonance circuit is electrically connected with the primary coil and is used for generating resonance current and outputting the resonance current to the primary coil, and the secondary coil generates coupling current based on the resonance current of the primary coil;

the rectifying circuit is electrically connected with the secondary coil and is used for rectifying the coupling current and outputting the rectified coupling current;

and the control circuit is coupled with the secondary coil and is used for collecting the current direction of the coupling current and controlling the rectifying circuit according to the current direction of the coupling current so as to enable the current direction of the coupling current to be matched with the current direction of the resonance current.

Optionally, in some embodiments of the present application, the control circuit includes:

the mutual inductance coil is coupled with the secondary coil and is used for obtaining sampling current based on the coupling current;

the signal processing circuit is connected with the mutual inductance coil and is used for obtaining a control signal according to the current direction of the sampling current;

the control circuit is used for controlling the rectifying circuit according to the control signal.

Optionally, in some embodiments of the present application, the rectifying circuit includes:

one end of the first rectifying unit is electrically connected with the first end of the secondary coil, and the other end of the first rectifying unit is electrically connected with the first output end of the rectifying circuit;

one end of the second rectifying unit is connected between the first rectifying unit and the first output end, and the other end of the second rectifying unit is electrically connected with the second end of the secondary coil;

one end of the third rectifying unit is electrically connected with the first end of the secondary coil, and the other end of the third rectifying unit is electrically connected with the second output end of the rectifying circuit;

one end of the fourth rectifying unit is connected between the third rectifying unit and the second output end, and the other end of the fourth rectifying unit is electrically connected with the second end of the secondary coil;

the first rectifying unit, the second rectifying circuit, the third rectifying circuit and the fourth rectifying circuit are all electrically connected with the control circuit.

Optionally, in some embodiments of the present application, the first rectifying unit includes a first MOS transistor, and a first diode connected in parallel with the first MOS transistor;

the second rectifying unit comprises a second MOS tube connected in series with the first MOS tube and a second diode connected in parallel with the second MOS tube;

the third rectifying unit comprises a third MOS tube and a third diode connected with the third MOS tube in parallel;

the fourth rectifying unit comprises a fourth MOS tube connected in series with the third MOS tube and a fourth diode connected in parallel with the fourth MOS tube;

the third MOS tube and the fourth MOS tube are connected in parallel with the two ends of the first MOS tube and the second MOS tube together;

the anodes of the first diode and the fourth diode are in the same direction, the anodes of the second diode and the third diode are in the same direction, the anodes of the first diode and the second diode are in reverse directions, and the source electrode of the MOS tube is in the same direction as the anodes of the diodes connected in parallel respectively.

Optionally, in some embodiments of the present application, the resonant circuit includes:

a first switch unit, one end of which is electrically connected with a first input end of the resonant circuit, and the other end of which is electrically connected with a first end of the primary coil;

a second switch unit, one end of which is electrically connected between the second input end of the resonant circuit and the second end of the primary coil, and the other end of which is electrically connected with the first end of the primary coil;

and one end of the resonance unit is electrically connected with the common end of the first switch unit and the second switch unit, and the other end of the resonance unit is electrically connected with the first end of the primary coil.

Optionally, in some embodiments of the present application, further includes:

when the first switch unit is turned on, the second switch unit is turned off, and the current direction of the coupling current is matched with the current direction of the resonance current, the control circuit is used for controlling the first MOS tube and the fourth MOS tube to be turned on and controlling the second MOS tube and the third MOS tube to be turned off;

when the first switch unit is turned on, the second switch unit is turned off, and the current direction of the coupling current is not matched with the current direction of the resonance current, the control circuit is used for controlling the second MOS tube and the third MOS tube to be turned on and controlling the first MOS tube and the fourth MOS tube to be turned off;

when the first switch unit is turned off, the second switch unit is turned on, and the current direction of the coupling current is matched with the current direction of the resonance current, the control circuit is used for controlling the second MOS tube and the third MOS tube to be turned on and controlling the first MOS tube and the fourth MOS tube to be turned off;

when the first switch unit is turned off, the second switch unit is turned on, and the current direction of the coupling current is not matched with the current direction of the resonance current, the control circuit is used for controlling the first MOS tube and the fourth MOS tube to be turned on and controlling the second MOS tube and the third MOS tube to be turned off.

Optionally, in some embodiments of the present application, the resonance unit includes:

one end of the resonance capacitor is electrically connected with the common end of the first switch unit and the second switch unit, and the other end of the resonance capacitor is electrically connected with the first end of the primary coil;

and the resonance inductor is connected in series between the resonance capacitor and the first end of the primary coil.

Optionally, in some embodiments of the present application, the rectifying circuit further includes:

and one end of the filter capacitor is electrically connected to the common end of the first rectifying unit and the second rectifying unit, and the other end of the filter capacitor is electrically connected to the common end of the third rectifying unit and the fourth rectifying unit.

Accordingly, an embodiment of the present application provides a control method of a resonant converter, where the control method is applied to any one of the resonant converters described above, and the control method includes:

controlling a resonant circuit to generate resonant current and outputting the resonant current to a primary coil of a transformer so that a secondary coil of the transformer generates coupling current based on the resonant current of the primary coil;

collecting the current direction of the coupling current, and controlling the rectifying circuit according to the current direction of the coupling current so as to enable the current direction of the coupling current to be matched with the current direction of the resonance current;

and controlling the rectifying circuit to rectify the coupling current and outputting the rectified coupling current.

Optionally, in some embodiments of the present application, the controlling the rectifying circuit according to the current direction of the coupling current includes:

and when the current direction of the coupling current is not matched with the current direction of the resonance current, controlling the conduction path of the rectification circuit so as to reverse the current direction of the coupling current.

The embodiment of the application provides a resonant converter and a control method of the resonant converter, which can control a resonant circuit to generate resonant current and output the resonant current to a primary coil of a transformer so that a secondary coil of the transformer generates coupling current based on the resonant current of the primary coil; then collecting the current direction of the coupling current, and controlling a rectifying circuit according to the current direction of the coupling current so as to enable the current direction of the coupling current to be matched with the current direction of the resonance current; and finally, controlling a rectifying circuit to rectify the coupling current and outputting the rectified coupling current. The current direction of coupling current can be collected through control circuit to control rectification current according to the current direction, thereby make coupling current's current direction and resonant current's current direction assorted, do not need the manual work to detect through LCR equipment, also do not need to adjust software or hardware through the manual work, so can reduce the consumption of manpower, reduce human cost and save time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a circuit architecture diagram of a resonant converter provided in an embodiment of the present application;

FIG. 2 is another circuit architecture diagram of a resonant converter provided in an embodiment of the present application;

fig. 3 is a schematic circuit diagram of a resonant converter according to an embodiment of the present disclosure;

fig. 4 is a flow chart of a control method of a resonant converter according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Embodiments of the present application provide a resonant converter that is capable of converting direct current electrical energy to alternating current electrical energy, or converting voltage or frequency from one level to another. In practical applications, the resonant converter may be an LLC resonant converter.

Because the resonant converter can use the MOS tube to replace the function of a diode in practical application, the conduction loss is reduced, however, in the development process, the same-name end of a coil of the transformer is reversed due to the design problem of engineering files or the design error of a transformer supplier, and the MOS tube is easily damaged in the power-on process.

The existing processing mode mainly has two cases, one is before the transformer is welded on the PCB (Printed Circuit Board) board, and the other is after the transformer is welded on the PCB board, and the different cases are usually processed differently.

For the first case, an LCR bridge is typically used to measure the inductance of a transformer winding, by shorting any two ends of one winding and measuring the inductance across the other winding, and by increasing or decreasing the inductance, determining the identity of the windings of the transformer.

However, for the first case solution, the LCR device is required to perform the measurement, and the windings of the transformer are required to be shorted, and multiple sets of data are required to be measured for multiple transformer samples, which is complicated to operate and consumes more time.

For the second case, the control code is usually changed by a software engineer, so that the output of the secondary side MOS transistor driving PWM is forbidden, or the hardware is changed, the secondary side MOS transistor driving PWM is disconnected, and the relation between the conduction of the secondary side diode and the conduction of the primary side MOS transistor is measured in operation.

However, in the second mode, a testing environment needs to be built, for products with smaller structures, the testing difficulty is high, the code is needed to be changed for testing, the workload of engineers is increased, when the error of the same name end is found, the transformer needs to be re-sampled, the consumed time is high, and the development process is easy to delay.

In order to solve the above-mentioned problems, the present application provides a resonant converter, and referring to fig. 1, fig. 1 is a circuit configuration diagram of the resonant converter according to an embodiment of the present application. The resonant converter includes a transformer 10, a resonant circuit 20, a rectifying circuit 30, and a control circuit 40. The transformer 10 is electrically connected to the resonance circuit 20 and the rectifier circuit 30, and the control circuit 40 is electrically connected to the rectifier circuit 30.

Specifically, the transformer 1010 includes a primary coil and a secondary coil coupled to the primary coil, and the resonant circuit 20 is electrically connected to the primary coil for generating a resonant current and outputting the generated resonant current to the primary coil, and then generates a coupling current at the secondary coil under the coupling action of the primary coil and the secondary coil.

And a control circuit 40 coupled to the secondary coil for collecting the current direction of the coupling current and controlling the rectifying circuit 30 according to the current direction of the coupling current so that the current direction of the coupling current matches the current direction of the resonant current.

Finally, the rectifying circuit 30 is electrically connected to the secondary coil, and is configured to rectify the coupling current and output the rectified coupling current, so that the resonant converter can operate normally, in this process, the control circuit 40 collects the current direction of the coupling current and controls the rectifying current according to the current direction, so that the current direction of the coupling current is matched with the current direction of the resonant current, and the detection by LCR equipment is not required, and the adjustment by software or hardware is not required, so that the consumption of manpower can be reduced, the manpower cost can be reduced, and the time can be saved.

In some embodiments, referring to fig. 2, fig. 2 is another circuit architecture diagram of a resonant converter provided in an embodiment of the present application, and the control circuit 40 includes a mutual inductor 401 and a signal processing circuit 402 connected to the mutual inductor 401.

Specifically, the transformer coil 401 is coupled to the secondary coil for obtaining a sampling current based on the coupling current, the signal processing circuit 402 is electrically connected to the transformer coil 401 for obtaining a control signal according to a current direction of the sampling current, and the control circuit 40 is controlled by the control signal so that the current direction of the coupling current is the same as a current direction of the resonance current.

In some embodiments, the mutual inductor 401 is preferably a non-contact current transformer such as a magnetic field current transformer, a hall effect current transformer or a magnetoresistive current transformer, although in other embodiments, a contact current transformer may be used to detect the current direction of the coupling current, and the specific choice may be determined according to practical requirements.

The signal processing circuit 402 is preferably a DSP (Digital Signal Processing) signal processing circuit 402, which is integrated in the DSP signal processing device, and the mutual inductor 401 is electrically connected to the DSP signal processing device, and the current signal can be determined as follows:

1. the DSP device performs sampling and calculation: the DSP device may determine the direction of the current by sampling the current signal (i.e., coupling the current) and performing calculations using a mathematical algorithm. By observing the waveform and amplitude change of the current signal, it can be determined whether the current direction is correct, and certainly, whether the current direction is correct or not is determined by determining whether the current direction of the coupling current matches the current direction of the resonance current according to the current direction of the resonance current.

2. Reference signal comparison: the DSP device may compare with the reference signal to determine whether the direction of the current flow coincides with the reference signal. The reference signal may be a current in a known direction or other signals, for example, when the resonant converter works normally, the current direction of the coupling current corresponding to the current direction of the resonant current is the reference signal, and by comparing the phase and amplitude of the current signal and the reference signal, it can be determined whether the current direction is correct.

Of course, the above only exemplifies two modes, and other modes can be used for determination, and the embodiment is not limited to this, and different determination modes can be selected according to actual requirements.

In some embodiments, the rectified current includes a first rectifying unit 301, a second rectifying unit 302, a third rectifying unit 303, and a fourth rectifying unit 304.

A first rectifying unit 301 having one end electrically connected to a first end of the secondary coil and the other end electrically connected to a first output end of the rectifying circuit 30; a second rectifying unit 302 having one end connected between the first rectifying unit 301 and the first output end and the other end electrically connected to the second end of the secondary coil; a third rectifying unit 303, one end of which is electrically connected to the first end of the secondary coil, and the other end of which is electrically connected to the second output end of the rectifying circuit 30; a fourth rectifying unit 304, one end of which is connected between the third rectifying unit 303 and the second output end, and the other end of which is electrically connected with the second end of the secondary coil; the first rectifying unit 301, the second rectifying circuit 30, the third rectifying circuit 30, and the fourth rectifying circuit 30 are all electrically connected to the control circuit 40.

After the signal processing circuit 402 obtains the control signal according to the sampling current, the current direction of the coupling current of the control circuit 40 may be adjusted by controlling the turn-on of the first rectifying unit 301 and the fourth rectifying unit 304, the turn-off of the second rectifying circuit 30 and the third rectifying circuit 30, or by controlling the turn-off of the first rectifying unit 301 and the fourth rectifying unit 304, the turn-on of the second rectifying circuit 30 and the third rectifying circuit 30, so that the current direction of the coupling current matches the current direction of the resonance current.

In a specific embodiment, referring to fig. 3, fig. 3 is a schematic circuit diagram of a resonant converter according to an embodiment of the present application, where the first rectifying unit 301 includes a first MOS transistor Q1 and a first diode D1 connected in parallel with the first MOS transistor Q1; the second rectifying unit 302 includes a second MOS transistor Q2 connected in series with the first MOS transistor Q1, and a second diode D2 connected in parallel with the second MOS transistor Q2; the third rectifying unit 303 includes a third MOS transistor Q3, and a third diode D3 connected in parallel with the third MOS transistor Q3; the fourth rectifying unit 304 includes a fourth MOS transistor Q4 connected in series with the third MOS transistor Q3, and a fourth diode D4 connected in parallel with the fourth MOS transistor Q4; the third MOS tube Q3 and the fourth MOS tube Q4 are connected in parallel at two ends of the first MOS tube Q1 and the second MOS tube Q2.

The anodes of the first diode D1 and the fourth diode D4 are in the same direction, the anodes of the second diode D2 and the third diode D3 are in the same direction, the anodes of the first diode D1 and the second diode D2 are in opposite directions, and the source electrode of the MOS transistor is in the same direction as the anodes of the diodes connected in parallel.

More specifically, the source electrode of the first MOS transistor Q1 is electrically connected to the first end of the secondary coil, the drain electrode of the first MOS transistor Q1 is electrically connected to the first output end of the rectifying circuit 30, wherein the anode of the first diode D1 is electrically connected to the source electrode of the first MOS transistor Q1, and the cathode of the first diode D1 is electrically connected to the drain electrode of the first MOS transistor Q1.

The drain electrode of the second MOS transistor Q2 is electrically connected to the negative electrode of the first diode D1 and the first output end of the rectifying circuit 30, and the source electrode of the second MOS transistor Q2 is electrically connected to the second end of the secondary coil, where the positive electrode of the second diode D2 is electrically connected to the source electrode of the second MOS transistor Q2, and the negative electrode of the second diode D2 is electrically connected to the drain electrode of the second MOS transistor Q2 and the first output end of the rectifying circuit 30.

The drain electrode of the third MOS transistor Q3 is electrically connected between the source electrode of the first MOS transistor Q1 and the first end of the secondary coil, the source electrode of the third MOS transistor Q3 is electrically connected to the second output end of the rectifying circuit 30, wherein the anode of the third diode D3 is electrically connected to the source electrode of the third MOS transistor Q3, and the cathode of the third diode D3 is electrically connected to the drain electrode of the third MOS transistor Q3.

The source electrode of the fourth MOS transistor Q4 is electrically connected between the positive electrode of the third diode D3 and the second output end of the rectifying circuit 30, the drain electrode of the fourth MOS transistor Q4 is electrically connected between the second end of the secondary coil and the positive electrode of the second diode D2, the positive electrode of the fourth diode D4 is electrically connected between the source electrode of the fourth MOS transistor Q4 and the second output end of the rectifying circuit 30, and the negative electrode of the fourth diode D4 is electrically connected between the second end of the secondary coil and the positive electrode of the second diode D2.

The gate of the first MOS transistor Q1, the gate of the second MOS transistor Q2, the gate of the third MOS transistor Q3, and the gate of the fourth MOS transistor Q4 are all electrically connected to the signal processing circuit 402, specifically, electrically connected to the signal output end of the DSP device, and capable of receiving the control signal output by the DSP device, so as to control the on and off of the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3, and the fourth MOS transistor Q4.

When the resonant circuit 20 is turned on to generate a resonant current, the rectifying circuit 30 generates a coupling current, at this time, under the control of the DSP device, the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3 and the fourth MOS transistor Q4 are all turned off, at this time, the coupling current in the rectifying circuit 30 forms a secondary current loop through the first diode D1, the second diode D2, the third diode D3, the fourth diode D4 and the secondary coil, at this time, the current direction of the coupling current is determined through the mutual inductance coil L2 and the signal processing circuit 402, so that it is convenient to determine whether the current direction is strived at this time, and further determine to control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned on, the second MOS transistor Q2 and the third MOS transistor Q3 to be turned off, or control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned off, and the second MOS transistor Q2 and the third MOS transistor Q3 to be turned on, so that thereby adjust the current direction of the coupling current and current direction of the coupling current matches with the current direction of the resonant current is matched with the current direction.

Still further, the rectifying circuit 30 further includes a filter capacitor C2, where one end of the filter capacitor C2 is electrically connected to the common terminal of the first rectifying unit 301 and the second rectifying unit 302, and the other end of the filter capacitor C2 is electrically connected to the common terminal of the third rectifying unit 303 and the fourth rectifying unit 304.

Specifically, one end of the filter capacitor C2 is electrically connected between the cathode of the second diode D2 and the first output end of the rectifying circuit 30, the other end of the filter capacitor C2 is electrically connected between the anode of the fourth diode D4 and the second output end of the rectifying circuit 30, the filter capacitor C2 can store and filter the output voltage of the rectifying circuit 30, and a load can be connected between the first output end and the second output end of the rectifying circuit 30.

Referring to fig. 2, in some embodiments, the resonant circuit 20 includes a first switching unit 201, a second switching unit 202, and a resonant unit 203, wherein one end of the first switching unit 201 is electrically connected to a first input terminal of the resonant circuit 20, and the other end is electrically connected to a first end of the primary coil. And a second switching unit 202 having one end electrically connected between the second input terminal of the resonant circuit 20 and the second terminal of the primary coil and the other end electrically connected with the first terminal of the primary coil. And a resonance unit 203 having one end electrically connected to a common terminal of the first and second switching units 201 and 202 and the other end electrically connected to the first end of the primary coil.

During the operation of the resonant converter, the first switch unit 201 and the second switch unit 202 are turned off and turned on alternately to form a resonant current, and generate a resonant square wave signal, and the resonant unit 203 and the primary coil together form a resonant cavity, so that the harmonic wave of the square wave signal can be filtered.

Specifically, referring to fig. 3, the first switching unit 201 is a fifth MOS transistor Q5, the second switching unit 202 is a sixth MOS transistor Q6, and the resonant unit 203 is a resonant capacitor C1 and a resonant inductor L1 connected in series. The drain electrode of the fifth MOS tube Q5 is electrically connected with the first input end of the resonant circuit 20, the source electrode of the fifth MOS tube Q5 is electrically connected with one end of the resonant capacitor C1 far away from the resonant inductor L1, and one end of the resonant inductor L1 far away from the resonant capacitor C1 is electrically connected with the first end of the primary coil. The negative electrode of the fifth diode is electrically connected with the drain electrode of the fifth MOS tube Q5, and the positive electrode of the fifth diode is electrically connected between the source electrode of the fifth MOS tube Q5 and the resonance capacitor C1.

The drain electrode of the sixth MOS transistor Q6 is electrically connected between the source electrode of the fifth MOS transistor Q5 and the resonance capacitor C1, the second end of the primary coil is electrically connected to the second input end of the resonance circuit 20, and the source electrode of the sixth MOS transistor Q6 is electrically connected between the second end of the primary coil and the second input end of the resonance circuit 20. The negative electrode of the sixth diode is electrically connected between the drain electrode of the sixth MOS transistor Q6 and the resonance capacitor C1, and the positive electrode of the sixth diode is electrically connected with the source electrode of the sixth MOS transistor Q6.

The gates of the fifth MOS transistor Q5 and the sixth MOS transistor Q6 are electrically connected to the signal processing circuit 402, and are configured to receive a control signal, for example, a PWM control signal.

In the working process, when the first switch unit 201 is turned on, the second switch unit 202 is turned off, and the current direction of the coupling current is matched with the current direction of the resonant current, the control circuit 40 is used for controlling the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned on, and controlling the second MOS transistor Q2 and the third MOS transistor Q3 to be turned off;

when the first switch unit 201 is turned on, the second switch unit 202 is turned off, and the current direction of the coupling current is not matched with the current direction of the resonant current, the control circuit 40 is configured to control the second MOS transistor Q2 and the third MOS transistor Q3 to be turned on, and control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned off;

when the first switch unit 201 is turned off, the second switch unit 202 is turned on, and the current direction of the coupling current matches the current direction of the resonant current, the control circuit 40 is configured to control the second MOS transistor Q2 and the third MOS transistor Q3 to be turned on, and control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned off;

when the first switch unit 201 is turned off, the second switch unit 202 is turned on, and the current direction of the coupling current is not matched with the current direction of the resonant current, the control circuit 40 is configured to control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned on, and control the second MOS transistor Q2 and the third MOS transistor Q3 to be turned off.

In a specific embodiment, referring to fig. 3, when the current direction of the coupling current does not match the current direction of the resonant current, the conduction path of the rectifier circuit 30 is controlled to reverse the current direction of the coupling current in the following manner:

when the fifth MOS transistor Q5 is turned on under the PWM control signal and the sixth MOS transistor Q6 is turned off under the PWM control signal, the current direction of the resonant circuit 20 is along the direction of the fifth MOS transistor Q5, the resonant capacitor C1, the resonant inductor L1, and the secondary winding, and this current direction is referred to as the first current direction.

When the fifth MOS transistor Q5 is turned off under the PWM control signal and the sixth MOS transistor Q6 is turned on under the PWM control signal, the current direction of the resonant circuit 20 is along the resonant capacitor C1, the sixth MOS transistor Q6, the resonant inductor L1 and the secondary coil, and the current direction is referred to as the second current direction

When the current direction of the resonant circuit 20 is the first current direction, the current direction of the sampling current in the rectifying circuit 30 is obtained through the mutual inductance coil 401 (i.e. the mutual inductance coil L2 in fig. 3) and the signal processing circuit 402, and the sampling current is obtained, the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3 and the fourth MOS transistor Q4 are all in the off state, and the coupling current obtained at this time is the sampling current.

If the same-name ends of the primary coil and the secondary coil of the transformer 10 are in the same direction, the correct current direction of the coupling current should be the direction from the second end of the secondary coil to the first end of the secondary coil, so the signal processing circuit 402 may specifically be a DSP device, and determines whether the current direction of the sampling current is the same as the correct current direction of the coupling current.

If the current direction of the coupling current is the same, the signal processing circuit 402 outputs a control signal, so that the first MOS transistor Q1 and the fourth MOS transistor Q4 are controlled to be conducted, the second MOS transistor Q2 and the third MOS transistor Q3 are controlled to be turned off, and the coupling current flows from the second end of the secondary coil to the first end of the secondary coil.

If the current direction of the coupling current is incorrect, the current direction of the coupling current is the direction from the first end of the secondary coil to the second end of the secondary coil, so that the signal processing circuit 402 outputs a new control signal to control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be closed and control the second MOS transistor Q2 and the third MOS transistor Q3 to be conducted in order to ensure that the rectifying circuit 30 can work normally and prevent the probability of damage to the MOS transistor of the rectifying circuit 30 as much as possible, and further realize the coupling current from the first end of the secondary coil to the second end of the secondary coil.

If the current direction of the resonant circuit 20 is the first current direction and the same-name ends of the primary winding and the secondary winding of the transformer 10 are different, the current direction of the coupling current should be the direction from the first end of the secondary winding to the second end of the secondary winding, so the signal processing circuit 402, specifically a DSP device, may determine whether the current direction of the sampling current is the same as the current direction of the coupling current.

If the current direction of the coupling current is the same, the signal processing circuit 402 outputs a control signal, so that the first MOS transistor Q1 and the fourth MOS transistor Q4 are controlled to be closed, the second MOS transistor Q2 and the third MOS transistor Q3 are controlled to be conducted, and the coupling current flows from the first end of the secondary coil to the second end of the secondary coil.

If the current direction of the coupling current is incorrect, the current direction of the coupling current is the direction from the second end of the secondary coil to the first end of the secondary coil, so that the signal processing circuit 402 outputs a new control signal to control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned on and control the second MOS transistor Q2 and the third MOS transistor Q3 to be turned off, and further realize that the coupling current flows from the second end of the secondary coil to the first end of the secondary coil in order to ensure that the rectifying circuit 30 can work normally and prevent the probability of damage to the MOS transistor of the rectifying circuit 30 as much as possible.

Through the control mode of the resonant converter, the flow direction of the coupling current in the rectifying circuit 30 can be adaptively adjusted, so that the current direction of the coupling current is matched with the current direction of the resonant current, the occurrence of damage to the MOS tube in the power-on process can be prevented as much as possible, a test environment does not need to be built, the difficulty of testing is small for a product with a smaller structure, code changing test is not needed, the workload of engineers is reduced, and when the error of the same name end is found, the transformer 10 does not need to be re-sampled, the consumed time is less, and the development process is not influenced. Meanwhile, LCR equipment is not needed for measurement, windings of the transformers 10 are not needed to be short-circuited, multiple groups of data do not need to be measured on multiple samples of the transformers 10, the operation is simple, and the consumed time is less.

The embodiment of the application also provides a control method of the resonant converter, which can be implemented by the resonant converter of any embodiment. Referring to fig. 4 and fig. 2, fig. 4 is a schematic flow chart of a control method of a resonant converter according to an embodiment of the present application. The control method of the resonant converter comprises the following steps:

101. the resonant circuit 20 generates a resonant current and outputs the resonant current to the primary coil of the transformer 10 so that the secondary coil of the transformer 10 generates a coupling current based on the resonant current of the primary coil;

102. collecting the current direction of the coupling current, and controlling the rectifying circuit 30 according to the current direction of the coupling current so that the current direction of the coupling current is matched with the current direction of the resonance current;

103. the control rectifying circuit 30 rectifies the coupling current and outputs the rectified coupling current.

In some embodiments, control circuit 40 includes:

a mutual inductance coil 401 coupled with the secondary coil for obtaining a sampling current based on the coupling current;

a signal processing circuit 402, connected to the mutual inductance coil 401, for obtaining a control signal according to a current direction of the sampling current;

the control circuit 40 is used for controlling the rectifying circuit 30 according to the control signal.

In some embodiments, the rectifying circuit 30 includes:

a first rectifying unit 301 having one end electrically connected to a first end of the secondary coil and the other end electrically connected to a first output end of the rectifying circuit 30;

a second rectifying unit 302 having one end connected between the first rectifying unit 301 and the first output end and the other end electrically connected to the second end of the secondary coil;

a third rectifying unit 303, one end of which is electrically connected to the first end of the secondary coil, and the other end of which is electrically connected to the second output end of the rectifying circuit 30;

a fourth rectifying unit 304, one end of which is connected between the third rectifying unit 303 and the second output end, and the other end of which is electrically connected with the second end of the secondary coil;

the first rectifying unit 301, the second rectifying circuit 30, the third rectifying circuit 30, and the fourth rectifying circuit 30 are all electrically connected to the control circuit 40.

In some embodiments, the first rectifying unit 301 includes a first MOS transistor Q1, and a first diode D1 connected in parallel with the first MOS transistor Q1;

the second rectifying unit 302 includes a second MOS transistor Q2 connected in series with the first MOS transistor Q1, and a second diode D2 connected in parallel with the second MOS transistor Q2;

the third rectifying unit 303 includes a third MOS transistor Q3, and a third diode D3 connected in parallel with the third MOS transistor Q3;

the fourth rectifying unit 304 includes a fourth MOS transistor Q4 connected in series with the third MOS transistor Q3, and a fourth diode D4 connected in parallel with the fourth MOS transistor Q4;

the third MOS tube Q3 and the fourth MOS tube Q4 are connected in parallel at two ends of the first MOS tube Q1 and the second MOS tube Q2 together;

In some embodiments, the resonant circuit 20 includes:

a first switching unit 201 having one end electrically connected to a first input terminal of the resonant circuit 20 and the other end electrically connected to a first end of the primary coil;

a second switching unit 202 having one end electrically connected between the second input end of the resonant circuit 20 and the second end of the primary coil and the other end electrically connected with the first end of the primary coil;

and a resonance unit 203 having one end electrically connected to a common terminal of the first and second switching units 201 and 202 and the other end electrically connected to the first end of the primary coil.

In some embodiments, when the first switch unit 201 is turned on, the second switch unit 202 is turned off, and the current direction of the coupling current matches the current direction of the resonant current, the control circuit 40 is configured to control the first MOS transistor Q1 and the fourth MOS transistor Q4 to be turned on, and control the second MOS transistor Q2 and the third MOS transistor Q3 to be turned off;

In some embodiments, the resonance unit 203 includes:

one end of the resonance capacitor C1 is electrically connected with the common end of the first switch unit 201 and the second switch unit 202, and the other end of the resonance capacitor C1 is electrically connected with the first end of the primary coil;

the resonant inductor L1 is connected in series between the resonant capacitor C1 and the first end of the primary coil.

In some embodiments, the rectifying circuit 30 further includes:

one end of the filter capacitor C2 is electrically connected to the common terminal of the first rectifying unit 301 and the second rectifying unit 302, and the other end is electrically connected to the common terminal of the third rectifying unit 303 and the fourth rectifying unit 304.

In some embodiments, the controlling the rectifying circuit 30 according to the current direction of the coupling current in step 102 includes: when the current direction of the coupling current does not match the current direction of the resonance current, the conduction path of the rectifying circuit 30 is controlled so that the current direction of the coupling current is reversed.

In the description of the present application, it should be understood that terms such as "first," "second," and the like are used merely to distinguish between similar objects and should not be construed to indicate or imply relative importance or implying any particular order of magnitude of the technical features indicated.

It should be noted that in the embodiments of the present application, "connected" is understood to mean electrically connected, and two electrical components may be connected directly or indirectly between two electrical components. For example, a may be directly connected to B, or indirectly connected to B via one or more other electrical components.

The analog-to-digital converter, the chip, the analog-to-digital conversion calibration method and the electronic device provided by the embodiment of the application are described in detail above. Specific examples are set forth herein to illustrate the principles and embodiments of the present application, with the description of the examples given above only to assist in understanding the present application. Meanwhile, those skilled in the art will have variations in the specific embodiments and application scope in light of the ideas of the present application, and the present description should not be construed as limiting the present application in view of the above.

Claims

1. A resonant converter, comprising:

2. The resonant converter of claim 1, wherein the control circuit comprises:

3. The resonant converter of claim 1, wherein the rectifying circuit comprises:

4. A resonant converter according to claim 3, characterized in that:

the first rectifying unit comprises a first MOS tube and a first diode connected in parallel with the first MOS tube;

5. The resonant converter of claim 4, wherein the resonant circuit comprises:

6. The resonant converter of claim 5, wherein:

7. The resonant converter of claim 5, wherein the resonant unit comprises:

8. A resonant converter according to claim 3, wherein the rectifying circuit further comprises:

9. A control method of a resonant converter, characterized in that the control method is applied to the resonant converter of any one of claims 1 to 8, the control method comprising:

10. The control method according to claim 9, characterized in that the controlling the rectifying circuit according to the current direction of the coupling current includes: