An input voltage and current feedforward combined control circuit and control method

Abstract

This invention relates to a combined input voltage and current feedforward control circuit and method, comprising an input voltage feedforward circuit and an input current feedforward circuit. The input voltage feedforward circuit acquires the input voltage at the input terminal of the power supply circuit and outputs a waveform control signal to limit the maximum duty cycle of the output voltage of the power supply circuit. The input current feedforward circuit rapidly responds to input transients in the power supply circuit and modulates the duty cycle of the waveform control signal. The combination of these two circuits results in minimal fluctuations in the output voltage of the power supply circuit under input transient conditions. The control circuit structure of this invention is simple, requiring only a comparator, switching devices, an operational amplifier, and an optocoupler to construct both the input voltage and current feedforward circuits. Furthermore, this invention combines input voltage feedforward to limit the maximum duty cycle and input current feedforward to control PWM, enabling rapid response to input changes and stabilizing the output of the power supply circuit, effectively solving the problems of overshoot or drop during input transients.

Description

Technical Field

[0001] This invention relates to the field of power supply design, and more specifically, to an input voltage and current feedforward combined control circuit and control method. Background Technology

[0002] As electronic devices place increasingly higher demands on power system performance, power systems are employing advanced technologies to provide faster and more stable responses, ensuring the reliability and performance of devices under various input conditions. Among these, optimizing the power system response has become particularly important.

[0003] Power system response refers to the dynamic response of a power system when encountering transient input voltage changes. In these transient situations, if the power system cannot quickly and accurately adjust the output voltage and current, overshoot or sag in the output will occur. This abnormal response may affect the normal operation of downstream devices connected to the power system, and may even lead to system-level failures, threatening the reliability and performance of the system.

[0004] Traditional power supply system designs typically sample the input voltage and limit the output duty cycle based on the sampling results. For example, a digital power supply input voltage feedforward control circuit disclosed in patent application CN202010455484.4 includes a first sampling circuit for acquiring the input voltage of the transformer and a second sampling circuit for acquiring the output voltage of the transformer. It is evident that the input terminal only samples the voltage, and this circuit also requires the use of a transformer, resulting in a complex circuit structure and high cost. This method of sampling the input voltage to limit the maximum duty cycle still suffers from overshoot and sag, and remains unsuitable for demanding systems.

[0005] The above problems are worth solving. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides an input voltage and current feedforward combined control circuit and control method.

[0007] The technical solution of this invention is as follows:

[0008] An input voltage and current feedforward combined control circuit, characterized in that it includes:

[0009] The input voltage feedforward circuit includes a voltage input terminal, a clock signal input terminal, an energy storage element, and a first comparator. The voltage input terminal is connected to the input terminal of the power supply circuit and obtains the input voltage. The negative input terminal of the first comparator is connected to the voltage input terminal and the energy storage element. The positive input terminal of the first comparator is connected to the clock signal input terminal, and the clock signal input terminal is also connected to the discharge control branch of the energy storage element. The output terminal of the first comparator is connected to the duty cycle controller.

[0010] The input current feedforward circuit includes a current sampling terminal, a first signal amplifier, a second signal amplifier, and an optocoupler. The current sampling terminal is connected to the input terminal of the power supply circuit and samples the current, and is input to the inverting input terminal of the first signal amplifier. The output terminal of the first signal amplifier is connected to the non-inverting input terminal of the second signal amplifier. The optocoupler is connected to the inverting input terminal of the second signal amplifier. The output terminal of the second signal amplifier is connected to the input terminal of the PWM waveform comparator.

[0011] According to the present invention based on the above scheme, the voltage input terminal of the input voltage feedforward circuit is provided with a first resistor and a second resistor connected in series, the other end of the second resistor is connected to the negative input terminal of the first comparator and a first capacitor used as the energy storage element, and the other end of the first capacitor is grounded.

[0012] Furthermore, a fourth resistor is connected in parallel with the first capacitor.

[0013] Furthermore, a fifth resistor is connected in series between the positive input and output terminals of the first comparator.

[0014] Furthermore, the fifth pin of the first comparator is connected to the power supply voltage, and a diode is provided between the fifth pin and the second resistor on the voltage input terminal; a second capacitor is connected between the fifth pin and the second pin of the first comparator.

[0015] Furthermore, the clock signal input terminal is provided with a third resistor, the other end of which is connected to the positive input terminal of the first comparator.

[0016] Furthermore, a sixth resistor is provided between the third resistor and the second capacitor.

[0017] According to the present invention described above, the discharge control branch of the energy storage element includes a first switch and a second switch. The input terminal of the conduction branch of the first switch is connected to the energy storage element. The control terminal of the first switch is connected to the input terminal of the conduction branch of the second switch, and this terminal is connected to the power supply voltage and the control terminal of the third switch. The control terminal of the second switch is connected to the clock signal input terminal.

[0018] Furthermore, the output terminals of the conduction branches of the first switch, the second switch, and the third switch are all grounded.

[0019] Furthermore, a seventh resistor is provided at the input terminal of the conduction branch of the second switching transistor.

[0020] According to the present invention of the above scheme, an eighth resistor is provided between the inverting input terminal and the current sampling terminal of the first signal amplifier, a ninth resistor is provided between the non-inverting input terminal and the ground terminal of the first signal amplifier, a third capacitor is connected between the eighth resistor and the ninth resistor, and a fourth capacitor and a fifth capacitor are respectively connected to the two ends of the third capacitor.

[0021] According to the present invention based on the above scheme, the positive input terminal of the first signal amplifier is also connected to a power supply voltage, and a tenth resistor and a sixth capacitor connected in parallel.

[0022] Furthermore, both the tenth resistor and the sixth capacitor are grounded.

[0023] According to the present invention based on the above scheme, an eleventh resistor and a seventh capacitor are connected in parallel between the inverting input terminal and the output terminal of the first signal amplifier.

[0024] Furthermore, the second pin of the first signal amplifier is grounded, and an eighth capacitor is provided between the second pin and the fifth pin; the fifth pin is also connected to the power supply voltage.

[0025] Furthermore, a resistor R29 is provided between the fifth pin and the supply voltage.

[0026] According to the present invention based on the above scheme, a twelfth resistor is provided between the positive input terminal of the second signal amplifier and the output terminal of the first signal amplifier.

[0027] According to the present invention based on the above scheme, a ninth capacitor and a tenth capacitor are provided in parallel between the positive input terminal and the output terminal of the second signal amplifier, and the tenth capacitor is connected in series with a thirteenth resistor.

[0028] According to the present invention based on the above scheme, the inverting input terminal of the second signal amplifier is connected to the power supply voltage and the input terminal of the optocoupler, and the output terminal of the optocoupler is grounded.

[0029] Furthermore, a resistor R105 is provided between the inverting input terminal of the second signal amplifier and the supply voltage.

[0030] According to the present invention based on the above scheme, the second pin of the second signal amplifier is grounded, the fifth pin is connected to the power supply voltage and the eleventh capacitor, and the other end of the eleventh capacitor is grounded.

[0031] The present invention also provides a control method based on the input voltage and current feedforward combined control circuit described above. The input voltage feedforward circuit obtains the input voltage of the power supply, controls the discharge time of the energy storage element through a clock signal, and then uses a first comparator to compare the clock signal level with the energy storage element level to limit the maximum duty cycle of the power supply output voltage with an output waveform control signal.

[0032] The input current feedforward circuit samples the input current of the power supply, and the first signal amplifier quickly responds to the transient input current and outputs the transient first signal. The first signal is quickly responded to by the second signal amplifier, and after amplification, it outputs the rapidly changing second signal. Combined with the input voltage feedforward circuit, it quickly responds to the input transient and stabilizes the output voltage.

[0033] According to the above-described solution, the beneficial effects of this invention are as follows:

[0034] The control circuit structure of this invention is simple. It can be built with only a comparator, a switching device, an operational amplifier and an optocoupler to form an input voltage feedforward circuit and an input current feedforward circuit. Furthermore, this invention combines the input voltage feedforward to limit the maximum duty cycle, and the input current feedforward circuit to quickly respond to the input transients of the power supply circuit, modulate the duty cycle of the waveform control signal, stabilize the output of the power supply circuit, and effectively solve the problems of overshoot or drop in input transients. Attached Figure Description

[0035] Figure 1 This is a circuit diagram of the input current feedforward circuit in this invention;

[0036] Figure 2 This is a circuit diagram of the input voltage feedforward circuit in this invention. Detailed Implementation

[0037] To better understand the purpose, technical solution, and technical effects of this invention, the invention will be further explained and described below in conjunction with the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also stated that the embodiments described below are only for explaining this invention and are not intended to limit this invention.

[0038] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intermediate component.

[0039] The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed when in use, or the orientation or positional relationship in which a person skilled in the art would normally understand it, or the orientation or positional relationship in which the product is usually placed when in use. It is only for the purpose of facilitating the description of this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] The terms “first,” “second,” “third,” “fourth,” “fifth,” “sixth,” “seventh,” “eighth,” “ninth,” “tenth,” “eleventh,” “twelfth,” and “thirteenth” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or specifying the number of technical features.

[0041] like Figure 1 and Figure 2 As shown, an input voltage and current feedforward combined control circuit includes:

[0042] The input voltage feedforward circuit includes a voltage input terminal VIN+, a clock signal input terminal (CLK terminal), an energy storage element, and a first comparator U10. The voltage input terminal VIN+ is connected to the input terminal of the power supply circuit and obtains the input voltage. The negative input terminal of the first comparator U10 is connected to the voltage input terminal VIN+ and the energy storage element. The positive input terminal of the first comparator U10 is connected to the clock signal input terminal (CLK terminal), and the clock signal input terminal (CLK terminal) is also connected to the discharge control branch of the energy storage element. The output terminal D-LIMT of the first comparator U10 is connected to the duty cycle controller and is used to output a waveform control signal.

[0043] The input current feedforward circuit includes a current sampling terminal (-IS), a first signal amplifier U4, a second signal amplifier U17, and an optocoupler OT1-A. The current sampling terminal (-IS) is connected to the input terminal of the power supply circuit and samples the current. It is also input to the inverting input terminal of the first signal amplifier U4. The output terminal of the first signal amplifier U4 is connected to the non-inverting input terminal of the second signal amplifier U17. The optocoupler OT1-A is connected to the inverting input terminal of the second signal amplifier U17. The output terminal (FB terminal) of the second signal amplifier U17 is connected to the input terminal of the PWM waveform comparator.

[0044] In one specific embodiment, the voltage input terminal VIN+ of the input voltage feedforward circuit has a first resistor R70 and a second resistor R66 connected in series. The other end of the second resistor R66 is connected to the negative input terminal of the first comparator U10 and a first capacitor C42, which serves as an energy storage element. The other end of the first capacitor C42 is grounded. A fourth resistor R67 is connected in parallel with the first capacitor C42. A fifth resistor R68 is connected in series between the positive input terminal and the output terminal of the first comparator U10. The fifth pin of the first comparator U10 is connected to the supply voltage (+5V). A diode D10 is provided between the fifth pin and the second resistor R66 on the voltage input terminal VIN+. A second capacitor C20 is connected between the fifth pin and the second pin of the first comparator U10.

[0045] In one specific embodiment, the clock signal input terminal (CLK terminal) is provided with a third resistor R64, the other end of which is connected to the positive input terminal of the first comparator U10. A sixth resistor R65 is provided between the third resistor R64 and the second capacitor C20.

[0046] In this invention, the discharge control branch of the energy storage element includes a first switch Q10-B and a second switch Q2-B. The input terminal of the conduction branch of the first switch Q10-B is connected to the energy storage element. The control terminal of the first switch Q10-B is connected to the input terminal of the conduction branch of the second switch Q2-B, and this terminal is connected to the supply voltage (+5V) and the control terminal of the third switch Q2-A. The control terminal of the second switch Q2-B is connected to the clock signal input terminal (CLK terminal). The output terminals of the conduction branches of the first switch Q10-B, the second switch Q2-B, and the third switch Q2-A are all grounded. A seventh resistor R69 is provided at the input terminal of the conduction branch of the second switch Q2-B.

[0047] In the input current feedforward circuit, an eighth resistor R16 is provided between the inverting input terminal and the current sampling terminal (-IS) of the first signal amplifier U4, and a ninth resistor R19 is provided between the non-inverting input terminal and the ground terminal of the first signal amplifier U4. A third capacitor C47 is connected between the eighth resistor R16 and the ninth resistor R19. A fourth capacitor C36 and a fifth capacitor C25 are connected to the two ends of the third capacitor C47, respectively.

[0048] The positive input terminal of the first signal amplifier U4 is also connected to the power supply voltage (+5V), and a tenth resistor R27 and a sixth capacitor C48 are connected in parallel. A resistor R251 is provided between the positive input terminal of the first signal amplifier U4 and the power supply voltage (+5V). Both the tenth resistor R27 and the sixth capacitor C48 are grounded.

[0049] The circuit principle of the input voltage feedforward circuit is as follows:

[0050] The clock signal input terminal (CLK terminal) receives a clock signal. When the clock signal is low, the second switch Q2-B is off, the third switch Q2-A is on, the "ON" terminal is high, the first switch Q10-B is on, and the first capacitor C42 discharges through the first switch Q10-B. When the clock signal flips to high, the second switch Q2-B is on, the third switch Q2-A is off, the "ON" terminal is low, the first switch Q10-B is off, the first capacitor C42 stops discharging, and the voltage input terminal VIN+ charges the first capacitor C42 through the first resistor R70 and the second resistor R66. In addition, the voltage at the third pin of the first comparator U10 is greater than the voltage at the fourth pin, causing the output terminal (i.e., the first pin) of the first comparator U10 to output a high level. Since the first capacitor C42 is in a charging state, when the charging voltage of the first capacitor C42 exceeds the voltage at the third pin, the output terminal of the first comparator U10 flips to low. The first capacitor C42 is discharged again after the clock signal CLK goes low. It can be seen that the present invention can achieve the maximum duty cycle of the output of the first pin of the first comparator U10 through the input voltage feedforward circuit.

[0051] The circuit principle of the input current feedforward circuit is as follows:

[0052] The inverting input terminal of the first signal amplifier U4 samples the input current. An optocoupler OT1-A is installed in the voltage loop feedback branch of this circuit. When the input current changes transiently, the first signal amplifier U4 responds quickly by increasing or decreasing. Due to the presence of the optocoupler OT1-A, the output response of the voltage loop feedback branch is slow. Therefore, the voltage at the third pin of the second signal amplifier U17 remains essentially unchanged, causing the output voltage at its first pin to decrease or increase rapidly. The larger the signal voltage at the output terminal (FB terminal) of the second signal amplifier U17, the larger the output duty cycle, and vice versa. Negative feedback voltage regulation is achieved through the output-side negative feedback circuit, comparing the input current with the optocoupler OT1-A, and the FB signal serves as the negative feedback dual-loop output.

[0053] By combining the aforementioned input voltage feedforward circuit and input current feedforward circuit, a rapid response to input transients can be achieved, and the output voltage can be quickly stabilized. Stabilizing the output voltage relies on a negative feedback loop, while voltage feedforward limits output variations.

[0054] In this invention, an eleventh resistor R26 and a seventh capacitor C39 are connected in parallel between the inverting input and output terminals of the first signal amplifier U4. The second pin of the first signal amplifier U4 is grounded, and an eighth capacitor C38 is located between the second and fifth pins; the fifth pin is also connected to a power supply voltage (+5V). A resistor R29 is located between the fifth pin and the power supply voltage (+5V).

[0055] A twelfth resistor R188 is provided between the positive input terminal of the second signal amplifier U17 and the output terminal of the first signal amplifier U4. A ninth capacitor C73 and a tenth capacitor C66 are connected in parallel between the positive input terminal and the output terminal of the second signal amplifier U17, and the tenth capacitor C66 is connected in series with a thirteenth resistor R108. The inverting input terminal of the second signal amplifier U17 is connected to the supply voltage (+5V) and the input terminal of the optocoupler OT1-A, and the output terminal of the optocoupler OT1-A is grounded. A resistor R105 is also provided between the inverting input terminal of the second signal amplifier U17 and the supply voltage (+5V). The second pin of the second signal amplifier U17 is grounded, and the fifth pin is connected to the supply voltage (+5V) and the eleventh capacitor, the other end of which is grounded.

[0056] The present invention also provides a control method based on the above-described scheme, which combines input voltage and current feedforward control circuit.

[0057] The input voltage feedforward circuit obtains the input voltage of the power supply, controls the discharge time of the energy storage element through the clock signal, and then uses the first comparator U10 to compare the clock signal level with the energy storage element level, and uses the output waveform control signal to limit the maximum duty cycle of the power supply output voltage.

[0058] The input current feedforward circuit samples the input current of the power supply, and the first signal amplifier U4 quickly responds to the transient input current and outputs the transient first signal. The first signal is quickly responded to by the second signal amplifier U17, and after amplification, it outputs the rapidly changing second signal. Combined with the waveform control signal output by the input voltage feedforward circuit, the output voltage is stabilized.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A combined input voltage and current feedforward control circuit, characterized in that, include: The input voltage feedforward circuit includes a voltage input terminal, a clock signal input terminal, an energy storage element, and a first comparator. The voltage input terminal is connected to the input terminal of the power supply circuit and obtains the input voltage. The negative input terminal of the first comparator is connected to the voltage input terminal and the energy storage element. The positive input terminal of the first comparator is connected to the clock signal input terminal, and the clock signal input terminal is also connected to the discharge control branch of the energy storage element. The output terminal of the first comparator is connected to the duty cycle controller. The input current feedforward circuit includes a current sampling terminal, a first signal amplifier, a second signal amplifier, and an optocoupler. The current sampling terminal is connected to the input terminal of the power supply circuit and samples the current, and is input to the inverting input terminal of the first signal amplifier. The output terminal of the first signal amplifier is connected to the non-inverting input terminal of the second signal amplifier. The optocoupler is connected to the inverting input terminal of the second signal amplifier. The output terminal of the second signal amplifier is connected to the input terminal of the PWM waveform comparator. An eighth resistor is provided between the inverting input terminal and the current sampling terminal of the first signal amplifier, and a ninth resistor is provided between the non-inverting input terminal and the ground terminal of the first signal amplifier. A third capacitor is connected between the eighth resistor and the ninth resistor, and a fourth capacitor and a fifth capacitor are respectively connected to the two ends of the third capacitor. The positive input terminal of the first signal amplifier is also connected to a power supply voltage, as well as a tenth resistor and a sixth capacitor connected in parallel.

2. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, The voltage input terminal of the input voltage feedforward circuit is provided with a first resistor and a second resistor connected in series. The other end of the second resistor is connected to the negative input terminal of the first comparator and a first capacitor used as the energy storage element. The other end of the first capacitor is grounded.

3. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, The discharge control branch of the energy storage element includes a first switch and a second switch. The input terminal of the conduction branch of the first switch is connected to the energy storage element. The control terminal of the first switch is connected to the input terminal of the conduction branch of the second switch, and this terminal is connected to the power supply voltage and the control terminal of the third switch. The control terminal of the second switch is connected to the clock signal input terminal.

4. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, An eleventh resistor and a seventh capacitor are connected in parallel between the inverting input and output terminals of the first signal amplifier.

5. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, A twelfth resistor is provided between the positive input terminal of the second signal amplifier and the output terminal of the first signal amplifier.

6. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, The second signal amplifier has a ninth capacitor and a tenth capacitor connected in parallel between its positive input and output terminals, and the tenth capacitor is connected in series with a thirteenth resistor.

7. The input voltage and current feedforward combined control circuit according to claim 1, characterized in that, The inverting input of the second signal amplifier is connected to the power supply voltage and the input of the optocoupler, and the output of the optocoupler is grounded.

8. A control method based on the input voltage and current feedforward combined control circuit according to any one of claims 1 to 7, characterized in that, The input voltage feedforward circuit obtains the input voltage of the power supply, controls the discharge time of the energy storage element through the clock signal, and then uses the first comparator to compare the clock signal level with the energy storage element level, and uses the output waveform control signal to limit the maximum duty cycle of the power supply output voltage. The input current feedforward circuit samples the input current of the power supply, and the first signal amplifier quickly responds to the transient input current and outputs the transient first signal. The first signal is quickly responded to by the second signal amplifier, and after amplification, it outputs the rapidly changing second signal. Combined with the input voltage feedforward circuit, it quickly responds to the input transient and stabilizes the output voltage.

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