A dc-dc voltage conversion device, power supply device and control method

Abstract

A DC-DC voltage conversion device, a power supply device and a control method thereof, which can improve the dynamic response speed of the DC-DC voltage conversion device. The device comprises a resonant conversion unit, a resonant signal sampling unit, an output voltage sampling unit and a controller. The resonant signal sampling unit is used for sampling the resonant voltage v cr of the transformer primary side in the resonant conversion unit and outputting the sampling reference voltage v sns ; the output voltage sampling unit is used for sampling the output voltage V out of the resonant conversion unit and outputting the feedback voltage V fb ; the controller is further used for obtaining the sampling reference voltage v sns and the feedback voltage V fb ; obtaining the time length parameter t fb according to the feedback voltage V lp ; outputting the switch control signal used for controlling the on-off of the switch S1 and the switch S2, and the switch control signal is determined according to the time length parameter t lp and the sampling reference voltage v sns .

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit, and more particularly, to a DC-DC voltage conversion device, a power supply device and a control method. BACKGROUND

[0002] In the field of power supply, such as personal computer (PC) power supply, communication power supply, industrial power supply and the like, switching converters, such as direct current to direct current (DC-DC) voltage converters, are used. In order to improve the efficiency of the switching converter, soft switching of the device needs to be realized. Among them, the resonant soft switching topology realizes soft switching control by making the current lag behind the voltage through resonant elements. For example, the resonant soft switching topology usually first obtains a high-frequency square wave through chopping of the direct current input, then realizes voltage regulation and soft switching through a resonant cavity and a transformer, and finally obtains the required direct current output through rectification and filtering.

[0003] Among them, the resonant switching circuit usually adopts pulse frequency modulation (PFM) control, and the PFM control usually adopts a voltage control mode. In a cycle, the input and output voltage gain of the resonant cavity is changed by adjusting the switching frequency fs to realize the adjustment of the output voltage. The control of the PFM is adjusted by sampling the output voltage feedback. If the output voltage is less than the reference voltage, the switching frequency fs is reduced to increase the voltage gain; if the output voltage is greater than the reference voltage, the switching frequency fs is increased. When the switching frequency reaches the maximum frequency limit, the resonant circuit enters the burst mode. In the burst mode, the circuit can stop for a period of time after working for a period of time to reduce the output power.

[0004] Under the PFM control mode, the resonant switching circuit has the problem of slow dynamic response between the light load mode and the heavy load mode, and the switching point of entering the light load mode is determined according to the switching frequency fs, rather than the load, so that the fluctuation of the resonant element parameters can cause the load point of entering the light load mode to change significantly, resulting in inaccurate control of the load point when switching in the light load mode. SUMMARY

[0005] The present application provides a DC-DC voltage conversion device, a power supply device and a control method, which can improve the dynamic response speed of the DC-DC voltage conversion device, more accurately configure the load point of the light load mode and the heavy load mode, and improve the control efficiency of the DC-DC voltage conversion device.

[0006] In a first aspect, a DC-DC voltage conversion device is provided, comprising: a resonant conversion unit including a high-frequency chopper circuit, a resonant cavity, a transformer, and a rectifier filter network, wherein the high-frequency chopper circuit includes switches S1 and S2; and a controller for controlling the on / off state of the switches S1 and S2 to convert the DC voltage V input to the high-frequency chopper circuit. in The AC voltage is converted into a high-frequency square wave. The resonant cavity and the transformer are used to receive the high-frequency square wave and couple electrical energy from the primary side of the transformer to the secondary side. The rectifier filter network is used to convert the AC voltage coupled to the secondary side of the transformer into a DC voltage, which is then used as the output voltage V. out The resonant signal sampling unit is used to sample the resonant voltage v on the primary side of the transformer. cr and output the sampling reference voltage v sns The sampling reference voltage v sns Used to reflect the resonant voltage v on the primary side of the transformer. cr and resonant current i cr The change in voltage; the output voltage sampling unit is used to sample the output voltage V of the resonant converter unit. out and output feedback voltage V fb The controller is further configured to: acquire the sampling reference voltage v sns and the feedback voltage V fb According to the feedback voltage V fb Obtain the time length parameter t lp Output a switch control signal for controlling the on / off state of switches S1 and S2, the switch control signal being based on the time length parameter t. lp and the sampling reference voltage v sns It's confirmed.

[0007] This scheme introduces a resonant current i cr and resonant voltage v cr The integrated sampling circuit, i.e., the sampling reference voltage v sns It can simultaneously reflect the resonant voltage v cr and resonant current i cr The change in voltage, therefore, is determined by utilizing the sampled reference voltage v. sns and time length parameter t lp Controlling the switching on and off of the switches in the DC-DC voltage converter enables rapid loop control, resulting in a faster dynamic response. Furthermore, by adjusting the RC parameters in the resonant signal sampling unit, the zero-crossing time under no-load and full-load conditions can be configured, allowing for accurate configuration of the control points at both load and no-load conditions. This facilitates easier adjustment of the entry and exit points for light-load modes, thereby improving control efficiency.

[0008] In conjunction with the first aspect, in one possible implementation, the controller is specifically configured to: at the reference voltage v sns The first timing begins at the moment t1 when the negative value crosses zero; the first timing continues until the time length parameter t is reached. lp After the second time t2, switch S1 is controlled to be in the off state, and then switch S2 is controlled to be in the on state; at the reference voltage v sns The second timing begins after the third time point t3, when the value crosses zero; the second timing continues until the time length parameter t is reached. lp After the fourth time t4, switch S2 is controlled to be in the off state, and then switch S1 is controlled to be in the on state.

[0009] Sampling reference voltage v sns It can simultaneously reflect the resonant voltage v cr and resonant current i cr The change in voltage is monitored within one clock cycle of switches S1 and S2 by monitoring the sampled reference voltage v. sns The zero-crossing time is determined, and the time length parameter t is used. lp Control sampling reference voltage v sns The time from zero crossing to switch off enables rapid loop control, resulting in a faster dynamic response speed.

[0010] In conjunction with the first aspect, in one possible implementation, the controller is specifically configured to: control the feedback voltage V fb The proportionality constant k is obtained through calculation. lp According to the formula The time length parameter t is obtained. lp ,in, This represents the average period of the most recent N switching cycles of switch S1 or switch S2, where N is an integer greater than 1.

[0011] Therefore, by calculating the average period of switch S1 (or switch S2) over the first N cycles... Make Thus, t lp The calculation is also related to the first N cycles, slowing down t. lp Despite the changes in V fb The rapid changes in the sampling signal also make the loop more stable, thereby optimizing the working performance of the DC-DC voltage converter.

[0012] In conjunction with the first aspect, in one possible implementation, the time length parameter t lp The time length parameter t meets at least one of the following conditions: lp With output voltage V outa negative correlation with the magnitude of the load current. lp a negative correlation with the magnitude of the load current.

[0013] In combination with the first aspect, in a possible implementation manner, the resonance signal sampling unit comprises: a first sampling capacitor C S1 , a second sampling capacitor C S2 , and a sampling resistor Rs, wherein a first end of the first sampling capacitor C S1 is configured to receive the resonance voltage V cr of the primary side of the transformer, a second end of the first sampling capacitor C S1 is configured to output a sampling reference voltage v sns , and the sampling resistor Rs and the second sampling capacitor C S1 are connected in parallel between the second end of the first sampling capacitor C S2 and the ground.

[0014] In the present solution, a comprehensive sampling circuit of the resonance current i cr and the resonance voltage v cr is introduced. The sampling resistor Rs is configured to sample the resonance current i cr , and the second sampling capacitor C S2 is configured to sample the resonance voltage v cr . By adjusting the values of Rs and C S2 , the sampling ratios of the resonance current i cr and the resonance voltage v cr can be adjusted, so that the time length parameter t lp is set within a reasonable range to achieve the purpose of easy detection. Moreover, by adjusting the values of Rs and C S2 , the zero-crossing time of different loads can be configured, the control of the load point is accurate, and the adjustment of the entry and exit points of the light load mode is easy to implement, thereby improving the control efficiency.

[0015] In a second aspect, a control method of a DC-DC voltage conversion device is provided, the DC-DC voltage conversion device comprising: a resonance conversion unit comprising a high-frequency chopper circuit, a resonance cavity, a transformer, and a rectification filter network, the high-frequency chopper circuit comprising switches S1 and S2; a controller configured to convert a direct current voltage V in input to the high-frequency chopper circuit into a high-frequency square wave by controlling the on-off of the switches S1 and S2, the resonance cavity and the transformer being configured to receive the high-frequency square wave and couple electrical energy from a primary side of the transformer to a secondary side, the rectification filter network being configured to convert an alternating current voltage coupled to the secondary side of the transformer into a direct current voltage and output as an output voltage V out ; and a resonance signal sampling unit configured to sample a resonance voltage v cr of the primary side of the transformer.and output the sampling reference voltage v sns The sampling reference voltage v sns Used to reflect the resonant voltage v on the primary side of the transformer. cr and resonant current i cr The change in voltage; the output voltage sampling unit is used to sample the output voltage V of the resonant converter unit. out and output feedback voltage V fb The method includes: the controller acquiring the sampled reference voltage v sns and the feedback voltage V fb The controller, based on the feedback voltage V fb Obtain the time length parameter t lp The controller outputs a switch control signal to control the on / off state of switches S1 and S2, the switch control signal being based on the time length parameter t. lp and the sampling reference voltage v sns Definite

[0016] In conjunction with the second aspect, in one possible implementation, the controller outputs a switch control signal for controlling the on / off state of switches S1 and S2, including: the controller at the reference voltage v sns The first timing begins at the first moment t1 when the negative value crosses zero; the controller reaches the time length parameter t during the first timing. lp After the second time t2, the controller controls switch S1 to be in the off state, and then controls switch S2 to be in the on state; the controller controls the reference voltage v sns The second timing begins after the third time point t3, when the value crosses zero; the controller reaches the time length parameter t during the second timing. lp After the fourth time t4, switch S2 is controlled to be in the off state, and then switch S1 is controlled to be in the on state.

[0017] In conjunction with the second aspect, in one possible implementation, the controller responds to the feedback voltage V fb Perform calculations to obtain the time. intermediate Length parameter t lp This includes: the feedback voltage V fb The proportionality constant k is obtained through calculation. lp According to the formula The time length parameter t is obtained. lp ,in, This represents the average period of the most recent N switching cycles of switch S1 or switch S2, where N is an integer greater than 1.

[0018] In combination with the second aspect, in a possible implementation manner, the time length parameter t lp meets at least one of the following conditions: the time length parameter t lp has a negative correlation with the presence of the output voltage V out ; and the time length parameter t lp has a negative correlation with the size of the load current.

[0019] In combination with the second aspect, in a possible implementation manner, the resonance signal sampling unit comprises: a first sampling capacitor C S1 , a second sampling capacitor C S2 , and a sampling resistor Rs, a first end of the first sampling capacitor C S1 is configured to receive the resonance voltage V cr of the transformer primary side, a second end of the first sampling capacitor C S1 is configured to output a sampling reference voltage v sns , and the sampling resistor Rs and the second sampling capacitor C S2 are connected in parallel between the second end of the first sampling capacitor C S1 and the ground.

[0020] The third aspect provides an electronic device, wherein the electronic device is provided with the DC-DC voltage conversion apparatus as described in the first aspect or any possible implementation manner of the first aspect.

[0021] The fourth aspect provides a computer readable storage medium for storing a computer program, the computer program comprising instructions for executing the method of the second aspect or any possible implementation manner of the second aspect.

[0022] The fifth aspect provides a computer program product comprising a computer program, the computer program comprising instructions for executing the method of the second aspect or any possible implementation manner of the second aspect.

[0023] The sixth aspect provides a control chip, wherein the control chip is provided with a circuit for executing the method of the second aspect or any possible implementation manner of the second aspect.

[0024] The seventh aspect provides a power supply device for supplying power to a load, the power supply device comprising: an alternating current to direct current (AC-DC) voltage conversion unit configured to convert an alternating voltage into a direct voltage; and the DC-DC voltage conversion apparatus as described in the first aspect or any possible implementation manner of the first aspect, configured to receive the direct voltage output by the AC-DC voltage conversion unit and perform direct voltage conversion. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of a DC-DC resonant converter according to an embodiment of the present application.

[0026] Figure 2 is a schematic diagram of a half-bridge LLC resonant converter 100 according to an embodiment of the present application.

[0027] Figure 3 is a schematic diagram of a DC-DC voltage conversion device 300 according to an embodiment of the present application.

[0028] Figure 4 is a schematic diagram of the working waveforms of a controller 320 according to an embodiment of the present application.

[0029] Figure 5 is a schematic diagram of an output voltage sampling unit 340 according to an embodiment of the present application.

[0030] Figure 6 is a schematic diagram of a resonant signal sampling unit 330 according to an embodiment of the present application.

[0031] Figure 7 is a schematic diagram of the resonant signal sampling unit 330 in Figure 6 .

[0032] Figure 8 is a schematic diagram of the resonant signal sampling unit 330 in Figure 6 .

[0033] Figure 9 is a schematic diagram of the working waveforms of the resonant signal sampling unit 330 in Figure 6 .

[0034] Figure 10 is a schematic diagram of a DC-DC voltage conversion device 400 according to another embodiment of the present application.

[0035] Figure 11 is a schematic diagram of a zero-crossing comparison unit 350 according to an embodiment of the present application.

[0036] Figure 12 is a schematic diagram of the working waveforms of a zero-crossing comparison unit 350 according to an embodiment of the present application.

[0037] Figure 13 is a schematic diagram of a control method implemented by a controller 320 according to an embodiment of the present application.

[0038] Figure 14 is a schematic diagram of the working waveforms of a controller 320 according to an embodiment of the present application.

[0039] Figure 15The working waveform diagram of the DC-DC voltage conversion device of an embodiment of the application working in a heavy load mode is shown.

[0040] Figure 16 The working waveform diagram of the DC-DC voltage conversion device of an embodiment of the application working in a heavy load mode is shown.

[0041] Figure 17 The working waveform diagram of the DC-DC voltage conversion device of an embodiment of the application working in a heavy load mode is shown.

[0042] Figure 18 The working waveform diagram of the DC-DC voltage conversion device of an embodiment of the application working in a heavy load mode is shown.

[0043] Figure 19 The function diagram of the control method realized by the controller 320 of another embodiment of the application is shown.

[0044] Figure 20 The working waveform diagram corresponding to the control method shown in Figure 19 Specific implementation

[0045] The technical solutions in the application will be described below with reference to the accompanying drawings.

[0046] Figure 1 The principle diagram of the DC-DC resonant converter of an embodiment of the application is shown. As shown in Figure 1 , the resonant converter obtains a high-frequency square wave by chopping the direct-current input voltage at high frequency, then realizes voltage regulation and soft switching through a resonant cavity and a transformer, and finally obtains a direct-current output voltage through rectification and filtering.

[0047] Among them, if the high-frequency chopping part adopts a half-bridge circuit, the resonant cavity adopts LLC type, and the rectification adopts full-wave rectification by diode, the half-bridge LLC resonant converter topology 100 shown in Figure 2 is obtained.

[0048] Figure 2 The topology diagram of the half-bridge LLC resonant converter 100 of an embodiment of the application is shown. As shown in Figure 2 , the resonant converter 100 includes a high-frequency chopping circuit 101, a resonant cavity 102, a transformer 103, and a rectification and filtering network 104. Among them, the high-frequency chopping circuit 101 includes an input filtering capacitor C I , switches S1 and S2. Among them, Figure 2 ​The diodes connected with switches S1 and S2 are body diodes, and the connected capacitors are parasitic capacitors. The resonant cavity 102 includes a resonant inductor Lr and a resonant capacitor Cr, the resonant inductor Lr includes leakage inductance of the transformer 103 and an added inductor, and can be integrated in the transformer 103. The transformer 103 can be a transformer Tr, and the magnetizing inductance of the primary side of the transformer Tr is represented as Lm; the rectification filter network 104 includes diodes D1 and D2, and an output filter capacitor C O .

[0049] The first end of the switch S1 is connected with the positive pole of the input voltage, the second end of the switch S1 and the first end of the switch S2 are connected, and the second end of the switch S2 is connected with the negative pole of the input terminal. The switch S1 is also called an upper drive tube or an upper tube, and the switch S2 is also called a lower drive tube or a lower tube. It should be understood that, for the convenience of description, the first end and the second end of the switch in the embodiments of the present application can respectively refer to the source and the drain of the transistor. In addition, the gate of the transistor can be used to receive the control signal of the switch.

[0050] In some examples, the switches S1 and S2 can be field-effect transistors (FETs) made of silicon (Si) or third-generation wide-bandgap semiconductor materials such as silicon carbide (SiC) or gallium nitride (GaN).

[0051] The half-bridge LLC usually adopts a PFM control mode, in one period, ignoring the dead time, S1 and S2 are each turned on for 50% of the time, the input-output voltage gain of the resonant cavity is changed by adjusting the switching frequency fs, and the adjustment of the output voltage is realized.

[0052] The embodiments of the present application propose a DC-DC voltage conversion device and a control method, by introducing a comprehensive sampling circuit of resonant current i cr and resonant voltage v cr , the dynamic response speed of the DC-DC voltage conversion device can be improved, and the load point of the conversion of the light load mode and the heavy load mode can be more accurately configured.

[0053] Optionally, the DC-DC voltage converter in this embodiment can be used as a power supply device to supply power to a load. The load may include, but is not limited to, personal computers, mobile phones, computers, television screens, etc. The power supply device can be a DC-DC conversion system, an AC-DC conversion system, or other types of voltage conversion systems. As an example, the power supply device may include an AC-DC conversion unit and the DC-DC voltage converter in this embodiment. The AC-DC conversion unit converts AC voltage to DC voltage and outputs it to the DC-DC voltage converter.

[0054] Figure 3 This is a schematic diagram of the structure of a DC-DC voltage converter 300 according to an embodiment of this application. Figure 3 As shown, the DC-DC voltage converter 300 includes a resonant converter unit 310, a controller 320, a resonant signal sampling unit 330, and an output voltage sampling unit 340. The working principle of the resonant converter unit 310 is similar to... Figure 1 as well as Figure 2 The resonant converter described in the previous section is similar and will not be repeated here.

[0055] The resonant converter unit 310 includes a high-frequency chopper circuit 311, a resonant cavity 312, a transformer 313, and a rectifier-filter network 314. The high-frequency chopper circuit 311 includes switches S1 and S2. The controller 320 controls the on / off state of switches S1 and S2 to convert the DC voltage V input to the high-frequency chopper circuit 311... in The AC voltage is converted into a high-frequency square wave. The resonant cavity 312 and transformer 313 are used to receive the high-frequency square wave and couple electrical energy from the primary side of transformer 313 to the secondary side. The rectifier filter network 314 is used to convert the AC voltage coupled to the secondary side of transformer 313 into DC voltage, which is then used as the output voltage V. out Output.

[0056] The resonant signal sampling unit 330 is used to sample the resonant voltage V on the primary side of the transformer. cr and output the sampling reference voltage v sns Sampling reference voltage v sns Used to reflect the resonant voltage v on the primary side of the transformer. cr and resonant current i cr The changes.

[0057] The output voltage sampling unit 340 is used to sample the output voltage V of the resonant converter unit 310. out and output feedback voltage V fb .

[0058] Controller 320 is also used to: acquire the sampling reference voltage v sns and feedback voltage Vfb ; according to the feedback voltage V fb , a time length parameter t lp is obtained ; a switch control signal for controlling the on-off of the switch S1 and the switch S2 is output, and the switch control signal is determined according to the time length parameter t lp and the sampling reference voltage v sns . In other words, the controller 320 can determine the on-off frequency fs of the switch S1 or the switch S2 according to the time length parameter t lp and the sampling reference voltage v sns .

[0059] It can be understood that, in the loop control, the time length parameter t lp can be used as the zero-crossing time of the sampling reference voltage v sns to control the switching period of the switch S1 or the switch S2, and the specific scheme is as follows.

[0060] In some examples, in determining the on-off frequency fs of the switch S1 or the switch S2 according to the time length parameter t lp and the reference sampling voltage v sns , the controller 320 is specifically configured to: start a first timing at a first time t1 when the reference voltage v sns starts to rise from a negative value to zero; turn off the switch S1 at a second time t2 when the first timing reaches the time length parameter t lp ; and turn on the switch S2. In addition, start a second timing at a third time t3 when the reference voltage v sns starts to fall from a positive value to zero; turn off the switch S2 at a fourth time t4 when the second timing reaches the time length parameter t lp ; and turn on the switch S1.

[0061] Figure 4 is a schematic diagram of the working waveform of the controller 320 of an embodiment of the present application. As shown in Figure 4 , in some examples, the control logic of the controller 320 is as follows: in one switching period, first, it is assumed that the time when the switch S1 is turned on is the starting time t0 of the period, at which time the v sns signal is a negative value. The time when the v sns signal crosses zero from a negative value is the first time t1, at which time the timer starts timing. When the timing of the timer reaches t lp , it is the second time t2, at which time the switch S1 is turned off. The timer is reset to zero, and then a dead time is entered, waiting for the switch S2 soft opening condition to be met. After the switch S2 soft opening condition is met or the fixed dead time ends, the switch S2 is turned on, at which time the v sns signal is a positive value. The v snsThe time when the signal crosses zero from positive to negative is the third time t3, at which time the timer starts to re-count. When the time counted by the timer reaches t lp , the switch S2 is turned off, and the dead zone is entered, waiting for the switch S1 to be turned on again. At this point, the control process of a switching cycle is completed.

[0062] Alternatively, the controller 320 can perform calculation processing on the feedback voltage V fb to obtain a time length parameter t lp . Specifically, the time length parameter t lp meets at least one of the following conditions: the time length parameter t lp has a negative correlation with the output voltage V out . The time length parameter t lp has a negative correlation with the size of the load current. In other words, the time length parameter t lp has a positive correlation with the size of the load.

[0063] It should be noted that the negative correlation between the time length parameter t lp and the output voltage V out and the load current can be linear or non-linear.

[0064] In some examples, the controller 320 can perform loop calculation according to the feedback voltage V fb to directly obtain the time length parameter t lp .

[0065] In some examples, the controller 320 can obtain a proportional coefficient k lp . And according to the proportional coefficient k lp and the average period of the last N switching cycles, the time length parameter t lp is obtained. For example, the controller 320 is specifically configured to: perform calculation processing on the feedback voltage V fb to obtain the proportional coefficient k lp ; and obtain the time length parameter t lp according to the formula , where represents the average period of the last N switching cycles of the switch S1 and the switch S2.

[0066] In terms of logic control, because the V fb signal is sufficient to feedback the change of the output load, if the switching cycle is still controlled by t lp , t lp changes quickly, and t lp is also affected by the output voltage V out , which may cause the loop to be unstable. Therefore, by calculating the average period of the switch S1 (or the switch S2) of the previous N cycles Make Thus, t lp The calculation is also related to the first N cycles, slowing down t. lp Despite the changes in V fb The rapid changes in the sampling signal also make the loop more stable, thereby optimizing the working performance of the DC-DC voltage converter.

[0067] Figure 5 This is a circuit diagram of an output voltage sampling unit 340 according to an embodiment of this application. Figure 5 As shown, the input terminal of the output sampling circuit unit 340 is used to connect the output voltage V. out The output terminal is used to output the feedback voltage V. fb .

[0068] The output sampling circuit unit 340 includes resistors R1 to R4, capacitor C1, a controllable voltage regulator TL, and an optocoupler device opt.

[0069] Among them, resistors R1 and R2 are used to regulate the input voltage (i.e., V). out The input voltage is divided and converted into current to drive the optocoupler (opt). Capacitor C1 and resistor R4 form the loop compensation circuit. The optocoupler (opt) is a device that uses light as a medium to transmit electrical signals; it is used to achieve sampling isolation between the primary and secondary sides of the transformer.

[0070] It should be understood that Figure 5 This is merely an example of the output voltage sampling unit 340, and not a limitation thereof; the output voltage sampling unit 340 may also be implemented using other circuit topologies.

[0071] Figure 6 This is a circuit diagram of a resonant signal sampling unit 330 according to an embodiment of this application. Figure 6 As shown, the resonant signal sampling unit 330 includes: a first sampling capacitor C S1 Second sampling capacitor C S2 Sampling resistor Rs, first sampling capacitor C S1 The first terminal is used to receive the resonant voltage V on the primary side of the transformer. cr The first sampling capacitor C S1 The second terminal is used to output the sampling reference voltage v sns The first sampling capacitor C S1 A sampling resistor Rs and a second sampling capacitor C are connected in parallel between the second terminal and ground. S2 .

[0072] It should be understood that Figure 6As an example of the resonant signal sampling unit 330, but not limited, the resonant signal sampling unit 330 can also be implemented in other circuit topologies.

[0073] Figure 7 is Figure 6 a circuit analysis schematic diagram of the resonant signal sampling unit 330 in Figure 7 As shown, if the second sampling capacitor C S2 is ignored, the first sampling capacitor C S1 and the sampling resistor Rs form a sampling circuit of the resonant current i cr The sampling reference voltage v sns can be represented by the following formula (1):

[0074]

[0075] Where Cr represents the resonant capacitance.

[0076] Figure 8 is Figure 6 a circuit analysis schematic diagram of the resonant signal sampling unit 330 in Figure 8 As shown, if the sampling resistor Rs is ignored, the first sampling capacitor C S1 and the second sampling capacitor C S2 form a sampling circuit of the resonant voltage v cr The sampling reference voltage v sns can be represented by the following formula (2):

[0077]

[0078] Figure 9 is Figure 6 a working waveform schematic diagram of the resonant signal sampling unit 330 in Figure 9 As shown, the sampling resistor Rs, the first sampling capacitor C S1 , and the second sampling capacitor C S2 combine the sampling of the resonant current i cr and the resonant voltage v cr , assuming that the first sampling capacitor C S1 is fixed, if the sampling resistor Rs takes a larger value, the resonant current i cr sampling occupies the dominant of the final sampling signal; if the second sampling capacitor C S2 takes a larger value, the resonant voltage i cr sampling occupies the dominant of the final sampling signal, so the waveform v sns of the resonant signal sampling output can be adjusted by adjusting the parameters of the resistance and capacitance.

[0079] Optionally, by adjusting the sampling resistor Rs or the second sampling capacitor CS2 the sampling reference voltage v sns the feedback resonance voltage v cr and the resonance current i cr of the sampling proportion.

[0080] In the embodiments of the present application, a comprehensive sampling circuit of the resonance current i cr and the resonance voltage v cr is introduced. The sampling resistor Rs can be used to sample the resonance current i cr , and the second sampling capacitor C S2 can be used to sample the resonance voltage v cr . By adjusting the values of Rs and C S2 , the sampling proportion of the resonance current i cr and the resonance voltage v cr can be adjusted, and the time between the zero-crossing point of different loads and the switching on and off can be adjusted. Thus, by adjusting the values of Rs and C S2 , the control point of the load point of no-load and full-load can be accurately configured, and the entry and exit points of the light-load mode are more easily adjusted, thereby improving the control efficiency.

[0081] Figure 10 is a structural schematic diagram of a DC-DC voltage conversion device 400 according to another embodiment of the present application. Unlike the DC-DC voltage conversion device 300 in Figure 3 , the DC-DC voltage conversion device 400 further comprises a zero-crossing comparison unit 350. The zero-crossing comparison unit 350 can be used to receive the sampling reference signal v sns , and output a comparison result signal cmp to the controller 320 after comparing v sns with a threshold voltage Vth. The threshold voltage Vth can be zero level. That is, the zero-crossing comparison unit 350 is used to output the comparison result cmp of v sns with zero level. The controller 320 can output the switch control signals p1 and p2 according to the comparison result cmp.

[0082] It should be understood that Figure 3 the controller 320 in can also realize the function of the zero-crossing comparison unit 350, that is, the zero-crossing comparison unit 350 can be integrated into the controller 320, or can be independent of the controller 320.

[0083] Figure 11 is a circuit schematic diagram of the zero-crossing comparison unit 350 according to an embodiment of the present application. As Figure 11 shown, the zero-crossing comparison unit 350 comprises a comparator CMP1. One input end of the comparator CMP1 is used to connect the threshold voltage Vth, and the other input end of the comparator CMP1 is used to receive the sampling reference voltage v snsThe comparator CMP1 is used to compare the sampling reference voltage v sns with the threshold voltage Vth and output the comparison result cmp.

[0084] Figure 12 is a working waveform diagram of the zero-crossing comparison unit 350 in an embodiment of the present application. As shown in the figure, when the sampling reference voltage v Figure 12 is greater than the threshold voltage Vth, the comparator CMP1 outputs a high voltage (or logic 1). When the sampling reference voltage v sns is less than the threshold voltage Vth, the comparator CMP1 outputs a low voltage (or logic 0). The threshold voltage Vth can be zero level. That is, when the sampling reference voltage v sns is greater than zero, the comparator CMP1 outputs logic 1; and when the sampling reference voltage v sns is less than zero, the comparator CMP1 outputs logic 0. sns

[0085] Figure 13 is a functional diagram of the control method implemented by the controller 320 in an embodiment of the present application. As shown in the figure, the controller 320 can include a loop calculation unit, a PWM control unit, a time counting unit, and a driving unit. The loop calculation unit is used to obtain the feedback voltage V fb and perform loop control according to the feedback voltage V fb . Specifically, the loop calculation unit generates a time length parameter t lp according to the feedback voltage V fb . The PWM control unit generates control signals pwm1 and pwm2 according to the time length parameter t lp . The driving unit is used to convert pwm1 and pwm2 into switch control signals p1 and p2 for directly driving the switches S1 and S2, and output the switch control signals to the switches S1 and S2. Figure 13 The time length parameter t lp is negatively correlated with the output voltage V out . When the output voltage V out increases, the time length parameter t lp decreases; and when the output voltage V out decreases, the time length parameter t lp increases. When the time length parameter t lp decreases, it is equivalent to increasing the on-off frequency fs of the switches S1 and S2, so as to reduce the voltage gain of the resonant conversion unit 310, thereby reducing the output voltage V out to achieve closed-loop control of the LLC loop.

[0086]

[0087] ​​Additionally, the time counting unit functions similarly to the timer mentioned earlier. It performs time counting based on the comparison result output by the zero-crossing comparison unit 350 and sends the timing length tc to the PWM control unit. This allows the PWM control unit to calculate the timing length tc and the time length parameter t. lp This generates control signals pwm1 and pwm2.

[0088] Figure 14 This is a waveform diagram of the controller 320 according to an embodiment of this application. Wherein, V SW This represents the voltage at the midpoint of the bridge arm, V. SW This represents the voltage at the midpoint of the bridge arm connecting switches S1 and S2. It should be understood that, for ease of analysis, the dead time between switches S1 and S2 is ignored in this paper. Figure 14 As shown, at time t0, controller 320 controls switch S1 to turn on, while S2 is in the off state. Next, the reference signal v is sampled. sns Starting from a negative value, as v increases... sns The moment when v rises to zero is time t1. After time t1, v sns When the value is greater than zero, the output of comparator CMP1 is high, and the time counting unit starts timing from time t1. When the timing length tc reaches the time length parameter t... lp ( Figure 14 The time ΔT1 is represented as time t2. At this time, controller 320 controls switch S1 to turn off and then controls switch S2 to turn on. When the sampled reference signal v sns The time when v begins to decrease from a positive value to zero is time t3. After time t3, v sns When the value is less than zero, the output of comparator CMP1 is low, and the time counting unit starts counting from time t3. When the counting length tc reaches the time length parameter t... lp ( Figure 14 The time t4 is represented by ΔT2. At this time, the controller 320 controls switch S2 to turn off and then controls switch S1 to turn on.

[0089] Figure 15 The diagram shows the operating waveforms of a DC-DC voltage converter according to an embodiment of this application in light load mode. Figure 16 The diagram shows the operating waveforms of a DC-DC voltage converter according to an embodiment of this application in heavy-load mode. Figure 15 and Figure 16 It can be seen that in light load mode, the time length parameter t lp The time length parameter t is relatively small, especially in heavy-load mode. lp It is relatively large. Therefore, according to t lp The magnitude of t can determine the load status, thereby controlling the switching between light load mode and heavy load mode. For example, if tlp When the threshold is less than a certain value, the DC-DC voltage conversion device can enter a light load mode.

[0090] Figure 17 A working waveform diagram of the DC-DC voltage conversion device of another embodiment of the application in a light load mode is shown. Figure 18 A working waveform diagram of the DC-DC voltage conversion device of another embodiment of the application in a heavy load mode is shown.

[0091] As shown in Figure 17 and Figure 18 , when only the sampling of the resonant current i cr is considered, t lp approaches Ts / 4 (ΔTi2 in Figure 17 ) in the case of no load, and t lp approaches Ts / 2 (ΔTi1 in Figure 18 ) in the case of full load. Wherein, Ts refers to the period length of the on-off of switches S1 and S2. When only the sampling of the resonant voltage v cr is considered, t lp approaches zero (ΔTv2 in Figure 17 ) in the case of no load, and t lp approaches Ts / 2 (ΔTv1 in Figure 18 ) in the case of full load. Therefore, the size of the zero-crossing point to the switch-off time of t sns at different loads can be adjusted by adjusting the parameters of the resistance and the capacitance in the resonant sampling circuit.

[0092] As shown in Figure 17 , in the case of no load, t lp = ΔTiv2, which is between ΔTi2 and ΔTv2. As shown in Figure 18 , in the case of full load, t lp = ΔTiv1, which is between ΔTi1 and ΔTv1. Therefore, by adjusting the size of the sampling resistance Rs and the second sampling capacitance C S2 , the value of t lp corresponding to no load and full load can be adjusted, so that the load point of the entry and exit of the light load mode can be conveniently adjusted.

[0093] In the embodiments of the application, a comprehensive sampling circuit of the resonant current i cr and the resonant voltage v cr is introduced, that is, the sampling reference voltage v sns can reflect the changes of the resonant voltage v cr and the resonant current i cr at the same time, so that the sampling reference voltage v sns and the time length parameter tlp Controlling the switching on and off of the switches in the DC-DC voltage converter enables rapid loop control, resulting in a faster dynamic response. Furthermore, by adjusting the RC parameters in the resonant signal sampling unit, the zero-crossing time under no-load and full-load conditions can be configured, allowing for accurate configuration of the control points at both load and no-load conditions. This facilitates easier adjustment of the entry and exit points for light-load modes, thereby improving control efficiency.

[0094] By adjusting the RC parameters in the resonant signal sampling unit 330, the zero-crossing time to switch off time under different loads can be easily configured, or in other words, the ratio of the zero-crossing time to switch off time to the cycle. This allows for accurate control of the load point and easy adjustment of the entry and exit points in light load mode, thereby improving control efficiency.

[0095] Figure 19 This is a functional schematic diagram of a control method implemented by controller 320 according to another embodiment of this application. Figure 19 As shown, the output of the loop calculation unit is a time ratio k. lp In addition to outputting the timing length tc, the time counting unit is also used to calculate the average period of the most recent N periods. It can be calculated according to formula (3).

[0096]

[0097] Among them, T S1 T represents the most recent first period. SN This represents the most recent Nth cycle, where N is an integer greater than 1.

[0098] Among them, the time length parameter t lp for With k lp The product of, i.e.

[0099] Figure 20 yes Figure 19 The control method shown corresponds to the operating waveform diagram. For example... Figure 20 As shown, at time t1, v sns As the value rises from negative to zero, comparator CMP1 outputs a high level, and the time counter unit begins timing tc. At time t2, tc reaches t. lp ,Right now At (time) Figure 20 In the middle, the t here lp Represented as ΔT1), controller 320 controls switch S1 to turn off and switch S2 to turn on. At time t3, v snsAs the value drops from positive to zero, comparator CMP1 outputs a high level, and the time counter unit begins timing tc. At time t4, tc reaches t. lp ,Right now At (time) Figure 20 In the middle, the t here lp (Represented as ΔT2), controller 320 controls switch S2 to turn off and control switch S1 to turn on.

[0100] exist Figure 19 and Figure 20 In the control method shown, based on the sampled reference voltage V sns The calculated switching cycles were averaged to stabilize T. S And omitting V fb The RC compensation section of the signal increases V. fb The bandwidth of the feedback loop is sufficient to respond to load changes in a timely and effective manner, thereby improving the load response rate.

[0101] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0105] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present alone, or two or more units can be integrated in one unit.

[0106] The functions, if realized in the form of software functional units and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0107] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A DC-DC voltage converter, characterized in that, include: The resonant converter unit includes a high-frequency chopper circuit, a resonant cavity, a transformer, and a rectifier filter network. The high-frequency chopper circuit includes switch S1 and switch S2. The controller is used to control the on / off state of switches S1 and S2 to control the DC voltage V input to the high-frequency chopper circuit. in The AC voltage is converted into a high-frequency square wave. The resonant cavity and the transformer are used to receive the high-frequency square wave and couple electrical energy from the primary side of the transformer to the secondary side. The rectifier filter network is used to convert the AC voltage coupled to the secondary side of the transformer into a DC voltage, which is then used as the output voltage V. out ; The resonant signal sampling unit is used to sample the resonant voltage v on the primary side of the transformer. cr and output the sampling reference voltage v sns The sampling reference voltage v sns Used to reflect the resonant voltage v on the primary side of the transformer. cr and resonant current i cr Changes; The output voltage sampling unit is used to sample the output voltage V of the resonant converter unit. out and output feedback voltage V fb ; The controller is also used for: Obtain the sampling reference voltage v sns and the feedback voltage V fb ; According to the feedback voltage V fb Obtain the time length parameter t lp ; At the sampling reference voltage v sns The first timing begins at the moment t1 when the negative value crosses zero; The first timing reaches the time length parameter t. lp After the second time t2, switch S1 is controlled to be in the off state, and then switch S2 is controlled to be in the on state. At the sampling reference voltage v sns The second timing begins after the third moment t3, when the zero point is crossed. The second timing reaches the time length parameter t. lp After the fourth time t4, switch S2 is controlled to be in the off state, and then switch S1 is controlled to be in the on state.

2. The apparatus as claimed in claim 1, characterized in that, The controller is specifically used for: For the feedback voltage V fb The proportionality constant k is obtained through calculation. lp ; According to formula t lp =T S ×k lp The time length parameter t is obtained. lp , among which, T S This represents the average period of the most recent N switching cycles of switch S1 or switch S2, where N is an integer greater than 1.

3. The apparatus as described in claim 1 or 2, characterized in that, The time length parameter t lp Meets at least one of the following conditions: The time length parameter t lp With output voltage V out There is a negative correlation; The time length parameter t lp There is a negative correlation with the magnitude of the load current.

4. The apparatus as described in claim 1 or 2, characterized in that, The resonant signal sampling unit includes: a first sampling capacitor C S1 Second sampling capacitor C S2 Sampling resistor Rs, first sampling capacitor C S1 The first terminal is used to receive the resonant voltage V on the primary side of the transformer. cr The first sampling capacitor C S1 The second terminal is used to output the sampling reference voltage v sns The first sampling capacitor C S1 The sampling resistor Rs and the second sampling capacitor C are connected in parallel between the second terminal and ground. S2 .

5. A control method for a DC-DC voltage converter, characterized in that, The DC-DC voltage conversion device includes: a resonant conversion unit, comprising a high-frequency chopper circuit, a resonant cavity, a transformer, and a rectifier filter network; the high-frequency chopper circuit includes switches S1 and S2; and a controller, used to control the on / off state of switches S1 and S2 to convert the DC voltage V input to the high-frequency chopper circuit. in The AC voltage is converted into a high-frequency square wave. The resonant cavity and the transformer are used to receive the high-frequency square wave and couple electrical energy from the primary side of the transformer to the secondary side. The rectifier filter network is used to convert the AC voltage coupled to the secondary side of the transformer into a DC voltage, which is then used as the output voltage V. out The resonant signal sampling unit is used to sample the resonant voltage v on the primary side of the transformer. cr and output the sampling reference voltage v sns The sampling reference voltage v sns Used to reflect the resonant voltage v on the primary side of the transformer. cr and resonant current i cr The change in voltage; the output voltage sampling unit is used to sample the output voltage V of the resonant converter unit. out and output feedback voltage V fb ; The method includes: The controller acquires the sampling reference voltage v sns and the feedback voltage V fb ; The controller is based on the feedback voltage V fb Obtain the time length parameter t lp ; The controller is at the sampling reference voltage v sns The first timing begins at the moment t1 when the negative value crosses zero; The controller reaches the time length parameter t at the first timing. lp After the second time t2, switch S1 is controlled to be in the off state, and then switch S2 is controlled to be in the on state. The controller is at the sampling reference voltage v sns The second timing begins after the third moment t3, when the zero point is crossed. The controller reaches the time length parameter t at the second timing. lp After the fourth time t4, switch S2 is controlled to be in the off state, and then switch S1 is controlled to be in the on state.

6. The method as described in claim 5, characterized in that, The controller responds to the feedback voltage V fb The time length parameter t is obtained through calculation. lp ,include: For the feedback voltage V fb The proportionality constant k is obtained through calculation. lp ; According to formula t lp =T S ×k lp The time length parameter t is obtained. lp , among which, T S This represents the average period of the most recent N switching cycles of switch S1 or switch S2, where N is an integer greater than 1.

7. The method as described in claim 5 or 6, characterized in that, The time length parameter t lp Meets at least one of the following conditions: The time length parameter t lp With output voltage V out There is a negative correlation; The time length parameter t lp There is a negative correlation with the magnitude of the load current.

8. The method as described in claim 5 or 6, characterized in that, The resonant signal sampling unit includes: a first sampling capacitor C S1 Second sampling capacitor C S2 Sampling resistor Rs, first sampling capacitor C S1 The first terminal is used to receive the resonant voltage V on the primary side of the transformer. cr The first sampling capacitor C S1 The second terminal is used to output the sampling reference voltage v sns The first sampling capacitor C S1 The sampling resistor Rs and the second sampling capacitor C are connected in parallel between the second terminal and ground. S2 .

9. A power supply device, characterized in that, The power supply equipment is used to supply power to the load, and the power supply equipment includes: An AC-DC voltage conversion unit is used to convert AC voltage into DC voltage. The DC-DC-DC voltage converter according to any one of claims 1 to 4 is used to receive the DC voltage output by the AC-DC voltage converter unit and perform DC voltage conversion.

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