Adaptive driving method and apparatus for switching power supply, and switching power supply

Abstract

An adaptive driving method and apparatus for a switching power supply, and a switching power supply, relating to the technical field of power electronics. In this solution, a plurality of operating parameters of a switching power supply under a current operating condition are acquired; a target rise time corresponding to the current operating condition is determined on the basis of the plurality of operating parameters; and a driving voltage of a power switch is controlled to rise from an initial value to a preset turn-on value within the target rise time, so as to turn on the power switch. Hence, in the present invention, by acquiring the plurality of operating parameters under the current operating condition, determining the target rise time, and controlling the turn-on of the power switch, precise control of the power switch of the switching power supply is achieved, and thus a balance between device temperature rise and secondary-side stress under all operating conditions can be achieved, thereby prolonging the service life of the switching power supply and improving the reliability and stability thereof.

Description

An adaptive driving method, apparatus, and switching power supply for a switching power supply.

[0001] This application claims priority to Chinese Patent Application No. 202411572096.9, filed on November 5, 2024, entitled "An Adaptive Driving Method, Apparatus and Switching Power Supply for a Switching Power Supply", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of power electronics technology, and in particular to an adaptive driving method, apparatus and switching power supply for a switching power supply. Background Technology

[0003] The secondary rectifier circuit of a switching power supply converts the AC voltage generated by the transformer into a DC voltage on the secondary side. However, when the rectifier diodes operate, the secondary inductor generates electromagnetic induction, causing instability in the current waveform and producing a reverse voltage spike, Vspike. Vspike is a major factor affecting the voltage stress on the secondary rectifier diodes. If Vspike is too high, it leads to increased switching losses in the rectifier diodes and a surge in reverse recovery current, thus affecting device efficiency and lifespan. However, reducing Vspike generally results in a rapid increase in the surface temperature of the power devices, meaning that there is often a trade-off between addressing these two issues.

[0004] The main solution for traditional silicon (Si) devices is to reduce the turn-on speed of the power switch and reduce Vspike by increasing the series gate resistor, thereby reducing the voltage stress on the rectifier.

[0005] Compared to traditional silicon (Si) devices, gallium nitride (GaN) power semiconductor devices have the advantages of greater temperature tolerance and are more suitable for high power density and high frequency applications. However, they also have dynamic on-resistance caused by current collapse effect. During use, due to the characteristics of its dynamic on-resistance, the resistance may increase, resulting in additional power consumption and severe temperature rise of the device, thereby affecting the device efficiency and lifespan.

[0006] Furthermore, AC-DC systems typically operate under complex conditions, such as wide input voltage range, wide output voltage range, and multiple operating modes. Especially given the dynamic on-resistance of gallium nitride (GaN) power semiconductors, simply adding a series gate resistor as a fixed driving method makes it even more difficult to balance the aforementioned rectifier voltage stress and power device temperature rise under different environmental conditions.

[0007] In summary, providing a driving method to achieve a balance between device temperature rise and secondary side stress under all operating conditions is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide an adaptive driving method, device, and power supply for a switching power supply. By acquiring multiple operating parameters under the current operating conditions, determining the target rise time, and controlling the power switch to turn on, precise control of the power switch of the switching power supply can be achieved. This can balance the temperature rise of the device and the secondary side stress under all operating conditions, thereby extending the service life of the switching power supply and improving its reliability and stability.

[0009] To address the aforementioned technical problems, this invention provides an adaptive driving method for a switching power supply, comprising:

[0010] Obtain multiple operating parameters of the switching power supply under the current operating conditions;

[0011] Based on the multiple operating parameters, select the target rise time required for the power switch to turn on according to the current operating condition;

[0012] The driving voltage of the power switch is controlled to rise from an initial value to a preset conduction value within the target rise time, so as to turn on the power switch.

[0013] Preferably, the power switch is a gallium nitride power switch.

[0014] Preferably, the preset conduction value is the threshold voltage of the power switch.

[0015] Preferably, the operating parameters include at least the input voltage of the switching power supply and / or the load value connected to the switching power supply.

[0016] Preferably, determining the target rise time corresponding to the current operating condition based on multiple operating parameters includes:

[0017] Determine whether the input voltage of the switching power supply is less than the preset input voltage;

[0018] If it is less than the preset input voltage, then the target rise time is selected as the first rise time;

[0019] If it is not less than the preset input voltage, then the target rise time is selected as the second rise time;

[0020] Wherein, the first rise time is less than the second rise time.

[0021] Preferably, before selecting the target rise time as the second rise time, the method further includes:

[0022] Determine whether the load value connected to the switching power supply is greater than a preset load threshold;

[0023] If it exceeds the preset load threshold, then the target rise time is selected as the second rise time;

[0024] If it is not greater than the preset load threshold, then the target rise time is selected as the third rise time;

[0025] Wherein, the first rise time < the second rise time < the third rise time.

[0026] Preferably, the switching power supply includes a voltage divider circuit, the input terminal of which is connected to the output terminal of the auxiliary winding of the switching power supply. When the operating parameters include the input voltage, the input voltage of the switching power supply is obtained as follows:

[0027] The input voltage of the switching power supply is determined by collecting the voltage of the voltage divider circuit.

[0028] Preferably, the voltage divider circuit is a resistor voltage divider circuit or a winding voltage divider circuit.

[0029] Preferably, when the operating parameters include the load value connected to the switching power supply, the load value connected to the switching power supply is obtained in the following way:

[0030] Obtain the output power of the switching power supply, and determine the load value of the switching power supply based on the output power.

[0031] Preferably, obtaining the output power of the switching power supply includes:

[0032] Obtain the feedback voltage output from the feedback pin of the switching power supply, and determine the output power of the switching power supply based on the feedback voltage.

[0033] Preferably, obtaining the output power of the switching power supply includes:

[0034] Determine the number of valleys in the resonant waveform corresponding to the conduction phase of the primary-side power switch, and determine the output power based on the number of valleys.

[0035] Preferably, obtaining the output power of the switching power supply includes:

[0036] Obtain the output current on the primary side of the switching power supply, and determine the output power based on the output current.

[0037] Preferably, the switching power supply includes a driving circuit, which includes a driving capacitor, a first driving switch, and a second driving switch. The first terminal of the driving capacitor is grounded, and the second terminal of the driving capacitor is connected to the control terminal of the first driving switch. The first terminal of the first driving switch is connected to the power supply, and the second terminal of the first driving switch is connected to the control terminal of the power switch and the first terminal of the second driving switch, respectively. The second terminal of the second driving switch is grounded.

[0038] Controlling the drive voltage of the power switch to rise from its initial value to a preset on-time value within the target rise time includes:

[0039] By charging and discharging the driving capacitor, the voltage of the driving capacitor is adjusted so that the voltage of the driving capacitor rises from the initial value to the first voltage value within the target rise time, thereby turning on the first driving switch.

[0040] When the voltage of the driving capacitor reaches the first voltage value, the second driving switch is turned off, and when the voltage at the control terminal of the power switch reaches the preset conduction value, the power switch is turned on.

[0041] To solve the above-mentioned technical problems, the present invention provides an adaptive drive device for switching power supplies, comprising:

[0042] The detection circuit is used to acquire multiple operating parameters of the switching power supply under the current operating conditions.

[0043] An adjustment circuit is used to select, based on multiple operating parameters, the target rise time required for the power switch to turn on according to the current operating condition;

[0044] A driving circuit is used to control the driving voltage of the power switch to rise from an initial value to a preset conduction value within the target rise time, so as to turn on the power switch.

[0045] Preferably, the driving circuit includes a driving capacitor, a first driving switch, and a second driving switch. The first end of the driving capacitor is grounded, and the second end of the driving capacitor is connected to the control terminal of the first driving switch. The first end of the first driving switch is connected to a power supply, and the second end of the first driving switch is connected to the control terminal of the power switch and the first end of the second driving switch, respectively. The second end of the second driving switch is grounded, and the conduction state of the first driving switch is opposite to the conduction state of the second driving switch.

[0046] The driving circuit is specifically used to control the voltage of the driving capacitor to rise from the initial value to the first voltage value within the target rise time.

[0047] When the voltage of the driving capacitor reaches the first voltage value, the first driving switch is turned on and the second driving switch is turned off. When the voltage at the control terminal of the power switch reaches the preset turn-on value, the power switch is turned on.

[0048] Preferably, the driving circuit further includes:

[0049] A charging regulation circuit, one end of which is connected to the second end of the driving capacitor, and the other end of which is connected to the adjustment circuit;

[0050] The charging regulation circuit is used to adjust its own working state according to the target rise time selected by the adjustment circuit, so as to provide a target charging current for the driving capacitor, so that the voltage of the driving capacitor reaches the first voltage value within the target rise time.

[0051] The target charging current is negatively correlated with the target rise time.

[0052] Preferably, the charging regulation circuit includes:

[0053] A switching circuit, N constant current sources and M auxiliary capacitors, where N≥1, M≥0, N+M≥2, and N and M are both integers;

[0054] The first terminal of the switching circuit is connected to all the constant current sources, the second terminal of the switching circuit is connected to all the auxiliary capacitors, and the third terminal of the switching circuit is connected to the second terminal of the driving capacitor.

[0055] The constant current source is used to provide a constant current;

[0056] The switching circuit is used to adjust its own path state according to the target rise time, so as to select a first target number of constant current sources and a second target number of auxiliary capacitors to be connected to the circuit, so that the first target number of constant current sources charges the driving capacitor and the second target number of auxiliary capacitors.

[0057] The number of the first target is at least 1, the number of the second target is at least 0, the number of the first target is negatively correlated with the target rise time, and the number of the second target is positively correlated with the target rise time.

[0058] Preferably, when N > 1 and M = 0, the switching circuit includes:

[0059] Main switch, first switch circuit;

[0060] One end of the first switching circuit is connected to the output terminals of the n constant current sources, and the other end of the first switching circuit is connected to the output terminals of the other constant current sources besides the n constant current sources and one end of the main switch. The other end of the main switch is connected to the second terminal of the driving capacitor and the control terminal of the first driving switch. The control terminal of the first switching circuit is connected to the adjustment circuit; N > n ≥ 1, where n is an integer.

[0061] The main switch is used to turn on when charging the drive capacitor;

[0062] The first switching circuit is used to adjust its own path state to select a third number of constant current sources to be connected to the circuit, where the number of the first target - the number of the third target = Nn.

[0063] Preferably, when N=1 and M>0, the switching circuit includes:

[0064] Main switch and second switch circuit;

[0065] One end of the main switch is connected to all the constant current sources, one end of the second switch circuit is connected to the first end of the m auxiliary capacitors, and the other end of the second switch circuit is connected to the first end of the other auxiliary capacitors (excluding the m auxiliary capacitors), the other end of the main switch, the second end of the driving capacitor, and the control end of the first driving switch. The second end of all the auxiliary capacitors is grounded, and the second end of the second switch circuit is connected to the adjustment circuit. M ≥ m > 0, where m is an integer.

[0066] The main switch is used to turn on when charging the drive capacitor;

[0067] The second switching circuit is used to adjust its own circuit state to select the auxiliary capacitors of the fourth target number to be connected to the circuit, where the second target number minus the fourth target number equals Mm.

[0068] Preferably, when N > 1 and M > 0, the switching circuit includes:

[0069] Main switch, first switch circuit, and second switch circuit;

[0070] One end of the first switching circuit is connected to the output terminals of the n constant current sources. The other end of the first switching circuit is connected to the output terminals of the other constant current sources besides the n constant current sources and one end of the main switch. The other end of the main switch is connected to the first terminal of the second switching circuit, the first terminal of the other auxiliary capacitors besides the m auxiliary capacitors, the second terminal of the driving capacitor, and the control terminal of the first driving switch. The other end of the second switching circuit is connected to the m auxiliary capacitors. The second terminals of all the auxiliary capacitors are grounded. The control terminals of the first switching circuit and the second switching circuit are both connected to the adjustment circuit; N > n ≥ 1, M ≥ m > 0, where m and n are integers.

[0071] The main switch is used to turn on when charging the drive capacitor;

[0072] The first switching circuit is used to adjust its own path state to select a third number of constant current sources to be connected to the circuit, where the number of the first target - the number of the third target = Nn;

[0073] The second switching circuit is used to adjust its own circuit state to select the auxiliary capacitors of the fourth target number to be connected to the circuit, where the second target number minus the fourth target number equals Mm.

[0074] Preferably, the first switching circuit includes:

[0075] There are n controllable switches, each corresponding to one of the n constant current sources. Each controllable switch is located between the output terminal of its corresponding constant current source and one end of the main switch. The control terminal of each controllable switch is connected to the adjustment circuit.

[0076] The driving circuit also includes:

[0077] A control circuit is connected to at least one of n controllable switches, the control circuit including a first comparator, a second comparator, a NAND gate, and an OR gate;

[0078] Wherein, the positive input terminal of the first comparator receives a first comparison voltage value, the negative input terminal of the first comparator and the positive input terminal of the second comparator receive the preset conduction value, the negative input terminal of the second comparator receives a second comparison voltage value, the output terminals of the first comparator and the second comparator are respectively connected to the two input terminals of the NAND gate, the output terminal of the NAND gate is connected to the first input terminal of the OR gate, the second input terminal of the OR gate is connected to the adjustment circuit, and the output terminal of the OR gate is connected to the control terminal of at least one controllable switch.

[0079] The first comparison voltage value is greater than the second comparison voltage value.

[0080] Preferably, the second switching circuit includes:

[0081] The m sub-switch circuits, m third clamping circuits, and m resistors correspond one-to-one with each of the m sub-switch circuits, m third clamping circuits, m resistors, and m auxiliary capacitors.

[0082] The first terminal of each sub-switch circuit is connected to the first terminal of the auxiliary capacitor corresponding to itself, the first terminal of the third clamping circuit corresponding to itself, and the first terminal of the resistor corresponding to itself. The second terminal of each auxiliary capacitor and the second terminal of each third clamping circuit are grounded. The second terminal of each resistor is input with a preset clamping voltage. The control terminal of each sub-switch circuit is connected to the adjustment circuit.

[0083] Preferably, the driving circuit further includes:

[0084] NOT gate, third drive switch, first clamping circuit, second clamping circuit and PWM output module;

[0085] The first output terminal of the PWM output module is connected to the input terminal of the NOT gate and the control terminal of the third drive switch, respectively. The output terminal of the NOT gate is connected to the control terminal of the main switch. The first terminal of the third drive switch is connected to the first terminal of the first clamping circuit, the first terminal of the second clamping circuit, the second terminal of the drive capacitor, and the control terminal of the first drive switch, respectively. The second terminal of the third drive switch, the second terminal of the first clamping circuit, and the second terminal of the second clamping circuit are all grounded. The second output terminal of the PWM output module is connected to the control terminal of the second drive switch.

[0086] The two output terminals of the PWM output module output signal levels that are opposite.

[0087] To address the aforementioned technical problems, the present invention provides a switching power supply, including the switching power supply adaptive drive device as described above.

[0088] This invention provides an adaptive driving method, apparatus, and power supply for a switching power supply, relating to the field of power electronics technology. In this solution, multiple operating parameters of the switching power supply under the current operating condition are acquired; a target rise time corresponding to the current operating condition is determined based on these parameters; and the driving voltage of the power switch is controlled to rise from its initial value to a preset conduction value within the target rise time, thereby turning on the power switch. It is evident that by acquiring multiple operating parameters under the current operating condition, determining the target rise time, and controlling the power switch to turn it on, this invention achieves precise control of the power switch in the switching power supply. This balance between device temperature rise and secondary-side stress can be achieved under all operating conditions, thereby extending the service life of the switching power supply and improving its reliability and stability. Attached Figure Description

[0089] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0090] Figure 1 is a circuit block diagram of a switching power supply provided by the present invention;

[0091] Figure 2 is a schematic diagram of voltage stress in a secondary rectifier tube provided by the present invention;

[0092] Figure 3 is a schematic diagram of conduction in QR mode provided by the present invention;

[0093] Figure 4 is a schematic diagram of a Vspike with peak conduction provided by the present invention;

[0094] Figure 5 is a schematic diagram of a Vspike when conducting in a trough according to the present invention;

[0095] Figure 6 is a flowchart illustrating a switching power supply driving method provided by the present invention;

[0096] Figure 7 is a schematic diagram of the drive rise time of the power switch provided by the present invention;

[0097] Figure 8 is an internal schematic diagram of a primary-side controller provided by the present invention;

[0098] Figure 9 is a schematic diagram of a switching circuit that adjusts only the number of constant current sources provided by the present invention;

[0099] Figure 10 is a schematic diagram of a switching circuit that adjusts only the number of auxiliary capacitors provided by the present invention;

[0100] Figure 11 is a schematic diagram of a switching circuit that simultaneously adjusts the number of constant current sources and auxiliary capacitors provided by the present invention;

[0101] Figure 12 is a schematic diagram of another switching circuit provided by the present invention that simultaneously adjusts the number of constant current sources and auxiliary capacitors;

[0102] Figure 13 is a timing diagram of each device in the driving module provided by the present invention;

[0103] Figure 14 is a schematic diagram of the circuit and signal timing of the Non-Overlap module provided by the present invention;

[0104] Figure 15 is a circuit diagram of the Level-Shift module provided by the present invention;

[0105] Figure 16 is a circuit diagram of the Clamp module provided by the present invention;

[0106] Figure 17 is a schematic diagram of an implementation method of the Line Sense module provided by the present invention;

[0107] Figure 18 is a schematic diagram of another implementation method of the Line Sense module provided by the present invention;

[0108] Figure 19 is a schematic diagram of an implementation method of Load Sense provided by the present invention;

[0109] Figure 20 is a schematic diagram of another implementation of Load Sense provided by the present invention;

[0110] Figure 21 is a schematic diagram of the dynamic resistance of gallium nitride provided by the present invention;

[0111] Figure 22 is a schematic diagram of the effect of gate resistor on dynamic resistance provided by the present invention. Detailed Implementation

[0112] The core of this invention is to provide an adaptive driving method, device, and power supply for a switching power supply. By acquiring multiple operating parameters under the current operating conditions, determining the target rise time, and controlling the power switch to turn on, precise control of the power switch of the switching power supply can be achieved. This can balance the temperature rise of the device and the secondary side stress under all operating conditions, thereby extending the service life of the switching power supply and improving its reliability and stability.

[0113] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0114] Before describing the present invention, the principle of the switching power supply will be explained first. As shown in Figure 1, which is a circuit block diagram of a switching power supply provided by the present invention, the switching power supply mainly includes a rectifier bridge DB for converting AC power to DC power, an input capacitor Cbulk for smoothing rectified voltage fluctuations, a switch for controlling the primary-side power switch Qp, a primary-side controller for realizing the change of the transformer magnetic field, the primary-side power switch Qp, a transformer, a secondary-side rectifier for transmitting output power to the output capacitor Cout and finally providing it to the load, and an output capacitor Cout. The secondary-side rectifier can be a Schottky diode or a MOSFET, which is not limited here by the present invention.

[0115] As shown in Figure 2, which is a schematic diagram of the voltage stress of the secondary rectifier diode provided by the present invention, the secondary voltage stress of the secondary rectifier diode during the operation of the switching power supply is: Vds=Vout+Ns / Np×Vin+Vspike, where Np is the number of turns on the primary side of the transformer, Ns is the number of turns on the secondary side of the transformer, Vout is the output voltage, Vin is the input voltage, and Vspike is the reverse voltage spike of the rectifier diode (caused by the resonance of the transformer through the secondary leakage inductance, the equivalent capacitance of the rectifier diode, and the secondary stray capacitance under the influence of the rectifier diode's dv / dt (the rate of change of voltage between the transformer and the rectifier diode) and the diode's reverse recovery current (only in continuous mode)). If the voltage stress of the secondary rectifier diode is too high, it will lead to: a) a sharp increase in the switching loss of the rectifier diode, an increase in device temperature rise, and a decrease in efficiency; b) a surge in the reverse recovery current of the rectifier diode, an increase in loss, and a decrease in efficiency; c) the use of a rectifier diode with a higher withstand voltage to meet the derating specifications, which increases the cost.

[0116] In traditional silicon device design practices, the turn-on speed of the primary-side MOS is typically slowed down by increasing the series gate resistor. A slower turn-on speed results in a slower drop in the primary-side drain voltage, thus reducing the voltage change rate at the transformer-rectifier junction and minimizing Vspike. However, gallium nitride (GaN) power semiconductor devices, due to their material properties, can operate at faster switching frequencies and have greater temperature tolerance, making them more suitable for high-frequency, high-power-density applications. As shown in Figure 21, which is a schematic diagram of the dynamic resistance of gallium nitride according to this invention, the high drain-source voltage in the off-state of gallium nitride leads to an increase in dynamic resistance.

[0117] However, a series of new problems also exist in its practical applications, among which the current collapse effect has the greatest impact. This effect manifests as dynamic on-resistance in specific device parameters. As shown in Figure 22, Figure 22 is a schematic diagram of the influence of gate resistance on dynamic resistance provided by the present invention. The dynamic resistance of GaN is not monotonic with the switching frequency. The switching frequency design mainly considers the system size / power. The highest switching frequency of most USB PD power supplies on the market is designed at 100KHz to 120KHz. Increasing the duty cycle is beneficial to reducing the dynamic resistance of GaN, but the maximum duty cycle design is constrained by a variety of factors (primary-side stress, secondary-side stress, operating mode), and the duty cycle is related to the operating conditions, leaving little room for adjustment. In applications, it is generally recommended to use a GaN drive voltage of 5 to 6V, which ensures that the drive voltage is much greater than the threshold voltage and avoids gate breakdown. The larger the gate series resistance, the longer the drive rise time during turn-on, and the larger the GaN dynamic resistance. Therefore, the method of slowing down the turn-on speed of the primary-side power switch by connecting the gate resistance in series is not suitable for GaN. In other words, due to the dynamic resistance of GaN, if an AC-DC system has complex operating conditions (wide input voltage range, wide output voltage range, multiple operating modes), it is difficult to achieve a balance between device temperature rise and secondary side stress under all operating conditions through a simple driving method (selecting only the series gate resistor).

[0118] Figure 3 shows a schematic diagram of the conduction in QR mode provided by this invention. Specifically, the QR (Quasi-Resonant) mode utilizes the valley of the resonant waveform to conduct the primary-side power switch, thereby reducing Vds at the moment the power device is turned on. Under heavy load conditions, it typically conducts at the first few valleys, significantly reducing Vds. Under light load conditions, due to the attenuation of the resonant waveform, the Vds corresponding to subsequent valleys increase. For power supplies with a wide output voltage range, the Vds corresponding to all valleys are relatively high at low output voltages because the amplitude of the resonant waveform decreases. Therefore, for high input voltage or high output voltage conditions, the system is suitable for using QR mode, where the power transistor conducts at the valley of the resonant waveform, effectively reducing switching losses. Under low input voltage and low output voltage conditions, the system is suitable for using CCM (Continuous Current Mode), where the switching frequency is highest under heavy load conditions, effectively reducing transformer current stress.

[0119] As shown in Figure 4, Figure 4 is a schematic diagram of Vspike when the peak is turned on, provided by the present invention. In DCM (Discontinuous Conduction Mode), if the primary GaN is turned on at the peak of the primary resonant waveform, the voltage difference ΔV between the transformer and the rectifier tube before and after the turn-on is the largest (ΔV=Ns / Np×Vin+Vout). At this time, the voltage change rate of the rectifier tube is the largest, and Vspike is the largest.

[0120] As shown in Figure 5, Figure 5 is a schematic diagram of Vspike when the device is turned on in the trough, provided by the present invention. Under heavy load in QR mode, the primary GaN turns on at the bottom of the (first few) primary resonant waveforms. The voltage difference ΔV between the transformer and the rectifier tube is the smallest before and after the turn-on (ΔV=Ns / Np×Vin-Vout). At this time, the voltage change rate of the rectifier tube is the smallest, and Vspike is the smallest.

[0121] Under light load, the amplitude of the resonant waveform decays. When the primary GaN is turned on, the voltage difference ΔV between the transformer and the rectifier diode terminals rises to Ns / Np×Vin before and after turn-on. At this time, the voltage change rate of the rectifier diode is moderate, and Vspike is moderate (as shown in Figure 2). At this point, the turn-on speed of the primary GaN can be slowed down to reduce the voltage change rate of the rectifier diode again and minimize Vspike.

[0122] Under CCM, due to the dynamic resistance effect of GaN, the turn-on speed of the primary GaN needs to be accelerated. When the primary GaN is turned on, the voltage difference ΔV between the transformer and the rectifier diode terminals before and after turn-on is the largest (ΔV=Ns / Np×Vin+Vout); at this time, the voltage change rate of the rectifier diode is the largest, and the di / dt during the reverse recovery current drop time will also generate a voltage on the secondary leakage inductance (including stray inductance). The maximum value of the superimposed Vspike is to reduce Vds, so it is necessary to avoid the system operating in CCM under high Vin conditions.

[0123] In the existing technology, there is only one driving waveform for controlling gallium nitride. Correspondingly, there is only a single rise time when gallium nitride is turned on. Even if the rise time can be adjusted by changing the external series resistor during the design, it is impossible to set different rise times according to different operating conditions, and the secondary voltage stress and device temperature stress cannot be balanced.

[0124] To address the aforementioned technical problems, the design concept of the switching power supply driving method provided by this invention lies in controlling the conduction time of the power switch by real-time monitoring and analysis of the operating parameters of the switching power supply and setting a target rise time, thereby optimizing the system's circuit design and operating efficiency. The technical principle is that by controlling the conduction time of the power switch, the reverse voltage spike generated by the secondary inductor can be effectively reduced, thereby decreasing the device stress and switching losses of the rectifier diode, while simultaneously improving the system's response speed and stability.

[0125] As shown in Figure 6, Figure 6 is a schematic flowchart of a switching power supply driving method provided by the present invention, the method comprising:

[0126] S11: Obtain multiple operating parameters of the switching power supply under the current operating conditions;

[0127] Specifically, the operating parameters of a switching power supply are fundamental to ensuring its stable operation and reflect its current operating condition. Based on the concept of multi-parameter control, by acquiring multiple operating parameters of the switching power supply under its current condition, we can more accurately understand its current operating status. This allows us to determine the power supply's operating state and the requirements for achieving the target output waveform, thus enabling further control over the power supply's turn-on and turn-off times.

[0128] It should be noted that several key operating parameters of the switching power supply under current operating conditions, such as input voltage, output voltage, output current, power factor, and load, can be obtained through sensors or monitoring systems. This data can be acquired in real-time.

[0129] In a preferred embodiment, the operating parameters include at least the input voltage of the switching power supply and / or the load value connected to the switching power supply. The input voltage directly affects the setting of the drive voltage. In a switching power supply, the drive voltage needs to be within a specific range to ensure the power switch conducts normally. Changes in the input voltage will lead to adjustments in the required drive voltage to ensure that the power switch can provide sufficient current when turned on, thus affecting the output power. If the input voltage is low, a longer rise time may be required for the drive voltage to reach the preset value; conversely, if the input voltage is high, the rise time may be shortened, thereby accelerating the turn-on speed of the power switch.

[0130] The load value determines the current that the power switch needs to handle. Changes in the load will cause changes in the power supply's output power, which in turn affects the switch's drive requirements. For example, when the load is heavy, the power switch needs more current to meet the load's demands, which may lead to higher requirements for the drive voltage and a longer rise time. Conversely, under light load conditions, the current required for the power switch to turn on is relatively small, thus shortening the target rise time and improving the system's response speed.

[0131] It is evident that the input voltage and load value indirectly determine the target rise time by influencing the setting of the drive voltage and the conduction requirements of the power switch, thus playing a crucial role in the operation of the switching power supply. Therefore, by acquiring these operating parameters in real time, the drive voltage of the power switch can be dynamically adjusted according to actual operating conditions, ensuring optimal conduction performance under different input voltage and load conditions, thereby improving the overall efficiency and reliability of the switching power supply.

[0132] S12: Select the target rise time required for the power switch to turn on according to multiple operating parameters and the current operating condition;

[0133] Specifically, the target rise time is a crucial operating parameter of a switching power supply, affecting its stability, safety, and efficiency. By determining the target rise time corresponding to the current operating condition, the operating state of the switching power supply can be controlled more accurately, thereby improving its performance and efficiency.

[0134] Specifically, after determining multiple operating parameters under the current operating condition, this step determines the target rise time corresponding to the current operating condition based on these parameters. This target rise time is derived based on the control requirements of the switching power supply and the system response speed. Generally speaking, in practical applications, to ensure the stability and reliability of the system, this target rise time can be adjusted within a certain range according to actual needs.

[0135] By determining the target rise time corresponding to the current operating conditions in this step, the working state of the switching power supply can be controlled more precisely, improving performance and efficiency, while also effectively reducing energy consumption and saving energy.

[0136] S13: Controls the drive voltage of the power switch to rise from its initial value to a preset turn-on value within a target rise time, so as to turn on the power switch.

[0137] The key to this step lies in dynamically adjusting the rise time of the drive voltage to adapt to different operating conditions and environments, thereby effectively controlling the temperature rise of power devices while ensuring voltage stress on the power switch. Specifically, the power switch is one of the important components of a switching power supply. By controlling the conduction time, the output voltage and output current of the switching power supply can be rapidly increased, thus ensuring stable operation of the switching power supply under different operating conditions. Adjusting the speed at which the drive voltage of the power switch reaches the threshold voltage can improve the voltage stress on the secondary rectifier diode and the temperature rise of the primary power switch.

[0138] By controlling the power switch in the switching power supply to turn on within the target rise time, the reverse voltage spike generated by the secondary inductor can be effectively reduced, and the device stress of the power switch can be reduced, thereby improving the system efficiency and lifespan.

[0139] As a preferred embodiment, the power switch is a gallium nitride (GaN) power switch. This choice is based on the significant advantages of GaN power semiconductor devices in high-temperature and high-frequency applications, while also taking into account their unique challenges in dynamic on-resistance characteristics. GaN power switches offer higher electron mobility and lower on-resistance, making them excellent for high-frequency and high-power-density applications. However, the dynamic on-resistance characteristics of GaN devices can lead to increased resistance during switching, resulting in additional power consumption and temperature rise. This characteristic is particularly pronounced under complex operating conditions, such as wide input voltage ranges, wide output voltage ranges, and multiple operating modes.

[0140] In a preferred embodiment, the preset conduction value is the threshold voltage of the power switch. Specifically, the threshold voltage of the power switch refers to the minimum voltage at which the switching device begins to conduct under specific conditions, enabling the switch to conduct normally. Gallium nitride (GaN) power switches have low on-resistance and high efficiency, but their conduction characteristics depend on the magnitude of the input voltage. When the drive voltage is below the threshold voltage, the power switch cannot fully conduct, which may lead to unstable switch operation or increased losses. When the drive voltage reaches and is maintained above the threshold voltage, the power switch will be in the conducting state, allowing current to flow smoothly, thereby effectively controlling the power output. Therefore, in this driving method, setting the preset conduction value to the threshold voltage ensures that the power switch can operate reliably under various operating conditions, achieving efficient power conversion and stable power supply performance.

[0141] In summary, the switching power supply driving method provided by this invention achieves precise control of the power switch by acquiring multiple operating parameters under the current operating conditions, determining the target rise time, and controlling the power switch conduction. The switching power supply can achieve a balance between device temperature rise and secondary-side stress under all operating conditions, avoiding voltage stress problems caused by excessive voltage spikes and effectively controlling the temperature rise of the power devices, thereby improving the overall efficiency and reliability of the system. This adaptive driving method is not only applicable to traditional silicon (Si) devices but also particularly suitable for gallium nitride (GaN) power semiconductor devices with dynamic on-resistance characteristics, enabling superior performance under complex operating conditions.

[0142] Based on the above embodiments:

[0143] As a preferred embodiment, determining the target rise time corresponding to the current operating condition based on multiple operating parameters includes: determining whether the input voltage of the switching power supply is less than a preset input voltage; if it is less than the preset input voltage, then selecting the target rise time as the first rise time; if it is not less than the preset input voltage, then selecting the target rise time as the second rise time; wherein, the first rise time < the second rise time.

[0144] Specifically, rise time control is crucial in the operation of a switching power supply. If the rise time is too long, the power switch temperature will rise, affecting the stability and reliability of the circuit; if the rise time is too short, the secondary rectifier diode voltage stress will be high, affecting the reliability of the switching power supply. Therefore, determining a reasonable target rise time based on the current operating conditions is an important issue in switching power supply design.

[0145] To address this technical problem, this embodiment provides a method for determining a target rise time based on the current operating conditions. The specific process is as follows: The current operating conditions are determined based on multiple operating parameters; based on the current operating conditions, the relationship between the input voltage and a preset input voltage is determined; based on this relationship, the target rise time is determined to be either a first rise time or a second rise time, to control the conduction of the power switch. The first rise time is shorter and suitable for cases with lower input voltages; the second rise time is longer and suitable for cases with higher input voltages.

[0146] In other words, the core of this embodiment is to select an appropriate rise time based on the magnitude of the input voltage during the power switch conduction process. By setting different first and second rise times, the rise time can be dynamically adjusted according to the input voltage level. A shorter first rise time is selected when the input voltage is low to reduce the temperature rise of the power switch; a longer second rise time is selected when the input voltage is high to reduce the voltage stress on the secondary rectifier diode. This strategy allows the system to respond flexibly to current operating conditions, improving the overall power supply's operating efficiency and reliability, while effectively extending the equipment's lifespan. By controlling the time it takes for the power switch's drive voltage to reach the threshold voltage (i.e., the target rise time), Vspike can be precisely adjusted, further optimizing circuit performance.

[0147] Specifically, the operating characteristic curves of a switching power supply can be obtained by measuring parameters such as output voltage, input current, and power switch on-time under different input voltages. Based on these curves, a reasonable target rise time under different input voltages can be determined to ensure output voltage stability. The specific implementation method is described below.

[0148] The specific implementation method in this embodiment is as follows: First, the current operating condition is determined based on multiple operating parameters. For example, the current operating condition can be determined based on the input voltage. Next, it is determined whether the input voltage is less than a preset input voltage. If it is less than the preset input voltage, the first rise time is selected as the target rise time, that is, the driving voltage rises to the preset conduction value relatively quickly from the initial value to ensure that the power switch turns on as soon as possible; if it is not less than the preset input voltage, the second rise time is selected as the target rise time, that is, the driving voltage rises to the preset conduction value relatively slowly from the initial value. It should be noted that the first rise time should be less than the second rise time to ensure that the switching power supply can avoid overstressing the power devices under different operating conditions.

[0149] In summary, the method for determining the target rise time based on the current operating conditions provided in this embodiment can avoid overstressing of power devices under different operating conditions by selecting different rise times. This not only optimizes the performance of the switching power supply but also improves the operating efficiency and safety of the circuit.

[0150] In a preferred embodiment, before selecting the target rise time as the second rise time, the method further includes: determining whether the load value connected to the switching power supply is greater than a preset load threshold; if it is greater than the preset load threshold, then selecting the target rise time as the second rise time; if it is not greater than the preset load threshold, then selecting the target rise time as the third rise time; wherein, the first rise time < the second rise time < the third rise time.

[0151] Specifically, it is further considered that when a switching power supply is connected to different loads, it needs to have different rise times to avoid overstressing the power devices. However, traditional switching power supply designs usually have only one fixed rise time, which cannot be adjusted for different situations, and can easily lead to damage to the switching transistors or unstable operation.

[0152] To address the aforementioned technical problems, this embodiment proposes another adaptive rise time control method for switching power supplies. By acquiring multiple operating parameters, different target rise times are determined based on the preset input voltage and load threshold. The driving voltage of the power switch is then controlled to rise from its initial value to a preset conduction value within the target rise time, thereby turning on the power switch.

[0153] The key to this embodiment lies in determining a suitable target rise time based on two factors: input voltage and load value, to ensure stable conduction of the switching transistor. Different target rise times can be set for different input voltages and load thresholds. When controlling the power switching transistor to turn on, the rising edge of the drive waveform is adjusted according to the different target rise time requirements to achieve adaptive control. This allows the switching power supply to operate more stably and reliably under different conditions, achieving a relative balance between temperature rise and stress.

[0154] Figure 7 shows a schematic diagram of the drive rise time of the power switch provided by the present invention. In one specific embodiment, drive waveform TR1 corresponds to the first rise time, drive waveform TR2 corresponds to the second rise time, and drive waveform TR3 corresponds to the third rise time. The criteria for selecting the waveforms are shown in Table 1.

[0155] Table 1

[0156] In Table 1, under CCM mode: the current waveform rises rapidly after conduction, requiring the selection of a fast-rise drive waveform TR1 to suppress dynamic resistance effects and alleviate temperature stress. At this time, the secondary rectifier voltage Vspike is relatively large, necessitating a limit on the input voltage to meet the secondary rectifier voltage stress. In this embodiment, the input voltage limit is set to 140V. When the input voltage is less than 140V, regardless of whether it is a heavy or light load, TR1 is selected as the drive waveform.

[0157] In QR mode, under heavy load (i.e., when the primary-side power device's drain voltage before turn-on is significantly reduced by utilizing the valleys of the (first few) resonant waveforms), a lower drain voltage is beneficial for reducing the secondary-side rectifier voltage spike Vspike, resulting in a larger voltage stress margin for the secondary-side rectifier. A lower drain voltage is also beneficial for reducing the dynamic resistance effect of GaN. However, at this time, the peak current flowing through the device is large, the device surface temperature is high, and the temperature margin is small. Therefore, the drive waveform TR2 with a medium rise time is selected to focus on improving temperature stress while also considering the voltage stress of the secondary-side rectifier. Under light load, after the resonant waveform decays, the valley can no longer significantly reduce the primary-side power device's drain voltage before turn-on. A higher drain voltage is not conducive to reducing the secondary-side rectifier voltage spike Vspike, resulting in a small voltage stress margin for the secondary-side rectifier. A higher drain voltage will enhance the dynamic resistance effect of GaN, but at this time, the peak current flowing through the device is reduced, the device surface temperature is low, and the temperature margin is large. Therefore, the drive waveform TR3 with a slow rise time is selected to focus on suppressing the voltage stress of the secondary-side rectifier. In this embodiment, when the input voltage is greater than 140V and it is a heavy load (judged by the number of valleys conducting; if it conducts in the 1st to 3rd valley, it is determined to be a heavy load), TR2 is selected as the driving waveform. If it is a light load (conducting in the 4th to nth valley (n is an integer greater than 4)), TR3 is selected as the driving waveform.

[0158] In implementing the aforementioned adaptive rise time control method, operating parameters such as input voltage and load current can be acquired in real time using a microprocessor or analog circuit to calculate the corresponding target rise time and implement control. Alternatively, a pre-defined input voltage-load value-rise time correspondence can be invoked to determine the target rise time corresponding to the current input voltage and load value. The specific implementation method may need to be adjusted according to the specific circuit design.

[0159] In summary, the method in this embodiment can adjust the rise time differently for different input voltages and load conditions, thereby improving the stability and reliability of the switching power supply. Simultaneously, it can effectively extend the lifespan of the power switching transistors, improving the operating efficiency and lifespan of the switching power supply.

[0160] As shown in Figure 8, which is an internal schematic diagram of a primary-side controller provided by the present invention, UVLO is used to detect whether the VCC voltage is within a reasonable range, DC bias is used to provide bias current and bias voltage for other modules, OSC is used to generate PWM signals, OCP is used to prevent output overcurrent, Valley is used to detect changes in the transformer's magnetic field, the drive module is used to adjust the rise time of the Gate output signal, Line sense is used to detect whether the input voltage is normal, and Load sense is used to monitor whether the load current is overloaded, etc. Specifically, in the drive module, S1 / S2 is used to control the rise time of the Gate output signal.

[0161] In a preferred embodiment, the switching power supply includes a voltage divider circuit, the input terminal of which is connected to the output terminal of the auxiliary winding of the switching power supply. When the operating parameters include the input voltage, the input voltage of the switching power supply is obtained by acquiring the voltage of the voltage divider circuit to determine the input voltage of the switching power supply.

[0162] Specifically, as can be seen from the above embodiments, the input voltage of the switching power supply has a direct impact on its stability and efficiency. Therefore, it is necessary to accurately measure the input voltage and make corresponding adjustments to improve its efficiency and stability.

[0163] This embodiment uses a voltage divider circuit to measure the input voltage of the switching power supply. The output voltage of the voltage divider circuit is proportional to the input voltage, which can improve the measurement accuracy of the input voltage within a certain range. Furthermore, in the circuit design, the parameters of the voltage divider circuit should be reasonably selected according to the actual operating conditions to meet the input voltage measurement requirements under different operating conditions of the switching power supply.

[0164] As shown in Figure 17, which is a schematic diagram of an implementation of the Line Sense module provided by the present invention, in a preferred embodiment, the voltage divider circuit is a resistive voltage divider circuit. The resistive voltage divider circuit can achieve voltage drop by connecting one or more resistors, thereby dividing the input voltage. In the circuit, selecting appropriate resistors (or windings) can effectively control the voltage drop, thereby improving measurement accuracy.

[0165] For example, in a voltage divider circuit, if the input voltage is Vin, the output voltage is Vo, and the voltage divider resistors are R1 and R2, then: Vo = Vin × R2 / (R1 + R2). Based on this formula, the relationship between the output voltage and the input voltage can be obtained, and the magnitude of the input voltage can be calculated. In Figure 14, Vin is specifically detected by resistor voltage division using the HV pin. If Line = L and Vin > VrefH1 × (R1 + R2) / R2, then the driving waveform is TR1. If Line = H and Vin < VrefH1 × (R1 + R2) / R2, then the driving waveform is TR2.

[0166] It should be noted that in actual circuit design, appropriate resistors can be selected based on factors such as the required measurement accuracy and operating current. Furthermore, to ensure measurement accuracy and stability, components such as filter capacitors need to be added to optimize the circuit.

[0167] In addition to voltage divider circuits, other circuit methods can be used for input voltage measurement, such as current sensors and capacitance measurements. When selecting a specific measurement method, factors such as measurement range, accuracy requirements, and power consumption must be considered.

[0168] In addition, as shown in Figure 18, which is a schematic diagram of another implementation of the Line Sense module provided by the present invention, in a preferred embodiment, the voltage divider resistor is a wound voltage divider resistor.

[0169] Furthermore, considering the significant error inherent in resistive voltage divider measurements, a winding-based voltage divider circuit can be used to acquire the input voltage of the switching power supply. This circuit utilizes the principle of a transformer, using an auxiliary winding to reduce the input voltage to a suitable measurement range, and performs accurate measurements without affecting the operation of the switching power supply. It primarily leverages the principle of a proportional transformer, where the input voltage (Vin) is directly proportional to the output voltage (Vo).

[0170] In Figure 18, Vin is detected by winding group voltage detection using DEM Pin, Line = L, and Then select the driving waveform as TR1; Line = H, and The drive waveform is then selected as TR2; where Np is the number of turns in the transformer primary winding, Na is the number of turns in the transformer auxiliary winding, and K is the current proportionality coefficient. According to this formula, we can achieve precise positioning and transformation of the output voltage by adjusting the turns ratio of the windings. For example, when the input voltage is high, the output voltage can be reduced by increasing the turns ratio of the windings, thereby achieving measurement and control of high voltages. Furthermore, by increasing the number of converters, multi-channel voltage measurement and switching can be achieved to measure various voltages.

[0171] It is evident that using a winding voltage divider circuit to acquire the input voltage of a switching power supply can improve the accuracy and stability of the measurement, ensure the normal operation of the circuit, and enhance the reliability and stability of the entire circuit.

[0172] In summary, the voltage divider circuit (resistor voltage divider or winding) used in this embodiment to measure input voltage can improve its accuracy and stability, thereby improving the working efficiency and stability of the switching power supply. At the same time, this method has a certain degree of universality and can also be applied in other circuit designs.

[0173] As a preferred embodiment, when the working parameters include the load value connected to the switching power supply, the way to obtain the load value connected to the switching power supply is as follows: obtain the output power of the switching power supply, and determine the load value of the switching power supply according to the output power.

[0174] To solve the problem of accurately measuring the load value, in this embodiment, the load value can be determined by calculating the output power of the switching power supply. The specific implementation method is to use a power meter to measure the power, and then the corresponding load value can be obtained through simple calculation.

[0175] Specifically, the output power of the switching power supply can be calculated by the product of voltage and current. The power meter collects and processes the voltage and current signals, and then calculates the power value. In an existing switching power supply system, a power measurement module can be added, and a power meter is used to measure the power value and calculate the load value according to the above calculation formula. Specifically, the power meter can directly calculate the power value by collecting the voltage and current signals. During measurement, the corresponding signal values can be collected according to the output voltage and current of the switching power supply, and then the power calculation can be performed to obtain the corresponding load value. Assuming that the output voltage of the switching power supply is U and the output current is I, the output power is P = U×I.

[0176] In addition to the above implementation method, digital signal processing technology can also be used to perform processing such as filtering, sampling, and quantization on the collected voltage and current signals to improve the measurement accuracy.

[0177] In summary, in this embodiment, by using power measurement technology, the load value connected to the switching power supply can be accurately obtained, ensuring the system stability and working efficiency. This is particularly important for some system applications with high load requirements.

[0178] As a preferred embodiment, obtaining the output power of the switching power supply includes: obtaining the feedback voltage output by the feedback pin of the switching power supply, and determining the output power of the switching power supply according to the feedback voltage.

[0179] A common circuit for obtaining the feedback voltage and output power is to use a differential amplifier. Its principle is to perform a difference between the voltage of the feedback pin and the reference voltage, and the differential signal is amplified and filtered by the amplifier to obtain the magnitude of the feedback voltage. Then, the output power value is calculated using the proportional relationship between the feedback voltage and the reference voltage. As shown in FIG. 19, FIG. 19 is a schematic diagram of an implementation method of Load Sense provided by the present invention. In this embodiment, the system output power is characterized by the FB Pin voltage. If Load = H and VFB > VrefH3, it is determined as a heavy load; if Load = L and VFB < VrefL3, it is determined as a light load.

[0180] As a preferred embodiment, obtaining the output power of the switching power supply includes: determining the number of valleys in the resonant waveform corresponding to the conduction phase of the primary-side power switch, and determining the output power based on the number of valleys.

[0181] In this embodiment, the output power of the switching power supply is obtained by analyzing the resonant waveform generated during the conduction phase of the primary-side power switch Qp. Specifically, the number of valleys in the resonant waveform is an important characteristic parameter that reflects the dynamic response of the power supply under specific operating conditions. When Qp is turned on, changes in current and voltage cause resonance, generating periodic waveforms. By observing the number of valleys in these waveforms, the power variation within each cycle can be determined. Generally, an increase in the number of valleys indicates an increase in output power, as this means the power supply has completed more energy conversion and transmission within a certain time. Conversely, a decrease in the number of valleys may indicate a decrease in output power. Therefore, by monitoring and counting the valleys of the resonant waveform in real time, combined with the system parameters and operating conditions, the output power of the switching power supply can be calculated.

[0182] To measure the number of valleys in the resonant waveform, the signal output from the resonant circuit for measuring the resonant waveform can be input into a microprocessor. The microprocessor samples the input signal and performs digital signal processing to accurately measure the number of valleys in the resonant waveform and calculate the output power based on the number of valleys. Figure 20 illustrates another implementation of Load Sense provided by this invention. In one embodiment, if Load = H and the number of valleys N > 4, it is determined to be a heavy load; if Load = L and the number of valleys N ≤ 4, it is determined to be a light load.

[0183] This method of determining output power can significantly reduce costs and time.

[0184] In a preferred embodiment, obtaining the output power of the switching power supply includes: obtaining the output current on the primary side of the switching power supply, and determining the output power based on the output current.

[0185] This embodiment aims to provide an alternative method for obtaining the output power of a switching power supply. Generally, the output power of a switching power supply is obtained by measuring the primary-side output current, as the primary-side output current directly reflects the power supply's output power. This method essentially utilizes the relationship between current and voltage. By measuring the voltage and resistance values, the current magnitude is calculated, and then multiplied by the voltage to obtain the power. When selecting a resistor, it is necessary to consider the rated output current of the power supply to ensure that the resistor can withstand the current intensity without damage. Furthermore, in actual measurements, attention must be paid to the resistor's temperature rise to avoid erroneous measurement results due to excessive temperature rise.

[0186] As shown in Figure 20, in one embodiment, the output current is calculated using the CS Pin voltage and Tsw, Tons. Characterizes the system output power. Load = H, if Io > IrefH, then it is a heavy load; Load = L, if Io < IrefL, then it is a light load.

[0187] In a preferred embodiment, the switching power supply includes a drive circuit, which includes a drive capacitor, a first drive switch, and a second drive switch. The first terminal of the drive capacitor is grounded, and the second terminal of the drive capacitor is connected to the control terminal of the first drive switch. The first terminal of the first drive switch is connected to a power supply, and the second terminal of the first drive switch is connected to both the control terminal of a power switch and the first terminal of the second drive switch. The second terminal of the second drive switch is grounded. Controlling the drive voltage of the power switch to rise from an initial value to a preset conduction value within a target rise time includes: charging and discharging the drive capacitor to adjust its voltage, causing the voltage of the drive capacitor to rise from its initial value to a first voltage value within the target rise time, thereby turning on the first drive switch. When the voltage of the drive capacitor reaches the first voltage value, the second drive switch is turned off, and when the voltage at the control terminal of the power switch reaches the preset conduction value, the power switch turns on. The drive capacitor can be referenced to Cp in Figures 9-12, where Cp represents the total parasitic capacitance of the N1 control terminal to ground, and is not a physical capacitor.

[0188] In this embodiment, the switching power supply controls the conduction process of the power switch through a drive circuit, with the core being the charging and discharging process of the drive capacitor. First, the initial voltage of the drive capacitor is low. By charging it, the capacitor voltage is gradually increased to achieve a preset target rise time. During the target rise time, the voltage of the drive capacitor rises smoothly, ensuring that it can stably control the conduction of the first drive switch when it reaches the first voltage value. At this time, the conduction of the first drive switch provides sufficient drive voltage to the control terminal of the power switch, thereby enabling conduction. Simultaneously, the second drive switch remains in the off state during the voltage rise of the drive capacitor. This state ensures that the power switch is activated at the appropriate time, avoiding unnecessary interference or false triggering.

[0189] By precisely controlling the voltage changes of the drive capacitor, the system can effectively manage the on-time of the power switch, improve the overall efficiency and stability of the switching power supply, reduce the temperature rise of the power switch, and optimize the output performance of the power supply.

[0190] To solve the above-mentioned technical problems, as shown in Figures 9-12, the present invention provides an adaptive drive device for switching power supplies, comprising:

[0191] The detection circuit is used to acquire multiple operating parameters of the switching power supply under the current operating conditions.

[0192] The adjustment circuit is used to select the target rise time required for the power switch to turn on according to multiple operating parameters and the current operating condition.

[0193] The driving circuit is used to control the driving voltage of the power switch to rise from its initial value to a preset conduction value within a target rise time, so as to turn on the power switch.

[0194] The adaptive drive device for switching power supplies in this invention optimizes the conduction process of the power switch through the coordinated operation of three main circuits to meet performance requirements under different operating conditions. First, the detection circuit acquires multiple operating parameters of the switching power supply in real time, such as input voltage, load conditions, and other operating status information. These parameters provide the necessary data foundation for the adjustment circuit, enabling it to analyze the characteristics of the current operating condition. Next, the adjustment circuit selects an appropriate target rise time based on the acquired operating parameters to adapt to the dynamic response required for the power switch to conduct under the current operating condition. The target rise time is set to balance the conduction efficiency and safety of the power switch, thereby avoiding excessive temperature rise or voltage stress. Finally, the drive circuit smoothly increases the drive voltage of the power switch from its initial value to the preset conduction value within the set target rise time, ensuring that the power switch conducts stably at the optimal time. Through this adaptive drive mechanism, the entire switching power supply system can flexibly adjust its operating parameters according to the real-time operating status, improving system stability and efficiency, and ensuring reliable operation of the power supply under various conditions.

[0195] In a preferred embodiment, the driving circuit includes a driving capacitor, a first driving switch, and a second driving switch. The first end of the driving capacitor is grounded, and the second end of the driving capacitor is connected to the control terminal of the first driving switch. The first end of the first driving switch is connected to a power supply, and the second end of the first driving switch is connected to the control terminal of the power switch and the first end of the second driving switch, respectively. The second end of the second driving switch is grounded, and the conduction state of the first driving switch is opposite to the conduction state of the second driving switch.

[0196] The driving circuit is specifically used to control the voltage of the driving capacitor to rise from an initial value to a first voltage value within a target rise time.

[0197] When the voltage of the driving capacitor reaches the first voltage value, the first driving switch is turned on and the second driving switch is turned off. When the voltage at the control terminal of the power switch reaches the preset turn-on value, the power switch is turned on. The driving capacitor can be referred to as Cp in Figure 9-12. Cp is the sum of the parasitic capacitance of the N1 control terminal to ground, and is not a physical capacitor.

[0198] In this embodiment, the drive circuit is designed to precisely control the conduction process of the power switch through the cooperation of the drive capacitor and its control switch. Initially, the drive capacitor has a low voltage. By charging it, the voltage of the drive capacitor gradually increases within a set target rise time. When the voltage rises to a first voltage value, the state change of the drive capacitor triggers the first drive switch to conduct, while simultaneously keeping the second drive switch in the off state. This control strategy ensures that the power switch is activated only when the voltage of the drive capacitor reaches the preset value, thus achieving stable conduction. The conduction of the first drive switch provides the necessary drive voltage for the power switch, ensuring that the power switch can conduct smoothly at the appropriate time, thereby controlling the power supply output. Through this precise voltage control mechanism, the drive circuit can effectively manage the conduction time of the power switch, improving the overall performance and efficiency of the switching power supply and ensuring the reliability and stability of the power supply under various operating conditions.

[0199] In a preferred embodiment, the driving circuit further includes: a charging regulation circuit, one end of which is connected to the second end of the driving capacitor, and the other end of which is connected to the adjustment circuit; the charging regulation circuit is used to adjust its own working state according to the target rise time selected by the adjustment circuit, so as to provide a target charging current for the driving capacitor, so that the voltage of the driving capacitor reaches a first voltage value within the target rise time; wherein, the target charging current is negatively correlated with the target rise time.

[0200] In this embodiment, the design of the charging regulation circuit is closely linked to the charging process of the driving capacitor to achieve precise control of the target rise time. Specifically, the charging regulation circuit dynamically adjusts its operating state according to the target rise time selected by the adjustment circuit to provide an appropriate target charging current to the driving capacitor. Since the target charging current is negatively correlated with the target rise time, this means that when the target rise time is short, the charging regulation circuit will increase the charging current, thereby accelerating the voltage rise rate of the driving capacitor; conversely, when the target rise time is long, the charging current will decrease to reduce the charging rate. This design allows the system to flexibly adjust the charging process under different operating conditions to ensure that the voltage of the driving capacitor accurately reaches the first voltage value within the set target rise time.

[0201] Through this mechanism, the charging regulation circuit can not only optimize the turn-on timing of the power switch, but also improve the overall efficiency and response speed of the switching power supply, ensuring its stability and reliability under different operating conditions.

[0202] In a preferred embodiment, the charging regulation circuit includes: a switching circuit, N constant current sources and M auxiliary capacitors, where N≥1, M≥0, N+M≥2, and N and M are both integers; the first terminal of the switching circuit is connected to all constant current sources, the second terminal of the switching circuit is connected to all auxiliary capacitors, and the third terminal of the switching circuit is connected to the second terminal of the driving capacitor; the constant current sources are used to provide a constant current; the switching circuit is used to adjust its own path state according to the target rise time to select a first target number of constant current sources and a second target number of auxiliary capacitors to be connected to the circuit, so that the first target number of constant current sources charges the driving capacitor and the second target number of auxiliary capacitors; the first target number is at least 1, the second target number is at least 0, the first target number is negatively correlated with the target rise time, and the second target number is positively correlated with the target rise time.

[0203] In this embodiment, the charging regulation circuit is designed to precisely manage the charging process of the driving capacitor by flexibly controlling the number of constant current sources and auxiliary capacitors. Specifically, the charging regulation circuit dynamically adjusts the number of constant current sources and auxiliary capacitors connected to the circuit based on the set target rise time via a switching circuit. As the target rise time changes, when the target rise time is short, the switching circuit can choose to connect more constant current sources to provide a larger charging current, and / or reduce the number of auxiliary capacitors connected, thereby accelerating the charging speed of the driving capacitor and enabling it to reach the first voltage value more quickly. This negative correlation ensures that the driving capacitor can charge to the expected voltage in a shorter time when a fast response is required. On the other hand, when the target rise time is long, the switching circuit can reduce the number of constant current sources connected and / or increase the number of auxiliary capacitors connected. The auxiliary capacitors share the charging current of the driving capacitor during the charging process, thereby achieving a slower voltage rise rate.

[0204] With flexible configuration, the charging regulation circuit can optimize the charging characteristics of the drive capacitor under various operating conditions, thereby improving the response speed and overall performance of the switching power supply.

[0205] In a preferred embodiment, when N > 1 and M = 0, the switching circuit includes: a main switch and a first switching circuit; one end of the first switching circuit is connected to the output terminals of n constant current sources, the other end of the first switching circuit is connected to the output terminals of other constant current sources besides the n constant current sources and one end of the main switch, the other end of the main switch is connected to the second terminal of the driving capacitor and the control terminal of the first driving switch, and the control terminal of the first switching circuit is connected to the adjustment circuit; N > n ≥ 1, where n is an integer; the main switch is used to turn on when charging the driving capacitor; the first switching circuit is used to adjust its own path state to select a third target number of constant current sources to be connected to the circuit, where the first target number - the third target number = Nn.

[0206] In this embodiment, when N is greater than 1 and M is 0, the design of the charging regulation circuit focuses on optimizing the charging process of the driving capacitor by flexibly adjusting the number of constant current sources. Specifically, the switching circuit includes a master switch and a first switching circuit. The master switch is responsible for conducting during charging to ensure that the driving capacitor can receive current. The first switching circuit dynamically selects the number of constant current sources connected to the circuit according to the control signal of the adjustment circuit. Here, n constant current sources are flexibly adjustable, while the other constant current sources besides n constant current sources are pre-fixed constant current sources, specifically providing a stable charging current for the driving capacitor and are not affected by adjustment. By adjusting the path state of the first switching circuit, the system can select a second target number of constant current sources to be connected from the n constant current sources. This design ensures that at any given target rise time, the first target number of constant current sources always provides charging current to the driving capacitor, and this first target number minus the third target number is the number of non-adjustable Nn constant current sources.

[0207] As shown in Figure 9, the number of constant current sources N is 3, n is 2, P1 is the main switch, and P2 and P3 form the first switching circuit. The charging current is adjusted according to the target rise time, and the rising edge waveform is set. The output Gate is used to drive the power switch. The first inflection point of the Gate waveform (refer to time t1 in Figure 13) is determined by the VL voltage, and the second inflection point (refer to time t2 in Figure 13) is determined by the VH voltage. S1+Gate compares the waveform to switch Ib3, and S2 switches Ib2.

[0208] S1 = H, enable Ib3 in the middle of the ascent; S2 = H, enable Ib2, corresponding to the shortest target ascent time and the fastest Gate ascent.

[0209] S1 = L, disable Ib3 during the middle of the ascent; S2 = H, enable Ib2, corresponding to a medium target ascent time and a medium Gate ascent.

[0210] S1 = L, disable Ib3 in the middle of the ascent; S2 = L, disable Ib2, corresponding to the slowest ascent time for the target and the slowest ascent for the Gate.

[0211] In this way, the system can flexibly adapt to different operating conditions, quickly respond to changes in target rise time, and enable the drive capacitor to reach the required voltage within a set time, thereby improving the performance and reliability of the switching power supply.

[0212] In a preferred embodiment, when N=1 and M>0, the switching circuit includes: a main switch and a second switching circuit; one end of the main switch is connected to all constant current sources, one end of the second switching circuit is connected to the first end of m auxiliary capacitors, the other end of the second switching circuit is connected to the first end of the other auxiliary capacitors besides the m auxiliary capacitors, the other end of the main switch, the second end of the driving capacitor, and the control terminal of the first driving switch, the second end of all auxiliary capacitors is grounded, and the second end of the second switching circuit is connected to the adjustment circuit, M≥m>0, where m is an integer; the main switch is used to turn on when charging the driving capacitor; the second switching circuit is used to adjust its own path state to select the fourth target number of auxiliary capacitors to be connected to the circuit, the second target number - the fourth target number = Mm.

[0213] In this embodiment, when N is 1 and M is greater than 0, the charging regulation circuit is designed to optimize the charging process of the driving capacitor by adjusting the number of auxiliary capacitors. At this time, the main switch is responsible for conducting during charging to ensure that the driving capacitor receives a fixed charging current from the constant current source. Simultaneously, the function of the second switching circuit is to flexibly adjust the number of auxiliary capacitors connected to the circuit to share the charging current of the driving capacitor. In this embodiment, there are m adjustable auxiliary capacitors and Mm fixed auxiliary capacitors, the latter (which can be as few as 0) pre-set and used to stably share the charging current. The second switching circuit dynamically selects the number of auxiliary capacitors connected based on the target rise time, ensuring effective management of the charging current distribution within a given time and ensuring that the driving capacitor receives an appropriate charging current. Wherein, the fourth target number + the number of other auxiliary capacitors besides the m auxiliary capacitors = the second target number. In this case, the number of adjusted m auxiliary capacitors can directly affect the charging speed of the driving capacitor and optimize its voltage rise process.

[0214] As shown in Figure 10, there is one constant current source and two auxiliary capacitors M (C1 and C2 respectively). P1 is the main switch, and N4-N7 form the second switching circuit. The number of auxiliary capacitors connected is adjusted according to the target rise time to set the rising edge waveform. The output Gate is used to drive the power switch. The first inflection point of the Gate waveform (refer to time t1 in Figure 13) is determined by the Clamp voltage. The second inflection point (refer to time t2 in Figure 13) is due to the turnoff of N4 / N6. S1 switches C1, and S2 switches C2. C1 and C2 need to be controlled by a bidirectional isolation switch. The bidirectional isolation switch can be composed of P and N connected in series or N and N connected in series.

[0215] S1 = H, disable C1; S2 = H, disable C2, corresponding to the shortest target rise time and the fastest Gate rise.

[0216] S1 = L, enable C1; S2 = H, disable C2, corresponding to a medium target rise time and a medium gate rise.

[0217] S1 = L, enable C1; S2 = L, enable C2, corresponding to the slowest target ascent time and the slowest gate ascent time.

[0218] This flexible design allows the system to adapt to different operating conditions, ensuring that the drive capacitor can be charged stably and efficiently while meeting specific rise time requirements, thereby improving the performance and reliability of the switching power supply.

[0219] In a preferred embodiment, when N > 1 and M > 0, the switching circuit includes: a main switch, a first switching circuit, and a second switching circuit; one end of the first switching circuit is connected to the output terminals of n constant current sources, and the other end of the first switching circuit is connected to the output terminals of the other constant current sources besides the n constant current sources and one end of the main switch; the other end of the main switch is connected to the first terminal of the second switching circuit, the first terminal of the other auxiliary capacitors besides the m auxiliary capacitors, the second terminal of the driving capacitor, and the control terminal of the first driving switch; the other end of the second switching circuit is connected to the m auxiliary capacitors. All auxiliary capacitors have their second terminals grounded. The control terminals of the first and second switching circuits are both connected to the adjustment circuit. N > n ≥ 1, M ≥ m > 0, where m and n are integers. The main switch is used to turn on the circuit when charging the driving capacitor. The first switching circuit is used to adjust its own circuit state to select the number of constant current sources of the third target to be connected to the circuit. The number of the first target - the number of the third target = Nn. The second switching circuit is used to adjust its own circuit state to select the number of auxiliary capacitors of the fourth target to be connected to the circuit. The number of the second target - the number of the fourth target = Mm.

[0220] In this embodiment, when both N and M are greater than 0 and N is greater than 1, the charging regulation circuit design incorporates flexible adjustment of the number of constant current sources and auxiliary capacitors to optimize the charging process of the driving capacitor. First, the main switch is turned on during charging to provide the necessary power to the driving capacitor. Next, the first switching circuit is responsible for adjusting the number of constant current sources connected to the circuit to dynamically select a suitable constant current source based on the target rise time. During this process, the outputs of n constant current sources are connected to the first switching circuit, and through the adjustment of this switch, a suitable third target number of constant current sources is selected to be connected to the circuit. Among these, the n constant current sources can be flexibly adjusted, while the other constant current sources are used to stably provide the charging current to the driving capacitor. This allows the system to adapt to changes in demand and flexibly configure the charging current during the charging process.

[0221] Meanwhile, the second switching circuit controls the connection of auxiliary capacitors. Through adjustment of its control terminal, it selects the fourth target number of auxiliary capacitors to be connected based on the target rise time. At this point, the number of m auxiliary capacitors can be flexibly adjusted, while the other auxiliary capacitors besides the m ones are used to stably share the charging current of the drive capacitor.

[0222] As shown in Figures 11 and 12, there are 2 constant current sources and 1 auxiliary capacitor (C1). P1 is the main switch, P2 is the first switching circuit, and P3 and N4, or N4 and N5, form the second switching circuit. The number of constant current sources and the number of auxiliary capacitors are adjusted according to the target rise time to set the rising edge waveform. The output gate is used to drive the power switch. The first inflection point of the gate waveform (refer to time t1 in Figure 13) is determined by the Clamp voltage. The second inflection point (refer to time t2 in Figure 13) occurs because VC1 rises, N4 turns off, and S1 switches C1. C1 needs to be controlled by a bidirectional isolating switch, which can be composed of P3 and N4 in series, or N4 and N5 in series. S2 switches the constant current sources.

[0223] S1 = H, disable C1; S2 = H, IB = Ib1 + Ib2, corresponding to the shortest target rise time and the fastest Gate rise.

[0224] S1 = L, enable C1; S2 = H, IB = Ib1 + Ib2, corresponding to a medium target rise time and a medium gate rise.

[0225] S1 = L, enable C1; S2 = L, IB = Ib1, corresponding to the slowest target ascent time and the slowest Gate ascent time.

[0226] This design allows the system to flexibly adjust the number of constant current sources and auxiliary capacitors under different operating conditions, ensuring that the drive capacitor is effectively charged within a predetermined target rise time, thereby improving the overall performance and reliability of the switching power supply. By combining the adjustment of the constant current source and auxiliary capacitors, the system can more accurately meet dynamically changing demands and optimize the power supply's response capability.

[0227] In a preferred embodiment, the first switching circuit includes: n controllable switches, each corresponding to one of the n constant current sources. Each controllable switch is positioned between the output terminal of its corresponding constant current source and one end of the main switch. The control terminal of each controllable switch is connected to the adjustment circuit. The driving circuit further includes: a control circuit connected to at least one of the n controllable switches. The control circuit includes a first comparator, a second comparator, a NAND gate, and an OR gate. The positive input terminal of the first comparator receives a first comparison voltage value, the negative input terminal of the first comparator receives a preset conduction value from the positive input terminal of the second comparator, the negative input terminal of the second comparator receives a second comparison voltage value, the output terminals of the first and second comparators are respectively connected to the two input terminals of the NAND gate, the output terminal of the NAND gate is connected to the first input terminal of the OR gate, the second input terminal of the OR gate is connected to the adjustment circuit, and the output terminal of the OR gate is connected to the control terminal of at least one of the controllable switches. The first comparison voltage value is greater than the second comparison voltage value.

[0228] In this embodiment, the first switching circuit corresponds to n constant current sources via n controllable switches, aiming to flexibly adjust the connection of constant current sources according to actual needs to optimize the charging process of the driving capacitor. The control terminal of each controllable switch is connected to a control circuit, the core function of which is to monitor and adjust the charging state in real time. Specifically, the control circuit consists of a first comparator, a second comparator, a NAND gate, and an OR gate. The first comparator is responsible for comparing a first comparison voltage value with a preset conduction value to assess whether the current charging state has reached the required level; if the first comparison voltage value is higher than the preset conduction value, the first comparator will output a high-level signal. At the same time, the function of the second comparator is to monitor the second comparison voltage value and compare it with the preset conduction value to ensure that the voltage during the charging process does not exceed the safe range. When the second comparison voltage value is lower than the preset conduction value, the second comparator will also output a corresponding signal. Subsequently, the output results of the first and second comparators are jointly input to the NAND gate, and a comprehensive judgment of the charging state is obtained through logical operation. This judgment result is further passed to the OR gate, and the output of the OR gate will affect the control terminal of at least one controllable switch, thereby determining whether to turn on or off a specific constant current source.

[0229] Through such a monitoring and control mechanism, the number of constant current sources connected can be dynamically adjusted to ensure that the driving capacitor remains within a safe and effective operating range during the charging process, thereby improving the reliability and efficiency of the switching power supply.

[0230] In a preferred embodiment, the second switching circuit includes: m sub-switching circuits, m third clamping circuits, and m resistors. The m sub-switching circuits, m third clamping circuits, m resistors, and m auxiliary capacitors correspond one-to-one. The first terminal of each sub-switching circuit is connected to the first terminal of its corresponding auxiliary capacitor, the first terminal of its corresponding third clamping circuit, and the first terminal of its corresponding resistor. The second terminal of each auxiliary capacitor and the second terminal of each third clamping circuit are grounded. The second terminal of each resistor is input with a preset clamping voltage. The control terminal of each sub-switching circuit is connected to an adjustment circuit.

[0231] In this embodiment, the second switching circuit is designed primarily for flexible adjustment and precise control of the m auxiliary capacitors to optimize the performance of the switching power supply. Each sub-switching circuit corresponds one-to-one with its auxiliary capacitor, third clamping circuit, and resistor, forming an independent control unit. When a sub-switching circuit is activated, it allows the auxiliary capacitors to connect to the circuit and participate in the charging process. Simultaneously, the third clamping circuit ensures that the voltage of the auxiliary capacitors does not exceed a preset clamping voltage during charging or discharging, thus preventing potential damage due to overvoltage. Each resistor provides a reference point; by inputting the preset clamping voltage, the accuracy of voltage control is further improved. The adjustment circuit dynamically selects whether to connect a specific auxiliary capacitor by controlling the state of the sub-switching circuits, thereby flexibly adjusting the capacitor charging status according to the actual needs of the system.

[0232] This design allows for effective handling of different operating environments while maintaining power supply stability, thereby improving overall efficiency and reliability. The flexibility and precision of this solution enable the switching power supply to better adapt to changing load conditions, achieving high-efficiency power management.

[0233] In a preferred embodiment, the driving circuit further includes: a NOT gate, a third driving switch, a first clamping circuit, a second clamping circuit, and a PWM output module; the first output terminal of the PWM output module is connected to the input terminal of the NOT gate and the control terminal of the third driving switch, the output terminal of the NOT gate is connected to the control terminal of the main switch, the first terminal of the third driving switch is connected to the first terminal of the first clamping circuit, the first terminal of the second clamping circuit, the second terminal of the driving capacitor, and the control terminal of the first driving switch, the second terminal of the third driving switch, the second terminal of the first clamping circuit, and the second terminal of the second clamping circuit are all grounded, and the second output terminal of the PWM output module is connected to the control terminal of the second driving switch; the signal levels output by the two output terminals of the PWM output module are opposite.

[0234] In this embodiment, the drive circuit design primarily achieves precise control of the switching power supply through the cooperation of a PWM output module, a NOT gate, and a third drive switch. The pulse width modulation signal generated by the PWM output module produces an opposite output through the NOT gate. This symmetrical signal output mechanism allows for effective control of the main switch's on / off state under different operating conditions. Specifically, the PWM signal is used to adjust the control terminal of the third drive switch, thereby regulating its conduction state and affecting the charging of the drive capacitor. The first and second clamping circuits ensure that the drive capacitor operates within a set range, limiting the voltage to prevent excessively high or low voltages from affecting system stability. When the signal level of the PWM output module changes, the change in the NOT gate output signal affects the control of the main switch, thus achieving dynamic adjustment of the entire power supply state. This design flexibility allows the drive circuit to quickly respond to load changes, optimize power efficiency, and enhance system reliability and stability. Through precise voltage and state control, this embodiment effectively improves the adaptability and performance of the switching power supply under various operating conditions.

[0235] In the implementation provided in this embodiment, the workflow of each working device is as follows:

[0236] The timing diagram is shown in Figure 13. Figure 13 is a timing diagram of each device in the driving module provided by the present invention.

[0237] When S1 = H, N4 is off, and the rise time of the Gate is TR1. See Fig. 10 for the timing waveform. At time t0, the lower output transistor N2 is off; at time t1, P1 is on, capacitor Cp is charging, and the Gate rise slope dV / dt = IB / Cp, where IB = Ib1 or Ib1 + Ib2, and the upper output transistor N1 is on; at time t2, the Gate voltage reaches the clamping high level; at time t3, the upper output transistor N1 is off; at time t4, the lower output transistor N2 is on.

[0238] When S1 = L, N4, P3, and P4 are controlled by H; when S2 = L, P2 is cut off; the rise time of the Gate is TR2, and the timing waveform is shown in Figure 13. At time t0, the lower output transistor N2 is cut off, P4 is cut off, and N4 and P3 are off; at time t1, the transistor is turned on, capacitor C1 charges capacitor Cp, and the upper output transistor N1 is turned on; from time t1 to t2, P1 is turned on, capacitor Cp is charged, and the rise slope of the Gate is dV / dt = IB / (Cp+C1), IB = Ib1; at time t2, due to the rise of VC1 voltage, N4 is cut off, capacitor Cp is charged, and the rise slope of the Gate is dV / dt = IB / Cp, IB = Ib1; at time t3, the Gate voltage reaches the clamping high level; at time t4, the upper output transistor N1 is cut off, N4 and P3 are cut off, P4 is turned on, and Ib3 charges capacitor C1; at time t5, the lower output transistor N2 is turned on.

[0239] When S1 = L, N4, P3, and P4 are controlled by H; when S2 = H, P2 is on, and the Gate rise time is TR3. The timing waveform is shown in Figure 13. At time t0, the lower output transistor N2 is off; at time t1, P4 is off, N4 and P3 are on, capacitor C1 charges capacitor Cp, and the upper output transistor N1 is on; from time t1 to t2, P1 is on, capacitor Cp is charged, and the Gate rise slope dV / dt = IB / (Cp+C1), IB = Ib1+Ib2; at time t2, due to the rise of VC1 voltage, N4 is off, capacitor Cp is charged, and the Gate rise slope dV / dt = IB / Cp, IB = Ib1+Ib2; at time t3, the Gate voltage reaches the clamping high level; at time t4, the upper output transistor N1 is off, N4 and P3 are off, P4 is on, and Ib3 charges capacitor C1; at time t5, the lower output transistor N2 is on.

[0240] Where Cp is the total parasitic capacitance of node H_G, C1 is the auxiliary capacitance (C1>Cp), and Ib1 / Ib2 / Ib3 are constant current sources. The Non-overlap circuit is used to prevent N1 and N2 from being connected together, as shown in Figure 14. Figure 14 is a schematic diagram of the circuit and signal timing of the Non-Overlap module provided by the present invention. The LevelShift circuit is used for level conversion to control the gates of P1 and P2, as shown in Figure 15. Figure 15 is a schematic diagram of the LevelShift module provided by the present invention. Clamp1 is a high-level clamping circuit for GATE output, Clamp2 is a high-level clamping circuit for C1, and Clamp3 is a gate voltage clamping circuit for N1, as shown in Figure 16. Figure 16 is a schematic diagram of the Clamp module provided by the present invention.

[0241] In this embodiment, the driving circuit is implemented in hardware, which can achieve fast response and stable and reliable control, thus improving the efficiency and stability of the driving circuit.

[0242] To address the aforementioned technical problems, this invention provides a switching power supply, including the adaptive drive device described above. For a detailed description of the switching power supply, please refer to the above embodiments; further details will not be repeated here.

[0243] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0244] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A switching power supply adaptive driving method, characterized in that, include: Obtain multiple operating parameters of the switching power supply under the current operating conditions; Based on the multiple operating parameters, select the target rise time required for the power switch to turn on according to the current operating condition; The driving voltage of the power switch is controlled to rise from an initial value to a preset conduction value within the target rise time, so as to turn on the power switch.

2. The adaptive driving method for switching power supplies as described in claim 1, characterized in that, The power switch is a gallium nitride power switch.

3. The adaptive driving method for switching power supplies as described in claim 1, characterized in that, The preset conduction value is the threshold voltage of the power switch.

4. The adaptive driving method for switching power supplies as described in claim 1, characterized in that, The operating parameters include at least the input voltage of the switching power supply and / or the load value connected to the switching power supply.

5. The adaptive driving method for switching power supplies as described in claim 4, characterized in that, Determining the target rise time corresponding to the current operating condition based on multiple operating parameters includes: Determine whether the input voltage of the switching power supply is less than the preset input voltage; If it is less than the preset input voltage, then the target rise time is selected as the first rise time; If it is not less than the preset input voltage, then the target rise time is selected as the second rise time; Wherein, the first rise time is less than the second rise time.

6. The adaptive driving method for switching power supplies as described in claim 5, characterized in that, Before selecting the target rise time as the second rise time, the following are also included: Determine whether the load value connected to the switching power supply is greater than a preset load threshold; If it exceeds the preset load threshold, then the target rise time is selected as the second rise time; If it is not greater than the preset load threshold, then the target rise time is selected as the third rise time; Wherein, the first rise time < the second rise time < the third rise time.

7. The adaptive driving method for switching power supplies as described in claim 4, characterized in that, The switching power supply includes a voltage divider circuit, the input terminal of which is connected to the output terminal of the auxiliary winding of the switching power supply. When the operating parameters include the input voltage, the input voltage of the switching power supply is obtained as follows: The input voltage of the switching power supply is determined by collecting the voltage of the voltage divider circuit.

8. The adaptive driving method for switching power supplies as described in claim 7, characterized in that, The voltage divider circuit is a resistor voltage divider circuit or a winding voltage divider circuit.

9. The adaptive driving method for switching power supplies as described in claim 4, characterized in that, When the operating parameters include the load value connected to the switching power supply, the load value connected to the switching power supply is obtained in the following way: Obtain the output power of the switching power supply, and determine the load value of the switching power supply based on the output power.

10. The adaptive driving method for switching power supplies as described in claim 9, characterized in that, Obtaining the output power of the switching power supply includes: Obtain the feedback voltage output from the feedback pin of the switching power supply, and determine the output power of the switching power supply based on the feedback voltage.

11. The adaptive driving method for switching power supplies as described in claim 9, characterized in that, Obtaining the output power of the switching power supply includes: Determine the number of valleys in the resonant waveform corresponding to the conduction phase of the primary-side power switch, and determine the output power based on the number of valleys.

12. The adaptive driving method for switching power supplies as described in claim 9, characterized in that, Obtaining the output power of the switching power supply includes: Obtain the output current on the primary side of the switching power supply, and determine the output power based on the output current.

13. The adaptive driving method for a switching power supply as described in any one of claims 1-12, characterized in that, The switching power supply includes a driving circuit, which includes a driving capacitor, a first driving switch, and a second driving switch. The first end of the driving capacitor is grounded, and the second end of the driving capacitor is connected to the control end of the first driving switch. The first end of the first driving switch is connected to the power supply, and the second end of the first driving switch is connected to the control end of the power switch and the first end of the second driving switch, respectively. The second end of the second driving switch is grounded. Controlling the drive voltage of the power switch to rise from an initial value to a preset conduction value within the target rise time includes: By charging and discharging the driving capacitor, the voltage of the driving capacitor is adjusted so that the voltage of the driving capacitor rises from the initial value to the first voltage value within the target rise time, thereby turning on the first driving switch. When the voltage of the driving capacitor reaches the first voltage value, the second driving switch is turned off, and when the voltage at the control terminal of the power switch reaches the preset conduction value, the power switch is turned on.

14. A switching power supply adaptive drive device, characterized in that, include: The detection circuit is used to acquire multiple operating parameters of the switching power supply under the current operating conditions. An adjustment circuit is used to select, based on multiple operating parameters, the target rise time required for the power switch to turn on according to the current operating condition; A driving circuit is used to control the driving voltage of the power switch to rise from an initial value to a preset conduction value within the target rise time, so as to turn on the power switch.

15. The adaptive drive device for switching power supplies as described in claim 14, characterized in that, The driving circuit includes a driving capacitor, a first driving switch, and a second driving switch. The first end of the driving capacitor is grounded, and the second end of the driving capacitor is connected to the control terminal of the first driving switch. The first end of the first driving switch is connected to a power supply. The second end of the first driving switch is connected to the control terminal of the power switch and the first end of the second driving switch, respectively. The second end of the second driving switch is grounded. The conduction state of the first driving switch is opposite to the conduction state of the second driving switch. The driving circuit is specifically used to control the voltage of the driving capacitor to rise from the initial value to the first voltage value within the target rise time. When the voltage of the driving capacitor reaches the first voltage value, the first driving switch is turned on and the second driving switch is turned off. When the voltage at the control terminal of the power switch reaches the preset turn-on value, the power switch is turned on.

16. The adaptive drive device for switching power supplies as described in claim 15, characterized in that, The driving circuit also includes: A charging regulation circuit, one end of which is connected to the second end of the driving capacitor, and the other end of which is connected to the adjustment circuit; The charging regulation circuit is used to adjust its own working state according to the target rise time selected by the adjustment circuit, so as to provide a target charging current for the driving capacitor, so that the voltage of the driving capacitor reaches the first voltage value within the target rise time. The target charging current is negatively correlated with the target rise time.

17. The adaptive drive device for switching power supplies as described in claim 16, characterized in that, The charging regulation circuit includes: A switching circuit, N constant current sources and M auxiliary capacitors, where N≥1, M≥0, N+M≥2, and N and M are both integers; The first terminal of the switching circuit is connected to all the constant current sources, the second terminal of the switching circuit is connected to all the auxiliary capacitors, and the third terminal of the switching circuit is connected to the second terminal of the driving capacitor. The constant current source is used to provide a constant current; The switching circuit is used to adjust its own path state according to the target rise time, so as to select a first target number of constant current sources and a second target number of auxiliary capacitors to be connected to the circuit, so that the first target number of constant current sources charges the driving capacitor and the second target number of auxiliary capacitors. The number of the first target is at least 1, the number of the second target is at least 0, the number of the first target is negatively correlated with the target rise time, and the number of the second target is positively correlated with the target rise time.

18. The adaptive drive device for switching power supplies as described in claim 17, characterized in that, When N > 1 and M = 0, the switching circuit includes: Main switch, first switch circuit; One end of the first switching circuit is connected to the output terminals of the n constant current sources, and the other end of the first switching circuit is connected to the output terminals of the other constant current sources besides the n constant current sources and one end of the main switch. The other end of the main switch is connected to the second terminal of the driving capacitor and the control terminal of the first driving switch. The control terminal of the first switching circuit is connected to the adjustment circuit; N > n ≥ 1, where n is an integer. The main switch is used to turn on when charging the drive capacitor; The first switching circuit is used to adjust its own path state to select a third number of constant current sources to be connected to the circuit, where the number of the first target - the number of the third target = Nn.

19. The adaptive drive device for switching power supplies as described in claim 17, characterized in that, When N=1 and M>0, the switching circuit includes: Main switch and second switch circuit; One end of the main switch is connected to all the constant current sources, one end of the second switch circuit is connected to the first end of the m auxiliary capacitors, and the other end of the second switch circuit is connected to the first end of the other auxiliary capacitors (excluding the m auxiliary capacitors), the other end of the main switch, the second end of the driving capacitor, and the control end of the first driving switch. The second end of all the auxiliary capacitors is grounded, and the second end of the second switch circuit is connected to the adjustment circuit. M ≥ m > 0, where m is an integer. The main switch is used to turn on when charging the drive capacitor; The second switching circuit is used to adjust its own circuit state to select the auxiliary capacitors of the fourth target number to be connected to the circuit, where the second target number minus the fourth target number equals Mm.

20. The adaptive drive device for switching power supplies as described in claim 17, characterized in that, When N > 1 and M > 0, the switching circuit includes: Main switch, first switch circuit, and second switch circuit; One end of the first switching circuit is connected to the output terminals of the n constant current sources. The other end of the first switching circuit is connected to the output terminals of the other constant current sources besides the n constant current sources and one end of the main switch. The other end of the main switch is connected to the first terminal of the second switching circuit, the first terminal of the other auxiliary capacitors besides the m auxiliary capacitors, the second terminal of the driving capacitor, and the control terminal of the first driving switch. The other end of the second switching circuit is connected to the m auxiliary capacitors. The second terminals of all the auxiliary capacitors are grounded. The control terminals of the first switching circuit and the second switching circuit are both connected to the adjustment circuit; N > n ≥ 1, M ≥ m > 0, where m and n are integers. The main switch is used to turn on when charging the drive capacitor; The first switching circuit is used to adjust its own path state to select a third number of constant current sources to be connected to the circuit, where the number of the first target - the number of the third target = Nn; The second switching circuit is used to adjust its own circuit state to select the auxiliary capacitors of the fourth target number to be connected to the circuit, where the second target number minus the fourth target number equals Mm.

21. The adaptive drive device for switching power supplies as described in claim 18 or 20, characterized in that, The first switching circuit includes: There are n controllable switches, each corresponding to one of the n constant current sources. Each controllable switch is located between the output terminal of its corresponding constant current source and one end of the main switch. The control terminal of each controllable switch is connected to the adjustment circuit. The driving circuit also includes: A control circuit is connected to at least one of n controllable switches, the control circuit including a first comparator, a second comparator, a NAND gate, and an OR gate; Wherein, the positive input terminal of the first comparator receives a first comparison voltage value, the negative input terminal of the first comparator and the positive input terminal of the second comparator receive the preset conduction value, the negative input terminal of the second comparator receives a second comparison voltage value, the output terminals of the first comparator and the second comparator are respectively connected to the two input terminals of the NAND gate, the output terminal of the NAND gate is connected to the first input terminal of the OR gate, the second input terminal of the OR gate is connected to the adjustment circuit, and the output terminal of the OR gate is connected to the control terminal of at least one controllable switch. The first comparison voltage value is greater than the second comparison voltage value.

22. The adaptive drive device for switching power supplies as described in claim 19 or 20, characterized in that, The second switching circuit includes: The m sub-switch circuits, m third clamping circuits, and m resistors correspond one-to-one with each of the m sub-switch circuits, m third clamping circuits, m resistors, and m auxiliary capacitors. The first terminal of each sub-switch circuit is connected to the first terminal of the auxiliary capacitor corresponding to itself, the first terminal of the third clamping circuit corresponding to itself, and the first terminal of the resistor corresponding to itself. The second terminal of each auxiliary capacitor and the second terminal of each third clamping circuit are grounded. The second terminal of each resistor is input with a preset clamping voltage. The control terminal of each sub-switch circuit is connected to the adjustment circuit.

23. The adaptive drive device for switching power supplies as described in any one of claims 18-20, characterized in that, The driving circuit also includes: NOT gate, third drive switch, first clamping circuit, second clamping circuit and PWM output module; The first output terminal of the PWM output module is connected to the input terminal of the NOT gate and the control terminal of the third drive switch, respectively. The output terminal of the NOT gate is connected to the control terminal of the main switch. The first terminal of the third drive switch is connected to the first terminal of the first clamping circuit, the first terminal of the second clamping circuit, the second terminal of the drive capacitor, and the control terminal of the first drive switch, respectively. The second terminal of the third drive switch, the second terminal of the first clamping circuit, and the second terminal of the second clamping circuit are all grounded. The second output terminal of the PWM output module is connected to the control terminal of the second drive switch. The two output terminals of the PWM output module output signal levels that are opposite.

24. A switching power supply, characterized in that, Includes the switching power supply adaptive drive device as described in any one of claims 14-23.

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