Voltage control method

Abstract

The present application provides a voltage control method for controlling a power supply, the voltage control method comprising the following steps: obtaining a current output voltage value, the current output voltage value being associated with a current gain value; obtaining a predetermined output voltage value, the predetermined output voltage value being associated with a predetermined duty cycle; then, calculating a target gain value corresponding to the predetermined duty cycle based on a gain value correspondence formula; performing a weighted calculation on the current gain value and the target gain value to generate a buffered gain value; and finally, setting an output voltage command based on the buffered gain value, wherein the buffered gain value is between the current gain value and the target gain value.

Description

Technical Field

[0001] The present application relates to a voltage control method, and in particular to a voltage control method capable of dynamically adjusting a gain value. Background Art

[0002] In order to provide a stable output voltage to the load, traditional power supply systems usually use a feedback mechanism to monitor the output voltage. For example, a common practice is to make the output voltage track a reference voltage to make the output voltage more controllable. Generally speaking, in order to maintain the output voltage efficiency when pulling heavy loads, traditional power supply systems will choose to use a larger gain value. However, in some usage scenarios, such as light loading or floating, using a larger gain value will cause the low output voltage to have more obvious ripple, and the ripple may cause the power supply system to not meet the customer's specifications. Conversely, if a smaller gain value is chosen to solve the ripple problem, when a heavy load is suddenly pulled, it is easy to have the problem of insufficient instantaneous response.

[0003] Therefore, the industry needs a new voltage control method that can dynamically adjust the gain value to adapt to different load types, especially to balance the stability at low output voltage and the transient response speed under heavy load. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a voltage control method that can dynamically adjust the gain value at low voltage output to improve the ripple problem, and can also improve the transient response speed when pulling heavy loads.

[0005] The present application provides a voltage control method for controlling a power supply, the voltage control method comprising the following steps: obtaining a current output voltage value, the current output voltage value being associated with a current gain value; obtaining a predetermined output voltage value, the predetermined output voltage value being associated with a predetermined duty cycle; then, calculating a target gain value corresponding to the predetermined duty cycle based on a gain value correspondence formula; performing a weighted calculation on the current gain value and the target gain value to generate a buffered gain value; and finally, setting an output voltage command based on the buffered gain value, wherein the buffered gain value is between the current gain value and the target gain value.

[0006] In some embodiments, the step of calculating a target gain value corresponding to a predetermined duty cycle based on a gain value correspondence formula further includes the following steps: Determining whether the target gain value is lower than a first threshold or higher than a second threshold. Furthermore, when the target gain value is lower than the first threshold, the target gain value may be set to the first threshold. When the target gain value is higher than the second threshold, the target gain value may be set to the second threshold. Furthermore, the voltage control method further includes detecting an inductor current of the power supply. When a change in the inductor current is greater than a third threshold, a priority command may be generated. When a priority command exists, the output voltage command may be set based on the second threshold.

[0007] In some embodiments, when weighting the current gain value and the target gain value to generate the buffered gain value, a first weight may be assigned to the current gain value and a second weight may be assigned to the target gain value, wherein the first weight is greater than the second weight. Furthermore, the buffered gain value may be the sum of the product of the first weight and the current gain value and the product of the second weight and the target gain value.

[0008] In summary, the voltage control method provided by this application can dynamically adjust the gain value during low voltage output and reduce the instantaneous gain change, thereby improving ripple issues. Furthermore, this voltage control method can also detect whether the power supply is operating at a heavy load. When the power supply is operating at a heavy load, it directly generates a priority command to set a higher gain value, thereby improving transient response speed.

[0009] The details of other functions and embodiments of the present application are described below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0011] Figure 1 is a functional block diagram of a power supply applying a voltage control method according to an embodiment of the present application;

[0012] Figure 2 is a schematic diagram of the corresponding relationship between gain and duty cycle according to an embodiment of the present application;

[0013] Figure 3 is a flowchart of a voltage control method according to an embodiment of the present application.

[0014] Explanation of symbols

[0015] 1: Power supply 10: Control unit 12: Voltage output unit

[0016] 14: Voltage measurement unit 16: Inductor current measurement unit S20~S28: Step flow DETAILED DESCRIPTION

[0017] The positional relationships described in the following embodiments include up, down, left, and right. Unless otherwise specified, they are based on the directions of the components shown in the drawings.

[0018] Please refer to Figure 1 , Figure 1 FIG is a functional block diagram of a power supply using a voltage control method according to an embodiment of the present application. Figure 1 As shown, the voltage control method of the present application can be applied to a power supply system, such as a power supply 1. The power supply 1 can include a control unit 10, a voltage output unit 12, a voltage measuring unit 14, and an inductor current measuring unit 16. Here, the control unit 10 can be electrically connected to the voltage output unit 12, the voltage measuring unit 14, and the inductor current measuring unit 16, respectively. In an example, the voltage output unit 12 can be a buck converter circuit (buck converter) or other PWM voltage conversion circuit. The output stage of the voltage output unit 12 can be connected to a load (not shown), and the voltage measuring unit 14 is used to measure the voltage value output by the voltage output unit 12 to the load, which can be represented as the current output voltage value Vo. In addition, the inductor current measuring unit 16 is disposed in the voltage output unit 12 or electrically connected to the voltage output unit 12 to measure the inductor current in the voltage output unit 12 (e.g., the power stage of the voltage output unit 12).

[0019] Those with general knowledge in the relevant technical field should be able to understand that the voltage output unit 12 can determine the size of the output voltage based on the duty ratio of the control voltage switching duty cycle of the control unit 10. In practice, the control unit 10 can receive a predetermined output voltage value Vref from the outside, and obtain the current output voltage value Vo from the voltage measurement unit 14. The control voltage can be determined by the error between the predetermined output voltage value Vref and the current output voltage value Vo, which will not be described in detail in this embodiment. Traditionally, the loop gain of the voltage output unit does not change, but the loop gain of the voltage output unit 12 of this embodiment can be dynamically adjusted. In an example, the voltage output unit 12 can store a gain value correspondence formula, which can be a lookup table or a linear equation, which is not limited in this embodiment. To illustrate how the voltage output unit 12 adjusts the loop gain, please refer to Figure 1 and Figure 2 , Figure 2 This is a schematic diagram of the corresponding relationship between gain and duty cycle according to an embodiment of the present application. For example, assuming that the voltage output unit 12 outputs the current output voltage value Vo at a previous time point, the duty cycle of the voltage output unit 12 generating the current output voltage value Vo should be known, for example, the duty cycle corresponding to the current output voltage value Vo is r2. At this time, through Figure 2 From the relationship between gain and duty cycle (gain value correspondence formula), it can be inferred that when the duty cycle is r2, the corresponding gain value is k1 (current gain value).

[0020] Next, assuming that the voltage output unit 12 can obtain the predetermined output voltage value Vref at the next time point from the control voltage, the duty cycle (predetermined duty cycle) corresponding to the predetermined output voltage value Vref can also be calculated, for example, r3. Figure 2 From the relationship between gain and duty cycle (gain value correspondence formula), it can be inferred that when the duty cycle is r3, the corresponding gain value is k2 (target gain value). However, the voltage output unit 12 of this embodiment will not directly adjust the loop gain to k2 at the next time point. The reason is that directly changing the gain value k1 to the gain value k2 will cause the gain value to fluctuate, making the voltage waveform output by the voltage output unit 12 unstable (for example, there will be obvious ripples). Accordingly, the voltage output unit 12 of this embodiment will perform weight calculation on the gain value k1 (current gain value) and the gain value k2 (target gain value) to generate a weighted gain value k12 (buffered gain value). In an example, the voltage output unit 12 can give the gain value k1 a weight a1 (first weight) and give the gain value k2 a weight a2 (second weight). At this time, the weighted gain value kx can be expressed as the following weight calculation formula (1).

[0021] kx=a1*k1+a2*k2 (1)

[0022] As can be seen from the above formula (1), the buffer gain value kx is the sum of the product of the weight a1 (first weight) and the gain value k1 (current gain value), and the product of the weight a2 (second weight) and the gain value k2 (target gain value). Assuming that the weight a1 and the weight a2 can each be between 0 and 1, and the sum of them is equal to 1, the gain value kx (buffer gain value) will be between the gain value k1 (current gain value) and the gain value k2 (target gain value). In practice, in order to prevent the weighted gain value kx from fluctuating too much, the weight a1 can be greater than the weight a2. For example, the weight a1 can be 0.9 and the weight a2 can be 0.1, so that the gain value k12 will be closer to the gain value k1. In an example, the voltage output unit 12 will set the output voltage command based on the weighted gain value kx to generate the output voltage to be output to the load at the next time point.

[0023] It is worth mentioning that when the duty cycle is substituted into the gain value equation, the gain value may have upper and lower limits, and may not fully reflect the change in duty cycle. For example, Figure 2 The relationship between gain and duty cycle (gain value correspondence formula) shown in the figure shows that if the duty cycle is less than r1, the gain value will be limited to the lower limit gain value k0 (first threshold). Conversely, if the duty cycle is greater than r4, the gain value will be limited to the upper limit gain value k3 (second threshold). Similarly, it is assumed that the voltage output unit 12 outputs the current output voltage value Vo at the previous time point, and the current output voltage value Vo corresponds to a duty cycle of r2 and a current gain value of k1. At this time, assuming that the voltage output unit 12 calculates that the duty cycle corresponding to the predetermined output voltage value Vref is r0, according to the original gain value correspondence formula, the target gain value corresponding to the duty cycle r0 should be calculated as ka. However, since the target gain value ka is lower than the lower limit gain value k0, it will be directly limited to the gain value k0, that is, the voltage output unit 12 will set the target gain value to the gain value k0. At this time, the weighted gain value kx can be expressed as the following weight calculation formula (2).

[0024] kx=a1*k1+a2*k0 (2)

[0025] Similarly, assuming that the voltage output unit 12 calculates that the duty cycle corresponding to the predetermined output voltage value Vref is r5, according to the original gain value correspondence formula, the target gain value corresponding to the duty cycle r5 should be calculated as kb. However, because the target gain value kb is lower than the upper limit gain value k3, it is directly limited to the gain value k3. In other words, the voltage output unit 12 sets the target gain value to the gain value k3. At this time, the weighted gain value kx can be expressed as the following weight calculation formula (3).

[0026] kx=a1*k1+a2*k3 (3)

[0027] From the above example, we can see that the gain value correspondence is the correspondence between gain and duty cycle, which can also be seen as Figure 2The slope of the line in FIG. 2 is not limited in this embodiment. Furthermore, this embodiment does not limit the setting values ​​of the lower or upper gain limits; those skilled in the art may freely choose to use these values. Generally speaking, the above-described example of using weighted calculation to obtain a weighted gain value is more suitable for applications where the load being drawn by the power supply 1 is light or no-load. If the load being drawn by the power supply 1 suddenly becomes heavy (e.g., drawing a large current), the voltage output unit 12 may no longer use weighted calculation. In practice, when the load being drawn by the power supply 1 suddenly becomes heavy, the inductor current measurement unit 16 detects a change in the inductor current. For example, if the change in the inductor current exceeds a predetermined threshold (the third threshold), the signal output by the inductor current measurement unit 16 will be equivalent to a priority command. At this point, based on the priority command, the voltage output unit 12 will directly set the output voltage command using the highest gain value (e.g., the second threshold) to generate the output voltage to be output to the load at the next point in time. In other words, when the voltage output unit 12 is lightly loaded or unloaded, it can use a weighted gain value to set the output voltage command, thus preventing sudden fluctuations in the gain value that could cause an unstable voltage waveform output by the voltage output unit 12. Furthermore, when the voltage output unit 12 is heavily loaded, it can use a priority command to skip the weight calculation and directly use the maximum gain value to set the output voltage command, thus preventing a slowdown in voltage response when loading.

[0028] To illustrate the voltage control method of this application, please refer to Figures 1 to 3 , Figure 3 This is a flowchart of the steps of the voltage control method according to an embodiment of the present application. As shown in the figure, in step S20, the voltage measurement unit 14 can measure the current output voltage value Vo output by the voltage output unit 12 to the load, and the current output voltage value Vo will have a corresponding gain value (current gain value) and duty cycle. In step S22, the control unit 10 will receive the predetermined output voltage value, and the predetermined output voltage value will also have a corresponding gain value and duty cycle (predetermined duty cycle). In step S24, the voltage output unit 12 can calculate the target gain value corresponding to the predetermined duty cycle based on the gain value corresponding formula. In step S26, the voltage output unit 12 can perform weighted calculation on the current gain value and the target gain value to generate a buffered gain value, such as the above formula (1) to formula (3). Finally, the voltage output unit 12 sets the output voltage command based on the buffered gain value to generate the output voltage to be output to the load at the next time point.

[0029] In summary, the voltage control method provided by this application can dynamically adjust the gain value during low voltage output and reduce the instantaneous gain change, thereby improving ripple issues. Furthermore, this voltage control method can also detect whether the power supply is operating at a heavy load. When the power supply is operating at a heavy load, it directly generates a priority command to set a higher gain value, thereby improving transient response speed.

[0030] The embodiments and / or implementation methods described above are only used to illustrate the preferred embodiments and / or implementation methods for realizing the technology of the present application, and do not impose any form of limitation on the implementation methods of the technology of the present application. Any person skilled in the art may make slight changes or modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present application, but they should still be regarded as technologies or embodiments that are essentially the same as those of the present application.

Claims

1. A voltage control method for controlling a power supply, characterized in that: The voltage control method comprises: Obtaining a current output voltage value, where the current output voltage value is associated with a current gain value; Obtaining a predetermined output voltage value, the predetermined output voltage value being associated with a predetermined duty cycle; Calculating a target gain value corresponding to the predetermined duty cycle according to a gain value corresponding formula; Performing a weight calculation on the current gain value and the target gain value to generate a buffered gain value; as well as setting an output voltage command according to the buffer gain value; The buffer gain value is between the current gain value and the target gain value.

2. The voltage control method according to claim 1, wherein: The step of calculating the target gain value corresponding to the predetermined duty cycle according to the gain value corresponding formula further includes: Determining whether the target gain value is lower than a first threshold; When the target gain value is lower than the first threshold, setting the target gain value to the first threshold; and Determining whether the target gain value is higher than a second threshold; When the target gain value is higher than the second threshold, the target gain value is set to the second threshold.

3. The voltage control method according to claim 2, wherein: Also includes: detecting an inductor current of the power supply; When a change in the inductor current is greater than a third threshold, a priority command is generated; and When the priority command exists, the output voltage command is set according to the second threshold.

4. The voltage control method according to claim 1, wherein: In the step of performing the weight calculation on the current gain value and the target gain value to generate the buffer gain value, a first weight is further provided to the current gain value, and a second weight is provided to the target gain value, wherein the first weight is greater than the second weight.

5. The voltage control method according to claim 4, wherein: The buffer gain value is the sum of the product of the first weight and the current gain value and the product of the second weight and the target gain value.

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