Voltage conversion device, control method, and power supply device

Abstract

The application provides a voltage conversion device, a control method and a power supply device. The voltage conversion device comprises a control circuit. The control circuit is configured to: obtain a first sampling voltage and a second sampling voltage; determine, according to the first sampling voltage, when the voltage interval of the output voltage of the voltage conversion device changes and exceeds a voltage threshold, detect a resonance period according to the second sampling voltage; and output a driving signal according to the detected resonance period, the driving signal being used to control the on-off of a first switch tube and a second switch tube. The application can improve the conversion efficiency of the voltage conversion device under wide-range output by monitoring the change of the direct-current output voltage, adaptively detecting and updating the resonance period of the voltage conversion device, and adjusting the driving signal according to the updated resonance period.

Description

Technical Field

[0001] This application relates to the field of circuits, and more particularly to a voltage conversion device, control method, and power supply equipment. Background Technology

[0002] Voltage conversion devices such as mobile phone adapters and laptop adapters typically use DC-DC voltage converters. DC-DC voltage converters usually employ an asymmetrical half-bridge (AHB) flyback converter circuit to achieve a wide output range.

[0003] The aforementioned AHB flyback converter circuit typically includes a main power transistor, an auxiliary power transistor, a transformer, a resonant capacitor, and a resonant inductor. The parasitic capacitances of the main and auxiliary power transistors, the resonant capacitance, the resonant inductor, and the magnetizing inductance on the primary side of the transformer all resonate together. However, the parasitic capacitances of the main and auxiliary power transistors often change with variations in the output voltage. Consequently, the resonant parameters of the AHB flyback converter circuit (e.g., the resonant period) also change. Clearly, if the resonant parameters cannot be adaptively detected and updated, it will lead to improper control of the main and auxiliary power transistors, thereby affecting the conversion efficiency of the voltage converter. Summary of the Invention

[0004] In view of this, this application provides a voltage conversion device, control method, and power supply equipment that can adaptively detect and update the resonant period by monitoring changes in DC output voltage, thereby improving the conversion efficiency of the voltage conversion device under a wide output range.

[0005] In a first aspect, this application provides a voltage conversion device having a resonant period and including an asymmetric half-bridge conversion unit and a control circuit; the asymmetric half-bridge conversion unit includes a first switch and a second switch; the control circuit is used to: acquire a first sampling voltage and a second sampling voltage; when the voltage range of the output voltage of the voltage conversion device changes according to the first sampling voltage, detect the resonant period according to the second sampling voltage; and output a drive signal according to the detected resonant period, the drive signal being used to control the on / off state of the first switch and the second switch.

[0006] It is understandable that by acquiring the first and second sampled voltages, changes in the output voltage can be monitored, and the resonant period of the voltage converter can be adaptively detected and updated. Thus, by adjusting the drive signal according to the updated resonant period, the conversion efficiency of the voltage converter under a wide output range can be improved.

[0007] In conjunction with the first aspect, in one possible implementation, the control circuit includes: a sample and hold unit, a voltage grouping unit, and a control unit; the sample and hold unit is used to sample and hold a first sampled voltage and output a sampled signal; the voltage grouping unit is used to receive the sampled signal and generate a first enable signal when it determines that the voltage range in which the output voltage is located has changed based on the sampled signal; the control unit is used to determine that the voltage range in which the output voltage is located has changed based on the first enable signal.

[0008] It is understandable that by setting a sample-and-hold unit to receive the first sample signal, and by using a voltage grouping unit to group the sample signal output by the sample-and-hold unit, the sample signal can be included in different voltage ranges, thereby enabling the monitoring of changes in the output voltage of the voltage conversion device.

[0009] In conjunction with the first aspect, in one possible implementation, the control circuit includes: a threshold timing unit; the threshold timing unit is used to acquire a second sampled voltage, and when the control unit determines that the voltage range in which the output voltage is located changes, it determines the resonant period based on the second sampled voltage.

[0010] In conjunction with the first aspect, in one possible implementation, the threshold timing unit includes a comparator and a timer; the comparator is used to acquire the second sampled voltage and the reference voltage, and output a comparison signal; the timer is used to determine the resonant period based on the period of the comparison signal.

[0011] It is understandable that the change in output voltage reflects the resonant period of the voltage converter, and the second sampled voltage is used to characterize the change in output voltage. Therefore, by setting a comparator and comparing the second sampled voltage with a reference voltage, the second reference voltage is converted into a comparison signal. Then, by obtaining the signal period of the comparison signal, the period of the output voltage can be determined, thereby obtaining the resonant period of the voltage converter.

[0012] In conjunction with the first aspect, in one possible implementation, the voltage conversion device includes a first mode and a second mode. The first mode is a continuous resonant current mode, and the second mode is a discontinuous resonant current mode. The second mode includes a continuous control state and a discontinuous control state. In the discontinuous control state, both the first and second switches are in the off state. The voltage conversion device includes an output voltage acquisition unit, which receives the output voltage and outputs a feedback voltage. The control unit is used to: acquire the feedback voltage; determine whether the voltage conversion device is in the first mode or the second mode based on the feedback voltage; when it is determined that the voltage conversion device is in the first mode and the voltage range of the output voltage changes, control the first and second switches to turn off, and obtain the resonant period based on the second sampled voltage; when it is determined that the voltage conversion device is in the second mode and the voltage range of the output voltage changes, and the voltage conversion device switches from the continuous control state to the discontinuous control state, obtain the resonant period based on the second sampled voltage.

[0013] It is understandable that determining the resonant period requires the voltage conversion device to be in a free resonant state. The voltage conversion device has different operating modes. In the first mode, the first and second switches need to be turned off to allow the device to enter a free resonant state. In the second mode, the resonant period can be detected only during discontinuous control without turning off the first and second switches. By employing different strategies for resonant period detection in different modes, the detection efficiency can be improved.

[0014] In conjunction with the first aspect, in one possible implementation, the asymmetric half-bridge converter unit includes a transformer, which includes a primary winding and a secondary winding, and the second sampling voltage is the voltage across one of the primary winding and the secondary winding.

[0015] In conjunction with the first aspect, in one possible implementation, the transformer includes an auxiliary winding coupled to the primary winding, and the second sampled voltage is the voltage across the auxiliary winding.

[0016] In conjunction with the first aspect, in one possible implementation, the first sampling voltage and the second sampling voltage are the same voltage.

[0017] In conjunction with the first aspect, in one possible implementation, the asymmetric half-bridge converter unit includes a resonant capacitor; the first sampling voltage is the voltage across the resonant capacitor.

[0018] In conjunction with the first aspect, in one possible implementation, the voltage conversion device includes an isolation sampling unit for receiving an output voltage; the first sampling voltage is the voltage output by the isolation sampling unit.

[0019] It is understandable that both the first sampling voltage and the second sampling voltage are used to characterize the change in the output voltage of the voltage conversion device. Therefore, the first sampling voltage and the second sampling voltage can be the same or different, and can be the voltage on the primary winding, secondary winding or auxiliary winding, the voltage across the resonant capacitor, or the output voltage.

[0020] Secondly, this application also provides a control circuit applied to a voltage conversion device. The voltage conversion device has a resonant period and includes an asymmetric half-bridge conversion unit and a control circuit. The asymmetric half-bridge conversion unit includes a first switch and a second switch. The control circuit is used to: acquire a first sampling voltage and a second sampling voltage; when the voltage range of the output voltage of the voltage conversion device changes according to the first sampling voltage, detect the resonant period according to the second sampling voltage; and output a drive signal according to the detected resonant period, the drive signal being used to control the on / off state of the first switch and the second switch.

[0021] In conjunction with the second aspect, in one possible implementation, the control circuit includes: a sample and hold unit, a voltage grouping unit, and a control unit; the sample and hold unit is used to sample and hold a first sampled voltage and output a sampled signal; the voltage grouping unit is used to receive the sampled signal and generate a first enable signal when it determines that the voltage range in which the output voltage is located has changed based on the sampled signal; the control unit is used to determine that the voltage range in which the output voltage is located has changed based on the first enable signal.

[0022] In conjunction with the second aspect, in one possible implementation, the control circuit includes: a threshold timing unit; the threshold timing unit is used to acquire a second sampled voltage, and when the control unit determines that the voltage range in which the output voltage is located changes, it determines the resonant period based on the second sampled voltage.

[0023] In conjunction with the second aspect, in one possible implementation, the threshold timing unit includes a comparator and a timer; the comparator is used to acquire the second sampled voltage and the reference voltage, and output a comparison signal; the timer is used to determine the resonant period based on the period of the comparison signal.

[0024] In conjunction with the second aspect, in one possible implementation, the voltage conversion device includes a first mode and a second mode. The first mode is a continuous resonant current mode, and the second mode is a discontinuous resonant current mode. The second mode includes a continuous control state and a discontinuous control state. In the discontinuous control state, both the first and second switches are in the off state. The voltage conversion device includes an output voltage acquisition unit, which receives the output voltage and outputs a feedback voltage. The control unit is used to: acquire the feedback voltage; determine whether the voltage conversion device is in the first mode or the second mode based on the feedback voltage; when it is determined that the voltage conversion device is in the first mode and the voltage range of the output voltage changes, control the first and second switches to turn off, and obtain the resonant period based on the second sampled voltage; when it is determined that the voltage conversion device is in the second mode and the voltage range of the output voltage changes, and the voltage conversion device switches from the continuous control state to the discontinuous control state, obtain the resonant period based on the second sampled voltage.

[0025] Thirdly, this application also provides a control method for a voltage conversion device, the voltage conversion device having a resonant period and including an asymmetric half-bridge conversion unit and a control circuit; the asymmetric half-bridge conversion unit includes a first switch and a second switch; the method includes: acquiring a first sampling voltage and a second sampling voltage; determining, based on the first sampling voltage, when the voltage range of the output voltage of the voltage conversion device changes, obtaining the resonant period based on the second sampling voltage; and outputting a drive signal based on the resonant period, the drive signal being used to control the on / off state of the first switch and the second switch.

[0026] In conjunction with the third aspect, in one possible implementation, the method includes: sampling and holding a first sampled voltage and outputting a sampled signal; receiving the sampled signal and generating a first enable signal when it is determined, based on the sampled signal, that the voltage range in which the output voltage is located has changed; and determining, based on the first enable signal, that the voltage range in which the output voltage is located has changed.

[0027] In conjunction with the third aspect, in one possible implementation, the method includes: acquiring a second sampling voltage and a reference voltage, and outputting a comparison signal; and determining the resonant period based on the period of the comparison signal.

[0028] In conjunction with the third aspect, in one possible implementation, the voltage conversion device includes a first mode and a second mode. The first mode is a continuous resonant current mode, and the second mode is a discontinuous resonant current mode. The second mode includes a continuous control state and a discontinuous control state. In the discontinuous control state, both the first and second switches are in the off state. The voltage conversion device includes an output voltage acquisition unit, which receives the output voltage and outputs a feedback voltage. The method includes: acquiring the feedback voltage; determining whether the voltage conversion device is in the first mode or the second mode based on the feedback voltage; when it is determined that the voltage conversion device is in the first mode and the voltage range of the output voltage changes, controlling the first and second switches to turn off, and obtaining the resonant period based on the second sampled voltage; when it is determined that the voltage conversion device is in the second mode and the voltage range of the output voltage changes, and the voltage conversion device switches from the continuous control state to the discontinuous control state, obtaining the resonant period based on the second sampled voltage.

[0029] Fourthly, this application also provides a power supply device, comprising: an AC-DC voltage conversion unit for converting AC voltage into DC input voltage; and a voltage conversion device for receiving the DC input voltage output from the AC-DC voltage conversion unit and performing DC voltage conversion to output a DC output voltage; wherein the voltage conversion device has a resonant period and includes an asymmetric half-bridge conversion unit and a control circuit; the asymmetric half-bridge conversion unit includes a first switch and a second switch; the control circuit is configured to: acquire a first sampling voltage and a second sampling voltage; when the voltage range of the output voltage of the voltage conversion device changes according to the first sampling voltage, detect the resonant period according to the second sampling voltage; and output a drive signal according to the detected resonant period, the drive signal being used to control the on / off state of the first switch and the second switch.

[0030] Furthermore, the technical effects of any of the possible implementations in the second to fourth aspects can be found in the technical effects of different implementations in the first aspect, and will not be repeated here. Attached Figure Description

[0031] Figure 1A and Figure 1B This is a schematic diagram of the structure of the asymmetric half-bridge converter unit provided in the embodiments of this application.

[0032] Figure 2 This is a schematic diagram of the voltage conversion device provided in Embodiment 1 of this application.

[0033] Figure 3 for Figure 2 A schematic diagram of the output voltage levels of the voltage grouping unit in the voltage conversion device shown.

[0034] Figure 4 for Figure 2 The diagram shows the structure of the output voltage sampling unit in the voltage conversion device.

[0035] Figure 5 for Figure 2 A schematic diagram of the sample-and-hold unit in the voltage conversion device shown.

[0036] Figure 6 for Figure 2 The diagram shows a control unit module in the voltage conversion device.

[0037] Figure 7 The waveform diagram of the voltage conversion device provided in Embodiment 1 of this application when it is in the first mode.

[0038] Figure 8 The waveform diagram of the voltage conversion device provided in Embodiment 1 of this application when it is in the second mode.

[0039] Figure 9 This is a schematic diagram of the voltage conversion device provided in Embodiment 2 of this application.

[0040] Figure 10 This is a schematic diagram of the voltage conversion device provided in Embodiment 3 of this application.

[0041] Figure 11 This is a flowchart illustrating the control method of the voltage conversion device provided in the embodiments of this application.

[0042] Figure 12 This is a schematic diagram of the power supply equipment provided in an embodiment of this application. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0044] In the embodiments of this application, the voltage conversion device includes, but is not limited to, power supply equipment such as power adapters for terminal devices, industrial power supplies, aerospace power supplies, chargers, and mobile power supplies.

[0045] Voltage conversion devices typically use direct current to direct current (DC-DC) voltage converters. DC-DC voltage converters usually employ an asymmetrical half-bridge (AHB) flyback converter circuit to achieve a wide range of output.

[0046] For example, please see Figure 1AThe figure shown is a schematic diagram of the asymmetric half-bridge converter unit 100 provided in an embodiment of this application. In this embodiment, the asymmetric half-bridge converter unit 100 may be, for example, a DC-DC voltage converter, used to output a DC output voltage after the received DC input voltage is resonantly converted.

[0047] like Figure 1A As shown, the asymmetric half-bridge converter unit 100 includes an AHB flyback converter circuit 11 and a rectifier-filter circuit 12. The AHB flyback converter circuit 11 includes a first switch S1, a first switch S2, a transformer Tr, a resonant inductor Lr, and a resonant capacitor Cr. The magnetizing inductance on the primary side of the transformer Tr is represented as Lm (not shown in the figure).

[0048] The AHB flyback converter circuit 11 is used to receive the DC input voltage Vin. In the AHB flyback converter circuit 11, the first switch S1 and the second switch S2 are connected in series. In some embodiments, the first switch S1 and the second switch S2 can be field-effect transistors (FETs) made of semiconductor materials such as silicon (Si) or third-generation wide-gap semiconductor materials such as silicon carbide (SiC) or gallium nitride (GaN).

[0049] For example, the drain of the first switch S1 receives a DC input voltage Vin, the source of the first switch S1 is connected to the drain of the second switch S2, and the source of the second switch S2 is connected to ground. The gate of the first switch S1 receives a first drive signal Vgs1 from a control circuit (not shown), and the gate of the second switch S2 receives a second drive signal Vgs2 from the control circuit. The first switch S1 and the second switch S2 can be turned on or off under the drive of the first drive signal Vgs1 and the second drive signal Vgs2.

[0050] Transformer Tr includes a primary winding Np and a secondary winding Ns. The primary winding Np and secondary winding Ns of transformer Tr are coupled by a magnetic core. The primary winding Np of transformer Tr is connected in parallel between the source and drain of the second switching transistor S2 via a resonant capacitor Cr and a resonant inductor Lr. Specifically, the same-name terminal of the primary winding Np is connected to the first terminal of the resonant inductor Lr. The second terminal of the resonant inductor Lr is connected to the source of the first switching transistor S1 and the drain of the second switching transistor S2. The opposite-name terminal of the primary winding Np is connected to the first terminal of the resonant capacitor Cr, and the second terminal of the resonant capacitor Cr is connected to the source of the second switching transistor S2. The secondary winding Ns of transformer Tr, after passing through the rectifier and filter circuit 12, yields a DC output voltage Vout.

[0051] It is understood that in this embodiment, the resonant inductor Lr includes the leakage inductance of the transformer Tr and the external inductance. Of course, in other embodiments, the resonant inductor Lr can also be entirely integrated into the transformer Tr.

[0052] The rectifier and filter circuit 12 receives power from the transformer Tr in the AHB flyback converter circuit 11 and outputs a DC output voltage Vout to power the load. That is, the AHB flyback converter circuit 11 supplies power to the load via the rectifier and filter circuit 12.

[0053] In one possible implementation, the rectifier-filter circuit 12 includes a rectifier diode D1 and an output capacitor Co. The anode of the rectifier diode D1 is connected to the opposite-named terminal of the secondary winding Ns, and the cathode of the rectifier diode D1 is connected to the first terminal of the output capacitor Co. The second terminal of the output capacitor Co is connected to the same-named terminal of the secondary winding Ns.

[0054] For example, please refer to the following: Figure 1B The diagram shown is a schematic of an asymmetric half-bridge converter unit 100a provided in another embodiment of this application. Figure 1B As shown, the asymmetric half-bridge converter unit 100a includes an AHB flyback converter circuit 11a and a rectifier-filter circuit 12. The AHB flyback converter circuit 11a includes a first switch S1, a first switch S2, a transformer Tra, a resonant inductor Lr, and a resonant capacitor Cr. The rectifier-filter circuit 12 includes a rectifier diode D1 and an output capacitor Co.

[0055] Understandable, Figure 1B In the embodiment shown, the difference between the asymmetric half-bridge converter unit 100a and the asymmetric half-bridge converter unit 100 is that the connection method between the transformer Tra and the first switching transistor S1 in the AHB flyback converter circuit 11a is different.

[0056] Specifically, such as Figure 1B As shown, the primary winding Np of transformer Tra is connected in parallel between the source and drain of the first switching transistor S1 through resonant capacitor Cr and resonant inductor Lr.

[0057] Understandable, such as Figure 1A and Figure 1B The asymmetric half-bridge converter unit 100 / 100a can regulate the DC output voltage Vout by adjusting the switching frequencies of the first switch S1 and the second switch S2. Additionally, as... Figure 1A and 1BThe resonant inductance Lr of the asymmetric half-bridge converter unit 100 / 100a, the magnetizing inductance Lm of the transformer Tr, the resonant capacitor Cr, and the parasitic capacitances (not shown) of the first switch S1 and the second switch S2 will resonate together. However, as the DC output voltage Vout changes, the resonant components (such as the resonant capacitor C1 and the parasitic capacitances of the first switch S1 and the second switch S2) will change, causing changes in the resonant parameters (such as the resonant period) of the asymmetric half-bridge converter unit 100 / 100a. If the drive signals (such as Vgs1 and Vgs2) of the first switch S1 and the second switch S2 are determined based on the same resonant parameters under different output voltages, it will lead to improper control of the first switch S1 and the second switch S2, thereby affecting the voltage conversion efficiency of the asymmetric half-bridge converter unit 100 / 100a.

[0058] To address the aforementioned problems, this application provides a voltage conversion device. The voltage conversion device includes a control circuit and an asymmetric half-bridge conversion unit. The control circuit monitors changes in the output voltage of the asymmetric half-bridge conversion unit, adaptively detects and updates the resonant period of the asymmetric half-bridge conversion unit, and then adjusts the drive signal according to the updated resonant period, thereby improving the conversion efficiency of the voltage conversion device.

[0059] The circuit structure and working principle of the voltage conversion device are explained in detail below through Examples 1 to 3.

[0060] Example 1:

[0061] Please see Figure 2 The diagram shown is a structural schematic of the voltage conversion device 200 according to Embodiment 1 of this application.

[0062] like Figure 2 As shown, the voltage conversion device 200 includes an asymmetric half-bridge converter unit 210 and a control circuit 220. The asymmetric half-bridge converter unit 210 converts the received DC input voltage Vin to output a DC output voltage Vout. The asymmetric half-bridge converter unit 210 includes an AHB flyback converter circuit 211 and a rectifier-filter circuit 212. The AHB flyback converter circuit 211 couples the DC input voltage Vin from the primary side of the transformer Tr to the secondary side. The rectifier-filter circuit 212 converts the AC voltage coupled to the secondary side of the transformer Tr into a DC voltage, which is then output as the DC output voltage Vout.

[0063] It is understood that, in the embodiments of this application, the circuit structure and working principle of the asymmetric half-bridge converter unit 210 are similar to those of the other components. Figure 1A and Figure 1BThe asymmetric half-bridge converter unit 100 / 100a described herein is similar and will not be repeated here. For ease of description, the following text will use the asymmetric half-bridge converter unit 210 as an example. Figure 1A The asymmetric half-bridge transformation unit 100 in the example is used for illustration.

[0064] It is understood that, in the embodiments of this application, the control circuit 220 is used for:

[0065] Obtain the first sampling voltage Vs1 and the second sampling voltage Vs2.

[0066] It can be understood that both the first sampling voltage Vs1 and the second sampling voltage Vs2 are linearly related to the DC output voltage Vout. Therefore, the changes in the first sampling voltage Vs1 and the second sampling voltage Vs2 can characterize the changes in the DC output voltage Vout.

[0067] It is understood that, in the embodiments of this application, the control circuit 220 is also used for:

[0068] The DC output voltage Vout of the voltage conversion device 200 is determined based on the first sampling voltage Vs1; when the DC output voltage Vout changes, the resonance period is detected based on the second sampling voltage Vs2.

[0069] Specifically, the timing of resonant period detection can be determined using the first sampling voltage Vs1, and the resonant period can be detected using the second sampling voltage Vs2.

[0070] In one possible implementation, the resonant period is detected based on the second sampling voltage Vs2 when the voltage range of the DC output voltage Vout changes.

[0071] It is understood that, in the embodiments of this application, the control circuit 220 is also used for:

[0072] Based on the detected resonant period, a drive signal is output, such as a first drive signal Vgs1 and a second drive signal Vgs2, to control the switching on and off of the first switch S1 and the second switch S2.

[0073] Clearly, by acquiring the first sampled voltage Vs1 and the second sampled voltage Vs2, the control circuit 220 can monitor changes in the DC output voltage Vout of the voltage converter 200, such as monitoring the voltage range in which the DC output voltage Vout lies, and adaptively detect and update the resonant period of the voltage converter 200. Thus, by adjusting the drive signal according to the updated resonant period, the conversion efficiency of the voltage converter 200 under a wide output range can be improved.

[0074] like Figure 2As shown, the voltage conversion device 200 includes an output voltage sampling unit 230, which is connected to the rectifier filter circuit 212 and the control circuit 220. The output voltage sampling unit 230 is used to sample the DC output voltage Vout of the asymmetric half-bridge converter unit 210 and output the feedback voltage Vfb to the control circuit 220.

[0075] It can be understood that the feedback voltage Vfb is linearly related to the DC output voltage Vout, therefore the change in the feedback voltage Vfb can characterize the change in the DC output voltage Vout.

[0076] It can be understood that the voltage conversion device 200 includes two modes: a first mode and a second mode. The first mode is a continuous resonant current mode or a heavy-load mode. The second mode is a discontinuous resonant current mode or a light-load mode.

[0077] In the first mode, due to the heavy load, the first switch S1 and the second switch S2 need to be continuously and alternately turned on, that is, in a continuous waveform state, so that the voltage conversion device 200 can continuously provide the converted DC voltage to the load.

[0078] In the second mode, due to the lighter load, the first switch S1 and the second switch S2 can alternately conduct for a period of time, then simultaneously turn off for the next period of time, and then alternately conduct again for the next period of time, repeating this cycle. The period during which the first switch S1 and the second switch S2 alternately conduct is called the continuous control state, and the period during which the first switch S1 and the second switch S2 are simultaneously turned off is called the discontinuous control state. The instant when the continuous control state switches to the discontinuous control state, that is, the instant when the first switch S1 and the second switch S2 simultaneously turn off, is called the discontinuous moment.

[0079] Correspondingly, in this embodiment, the operating mode of the voltage conversion device 200 (first mode or second mode) can be determined by the feedback voltage Vfb. For example, when the feedback voltage Vfb is greater than or equal to a preset mode switching threshold, the voltage conversion device 200 is determined to be in the first mode. As another example, when the feedback voltage Vfb is less than the preset mode switching threshold, the voltage conversion device 200 is determined to be in the second mode. It can be understood that the preset mode switching threshold is a voltage value.

[0080] like Figure 2As shown, in some embodiments, the voltage conversion device 200 further includes an auxiliary winding Na, a first resistor R1, and a second resistor R2. The auxiliary winding Na is coupled to the primary winding Np of the transformer Tr through a magnetic core. The first resistor R1 and the second resistor R2 are connected in series across the two ends of the auxiliary winding Na. For example, the first end of the first resistor R1 is connected to the same-named end of the auxiliary winding Na, the first end of the second resistor R2 is connected to the second end of the second resistor R1, and the second end of the second resistor R2 is connected to the opposite-named end of the auxiliary winding Na. The connection node of the first resistor R1 and the second resistor R2 is connected to the control circuit 220 for outputting the aforementioned first sampling voltage Vs1 and second sampling voltage Vs2. That is, in the embodiments of this application, the first sampling voltage Vs1 and the second sampling voltage Vs2 are the same. Of course, based on the working principle of the transformer Tr, it is known that the voltages across the primary winding Np, the secondary winding Ns, and the auxiliary winding Na in the transformer Tr all have a certain proportional relationship with each other. Furthermore, in some embodiments, the first sampling voltage Vs1 or the second sampling voltage Vs2 can be the voltage across either winding of the transformer Tr.

[0081] As can be understood, as described above, the voltage across the auxiliary winding Na can be sampled by the control circuit 220 after being divided by the first resistor R1 and the second resistor R2. Of course, in some other embodiments, the control circuit 220 can also directly sample the voltage across the auxiliary winding Na.

[0082] like Figure 2 As shown, the control circuit 220 includes a sample and hold unit 221, a voltage grouping unit 222, a control unit 223, and a threshold timing unit 224.

[0083] The first terminal of the sample-and-hold unit 221 is connected between the first resistor R1 and the second resistor R2 to receive the first sample voltage Vs1, hold it, and then output the sample signal Vsh.

[0084] In this embodiment, the voltage grouping unit 222 can be, for example, a hysteresis comparator, and the specific structure of the voltage grouping unit 222 is not limited here. Figure 2 As shown, the first terminal of the voltage grouping unit 222 is connected to the second terminal of the sample-and-hold unit 221, and is used to receive the sampled signal Vsh and group the sampled signal Vsh to determine the level of the DC output voltage Vout. The second terminal of the voltage grouping unit 222 is connected to the control unit 223. It can be understood that the voltage grouping unit 222 is used to receive the sampled signal Vsh, and when it determines that the level of the DC output voltage Vout has changed according to the sampled signal Vsh, it generates a first enable signal CS1 to the control unit 223.

[0085] Specifically, please refer to the following: Figure 3The diagram shows the voltage grouping unit 222 determining the DC output voltage Vout level. It can be understood that in this embodiment, each DC output voltage Vout level has at least one voltage range; when the voltage range of the DC output voltage Vout changes, the voltage level switches accordingly.

[0086] For example, when the DC output voltage Vout has two voltage ranges, 5V-9V and 9V-12V, and Vout is stable at any value within the 5V-9V range, or when its fluctuation range remains consistently within the 5V-9V range, the voltage range remains unchanged, and therefore, there is no need to detect the resonant period. However, when the DC output voltage Vout changes from a value within the 5V-9V range, such as 8V, to a value within the 9V-12V range, such as 10V, the voltage range changes, and thus, resonant period detection is required. It can be understood that the DC output voltage Vout can have multiple voltage ranges, not limited to two, and the boundary values ​​of each range are not limited to the specific values ​​in the example above.

[0087] In one possible implementation, taking the voltage grouping unit 222 dividing the DC output voltage Vout into three levels as an example, the DC output voltage Vout can be divided into three levels: a high-voltage level (HIGH), a medium-voltage level (MIDDLE), and a low-voltage level (LOW). Each level has two reference voltages. For example, the high-voltage level (HIGH) has a first high-voltage reference voltage VRH1 and a second high-voltage reference voltage VRH2. The first high-voltage reference voltage VRH1 is greater than the second high-voltage reference voltage VRH2.

[0088] For example, the MIDDLE medium voltage setting has a first medium voltage reference voltage VRM1 and a second medium voltage reference voltage VRM2. The first medium voltage reference voltage VRM1 is greater than the second medium voltage reference voltage VRM2.

[0089] For example, the low-voltage range (LOW) has a first low-voltage reference voltage (VRL1) and a second low-voltage reference voltage (VRL2). The first low-voltage reference voltage (VRL1) is greater than the second low-voltage reference voltage (VRL2).

[0090] In this embodiment, VRH1 > VRH2 > VRM1 > VRM2 > VRL1 > VRL2.

[0091] It can be understood that in this embodiment, the signal received by the voltage grouping unit 222 is the sampling signal Vsh provided by the sample-and-hold unit 221. The sampling signal Vsh is proportional to the DC output voltage Vout. Thus, by judging and classifying the magnitude of the sampling signal Vsh, the range of the DC output voltage Vout can be classified. Figure 3 As illustrated, for example, when the value of the sampled signal Vsh changes from falling in the MIDDLE range to falling in the HIGH or LOW range, the voltage grouping unit 222 can determine that the range of the DC output voltage Vout of the voltage conversion device 200 has changed, and then generates a first enable signal CS1 to the control unit 223. Similarly, when the range of the DC output voltage Vout switches arbitrarily between the HIGH, MIDDLE, and LOW ranges, the voltage grouping unit 222 will generate a first enable signal CS1 and send it to the control unit 223.

[0092] I understand, please refer to it again. Figure 2 The control unit 223 is connected to the second terminal of the voltage grouping unit 222. The control unit 223 receives a first enable signal CS1 and determines that the DC output voltage Vout has changed based on the first enable signal CS1. It then controls the operation of the threshold timing unit 224 when the DC output voltage Vout changes. Thus, the control unit 223 can trigger the threshold comparison and timing function of the threshold timing unit 224 when the DC output voltage Vout of the voltage converter 200 changes range, i.e., when the voltage range of the DC output voltage Vout changes, to re-acquire the resonant period of the voltage converter 200. In other words, whenever the DC output voltage Vout of the voltage converter 200 changes range, a new resonant period can be adaptively acquired, and the resonant period of the voltage converter 200 can be updated.

[0093] It can be understood that by setting the sample-and-hold unit 221 to receive the first sample signal Vs1, and by using the voltage grouping unit 220 to group the sample signal Vsh output by the sample-and-hold unit 221, the sample signal Vsh can be included in different voltage ranges, thereby enabling the monitoring of the change in the DC output voltage Vout of the voltage conversion device 200.

[0094] The control unit 223 is also used to receive the feedback voltage Vfb output by the output voltage sampling unit 230, and determine whether the voltage conversion device 200 is in a first mode or a second mode based on the feedback voltage Vfb. As mentioned above, in the second mode, the first switch S1 and the second switch S2 have continuous control states and discontinuous control states. When the first switch S1 and the second switch S2 are in a discontinuous control state, or when switching from a continuous state to a discontinuous control state (i.e., at a discontinuous moment), the control unit 223 can generate a second enable signal. It can be understood that since the control unit 223 is also used to control the on / off state of the first switch S1 and the second switch S2, the control unit 223 can identify the continuous state and the discontinuous state, as well as the switching point between the two states (i.e., the discontinuous moment), and generate a second enable signal in the discontinuous state or at the discontinuous moment.

[0095] It is understood that the detection of the resonant period of the voltage conversion device 200 needs to be performed when the voltage conversion device 200 is in a free resonance state, that is, when both the first switch S1 and the second switch S2 are turned off. Therefore, for the first mode and the second mode, the control unit 223 uses different strategies to trigger the timing unit 224 to work in order to detect the resonant period of the voltage conversion device 200.

[0096] Specifically, in the first mode, because the output load of the voltage conversion device 200 is relatively heavy, the control unit 223 needs to continuously generate waves, that is, control the first switch S1 and the second switch S2 to alternately turn on and off at a high switching frequency. Therefore, when it is necessary to detect the resonance period, the first switch S1 and the second switch S2 need to be turned off so that the voltage conversion device 200 enters a free resonance state, so as to facilitate the detection of the resonance period.

[0097] In the second mode, since the output load of the voltage conversion device 200 is relatively light, the control unit 223 does not need to continuously generate waves. That is, the first switch S1 and the second switch S2 alternately turn on and off for a period of time (i.e., continuous control state), and are both off for the next period of time (i.e., discontinuous control state). Therefore, it is only necessary to detect the resonance period during the time when both the first switch S1 and the second switch S2 are off (i.e., discontinuous control state), without having to separately control the first switch S1 and the second switch S2 to turn off.

[0098] Correspondingly, in one possible implementation, when the control unit 223 determines that the voltage conversion device 200 is in the first mode, the control unit 223 can determine the voltage range change of the DC output voltage Vout according to the first enable signal CS1, and then control the first switch S1 and the second switch S2 to turn off, and obtain the resonance period according to the second sampling voltage Vs2.

[0099] When the control unit 223 determines that the voltage conversion device 200 is in the second mode, the control unit 223 can determine, based on the first enable signal, that the voltage range in which the DC output voltage Vout is located has changed. When the voltage range in which the DC output voltage Vout is located changes, and the voltage conversion device 200 switches from a continuous control state to a discontinuous control state, the resonant period is obtained based on the second sampled voltage Vs2. The switching of the voltage conversion device 200 from a continuous control state to a discontinuous control state is determined by the second enable signal CS2 (refer to the second sampled voltage Vs2). Figure 7 It is certain.

[0100] It is understandable that determining the resonant period requires the voltage conversion device 200 to be in a free resonant state. The voltage conversion device 200 has different operating modes (i.e., the first operating mode and the second operating mode). By employing different strategies in different modes to detect the resonant period, the detection efficiency of the resonant period can be improved.

[0101] The threshold timing unit 224 is used to acquire the second sampling voltage Vs2 and determine the resonance period based on the second sampling voltage Vs2 when the voltage range of the DC output voltage Vout changes.

[0102] Specifically, the threshold timing unit 224 includes a comparator 2241 and a timer 2242. The first input of the comparator 2241 receives a comparison voltage (i.e., the second sampled voltage Vs2). The second input of the comparator 2241 is connected to a reference voltage Vref. The comparator 2241 generates a zero-crossing comparison signal ZCD based on the comparison result between the second sampled voltage Vs2 and the reference voltage Vref. When the threshold timing unit 224 (e.g., timer 2241) receives a timing trigger signal Ttri, the timer 2242 can determine the resonant period based on the period of the zero-crossing comparison signal ZCD.

[0103] It can be understood that the change in DC output voltage Vout can reflect the resonant period of the voltage changing device 200. The second sampling voltage Vs2 is used to characterize the change in DC output voltage Vout, and the zero-crossing comparison signal ZCD is obtained based on the second sampling voltage Vs2. Therefore, the resonant period of the voltage changing device 200 can be determined by obtaining the period of the zero-crossing comparison signal ZCD.

[0104] In one possible implementation, when the second sampled voltage Vs2 reaches the reference voltage Vref, i.e., is greater than or equal to the reference voltage Vref, the zero-crossing comparison signal ZCD output by comparator 2241 shows a rising edge signal. When the second sampled voltage Vs2 is lower than the reference voltage Vref, the zero-crossing comparison signal ZCD output by comparator 2241 shows a corresponding falling edge signal.

[0105] It is understood that, as mentioned above, the second sampling voltage Vs2 can be the same as the first sampling voltage Vs1. For example, as... Figure 2 As shown, the second sampling voltage Vs2 and the first sampling voltage Vs1 are both connected between resistors R1 and R2.

[0106] In this embodiment, the reference voltage Vref is a zero voltage value. Of course, in some other embodiments, the reference voltage Vref can also be any value greater than zero or less than zero, as long as the voltage conversion device 200 is in a free resonance state during the time period of resonant period detection (i.e., the time period from the start to the end of the timer 2242).

[0107] It is understood that the detection period of the resonant period includes a first moment (e.g., the start moment) and a second moment (e.g., the end moment). In this embodiment, the timer 2242 starts timing by recognizing the rising edge signal. Specifically, when the timer 2242 recognizes the first rising edge signal, i.e., the first moment, timing is triggered. When the timer 2242 recognizes the second rising edge signal, i.e., the second moment, timing ends and the timer is reset.

[0108] The timer 2242 can determine the period of the zero-crossing comparison signal ZCD based on the first and second time points, and then determine the resonant period of the voltage conversion device 200 and generate the resonant period signal Tc. In other words, the resonant period of the voltage conversion device 200 can be obtained based on the timing time of the timer 2242 (i.e., the time period between the first and second time points).

[0109] It is understandable that the voltage conversion device 200 only detects the resonant period when the DC output voltage Vout changes position, i.e., when the voltage range of the DC output voltage Vout changes. Therefore, the timer 2242 stops working after the timing ends, meaning that it will not trigger timing when a rising edge or falling edge appears later, until the next change in the DC output voltage Vout position.

[0110] The threshold timing unit 224 can send the resonant period signal Tc to the control unit 223. The control unit 223 then adjusts the drive signal based on the updated resonant period signal Tc, namely the first drive signal Vgs1 used to control the on / off state of the first switch S1 and the second drive signal Vgs2 used to control the on / off state of the second switch S2.

[0111] It is understood that the timing of timer 2242 only needs to be performed within one complete cycle of the zero-crossing comparison signal ZCD, that is, starting timing at the beginning of one cycle and ending timing at the end of one cycle. There is no restriction on the specific start or end time of timing. In this embodiment, timer 2242 is set to rise-edge triggering; in other embodiments, timer 2242 can also be set to fall-edge triggering. Specifically, timer 2242 can trigger timing when the first falling edge signal is detected, i.e., at the first moment. When timer 2242 detects the second falling edge, i.e., at the second moment, timing ends and resets. It is understood that in some other implementations, the time between the first rising edge signal and the first falling edge signal can be detected, and twice that time can be used as the period or resonant period of the zero-crossing comparison signal ZCD. Alternatively, twice the time between the detected first falling edge signal and the first rising edge signal can be used as the period or resonant period of the zero-crossing comparison signal ZCD.

[0112] Clearly, the control unit 223 can determine whether the voltage converter 200 is in the first mode or the second mode by using the feedback voltage Vfb output by the output voltage sampling unit 230. The sample-and-hold unit 222 and the voltage grouping unit 222 can determine whether the voltage range of the output voltage of the voltage converter 200 has changed based on the first sampled voltage Vs1. The control unit 223 uses different strategies in different modes to trigger the threshold timing unit 224 to determine the resonant period based on the second sampled voltage Vs2. Adjusting the drive signal according to the determined resonant period can improve the conversion efficiency of the voltage converter 200 under a wide output range.

[0113] In one possible implementation, the control unit 223 is further configured to generate an update completion signal Tf after receiving the resonant period signal Tc and send it to the voltage grouping unit 222. Upon receiving the update completion signal Tf, the voltage grouping unit 222 pulls down the first enable signal CS1, changing it from a high-level state to a low-level state. After the first enable signal CS1 is pulled down or changes to a low-level state, the control unit 223 pulls down the update completion signal Tf, changing it from a high-level state to a low-level state. After the update completion signal Tf changes to a low-level state, the control unit 223 adjusts the drive signal according to the resonant period signal, so that the first switch S1 and the second switch S2 continue to alternately conduct based on the adjusted drive signal.

[0114] It is understandable that the update completion signal Tf is used to indicate that the control unit 223 has received the resonant period signal Tc. The introduction of the update completion signal Tf enables the first enable signal CS1 to be reset (i.e., become low level), so that when the DC output voltage Vout level changes again, the first enable signal CS1 (becomes high level) can be generated again for identification.

[0115] Optionally, the control circuit 220 in this embodiment can be integrated into a single chip.

[0116] Please refer to the following: Figure 4 The diagram shown is a circuit schematic of the output voltage sampling unit 230 according to an embodiment of this application. Figure 4 As shown, the input terminal of the output sampling circuit unit 230 is used to receive the DC output voltage Vout, and the output terminal is used to output the feedback voltage Vfb.

[0117] The output voltage sampling unit 230 includes resistors R3-R6, capacitor C1, a controllable voltage regulator TL, and an optocoupler. The first terminals of resistors R3 and R5 are connected to receive the DC output voltage Vout. The second terminal of resistor R3 is connected to the first terminal of resistor R4, and the second terminal of resistor R4 is connected to the anode of the controllable voltage regulator TL, and both are connected to ground (GND). The reference terminal of the controllable voltage regulator TL is connected to the node between resistors R3 and R4. The cathode of the controllable voltage regulator TL is connected to the first input terminal of the optocoupler, and the second input terminal of the optocoupler is connected to the second terminal of resistor R5. The first output terminal of the optocoupler is used to output the feedback voltage Vfb, and the second output terminal of the optocoupler is connected to ground (GND). The first terminal of capacitor C1 is connected to the node between resistors R3 and R4, and the second terminal of capacitor C1 is connected to the first terminal of resistor R6. The second terminal of resistor R6 is connected to the node between the first input terminal of the optocoupler and the cathode of the controllable voltage regulator TL.

[0118] Resistors R3 and R4 are used to divide the DC output voltage Vout, and the controllable voltage regulator TL is used to convert the DC input voltage Vout into the current driving the optocoupler device opt. Capacitor C1 and resistor R6 form the loop compensation circuit. The optocoupler device 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 Tr.

[0119] It should be understood that Figure 4 This is merely an example of the output voltage sampling unit 230, and not a limitation thereof; the output voltage sampling unit 230 may also be implemented using other circuits.

[0120] Please refer to the following: Figure 5The diagram shows a sample-and-hold unit 221 provided in an embodiment of this application. The sample-and-hold unit 221 includes a voltage boosting circuit LS, a voltage buffer, a transmission gate TGsh, a holding resistor Rsh, and a holding capacitor Csh. The first terminal of the voltage boosting circuit LS is connected to the node between resistors R1 and R2, used to boost the first sampled voltage Vs1 to a positive voltage. The first terminal of the voltage buffer is connected to the second terminal of the voltage boosting circuit LS, used to improve the driving capability of the boosted voltage. The first terminal of the transmission gate TGsh is connected to the second terminal of the voltage buffer, the second terminal of the transmission gate TGsh is connected to the first terminal of the holding resistor Rsh, and the second terminal of the holding resistor Rsh is connected to the voltage grouping unit 222, used to output the sampled signal Vsh. The first terminal of the holding capacitor Csh is connected to the second terminal of the holding resistor Rsh, and the second terminal of the holding capacitor Csh is grounded.

[0121] The third terminal of the transmission gate TGsh is used to receive the second driving signal Vgs2. The transmission gate TGsh can be turned on and off under the drive of the second driving signal Vgs2. In one possible implementation, when the second driving signal Vgs2 is high, the second switch S2 is turned on. At this time, the sample-and-hold unit 221 is in the sampling stage, the transmission gate TGsh is closed, the circuit of the sample-and-hold unit 221 is turned on, the voltage output of the buffer charges the sampling capacitor Csh, and the output sampling signal Vsh always follows the first sampling voltage Vs1 at the input. When the second driving signal Vgs2 is low, the second switch S2 is turned off. At this time, the sample-and-hold unit 221 is in the holding stage, and the output sampling signal Vsh is held at the voltage value at the moment the circuit is turned off.

[0122] In this embodiment, the sampling signal Vsh can be obtained by formula (1). Where Vsh is the sampling signal, Na represents the number of turns in the auxiliary winding, Ns represents the number of turns in the secondary winding, Vout is the DC output voltage, and V... LS is the bias voltage of the voltage boost circuit LS, and k is the proportional coefficient.

[0123]

[0124] It should be understood that Figure 5 This is merely an example of sample-and-hold unit 221, and not a limitation; sample-and-hold unit 221 can also be implemented using other circuits.

[0125] Please refer to the following: Figure 6 The diagram shown is a schematic of the control unit 223 provided in an embodiment of this application. The control unit 223 includes: a first drive module 2231, a second drive module 2232, a mode confirmation module 2233, a signal generation module 2234, and a timing trigger module 2235.

[0126] The first driving module 2231 is connected to the gate of the first switching transistor S1 and is used to provide the first driving signal V. GS1 This controls the first switching transistor S1 to be turned on or off.

[0127] The second drive module 2232 is connected to the gate of the second switch S2 and is used to provide the second drive signal V. GS2 This is to control the second switch S2 to turn on or off.

[0128] The mode confirmation module 2233 is connected to the output voltage sampling unit 230 to receive the feedback voltage Vfb. The mode confirmation module 2233 is used to confirm whether the voltage conversion device 200 is currently in the first mode or the second mode based on the feedback voltage Vfb.

[0129] The signal generation module 2234 is connected to the first drive module 2231, the second drive module 2232, and the mode confirmation module 2233. When the voltage converter 200 is in the second mode, the signal generation module 2234 further confirms whether the voltage converter 200 is in a discontinuous control state or a continuous control state based on the first drive signal Vgs1 and the second drive signal Vgs2 output by the first drive module 2231 and the second drive module 2232. When confirming the switching of the voltage converter 200 from a continuous control state to a discontinuous control state (i.e., at a discontinuous moment) or when it is in a discontinuous control state, the signal generation module 2234 can generate the second enable signal CS2. In other words, when the voltage converter 200 is in the second mode and at a discontinuous moment or in a discontinuous control state, the signal generation module 2234 can generate the second enable signal CS2.

[0130] The timing trigger module 2235 is connected to the signal generation module 2234. When the mode confirmation module 2233 determines that the voltage conversion device 200 is in the first mode, the timing trigger module 2235 generates a trigger signal Ttri based on the first enable signal CS1 generated by the voltage grouping unit 222. When the mode confirmation module 2233 determines that the voltage conversion device 200 is in the second mode, the timing trigger module 2235 generates the trigger signal Ttri based on the first enable signal CS1 and the second enable signal CS2 generated by the signal generation module 2234. When the threshold timing unit 114 receives the trigger signal Ttri, it activates the threshold comparison function and the timing function.

[0131] In one possible implementation, the signal generation module 2234 is further configured to generate an update completion signal Tf after acquiring the resonant period signal Tc. The update completion signal Tf can be sent to the voltage grouping unit 222. After receiving the update completion signal Tf being set high, i.e., changing from a low level to a high level, the voltage grouping unit 222 can reset the first enable signal CS1.

[0132] It is understood that in some other implementations, the second enable signal CS2 and the update completion signal Tf can be implemented by different modules. That is, the signal generation module 2234 is only used to generate the second enable signal CS2, while the update completion signal Tf is implemented by other modules (not shown).

[0133] Please refer to the following: Figure 7 . Figure 7 The diagram shows the operating waveforms of the voltage conversion device 200 in its first mode. The operating principle of the voltage conversion device 200 in the first mode is as follows:

[0134] Between t0 and t1, due to the heavy load on the voltage conversion device 200 in the first mode, the first switch S1 and the second switch S2 need to continuously generate signals. Therefore, the first drive signal Vgs1 and the second drive signal Vgs2 need to continuously and alternately switch between high and low levels. That is, when the first drive signal Vgs1 switches from high to low, the second drive signal Vgs2 switches from low to high; when the second drive signal Vgs2 switches from high to low again, the first drive signal Vgs1 switches from low to high again.

[0135] At time t1, when the DC output voltage Vout of the voltage conversion device 200 switches, the first enable signal CS1 generated by the voltage grouping unit 222 is pulled high and output to the timing trigger module 2235.

[0136] Between times t1 and t2, the first drive module 2231 and the second drive module 2232 of the control unit 223 respectively control the first switch S1 and the second switch S2 to turn off. Thus, the voltage converter 200 begins to enter a free resonance state. The timing trigger module 2235, combining the signal from the mode confirmation mode 2233 indicating that the voltage converter 200 is in the first mode and the pulled-up first enable signal CS1, generates a trigger signal Ttri and sends it to the threshold timing unit 224. The timer 2242 waits for the rising edge signal of the comparator 2241 to begin timing.

[0137] At time t2, the second sampled voltage Vs2 is greater than or equal to the reference voltage Vref, and the zero-crossing comparison signal ZCD generated by comparator 2241 shows a rising edge. Timer 2242 starts counting.

[0138] From time t2 to t3, timer 2242 continues to keep time.

[0139] At time t3, the zero-crossing comparison signal ZCD generated by comparator 2241 rises again, timer 2242 ends timing, the resonant period is obtained based on the timing time, and the resonant period signal Tc containing the resonant period is transmitted to control unit 223.

[0140] Between times t3 and t4, after obtaining the resonant period signal Tc, the control unit 223 updates the resonant period of the voltage conversion device 200.

[0141] At time t4, the resonant period is updated.

[0142] Between t4 and t5, the control unit 223 generates an update completion signal Tf and sends it to the voltage grouping unit 222.

[0143] At time t5, the update completion signal Tf is pulled high.

[0144] Between t5 and t6, after the voltage grouping unit 222 receives the update completion signal Tf being set high, it resets the first enable signal CS1.

[0145] At time t6, the first enable signal CS1 is reset, i.e., pulled low.

[0146] Between t6 and t7, after the first enable signal CS1 is pulled low and reset, the control unit 223 resumes the conduction of the first switch S1 and the second switch S2.

[0147] At time t7, the update completion signal Tf is pulled low. After the update completion signal Tf goes low, the control unit 223 adjusts the drive signal (V) according to the resonant period signal. GS1 and V GS2 This allows the first switch S1 and the second switch S2 to continue to conduct alternately based on the adjusted switch drive signal.

[0148] Figure 8 The diagram shows the operating waveforms of the voltage converter 200 in its second mode. The operating principle of the voltage converter 200 in the second mode is as follows:

[0149] Between time t0 and t1, after the first driving signal Vgs1 and the second driving signal Vgs2 alternately switch between high and low levels for a period of time, that is, after the voltage conversion device 200 is in continuous control state, the first driving signal Vgs1 and the second driving signal Vgs2 will be in low level state for a period of time, that is, in discontinuous control state for a period of time.

[0150] It is understandable that during this period of discontinuous control, both the first switch S1 and the second switch S2 are in the off state. The voltage conversion device 200 is already in a free resonance state at this time. Therefore, the control unit 223 does not need to perform a separate shutdown operation to detect the resonance period in the second mode.

[0151] At time t1, when the DC output voltage Vout of the voltage conversion device 200 switches, the first enable signal CS1 generated by the voltage grouping unit 222 is pulled high and output to the timing trigger module 2235.

[0152] Between times t1 and t2, the control unit 223, such as the timing trigger module 2235, continuously identifies the high and low states of the second enable signal CS2. If the second enable signal CS2 is low, the control unit 223 waits for the second enable signal CS2 to become high.

[0153] At time t2, the second enable signal CS2 reaches a high level, and the timing trigger module 2235 generates a trigger signal Ttri and sends it to the threshold timing unit 224.

[0154] Understandably, in the second mode, since both the first switch S1 and the second switch S2 are in the off state for a period of time, the control unit 223, such as the signal generation module 2234, only needs to wait in the discontinuous control state, such as the discontinuous moment, i.e., time t2, which is the moment when the continuous control state begins to switch to the discontinuous control state, to generate the second enable signal CS2, so that the timing trigger module 2235 can trigger the timing by sending the trigger signal Ttri to the threshold timing unit 224.

[0155] Between times t2 and t3, after receiving the trigger signal Ttri generated by the timing trigger module 2235, the threshold timing unit 2242 waits for the rising edge signal of the comparator 2241 to start timing. At time t3, the second sampled voltage Vs2 is greater than or equal to the reference voltage Vref, and the zero-crossing comparison signal ZCD generated by the comparator 2241 shows a rising edge. The timer 2242 then starts timing.

[0156] From time t3 to t4, timer 2242 continues to count. At time t4, the zero-crossing comparison signal ZCD generated by comparator 2241 rises again, timer 2242 stops counting, the resonant period is obtained based on the counting time, and the resonant period signal Tc containing the resonant period is transmitted to control unit 223.

[0157] Between t4 and t5, after obtaining the resonant period signal Tc, the control unit 223 updates the resonant period of the voltage conversion device 200.

[0158] At time t5, the resonant period update is complete.

[0159] Between t5 and t6, the control unit 223 generates an update completion signal Tf and sends it to the voltage grouping unit 222.

[0160] At time t6, the update completion signal Tf is pulled high.

[0161] Between t6 and t7, after the voltage grouping unit 222 receives the update completion signal Tf being set high, it resets the first enable signal CS1.

[0162] At time t7, the first enable signal CS1 is reset, i.e., pulled low.

[0163] Between t7 and t8, after the first enable signal CS1 is pulled low and reset, the control unit 223 resets and updates the signal Tf.

[0164] Between times t8 and t9, after the update completion signal Tf is pulled low and reset, the control unit 223 waits for the discontinuous control state to end.

[0165] At time t9, the discontinuous control state ends, the second enable signal CS2 is pulled low, and the first drive signal VGS1 and the second drive signal VGS2 continue to alternately switch between high and low levels.

[0166] Example 2:

[0167] Please see Figure 9 The diagram shown is a schematic of the voltage conversion device 200a provided in Embodiment 2 of this application. In this embodiment, the voltage conversion device 200a includes an asymmetric half-bridge conversion unit 210, a control circuit 220, and an output voltage sampling unit 230. The control circuit 210 includes a sample-and-hold unit 221, a voltage grouping unit 222, a control unit 223, and a threshold timing unit 224. The threshold timing unit 224 includes a comparator 2241 and a timer 2242.

[0168] It is understood that in Embodiment 2, the structures of the asymmetric half-bridge converter 210, the control circuit 220 and the output voltage sampling unit 230, the sample and hold unit 221, the voltage grouping unit 222, the control unit 223 and the threshold timing unit 224 are basically the same as those in Embodiment 1. The only difference is that the first sampling voltage Vs1 and the second sampling voltage Vs2 are not the same.

[0169] Correspondingly, for the second sampled voltage Vs2, comparator 2241 is still connected to the node between resistors R1 and R2 to obtain the second sampled voltage Vs2. For the first sampled voltage Vs1, voltage conversion device 200a includes sampling resistors R7 and R8. Sampling resistors R7 and R8 are connected in parallel across the resonant capacitor Cr. The input terminal of sample-and-hold unit 221 is connected between sampling resistors R7 and R8. It can be understood that the voltage across the resonant capacitor Cr can be sampled by sample-and-hold unit 221 after being divided by sampling resistors R7 and R8 to obtain the first sampled voltage Vs1.

[0170] It is understandable that there is a certain proportional relationship between the voltage across the resonant capacitor Cr and the DC input voltage Vout. Therefore, acquiring the voltage across the resonant capacitor Cr can achieve the same effect as acquiring the voltage across the auxiliary winding Na.

[0171] Example 3:

[0172] Please see Figure 10 The diagram shown is a schematic of a voltage conversion device 200b provided in Embodiment 3 of this application. In this embodiment, the voltage conversion device 200b includes an asymmetric half-bridge conversion unit 210, a control circuit 220, and an output voltage sampling unit 230. The control circuit 210 includes a sample and hold unit 221, a voltage grouping unit 222, a control unit 223, and a threshold timing unit 224. The threshold timing unit 224 includes a comparator 2241 and a timer 2242.

[0173] It is understood that in Embodiment 3, the structures of the asymmetric half-bridge converter 210, the control circuit 220 and the output voltage sampling unit 230, the sample and hold unit 221, the voltage grouping unit 222, the control unit 223 and the threshold timing unit 224 are basically the same as those in Embodiment 1. The only difference is that the first sampling voltage Vs1 and the second sampling voltage Vs2 are not the same.

[0174] Correspondingly, for the second sampled voltage Vs2, comparator 2241 is still connected to the node between resistor R1 and resistor R2 to obtain the second sampled voltage Vs2.

[0175] For the first sampled voltage Vs1, the voltage conversion device 200b includes an isolation sampling unit 240. One end of the isolation sampling unit 240 is connected to the output terminal of the asymmetric half-bridge converter 210 to receive the DC output voltage Vout and convert the DC output voltage Vout into the first sampled voltage Vs1. The input terminal of the sample-and-hold unit 221 is connected to the other end of the isolation sampling unit 240 to receive the first sampled voltage Vs1.

[0176] In Embodiment 3, the structure of the isolation sampling unit 240 is not limited; for example, it can adopt the same structure as the output voltage sampling unit 230.

[0177] It is understandable that directly acquiring the DC output voltage Vout and obtaining the first sampling voltage Vs1 through the isolation sampling unit 240 can achieve the same effect as acquiring the voltage across the auxiliary winding Na.

[0178] Example 4:

[0179] Please see Figure 11 This application also provides a control method for a voltage conversion device, applicable to the voltage conversion devices 200 / 200a / 200b described above. For ease of description, the control method is described as applicable to... Figure 2 The voltage conversion device 200 shown is used as an example for illustration. Figure 11 As shown, the control method for the voltage conversion device includes:

[0180] S111, the control circuit 220 acquires the first sampling voltage Vs1 and the second sampling voltage Vs2.

[0181] Understandable, such as Figure 2 As shown, the control circuit 220 can obtain the first sampling voltage Vs1 and the second sampling voltage Vs2 through the auxiliary winding Na, the first resistor R1 and the second resistor R2. For its specific working principle, please refer to [reference needed]. Figure 2 The details and related descriptions will not be repeated here.

[0182] S112, the control circuit 220 determines whether the voltage range of the DC output voltage Vout of the voltage-side conversion device 200 has changed based on the first sampling voltage Vs1.

[0183] It is understandable that the control circuit 220 determines when it is necessary to detect the resonant period of the voltage conversion device 200 based on the first sampled voltage Vs1. For a detailed description, please refer to [link / reference needed]. Figure 2 The details and related descriptions will not be repeated here.

[0184] S113, when the voltage range of the DC output voltage Vout changes, the control circuit 220 detects the resonance period according to the second sampling voltage Vs2.

[0185] It is understandable that when it is necessary to detect the resonant period of the voltage conversion device 200, the control circuit 220 can detect and obtain the resonant period through the second sampling voltage Vs2. For details, please refer to [link / reference needed]. Figure 2 The details and related descriptions will not be repeated here.

[0186] S114 outputs a drive signal based on the detected resonant period. The drive signal is used to control the on / off state of the first and second switching transistors.

[0187] It is understandable that by monitoring the changes in the DC output voltage Vout, adaptively detecting and updating the resonant period of the voltage converter 200 / 200a / 200b, and then adjusting the drive signal according to the updated resonant period, the conversion efficiency of the voltage converter 200 / 200a / 200b under a wide output range can be improved.

[0188] Example 5:

[0189] Please see Figure 12 The diagram shown is a structural schematic of the power supply device 300 provided in Embodiment 5 of this application. The power supply device 300 can supply power to the load 400. The load 400 may include, but is not limited to, personal computers, mobile phones, computers, television screens, etc.

[0190] In one possible implementation, the power supply device 300 is an AC-DC (alternating current to direct current) conversion system. The power supply device 300 includes an AC-DC conversion unit 310 and a DC-DC voltage conversion device 320. The AC-DC conversion unit 310 converts AC voltage to DC voltage and outputs it to the voltage conversion device 320. It is understood that the voltage conversion device 320 in this embodiment can be any one of the voltage conversion devices 200 / 200a / 200b in the above embodiments, and will not be described further here.

[0191] In another possible implementation, the power supply device 300 can also be a DC-DC conversion system. Correspondingly, the power supply device 300 includes a DC-DC voltage converter 320 for converting a DC input voltage into a DC output voltage.

[0192] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A voltage conversion device, the voltage conversion device having a resonant period and including an asymmetric half-bridge conversion unit and a control circuit; the asymmetric half-bridge conversion unit includes a transformer, a first switching transistor, a second switching transistor, and a resonant capacitor; the transformer includes at least one winding, a first terminal of the first switching transistor receives a DC input voltage, a second terminal of the first switching transistor is connected to the first terminal of the second switching transistor, a third terminal of the first switching transistor is connected to the control circuit, a second terminal of the second switching transistor is grounded, and a third terminal of the second switching transistor is connected to the control circuit, characterized in that, The control circuit is used for: A first sampling voltage and a second sampling voltage are obtained. The first sampling voltage is the voltage across the resonant capacitor, and the second sampling voltage is the voltage across one of the windings. The first sampling voltage is linearly related to the output voltage of the voltage conversion device, and the second sampling voltage represents the change in the output voltage of the voltage conversion device. The change in the output voltage of the voltage conversion device represents the resonant period. When the voltage range of the output voltage of the voltage conversion device is determined to be changing based on the first sampling voltage, the resonance period is detected based on the second sampling voltage. and Based on the detected resonance period, a drive signal is output to the third terminal of the first switch and the second switch, and the drive signal is used to control the on and off of the first switch and the second switch.

2. The voltage conversion device as described in claim 1, characterized in that, The control circuit includes: a sample and hold unit, a voltage grouping unit, and a control unit; The sample-and-hold unit is used to sample and hold the first sampled voltage and output a sampled signal; The voltage grouping unit is used to receive the sampling signal and generate a first enable signal when the voltage range in which the output voltage is located changes, based on the sampling signal. The control unit is used to determine, based on the first enable signal, that the voltage range in which the output voltage is located has changed.

3. The voltage conversion device as described in claim 2, characterized in that, The control circuit includes a threshold timing unit; the threshold timing unit is used to acquire the second sampled voltage, and when the control unit determines that the voltage range in which the output voltage is located changes, it determines the resonance period based on the second sampled voltage.

4. The voltage conversion device as described in claim 3, characterized in that, The threshold timing unit includes a comparator and a timer; The comparator is used to acquire the second sampled voltage and the reference voltage, and output a comparison signal; The timer is used to determine the resonant period based on the period of the comparison signal.

5. The voltage conversion device as described in claim 2, characterized in that, The voltage conversion device includes a first mode and a second mode. The first mode is a continuous resonant current mode, and the second mode is a discontinuous resonant current mode. The second mode includes a continuous control state and a discontinuous control state. In the discontinuous control state, both the first and second switching transistors are in the off state. The voltage conversion device includes an output voltage acquisition unit, which is used to receive the output voltage and output a feedback voltage. The control unit is used for: Obtain the feedback voltage; The voltage conversion device is determined to be in the first mode or the second mode based on the feedback voltage; When it is determined that the voltage conversion device is in the first mode and the voltage range in which the output voltage is located changes, the first switch and the second switch are controlled to be turned off, and the resonance period is obtained according to the second sampled voltage; When it is determined that the voltage conversion device is in the second mode and the voltage range in which the output voltage is located changes, and the voltage conversion device switches from the continuous control state to the discontinuous control state, the resonance period is obtained according to the second sampled voltage.

6. The voltage conversion device as described in claim 1, characterized in that, The transformer includes a primary winding and a secondary winding, and the second sampling voltage is the voltage across one of the primary winding and the secondary winding.

7. The voltage conversion device as described in claim 6, characterized in that, The transformer includes an auxiliary winding coupled to the primary winding, and the second sampling voltage is the voltage across the auxiliary winding.

8. The voltage conversion device as described in claim 6 or 7, characterized in that, The first sampling voltage and the second sampling voltage are the same voltage.

9. The voltage conversion device as described in claim 6 or 7, characterized in that, The voltage conversion device includes an isolation sampling unit, which is used to receive the output voltage; the first sampling voltage is the voltage output by the isolation sampling unit.

10. A control method for a voltage conversion device, the voltage conversion device having a resonant period and including an asymmetric half-bridge conversion unit and a control circuit; the asymmetric half-bridge conversion unit includes a transformer, a first switching transistor, a second switching transistor, and a resonant capacitor; the transformer includes at least one winding, a first terminal of the first switching transistor receives a DC input voltage, a second terminal of the first switching transistor is connected to the first terminal of the second switching transistor, a third terminal of the first switching transistor is connected to the control circuit, a second terminal of the second switching transistor is grounded, and a third terminal of the second switching transistor is connected to the control circuit, characterized in that... The method includes: A first sampling voltage and a second sampling voltage are obtained. The first sampling voltage is the voltage across the resonant capacitor, and the second sampling voltage is the voltage across one of the windings. The first sampling voltage is linearly related to the output voltage of the voltage conversion device, and the second sampling voltage represents the change in the output voltage of the voltage conversion device. The change in the output voltage of the voltage conversion device represents the resonant period. When determining the voltage range of the output voltage of the voltage conversion device based on the first sampling voltage, the resonant period is detected based on the second sampling voltage; and Based on the detected resonance period, a drive signal is output to the third terminal of the first switch and the second switch, and the drive signal is used to control the on and off of the first switch and the second switch.

11. The method as described in claim 10, characterized in that, The method includes: Sample and hold the first sampled voltage, and output the sampled signal; Upon receiving the sampling signal and determining, based on the sampling signal, that the voltage range in which the output voltage falls changes, a first enable signal is generated; and The voltage range in which the output voltage is located is determined to have changed based on the first enable signal.

12. The method as described in claim 11, characterized in that, The method includes: Acquire the second sampled voltage and the reference voltage, and output a comparison signal; and The resonant period is determined based on the period of the comparison signal.

13. The method as described in claim 11, characterized in that, The voltage conversion device includes a first mode and a second mode. The first mode is a continuous resonant current mode, and the second mode is a discontinuous resonant current mode. The second mode includes a continuous control state and a discontinuous control state. In the discontinuous control state, both the first switch and the second switch are in the off state. The voltage conversion device includes an output voltage acquisition unit, which receives the output voltage and outputs a feedback voltage; the method includes: Obtain the feedback voltage; The voltage conversion device is determined to be in the first mode or the second mode based on the feedback voltage; When it is determined that the voltage conversion device is in the first mode and the voltage range in which the output voltage is located changes, the first switch and the second switch are controlled to be turned off, and the resonance period is obtained according to the second sampled voltage; When it is determined that the voltage conversion device is in the second mode and the voltage range in which the output voltage is located changes, and the voltage conversion device switches from the continuous control state to the discontinuous control state, the resonance period is obtained according to the second sampled voltage.

14. A power supply device, characterized in that, The power supply equipment includes: An AC-DC voltage conversion unit is used to convert AC voltage into DC input voltage; and A voltage conversion device is used to receive the DC input voltage output by the AC-DC voltage conversion unit, and output a DC output voltage after DC voltage conversion; The voltage conversion device has a resonant period and includes an asymmetric half-bridge conversion unit and a control circuit. The asymmetric half-bridge conversion unit includes a transformer, a first switch, a second switch, and a resonant capacitor. The transformer includes at least one winding. The first terminal of the first switch receives a DC input voltage. The second terminal of the first switch is connected to the first terminal of the second switch. The third terminal of the first switch is connected to the control circuit. The second terminal of the second switch is grounded. The third terminal of the second switch is connected to the control circuit. The control circuit is used to: acquire a first sampling voltage and a second sampling voltage, wherein the first sampling voltage is the voltage across the resonant capacitor, and the second sampling voltage is the voltage across one of the windings. The first sampling voltage is linearly related to the output voltage of the voltage conversion device, and the second sampling voltage characterizes the change in the output voltage of the voltage conversion device, which characterizes the resonant period. When the voltage range of the output voltage of the voltage conversion device is determined based on the first sampling voltage, the resonant period is detected based on the second sampling voltage. And based on the detected resonant period, a drive signal is output to the third terminals of the first and second switches, the drive signal being used to control the switching on and off of the first and second switches.

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