Charge pump circuit, control circuit and control method

Abstract

The invention provides a charge pump circuit, a control circuit and a control method, and the circuit comprises a compensation module which generates a compensation voltage based on a difference value between an output voltage of a charge pump circuit structure and an output reference; an oscillator generating an oscillation signal based on the compensation voltage; the control signal generation module is used for generating a charging control signal and a discharging control signal based on the oscillation signal and the compensation voltage to respectively control a charging switch and a discharging switch in the charge pump circuit structure; wherein when the charge pump circuit structure works in a light load mode, the duty ratio of the charge control signal is greater than the duty ratio of the discharge control signal. According to the charge pump circuit, the control circuit and the control method, the duty ratio of the charge control signal is controlled to be larger than the duty ratio of the discharge control signal in a light-load operation mode, so that the overshoot of the output voltage is relieved, the output ripple is reduced, and the working frequency is improved.

Description

Technical Field

[0001] This invention relates to the field of integrated circuits, and in particular to a charge pump circuit, a control circuit, and a control method. Background Technology

[0002] A charge pump circuit is an inductorless DC-DC converter that achieves voltage conversion (such as voltage multiplication, voltage reduction, and voltage fractionation) through the periodic charging and discharging of a switched capacitor network. Its core principle is to utilize the charge transfer characteristics of capacitors to convert the input voltage (VIN) into a higher, lower, or opposite polarity output voltage (VOUT). It offers advantages such as small size, low EMI, and simple design, and is widely used in low-power electronic devices (such as mobile phones, displays, and sensors).

[0003] Existing charge pump circuits typically employ a fixed switching frequency or a skip-cycle control mode, such as... Figure 1 and Figure 2 As shown, taking a single-negative-voltage charge pump architecture 100 as an example, it includes four switching transistors, a flying capacitor CFLY, and an output capacitor COUT. The charging control signal G1 and the discharging control signal G2 control the charging and discharging of the flying capacitor CFLY at a fixed frequency. The discharging control signals GT and G2 are in phase but have different amplitudes; the amplitude of the discharging control signal GT is adjustable. When the output voltage VOUT drops to a set lower limit, the cycle-skipping control signal Pskip is triggered, causing the output voltage VOUT to rise to a given value. However, both of these design schemes have limitations: while the fixed-frequency charge pump circuit design is simple and technically mature, under light load conditions, this control method leads to significant switching losses, thus affecting the overall system efficiency; cycle-skipping control adjusts the output voltage by skipping part of the switching cycle. Although it can improve conversion efficiency under light load or dynamic load conditions, the skipping of the switching cycle significantly increases the output voltage ripple, making it difficult to meet the requirements of ripple-sensitive electrical equipment. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a charge pump circuit, a control circuit, and a control method to solve the problems of large output ripple and low operating frequency of charge pump circuits in light-load operation mode in the prior art.

[0005] To achieve the above and other related objectives, the present invention provides a charge pump control circuit, comprising:

[0006] The compensation module generates a compensation voltage based on the difference between the output voltage and the output reference of the charge pump circuit structure.

[0007] An oscillator that generates an oscillation signal based on the compensation voltage; and

[0008] The control signal generation module generates charging control signals and discharging control signals based on the oscillation signal and the compensation voltage to control the charging switch and discharging switch in the charge pump circuit structure, respectively.

[0009] Specifically, when the charge pump circuit structure operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal.

[0010] Optionally, the compensation module includes an error amplifier that outputs the compensation voltage based on the difference between the feedback voltage of the output voltage and the reference voltage.

[0011] Optionally, the oscillator includes:

[0012] A controlled current source and a capacitor are connected in series between the operating power supply and the reference ground. The controlled current source generates the charging current of the capacitor based on the control of the compensation voltage.

[0013] A control switch, connected in parallel across the capacitor, controls the charging or discharging of the capacitor by switching the control switch on and off; and

[0014] The comparator has a first input terminal connected to the connection node between the controlled current source and the capacitor, a second input terminal receiving an oscillation reference signal, and outputting the oscillation signal.

[0015] Alternatively, the oscillator further receives an enable signal, and the oscillator further includes:

[0016] A first enabling switch, connected in series with the controlled current source to form a first charging branch, wherein the control terminal of the first enabling switch receives the enabling signal; and

[0017] The second charging branch is connected in parallel across the first charging branch and includes: a bias current source and a second enable switch connected in series. The control terminal of the second enable switch receives the inverted signal of the enable signal.

[0018] Optionally, the control signal generation module includes:

[0019] A logic module, connected to the output of the oscillator, generates a switching control signal based on the oscillation signal; and

[0020] The driving module generates the charging control signal and the discharging control signal, wherein the driving module controls the duty cycle of the charging control signal and the discharging control signal based on the switch control signal, and controls the amplitude of the control signal corresponding to any charging switch or discharging switch based on the compensation voltage.

[0021] Alternatively, it may also include a cycle skipping module, which generates a cycle skipping signal based on a comparison between the compensation voltage and the cycle skipping reference;

[0022] The control signal generation module further receives the cycle skipping signal and generates the charging control signal and the discharging control signal based on the oscillation signal, the compensation voltage, and the cycle skipping signal to control the charging switch and the discharging switch in the charge pump circuit structure, respectively.

[0023] To achieve the above and other related objectives, the present invention also provides a charge pump circuit, including the aforementioned charge pump control circuit, and further including a charge pump circuit structure, the charge pump circuit structure comprising:

[0024] Flying capacitor;

[0025] The first charging switch has one end connected to the input voltage and the other end connected to the first plate of the flying capacitor.

[0026] The second charging switch is connected at one end to the second plate of the flying capacitor and at the other end to ground.

[0027] The first discharge switch is connected at one end to the first plate of the flying capacitor and at the other end to ground.

[0028] The second discharge switch is connected at one end to the second plate of the flying capacitor, and at the other end serves as the output terminal of the charge pump circuit structure.

[0029] The first charging control signal controlling the first charging switch and the second charging control signal controlling the second charging switch are in phase, and the first discharging control signal controlling the first discharging switch and the second discharging control signal controlling the second discharging switch are in phase.

[0030] Optionally, the control signal generation module generates the first discharge control signal based on the compensation voltage and the oscillation signal, wherein the phase of the first discharge control signal corresponds to the phase of the oscillation signal, and the amplitude of the first discharge control signal corresponds to the amplitude of the compensation voltage; or

[0031] The control signal generation module generates the second discharge control signal based on the compensation voltage and the oscillation signal. The phase of the second discharge control signal corresponds to the phase of the oscillation signal, and the amplitude of the second discharge control signal corresponds to the amplitude of the compensation voltage.

[0032] Optionally, the control signal generation module generates the first charging control signal based on the compensation voltage and the oscillation signal, wherein the phase of the first charging control signal corresponds to the phase of the oscillation signal, and the amplitude of the first charging control signal corresponds to the amplitude of the compensation voltage; or

[0033] The control signal generation module generates the second charging control signal based on the compensation voltage and the oscillation signal. The phase of the second charging control signal corresponds to the phase of the oscillation signal, and the amplitude of the second charging control signal corresponds to the amplitude of the compensation voltage.

[0034] To achieve the above and other related objectives, the present invention also provides a charge pump control method, comprising:

[0035] S1) The output voltage of the feedback charge pump circuit structure is used to generate a compensation voltage based on the difference between the output voltage and the output reference;

[0036] S2) Generate an oscillation signal based on the compensation voltage;

[0037] S3) Based on the oscillation signal and the compensation voltage, a charging control signal and a discharging control signal are generated to control the charging switch and the discharging switch in the charge pump circuit structure, respectively.

[0038] Specifically, when the charge pump circuit structure operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal.

[0039] Optionally, the duty cycle of the charging control signal is negatively correlated with the compensation voltage, and the duty cycle of the discharging control signal is positively correlated with the compensation voltage; or

[0040] The duty cycle of the charging control signal is positively correlated with the compensation voltage, and the duty cycle of the discharging control signal is negatively correlated with the compensation voltage.

[0041] Optionally, in light-load mode, the duty cycle of the charging control signal is negatively correlated with the compensation voltage, and the duty cycle of the discharging control signal is positively correlated with the compensation voltage; or

[0042] The duty cycle of the charging control signal is positively correlated with the compensation voltage, and the duty cycle of the discharging control signal is negatively correlated with the compensation voltage.

[0043] In other modes, the duty cycles of the charging control signal and the discharging control signal remain constant.

[0044] Alternatively, the duty cycle can be fixed at 50%.

[0045] Alternatively, in step S3), the amplitude of the control signal of any charging switch or discharging switch is controlled based on the compensation voltage to adjust the corresponding charging current or discharging current.

[0046] Alternatively, when adjusting the control signal amplitude of the charging switch based on the compensation voltage, the corresponding control signal amplitude is negatively correlated with the compensation voltage; when adjusting the control signal amplitude of the discharging switch based on the compensation voltage, the corresponding control signal amplitude is positively correlated with the compensation voltage; or

[0047] When the amplitude of the control signal for the charging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is positively correlated with the compensation voltage; when the amplitude of the control signal for the discharging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is negatively correlated with the compensation voltage.

[0048] As described above, the charge pump circuit, control circuit, and control method of the present invention have the following beneficial effects:

[0049] The charge pump circuit, control circuit, and control method of the present invention adjust the switching duty cycle according to different load modes. In particular, in the light load operation mode, the duty cycle of the charging control signal is controlled to be greater than the duty cycle of the discharging control signal, thereby alleviating the overshoot of the output voltage, reducing the output ripple, and increasing the operating frequency.

[0050] The feedback loop of the charge pump circuit, control circuit and control method of the present invention adopts dual-loop control. In the light load operation mode, the output voltage is stabilized by simultaneously controlling the charging / discharging current and duration. The loop is stable and efficient. Attached Figure Description

[0051] Figure 1 The diagram shown is a schematic of an existing single negative pressure charge pump architecture.

[0052] Figure 2 Displayed as Figure 1 A schematic diagram of the working principle of a single negative pressure charge pump architecture.

[0053] Figure 3 The diagram shown is a schematic block diagram of the charge pump control circuit and charge pump of the present invention.

[0054] Figure 4 The diagram shown is a first specific structural schematic of the charge pump control circuit and charge pump circuit structure of the present invention.

[0055] Figure 5 The diagram shown is a structural schematic of the oscillator of the present invention.

[0056] Figure 6 The diagram shown is a flowchart of the charge pump control method of the present invention.

[0057] Figure 7 Displayed as Figure 3 A schematic diagram illustrating the working principle of the charge pump control circuit.

[0058] Figure 8 The diagram shown is a second specific structural schematic of the charge pump control circuit of the present invention.

[0059] Figure 9 The diagram shown is another structural schematic of the oscillator of the present invention.

[0060] Figure 10 The diagram shown is a third specific structural schematic of the charge pump control circuit of the present invention.

[0061] Figure 11 Displayed as Figure 10 A schematic diagram illustrating the working principle of the charge pump control circuit.

[0062] Figure 12 The diagram shown is a fourth specific structural schematic of the charge pump control circuit of the present invention.

[0063] Figure 13 The diagram shown is a fifth specific structural schematic of the charge pump control circuit of the present invention.

[0064] Component designation explanation

[0065] 100 - Single negative pressure charge pump architecture; 200, 500, 600, 700, 800 - Charge pump control circuits; 21 - Compensation module; 211 - Error amplifier; 22 - Oscillator; 221 - Controlled current source; 222 - Control switch; 223 - Comparator; 23 - Control signal generation module; 231 - Logic module; 232 - First drive module; 233 - Second drive module; 234 - Third drive module; 235 - Fourth drive module; 236 - Fifth drive module; 237 - Sixth drive module; 238 - Seventh drive module; 239 - Eighth drive module; 24 - Cycle skipping module; 300 - Charge pump circuit structure; 400 - Charge pump circuit. Detailed Implementation

[0066] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0067] Please see Figures 3-13 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0068] Example 1

[0069] like Figure 3 As shown, this embodiment provides a charge pump control circuit 200 and a charge pump circuit 400. The charge pump control circuit 200 and the charge pump circuit structure 300 together constitute the charge pump circuit 400. The charge pump control circuit 200 provides charging control signals and discharging control signals to the charge pump circuit structure 300. As an example, the charge pump circuit structure 300 includes a flying capacitor CFLY, a first charging switch S1, a second charging switch S3, a first discharging switch S2, a second discharging switch S4, and an output capacitor COUT. One end of the first charging switch S1 is connected to the input voltage VIN, and the other end is connected to the first plate CX1 of the flying capacitor CFLY, and is controlled by the first charging control signal GC1. One end of the first discharging switch S2 is connected to the first plate CX1 of the flying capacitor CFLY, and the other end is grounded to PGND, and is controlled by the first discharging control signal GD1. One end of the second charging switch S3 is connected to the second plate CX2 of the flying capacitor CFLY, and the other end is grounded to PGND, and is controlled by the second charging control signal. One end of the second discharge switch S4 serves as the voltage output terminal, and the other end is connected to the second plate CX2 of the flying capacitor CFLY, controlled by the second discharge control signal GD2; one end of the output capacitor COUT is connected to the voltage output terminal, and the other end is grounded. In this embodiment, a single-voltage charge pump architecture is used as an example. In actual use, the specific structure of the charge pump circuit structure 300 can be set as needed, including but not limited to multi-voltage charge pumps, reverse voltage multiplier charge pumps, and step-down charge pumps, which will not be described in detail here.

[0070] like Figure 3 As shown, the charge pump control circuit 200 includes: a compensation module 21, an oscillator 22, and a control signal generation module 23.

[0071] like Figure 3 As shown, the compensation module 21 generates a compensation voltage VCOMP based on the difference between the output voltage VOUT of the charge pump circuit structure 300 and the output reference.

[0072] Specifically, such as Figure 4 As shown, in this embodiment, the compensation module 21 includes an error amplifier 211. The error amplifier 211 outputs a compensation voltage VCOMP based on the difference between the feedback voltage VFB of the output voltage VOUT and the reference voltage VREF. The feedback voltage VFB and the output voltage VOUT have a preset proportional relationship. In this example, the non-inverting input terminal of the error amplifier 211 is connected to the feedback voltage VFB, and the inverting input terminal receives the reference voltage VREF. In actual use, the relationship between the input signal of the error amplifier 211 and the polarity of the corresponding input terminal can be adjusted as needed to satisfy the logic of this invention, and is not limited to this example.

[0073] It should be noted that the compensation module 21 is the core component in the output voltage VOUT feedback loop. It generates and adjusts the compensation voltage to offset system deviations and maintain stable and accurate output. Any circuit structure that can achieve the above function is applicable to this invention.

[0074] like Figure 3 As shown, oscillator 22 generates an oscillation signal Vosc based on the compensation voltage VCOMP.

[0075] Specifically, such as Figure 5 As shown, in this embodiment, the oscillator 22 includes a controlled current source 221, a capacitor C1, a control switch 222, and a comparator 223. The controlled current source 221 and capacitor C1 are connected in series between the operating power supply VCC and a reference ground. The controlled current source 221 generates a charging current for capacitor C1 based on the compensation voltage VCOMP. Specifically, one end of the controlled current source 221 is connected to the operating power supply VCC, and the other end is connected to the upper electrode of capacitor C1. The lower electrode of capacitor C1 is grounded. The control terminal of the controlled current source 221 is connected to the compensation voltage VCOMP and generates a charging current related to the magnitude of the compensation voltage VCOMP. The control switch 222 is connected in parallel across capacitor C1 and is controlled by the control signal clk. The switching of the control switch 222 controls the charging or discharging of capacitor C1. When the control switch 222 is open, the controlled current source 221 charges capacitor C1; when the control switch 222 is closed, capacitor C1 discharges. The non-inverting input of comparator 223 is connected to the connection node between the controlled current source 221 and capacitor C1 (which is the upper plate of C1 in this embodiment), and the inverting input receives the oscillation reference signal Vref_osc and outputs the oscillation signal Vosc. In actual use, the relationship between the input signal of comparator 223 and the polarity of the corresponding input terminal can be adjusted as needed to realize the control logic of the present invention.

[0076] Specifically, in this embodiment, the duty cycle of the oscillation signal Vosc is positively correlated with the compensation voltage VCOMP, that is, the duty cycle of the oscillation signal Vosc increases or decreases with the increase or decrease of the compensation voltage VCOMP. This positive correlation can be linear or nonlinear. In other examples, the duty cycle of the oscillation signal Vosc can also be negatively correlated with the compensation voltage VCOMP, which will not be elaborated here.

[0077] like Figure 3 As shown, the control signal generation module 23 generates charging control signals and discharging control signals based on the compensation voltage VCOMP and the oscillation signal Vosc, respectively controlling the charging switch and discharging switch in the charge pump circuit structure 300.

[0078] Specifically, in this embodiment, the control signal generation module 23 adjusts the discharge current of the charge pump circuit structure 300 based on the compensation voltage VCOMP, and controls the duty cycle of the charging control signal and the discharging control signal in the charge pump circuit structure 300 based on the oscillation signal Vosc. The operating modes of the charge pump circuit structure 300 include, but are not limited to, heavy load mode, medium load mode, and light load mode. The specific load size corresponding to each operating mode is determined according to the actual situation. Among them, in the light load mode, the charging energy of the output voltage VOUT in each cycle is minimal, while the discharging energy is large. If the charging duration of the charge pump circuit structure 300 is greater than or equal to the discharging duration in the light load mode, there is a problem of output voltage overshoot (the difference between the output voltage and the output reference reaches a preset value, which is set according to the specific operating conditions). Therefore, this invention adjusts the duty cycle of the oscillation signal Vosc in the light load mode, thereby making the duty cycle of the charging control signal greater than the duty cycle of the discharging control signal (i.e., the discharging duration of the charge pump circuit structure 300 in the light load mode is less than the charging duration).

[0079] Specifically, such as Figure 4As shown, in this embodiment, the control signal generation module 23 includes a logic module 231 and a driving module. The logic module 231 is connected to the output terminal of the oscillator 22 and generates switch control signals based on the oscillation signal Vosc. The first switch control signal G1 controls the charging switch in the charge pump circuit structure 300, and the second switch control signal G2 controls the discharging switch in the charge pump circuit structure 300. The first switch control signal G1 and the second switch control signal G2 are out of phase. The driving module generates charging control signals and discharging control signals. The driving module controls the duty cycle of the charging control signals and discharging control signals based on the switch control signals and controls the amplitude of the control signal corresponding to any discharging switch based on the compensation voltage VCOMP. In this example, the driving module includes a first driver 232, a second driver 233, a third driver 234, and a fifth driver 235. The first driver 232 generates a first charging control signal GC1 based on the first switch control signal G1. The phase of the first charging control signal GC1 corresponds to the phase of the oscillation signal Vosc (in this example, the phases are the same), and the amplitude is fixed (determined by the operating power supply of the first driver 232). The second driver 233 generates a first discharge control signal GD1 based on the second switch control signal G2 and the compensation voltage VCOMP. The phase of the first discharge control signal GD1 corresponds to the phase of the oscillation signal Vosc, and the amplitude corresponds to the amplitude of the compensation voltage VCOMP. In this example, when the second switch control signal G2 is low, the first discharge control signal GD1 is low, and the first discharge switch S2 is off. When the second switch control signal G2 is high, the first discharge control signal GD1 increases as the compensation voltage VCOMP increases (the discharge current in the charge pump circuit structure 300 increases), and the first discharge control signal GD1 decreases as the compensation voltage VCOMP decreases (the discharge current in the charge pump circuit structure 300 decreases). The third driver 234 generates a second charging control signal GC2 based on the first switch control signal G1. The phase of the second charging control signal GC2 corresponds to the phase of the oscillation signal Vosc, and the amplitude is fixed (determined by the operating power supply of the third driver 234). The fourth driver 235 generates a second discharge control signal GD2 based on the second switch control signal G2. The phase of the second discharge control signal GD2 corresponds to the phase of the oscillation signal Vosc, and its amplitude is fixed (determined by the operating power supply of the fourth driver 235). The first charging control signal GC1 and the second charging control signal GC2 are in phase, and the first discharge control signal GD1 and the second discharge control signal GD2 are in phase, with the charging control signal and the discharge control signal having opposite phases. In another example, the amplitude of the second discharge control signal GD2 can also be adjusted based on the compensation voltage VCOMP, which will not be elaborated here.

[0080] It should be noted that phase correspondence can be the same or complementary; amplitude correspondence can be equal, proportional, or inversely proportional, and does not necessarily mean that the actual values ​​are equal; the specific correspondence can be set according to actual needs, and will not be elaborated here. In actual use, the structure of the driving module is adapted to the specific structure of the charge pump circuit structure 300, and is not limited to this embodiment.

[0081] It should be noted that the feedback loop of the charge pump control circuit of this invention is a dual-loop control. The first loop changes the current (discharge current and / or charging current) of the charge pump circuit structure through a compensation voltage VCOMP, while the second loop changes the duty cycle of the oscillation signal Vosc through the compensation voltage VCOMP. To ensure loop stability, the speed of the second loop should be much smaller than the speed of the first loop. The speed of the first loop is set to N times the speed of the second loop, where N is a natural number greater than or equal to 5. N includes, but is not limited to, 7, 8, 9, 10, 15, and 20, which will not be elaborated here.

[0082] like Figure 6 As shown, this embodiment also provides a charge pump control method, including:

[0083] S1) The output voltage VOUT of the feedback charge pump circuit structure 300 is used to generate a compensation voltage VCOMP based on the difference between the output voltage VOUT and the output reference.

[0084] S2) Generate an oscillation signal Vosc based on the compensation voltage VCOPM; wherein the duty cycle of the oscillation signal Vosc is related to the compensation voltage VCOMP, including but not limited to positive correlation and negative correlation.

[0085] S3) Based on the oscillation signal Vosc and the compensation voltage VCOMP, a charging control signal and a discharging control signal are generated to control the charging switch and the discharging switch in the charge pump circuit structure 300, respectively. Among them, when the charge pump circuit structure 300 operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal, so that the charging time of the charge pump circuit structure 300 is greater than the discharging time.

[0086] Specifically, as an example, the duty cycle of the charging control signal is negatively correlated with the compensation voltage VCOMP, while the duty cycle of the discharging control signal is positively correlated with the compensation voltage VCOMP. That is, the larger the compensation voltage VCOMP, the shorter the charging time and the longer the discharging time of the charge pump circuit structure 300; the smaller the compensation voltage VCOMP, the longer the charging time and the shorter the discharging time of the charge pump circuit structure 300. As another example, the duty cycle of the charging control signal is positively correlated with the compensation voltage VCOMP, while the duty cycle of the discharging control signal is negatively correlated with the compensation voltage VCOMP. That is, the larger the compensation voltage VCOMP, the longer the charging time and the shorter the discharging time of the charge pump circuit structure 300; the smaller the compensation voltage VCOMP, the shorter the charging time and the longer the discharging time of the charge pump circuit structure 300. In practical applications, the relationship between the compensation voltage and the duty cycle of the charging and discharging control signals can be set according to the polarity of the output voltage VOUT and the compensation voltage VCOMP.

[0087] Specifically, in this embodiment, the amplitude of the control signal for any discharge switch is controlled based on the compensation voltage VCOMP to adjust the corresponding discharge current. The amplitude of the corresponding control signal is positively correlated with the compensation voltage VCOMP (it can also be negatively correlated, depending on the polarity of the output voltage VOUT and the compensation voltage VCOMP, as long as the output voltage VOUT is stable). As an example, the amplitude of the first discharge control signal GD1 controlling the first discharge switch S2 is adjusted based on the compensation voltage VCOMP; when the compensation voltage VCOMP decreases, the amplitude of the first discharge control signal GD1 decreases, the discharge current of the charge pump circuit structure 300 decreases, and the output voltage VOUT increases; when the compensation voltage VCOMP increases, the amplitude of the first discharge control signal GD1 increases, the discharge current of the charge pump circuit structure 300 increases, and the output voltage VOUT decreases. In other examples, the amplitude of the second discharge control signal GD2 can also be adjusted based on the compensation voltage VCOMP to achieve control of the discharge current.

[0088] like Figure 7As shown, in this embodiment, the charge pump control circuit 200 adaptively adjusts the duty cycle based on the compensation voltage VCOMP, and the duty cycle follows the change of the compensation voltage VCOMP. During the charging phase PH1 of each cycle, the first switch control signal G1 is high, the second switch control signal G2 is low, the first charging switch S1 and the second charging switch S3 are on, and the first discharging switch S3 and the second discharging switch S4 are off. The input voltage VIN is charged by the flying capacitor CFLY. During the discharging phase PH2 of each cycle, the second switch control signal G2 is high, the first switch control signal G1 is low, the first discharging switch S2 and the second discharging switch S4 are on, and the first charging switch S1 and the second charging switch S3 are off. The output voltage VOUT is discharged through the flying capacitor CFLY. Under light load conditions, the compensation voltage VCOMP decreases. To maintain charge balance at the output, the discharge current of the charge pump discharge phase PH2 is reduced, thus decreasing the discharge energy of the output voltage VOUT. Simultaneously, the decrease in VCOMP also reduces the duty cycle of the discharge control signal (which is less than the duty cycle of the charging control signal), meaning the charging time is longer than the discharging time. Shortening the duration of the charge pump discharge phase PH2 within a cycle also helps reduce the discharge energy of the output voltage VOUT within a cycle, resulting in a slower and smaller output overshoot. Ultimately, this helps reduce the output ripple of the output voltage VOUT, and the operating frequency is not significantly reduced (especially below 20kHz, which enters the audio range and should be avoided). In other operating modes, with a larger load, the compensation voltage VCOMP increases, increasing the discharge current of the charge pump discharge phase PH2 and controlling the charging time of the charge pump circuit structure 300 to be less than the discharging time (the duty cycle of the first switch control signal G1 is less than the duty cycle of the second switch control signal G2).

[0089] Example 2

[0090] like Figure 8 As shown, this embodiment provides a charge pump control circuit 500. The difference from the first embodiment is that the oscillator 22 also receives an enable signal EN_duty, and triggers adaptive adjustment of the duty cycle based on the enable signal EN_duty.

[0091] Specifically, such as Figure 9As shown, as an example, the oscillator 22, based on Embodiment 1, further includes: a first enable switch K1, a bias current source Ibias_osc, and a second enable switch K2. The first enable switch K1 is connected in series with the controlled current source 221 to form a first charging branch. In this example, the first enable switch K1 is connected between the controlled current source 221 and the corresponding input node of the comparator 223; the control terminal of the first enable switch K1 receives the enable signal EN_duty. The bias current source Ibias_osc and the second enable switch K2 are connected in series to form a second charging branch, wherein the second charging branch is connected in parallel with the first charging branch. In this example, the second enable switch K2 is connected between the bias current source Ibias_osc and the corresponding input node of the comparator 223; the control terminal of the second enable switch K2 receives the inverted signal ENB_duty (provided by the inverter) of the enable signal EN_duty. When the enable signal EN_duty is valid, the first charging branch is turned on and the second charging branch is turned off. The charging current is provided by the controlled current source 221, and the duty cycle of the oscillation signal Vosc varies with the compensation voltage VCOMP. When the enable signal EN_duty is invalid, the first charging branch is turned off and the second charging branch is turned on. The charging current is provided by the bias current source Ibias_osc, and the duty cycle of the oscillation signal Vosc remains constant.

[0092] The charge pump control method in this embodiment differs from that in Embodiment 1 in that, when the enable signal EN_duty is active, the oscillator 22 enters a light-load mode, and the duty cycle of the oscillation signal Vosc varies with the compensation voltage VCOMP. When the enable signal EN_duty is inactive, the duty cycle of the oscillation signal Vosc is a fixed value set internally by the oscillator 22; as an example, the fixed duty cycle of the oscillation signal Vosc is set to 50%.

[0093] The other structures of the charge pump control circuit 500 are similar to those of the charge pump circuit 400 formed by the charge pump circuit structure 300 and their working principles are similar to those in Embodiment 1, and will not be described in detail here.

[0094] Example 3

[0095] like Figure 10 As shown, this embodiment provides a charge pump control circuit 600, which differs from the first embodiment in that it also includes a cycle skipping module 24.

[0096] Specifically, such as Figure 10As shown, the cycle skipping module 24 generates a cycle skipping signal Pskip based on the comparison result between the compensation voltage VCOMP and the cycle skipping reference VREF_SKIP. As an example, the cycle skipping module 24 is implemented using a comparator. The inverting input of the cycle skipping module 24 receives the compensation voltage VCOMP, and the non-inverting input receives the cycle skipping reference VREF_SKIP. When the compensation voltage VCOMP is less than the cycle skipping reference VREF_SKIP, a valid cycle skipping signal Pskip is output. In practical applications, the relationship between the input signal and the polarity of the corresponding input terminal can be adjusted as needed, and is not limited to this embodiment.

[0097] Furthermore, the control signal generation module 23 receives the cycle skip signal Pskip and generates a charging control signal and a discharging control signal based on the oscillation signal Vosc, the compensation voltage VCOMP, and the cycle skip signal Pskip. When the cycle skip signal Pskip is valid, the charging control signal and the discharging control signal are configured to control the charge pump circuit structure 300 to maintain a charging state; details will not be elaborated here.

[0098] like Figure 11 As shown, the charge pump control circuit 700 in this embodiment adaptively adjusts the duty cycle based on the compensation voltage VCOMP and adjusts the discharge current. Simultaneously, in light-load mode, when the output voltage VOUT overshoots beyond a preset value, to ensure output stability, it enters the SKIP stage each time VOUT overshoots to a certain magnitude, causing the compensation voltage VCOMP to be less than the cycle skip reference VREF_SKIP. At this time, the cycle skip signal Pskip is active high, the first switch control signal G1 remains high, the second switch control signal G2 remains low, and the charge pump circuit structure 300 remains in a charging state. The output voltage VOUT slowly rises until the compensation voltage VCOMP is greater than the cycle skip reference VREF_SKIP, ending this stage and entering normal switching mode. This process is repeated to achieve stability.

[0099] The other structures of the charge pump control circuit 600, the charge pump circuit 400 formed by the charge pump circuit structure 300, and the control method are similar to those in Embodiment 1, and will not be described in detail here.

[0100] Example 4

[0101] like Figure 12 As shown, this embodiment provides a charge pump control circuit 700, which differs from Embodiment 2 in that it also includes a cycle skipping module 24. The structure and working principle of the cycle skipping module 24 are the same as those in Embodiment 3, and will not be described in detail here.

[0102] Example 5

[0103] like Figure 13As shown, this embodiment provides a charge pump control circuit 800. The difference from the first embodiment is that the drive module controls the duty cycle of the charging control signal and the discharging control signal based on the switch control signal, and controls the amplitude of the control signal corresponding to any charging switch based on the compensation voltage VCOMP, thereby realizing the control of the charging current.

[0104] Specifically, the driving module includes a fifth driver 236, a sixth driver 237, a seventh driver 238, and an eighth driver 239. The fifth driver 236 generates a first charging control signal GC1 based on a first switch control signal G1 and a compensation voltage VCOMP. The phase of the first charging control signal GC1 corresponds to the phase of the oscillation signal Vosc (in this example, the phases are complementary), and its amplitude corresponds to the amplitude of the compensation voltage VCOMP (as an example, the control signal amplitude is negatively correlated with the compensation voltage VCOMP; in other examples, it can also be positively correlated). In this example, when the first switch control signal G1 is low, the first charging control signal GC1 is low, and the first charging switch S1 is off. When the first switch control signal G1 is high, the first charging control signal GC1 decreases as the compensation voltage VCOMP increases (the charging current in the charge pump circuit structure 300 decreases), and the first charging control signal GC1 increases as the compensation voltage VCOMP decreases (the charging current in the charge pump circuit structure 300 increases). The sixth driver 237 generates a first discharge control signal GD1 based on the second switch control signal G2; the phase of the first discharge control signal GD1 corresponds to the phase of the oscillation signal Vosc, and its amplitude is fixed (determined by the operating power supply of the sixth driver 237). The second driver 233 generates the first discharge control signal GD1 based on the second switch control signal G2 and the compensation voltage VCOMP; the phase of the first discharge control signal GD1 corresponds to the phase of the oscillation signal Vosc, and its amplitude corresponds to the amplitude of the compensation voltage VCOMP; in this example, when the second switch control signal G2 is low, the first discharge control signal GD1 is low, and the first discharge switch S2 is off; when the second switch control signal G2 is high, the first discharge control signal GD1 increases as the compensation voltage VCOMP increases (the discharge current in the charge pump circuit structure 300 increases), and the first discharge control signal GD1 decreases as the compensation voltage VCOMP decreases (the discharge current in the charge pump circuit structure 300 decreases). The seventh driver 238 generates a second charging control signal GC2 based on the first switch control signal G1; the phase of the second charging control signal GC2 corresponds to the phase of the oscillation signal Vosc, and its amplitude is fixed (determined by the operating power supply of the seventh driver 238). The eighth driver 239 generates a second discharging control signal GD2 based on the second switch control signal G2; the phase of the second discharging control signal GD2 corresponds to the phase of the oscillation signal Vosc, and its amplitude is fixed (determined by the operating power supply of the eighth driver 239). The first charging control signal GC1 and the second charging control signal GC2 are in phase, the first discharging control signal GD1 and the second discharging control signal GD2 are in phase, and the charging control signal and the discharging control signal are in opposite phases. In another example, the amplitude of the second charging control signal GC2 can also be adjusted based on the compensation voltage VCOMP, which will not be elaborated here.

[0105] The driver module of this embodiment can also be applied to the schemes of Embodiments 2 to 4, which will not be described in detail here.

[0106] In summary, this invention provides a charge pump circuit, a control circuit, and a control method, comprising: a compensation module that generates a compensation voltage based on the difference between the output voltage of the charge pump circuit structure and the output reference; an oscillator that generates an oscillation signal based on the compensation voltage; and a control signal generation module that generates a charging control signal and a discharging control signal based on the oscillation signal and the compensation voltage, respectively controlling the charging switch and the discharging switch in the charge pump circuit structure; wherein, when the charge pump circuit structure operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal. The charge pump circuit, control circuit, and control method of this invention adjust the switch duty cycle accordingly under different load modes; particularly, in light load operation mode, the duty cycle of the charging control signal is controlled to be greater than the duty cycle of the discharging control signal, thereby mitigating output voltage overshoot, reducing output ripple, and increasing the operating frequency. Therefore, this invention effectively overcomes various shortcomings of the prior art and has high industrial applicability.

[0107] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A charge pump control circuit, comprising: The compensation module generates a compensation voltage based on the difference between the output voltage and the output reference of the charge pump circuit structure. An oscillator that generates an oscillation signal based on the compensation voltage; as well as The control signal generation module generates charging control signals and discharging control signals based on the oscillation signal and the compensation voltage to control the charging switch and discharging switch in the charge pump circuit structure, respectively. Specifically, when the charge pump circuit structure operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal.

2. The charge pump control circuit according to claim 1, wherein, The compensation module includes an error amplifier, which outputs the compensation voltage based on the difference between the feedback voltage of the output voltage and the reference voltage.

3. The charge pump control circuit according to claim 1, wherein, The oscillator includes: A controlled current source and a capacitor are connected in series between the operating power supply and the reference ground. The controlled current source generates the charging current of the capacitor based on the control of the compensation voltage. A control switch, connected in parallel across the capacitor, controls the charging or discharging of the capacitor by switching the control switch on and off; and The comparator has a first input terminal connected to the connection node between the controlled current source and the capacitor, a second input terminal receiving an oscillation reference signal, and outputting the oscillation signal.

4. The charge pump control circuit according to claim 3, wherein, The oscillator also receives an enable signal, and the oscillator further includes: A first enabling switch, connected in series with the controlled current source to form a first charging branch, wherein the control terminal of the first enabling switch receives the enabling signal; and The second charging branch is connected in parallel across the first charging branch and includes: a bias current source and a second enable switch connected in series. The control terminal of the second enable switch receives the inverted signal of the enable signal.

5. The charge pump control circuit according to claim 1, wherein, The control signal generation module includes: A logic module, connected to the output of the oscillator, generates a switching control signal based on the oscillation signal; and The driving module generates the charging control signal and the discharging control signal, wherein the driving module controls the duty cycle of the charging control signal and the discharging control signal based on the switch control signal, and controls the amplitude of the control signal corresponding to any charging switch or discharging switch based on the compensation voltage.

6. The charge pump control circuit according to any one of claims 1-5 further includes a cycle skipping module, wherein the cycle skipping module generates a cycle skipping signal based on the comparison result between the compensation voltage and the cycle skipping reference; in, The control signal generation module further receives the cycle skipping signal, and generates the charging control signal and the discharging control signal based on the oscillation signal, the compensation voltage and the cycle skipping signal to control the charging switch and the discharging switch in the charge pump circuit structure, respectively.

7. A charge pump circuit, comprising the charge pump control circuit as described in any one of claims 1-6, and further comprising a charge pump circuit structure, the charge pump circuit structure comprising: Flying capacitor; The first charging switch has one end connected to the input voltage and the other end connected to the first plate of the flying capacitor. The second charging switch is connected at one end to the second plate of the flying capacitor and at the other end to ground. The first discharge switch is connected at one end to the first plate of the flying capacitor and at the other end to ground. The second discharge switch is connected at one end to the second plate of the flying capacitor, and at the other end serves as the output terminal of the charge pump circuit structure. The first charging control signal controlling the first charging switch and the second charging control signal controlling the second charging switch are in phase, and the first discharging control signal controlling the first discharging switch and the second discharging control signal controlling the second discharging switch are in phase.

8. The charge pump circuit as described in claim 7, wherein: The control signal generation module generates the first discharge control signal based on the compensation voltage and the oscillation signal. The phase of the first discharge control signal corresponds to the phase of the oscillation signal, and the amplitude of the first discharge control signal corresponds to the amplitude of the compensation voltage. or The control signal generation module generates the second discharge control signal based on the compensation voltage and the oscillation signal. The phase of the second discharge control signal corresponds to the phase of the oscillation signal, and the amplitude of the second discharge control signal corresponds to the amplitude of the compensation voltage.

9. The charge pump circuit as described in claim 7, wherein: The control signal generation module generates the first charging control signal based on the compensation voltage and the oscillation signal. The phase of the first charging control signal corresponds to the phase of the oscillation signal, and the amplitude of the first charging control signal corresponds to the amplitude of the compensation voltage. or The control signal generation module generates the second charging control signal based on the compensation voltage and the oscillation signal. The phase of the second charging control signal corresponds to the phase of the oscillation signal, and the amplitude of the second charging control signal corresponds to the amplitude of the compensation voltage.

10. A charge pump control method, comprising: S1) The output voltage of the feedback charge pump circuit structure is used to generate a compensation voltage based on the difference between the output voltage and the output reference; S2) Generate an oscillation signal based on the compensation voltage; S3) Based on the oscillation signal and the compensation voltage, a charging control signal and a discharging control signal are generated to control the charging switch and the discharging switch in the charge pump circuit structure, respectively. Specifically, when the charge pump circuit structure operates in light load mode, the duty cycle of the charging control signal is greater than the duty cycle of the discharging control signal.

11. The charge pump control method as described in claim 10, wherein, The duty cycle of the charging control signal is negatively correlated with the compensation voltage, and the duty cycle of the discharging control signal is positively correlated with the compensation voltage. or The duty cycle of the charging control signal is positively correlated with the compensation voltage, and the duty cycle of the discharging control signal is negatively correlated with the compensation voltage.

12. The charge pump control method as described in claim 10, wherein, In light-load mode, the duty cycle of the charging control signal is negatively correlated with the compensation voltage, and the duty cycle of the discharging control signal is positively correlated with the compensation voltage. or The duty cycle of the charging control signal is positively correlated with the compensation voltage, and the duty cycle of the discharging control signal is negatively correlated with the compensation voltage. In other modes, the duty cycles of the charging control signal and the discharging control signal remain constant.

13. The charge pump control method as described in claim 12, wherein, The fixed duty cycle is 50%.

14. The charge pump control method according to any one of claims 10-13, wherein, In step S3), the amplitude of the control signal of any charging switch or discharging switch is controlled based on the compensation voltage to adjust the corresponding charging current or discharging current.

15. The charge pump control method as described in claim 14, wherein, When the amplitude of the control signal for the charging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is negatively correlated with the compensation voltage; when the amplitude of the control signal for the discharging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is positively correlated with the compensation voltage. or When the amplitude of the control signal for the charging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is positively correlated with the compensation voltage; when the amplitude of the control signal for the discharging switch is adjusted based on the compensation voltage, the amplitude of the corresponding control signal is negatively correlated with the compensation voltage.

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