Ripple compensation circuit and chip

Abstract

The utility model discloses a ripple compensation circuit and a chip, relates to the field of integrated circuit design, and solves the problem that the output voltage precision and the load regulation rate are low when the ripple of the output voltage is compensated. The ripple compensation circuit comprises a power tube which comprises an upper tube and a lower tube which are connected; the ripple generation circuit is connected with an output node and a voltage output end and is used for generating ripple voltage, and the output node is a node for connecting the upper tube and the lower tube; the adjusting circuit is connected with the ripple generating circuit, is also connected with the feedback node and the voltage output end, and is used for adjusting the direct current component of the ripple voltage according to the feedback voltage and the output voltage; and the compensation circuit is connected with the feedback node, is used for accessing a feedback voltage, is also connected with the ripple generation circuit, and is used for generating a ripple compensation voltage according to the feedback voltage and the alternating current component of the ripple voltage.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit design, and in particular to a ripple compensation circuit and chip. Background Technology

[0002] With the development of electronic devices, the requirements for the reliability and conversion efficiency of power management chips are becoming increasingly stringent. Currently, power management chips typically use a constant on-time (COT) architecture. Power management chips based on the COT architecture have the advantages of fast response speed and high conversion efficiency.

[0003] In power management chips based on the COT architecture, output voltage ripple is typically compensated. Specifically, the ripple voltage can be superimposed on the comparator for compensation, addressing subharmonic oscillations caused by excessively low ESR resistance of the load capacitor. However, this compensation method may result in an output voltage that is too high or too low, affecting output voltage accuracy and load regulation. Summary of the Invention

[0004] This invention provides a ripple compensation circuit and chip, which solves the problem of low output voltage accuracy and load regulation when compensating for output voltage ripple.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, this utility model provides a ripple compensation circuit, the ripple compensation circuit comprising:

[0007] A power transistor consists of an upper transistor and a lower transistor, which are connected together.

[0008] The ripple generation circuit is connected to the output node and the voltage output terminal to generate ripple voltage. The output node is the node connecting the upper and lower transistors.

[0009] The regulating circuit, connected to the ripple generation circuit, and also connected to the feedback node and voltage output terminal, is used to regulate the DC component of the ripple voltage according to the feedback voltage and the output voltage.

[0010] The compensation circuit, connected to the feedback node for receiving the feedback voltage, is also connected to the ripple generation circuit. The compensation circuit is used to generate a ripple compensation voltage based on the AC components of the feedback voltage and the ripple voltage.

[0011] In one possible implementation, the compensation circuit includes: a buffer;

[0012] The input of the buffer is connected to the feedback node, and the output is connected to the ripple generation circuit. It is used to generate a ripple compensation voltage based on the AC components of the feedback voltage and the ripple voltage.

[0013] In one possible implementation, the buffer includes a first operational amplifier and a first resistor;

[0014] The first input terminal of the first operational amplifier is connected to the feedback node, and the second input terminal is connected to the output terminal of the first operational amplifier and one end of the first resistor;

[0015] The other end of the first resistor is connected to the ripple generation circuit.

[0016] In one possible implementation, the first resistor is an adjustable resistor.

[0017] In one possible implementation, the ripple generation circuit includes a second resistor and a capacitor;

[0018] One end of the second resistor is connected to the output node, and the other end is connected to one end of the capacitor, the adjustment circuit, and the compensation circuit.

[0019] The other end of the capacitor is connected to the voltage output terminal.

[0020] In one possible implementation, the regulating circuit includes a current mirror and an operational amplifier circuit.

[0021] The first end of the current mirror is connected to the ripple generation circuit and the compensation circuit, the second end is grounded, the third end is connected to the output terminal of the operational amplifier circuit, and the fourth end is connected to the first input terminal of the operational amplifier circuit.

[0022] The first input terminal of the operational amplifier circuit is connected to the output voltage;

[0023] The second input terminal of the operational amplifier circuit is connected to the feedback voltage.

[0024] In one possible implementation, the current mirror includes a first transistor and a second transistor;

[0025] The control electrode of the first transistor is connected to the control electrode of the second transistor and the output terminal of the operational amplifier circuit.

[0026] The first terminal of the first transistor is connected to the ripple generation circuit and the compensation circuit, and the second terminal is grounded.

[0027] The first terminal of the second transistor is connected to the first input terminal of the operational amplifier circuit, and the second terminal is grounded.

[0028] In one possible implementation, the operational amplifier circuit includes a second operational amplifier and a third resistor;

[0029] One end of the third resistor is connected to the output voltage, and the other end is connected to the first input terminal of the second operational amplifier and the fourth terminal of the current mirror.

[0030] The second input terminal of the second operational amplifier is connected to the feedback voltage;

[0031] The output of the second operational amplifier is connected to the third terminal of the current mirror.

[0032] In one possible implementation, both the first transistor and the second transistor are NMOS transistors.

[0033] Secondly, this utility model provides a chip that may include the ripple compensation circuit of the first aspect and any possible implementation thereof.

[0034] The ripple compensation circuit provided by this invention generates a ripple compensation voltage based on the AC components of the feedback voltage and the ripple voltage. This separates the feedback node and the ripple compensation voltage node, preventing the residual DC component of the ripple voltage generated by the ripple generation circuit from interfering with the feedback node. This avoids affecting the output voltage and improves the accuracy and load regulation of the output voltage. Furthermore, after generating the ripple compensation voltage, this voltage is superimposed on the comparator in the subsequent stage for compensation, effectively solving the problem of subharmonic oscillation. Attached Figure Description

[0035] Figure 1 A circuit schematic diagram of a ripple compensation circuit provided for related technologies;

[0036] Figure 2 A circuit block diagram of a ripple compensation circuit provided for an embodiment of this utility model;

[0037] Figure 3 This is a circuit diagram of a ripple compensation circuit provided for an embodiment of the present invention. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0039] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, the use of "based on" or "according to" implies openness and inclusiveness, because processes, steps, calculations, or other actions "based on" or "according to" one or more of the stated conditions or values ​​may in practice be based on additional conditions or beyond the stated values.

[0040] Figure 1 A circuit diagram of a ripple compensation circuit provided for related technologies. For example... Figure 1 As shown, the circuit principle of this ripple compensation circuit is as follows: Since R1=R2, and due to the virtual short principle of the op-amp, therefore... Figure 1 I3 = (Vout - VFB) / R2. Due to the current mirror's current replication effect, I2 = I3. Current I1 flows out from the output node (SW) and contains both DC and AC components. After subtracting the DC component I2 from I1, the remaining AC component I4 charges capacitor Cr, generating a ripple voltage RAMP. This ripple voltage RAMP is then added to the subsequent comparator (…). Figure 1 (Not shown in the image) is used for compensation to solve the subharmonic oscillation problem caused by the low ESR of the output capacitor Cout. However, the existing ripple compensation circuit has the following problem: since the difference between I1 and I2 is not entirely the AC component I4, I4 may contain a residual DC component. This residual DC component will flow to the VFB node, causing the output voltage Vout to be too high or too low, which in turn affects the output voltage accuracy and load regulation.

[0041] To address the issue of low output voltage accuracy and load regulation when compensating for output voltage ripple, this invention provides a ripple compensation circuit that separates the feedback node and the ripple compensation voltage node. This prevents the residual DC component of the ripple voltage generated by the ripple generation circuit from interfering with the feedback node, thereby improving the output voltage accuracy and load regulation, while also resolving the subharmonic oscillation problem.

[0042] Figure 2 This is a circuit block diagram illustrating the principle of a ripple compensation circuit provided in an embodiment of the present invention. (See diagram below.) Figure 2 As shown, the ripple compensation circuit may include: a power transistor 21, a ripple generation circuit 22, an adjustment circuit 23, and a compensation circuit 24.

[0043] The power transistor 21 includes an upper transistor and a lower transistor, which are connected together. The node connecting the upper and lower transistors is the output node (SW).

[0044] The ripple generation circuit 22 is connected to the output node SW and the voltage output terminal Vout, and is used to generate ripple voltage.

[0045] The regulating circuit 23 is connected to the ripple generation circuit 22, and also to the feedback node VFB and the voltage output terminal Vout. It is used to adjust the DC component of the ripple voltage according to the feedback voltage and the output voltage.

[0046] The compensation circuit 24 is connected to the feedback node VFB for receiving the feedback voltage and is also connected to the ripple generation circuit 22. The compensation circuit 24 is used to generate the ripple compensation voltage RAMP based on the AC components of the feedback voltage and the ripple voltage.

[0047] The ripple compensation circuit provided by this invention generates a ripple compensation voltage based on the AC components of the feedback voltage and the ripple voltage. This separates the feedback node and the ripple compensation voltage node, preventing the residual DC component of the ripple voltage generated by the ripple generation circuit from interfering with the feedback node. This avoids affecting the output voltage and improves the accuracy and load regulation of the output voltage. Furthermore, after generating the ripple compensation voltage, this voltage is superimposed on the comparator in the subsequent stage for compensation, effectively solving the problem of subharmonic oscillation.

[0048] Optionally, in this embodiment of the invention, the compensation circuit 24 may include a buffer.

[0049] The input terminal of the buffer is connected to the feedback node VFB, and the output terminal is connected to the ripple generation circuit 22, which is used to generate a ripple compensation voltage based on the AC components of the feedback voltage and the ripple voltage.

[0050] In other words, in this embodiment of the invention, a buffer is used to separate the feedback node VFB and the ripple compensation voltage node RAMP to avoid the residual DC component of the ripple voltage generated by the ripple generation circuit from interfering with the feedback node, thereby avoiding affecting the output voltage.

[0051] Optional, Figure 3 This is a circuit diagram of a ripple compensation circuit provided for an embodiment of the present utility model. Combined with... Figure 2 ,like Figure 3 As shown, the buffer may include a first operational amplifier A1 and a first resistor R1.

[0052] The first input terminal of the first operational amplifier A1 is connected to the feedback node VFB, and the second input terminal is connected to the output terminal of the first operational amplifier A1 and one end of the first resistor R1.

[0053] The other end of the first resistor R1, RAMP, is connected to the ripple generation circuit 22.

[0054] In one possible implementation, the first resistor is an adjustable resistor. Specifically, the first resistor can be a trim resistor or a metal change resistor.

[0055] Thus, the first resistor is an adjustable resistor, which can change the amplitude of the ripple compensation voltage, thereby allowing the dynamic response characteristics and loop stability of the chip to be adjusted according to the actual application scenario.

[0056] Optionally, in embodiments of this utility model, such as Figure 3 As shown, the ripple generation circuit 22 may include a second resistor R2 and a capacitor Cr.

[0057] One end of the second resistor R2 is connected to the output node SW, and the other end is connected to one end of the capacitor Cr, the adjustment circuit 23, and the compensation circuit 24.

[0058] The other end of capacitor Cr is connected to the voltage output terminal Vout.

[0059] The current flowing out from the output node SW has both DC and AC components, which generates ripple voltage.

[0060] Optionally, in embodiments of this utility model, such as Figure 3 As shown, the adjustment circuit 23 may include a current mirror and an operational amplifier circuit.

[0061] The first end of the current mirror is connected to the ripple generation circuit 22 and the compensation circuit 24, the second end is grounded, the third end is connected to the output end of the operational amplifier circuit, and the fourth end is connected to the first input end of the operational amplifier circuit.

[0062] The first input terminal of the operational amplifier circuit is connected to the output voltage.

[0063] The second input terminal of the operational amplifier circuit is connected to the feedback voltage.

[0064] In one possible implementation, the current mirror may include a first transistor and a second transistor.

[0065] The control electrode of the first transistor is connected to the control electrode of the second transistor and the output terminal of the operational amplifier circuit.

[0066] The first terminal of the first transistor is connected to the ripple generation circuit 22 and the compensation circuit 24, while the second terminal is grounded.

[0067] The first terminal of the second transistor is connected to the first input terminal of the operational amplifier circuit, and the second terminal is grounded.

[0068] In one possible implementation, the operational amplifier circuit includes a second operational amplifier A2 and a third resistor R3.

[0069] One end of the third resistor R3 is connected to the output voltage, and the other end is connected to the first input terminal of the second operational amplifier and the fourth terminal of the current mirror.

[0070] The second input terminal of the second operational amplifier A2 is connected to the feedback voltage.

[0071] The output of the second operational amplifier is connected to the third terminal of the current mirror.

[0072] In one possible implementation, both the first transistor and the second transistor are NMOS transistors. Figure 3 The example is illustrated using NM1 and NM2 as the first and second transistors, respectively.

[0073] In one possible implementation, such as Figure 3 As shown, the ripple compensation circuit may also include: voltage divider resistors R4 and R5, output capacitor Cout, and load Iload. The node connected by R4 and R5 is the feedback node VFB.

[0074] Figure 3 The circuit principle of the ripple compensation circuit is as follows: Utilizing the virtual short effect of the second operational amplifier A2, I1 - I2 = I4. I4 charges the capacitor Cr, generating a ripple voltage. A buffer is used to separate the feedback node VFB and the ripple compensation voltage node RAMP, thereby preventing the residual DC component of the ripple voltage from interfering with VFB and affecting the accuracy of the output voltage. After generating the ripple compensation voltage, the compensation circuit sends it to the comparator in the subsequent loop (not in...). Figure 3 (As shown in the figure) is compared to control the power transistor's on and off states.

[0075] The ripple compensation circuit provided by this invention separates the feedback node and the ripple compensation voltage node to prevent the residual DC component of the ripple voltage generated by the ripple generation circuit from interfering with the feedback node, thereby avoiding impact on the output voltage and improving the accuracy of the output voltage and load regulation. Furthermore, after the compensation circuit generates the ripple compensation voltage, this voltage is superimposed on the subsequent comparator for compensation, which can solve the problem of subharmonic oscillation.

[0076] This utility model embodiment also provides a chip, which may include, as shown in the example below. Figures 2-3 Any ripple compensation circuit in the circuit.

[0077] In one possible implementation, the chip can be a power management chip, or other types of chips including ripple compensation circuitry, without specific limitations.

[0078] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A ripple compensation circuit, characterized by, The chip comprises: a power tube comprising an upper tube and a lower tube, the upper tube being connected with the lower tube; a ripple generating circuit connected with an output node and a voltage output terminal, for generating a ripple voltage, the output node being a node connected with the upper tube and the lower tube; an adjusting circuit connected with the ripple generating circuit, also connected with a feedback node and the voltage output terminal, for adjusting a direct current component of the ripple voltage according to a feedback voltage and an output voltage; a compensation circuit connected with the feedback node for accessing the feedback voltage, also connected with the ripple generating circuit, the compensation circuit being used for generating a ripple compensation voltage according to an alternating current component of the feedback voltage and the ripple voltage.

2. The ripple compensation circuit of claim 1, wherein, The compensation circuit comprises a buffer; an input terminal of the buffer being connected with the feedback node, an output terminal of the buffer being connected with the ripple generating circuit, for generating the ripple compensation voltage according to the alternating current component of the feedback voltage and the ripple voltage.

3. The ripple compensation circuit of claim 2, wherein, The buffer comprises a first operational amplifier and a first resistor; a first input terminal of the first operational amplifier being connected with the feedback node, a second input terminal of the first operational amplifier being connected with an output terminal of the first operational amplifier and one end of the first resistor; the other end of the first resistor being connected with the ripple generating circuit.

4. The ripple compensation circuit of claim 3, wherein, The first resistor is an adjustable resistor.

5. The ripple compensation circuit according to any one of claims 1 to 4, characterized in that, The ripple generating circuit comprises a second resistor and a capacitor; one end of the second resistor being connected with the output node, the other end of the second resistor being connected with one end of the capacitor, the adjusting circuit and the compensation circuit; the other end of the capacitor being connected with the voltage output terminal.

6. The ripple compensation circuit according to any one of claims 1 to 4, characterized by, The adjusting circuit comprises a current mirror and an operational amplifier circuit; a first terminal of the current mirror being connected with the ripple generating circuit and the compensation circuit, a second terminal of the current mirror being grounded, a third terminal of the current mirror being connected with an output terminal of the operational amplifier circuit, a fourth terminal of the current mirror being connected with a first input terminal of the operational amplifier circuit; a first input terminal of the operational amplifier circuit accessing the output voltage; a second input terminal of the operational amplifier circuit accessing the feedback voltage.

7. The ripple compensation circuit of claim 6, wherein, The current mirror comprises a first transistor and a second transistor; a control electrode of the first transistor being connected with a control electrode of the second transistor and an output terminal of the operational amplifier circuit; a first electrode of the first transistor being connected with the ripple generating circuit and the compensation circuit, a second electrode of the first transistor being grounded; a first electrode of the second transistor being connected with the first input terminal of the operational amplifier circuit, a second electrode of the second transistor being grounded.

8. The ripple compensation circuit of claim 6, wherein, The operational amplifier circuit comprises a second operational amplifier and a third resistor; one end of the third resistor accessing the output voltage, the other end of the third resistor being connected with a first input terminal of the second operational amplifier and the fourth terminal of the current mirror; a second input terminal of the second operational amplifier accessing the feedback voltage; an output terminal of the second operational amplifier being connected with the third terminal of the current mirror.

9. The ripple compensation circuit of claim 7, wherein, The first transistor and the second transistor are both NMOS tubes.

10. A chip, characterized by The chip comprises the ripple compensation circuit according to any one of claims 1-9.

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