Multiphase DC-DC converter, control circuit and electronic equipment

Abstract

The embodiment of the invention discloses a multiphase direct current-direct current converter, a control circuit and electronic equipment. N control circuits which generate pulse width modulation signals according to voltage error signals and current error signals of the corresponding power level units so as to control the corresponding power level units to work are arranged in the multi-phase direct current-direct current converter with N power level units which are connected in parallel, the voltage error signals of the N control circuits are the same signals, the current error signals are determined according to the current sampling signals and the current reference signals of the corresponding power level circuits, and the numerical value of the current reference signals is determined by the numerical value of the voltage error signals. Therefore, the current sharing of each phase of the multiphase DC-DC converter can be realized by multiplexing the voltage error signal pins among different control circuits, the structure of the circuit is simplified, and the pin packaging resource of a chip is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a multi-phase DC-DC converter, a control circuit and an electronic device. Background Art

[0002] Multiphase DC-DC converters are currently widely used due to their advantages such as flexible power expansion and improved dynamic performance. Current sharing is required between the multiple phases of a multiphase DC-DC converter. This ensures uniform power distribution across all phases, preventing local overheating, reducing input and output ripple, and improving transient response.

[0003] Optimizing the design of multiphase current sharing schemes for multiphase DC-DC converters is currently a major challenge. Conventional multiphase DC-DC converters implement this by providing an additional pin on both the master and slave phase chips. The pin on the master phase chip connects to pins on each slave phase chip, transmitting the master phase's current sampling signal to each slave phase chip. The slave phase chips receive this current sampling signal and control the power stage units, achieving current sharing among the phases.

[0004] However, adding additional pins to implement the current sharing function increases the chip's pin packaging resources, thereby increasing packaging costs and making the circuit structure more complex. Therefore, a solution that does not require additional pins is needed to simplify the circuit structure and save chip pin packaging resources. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a multi-phase DC-DC converter, a control circuit, and an electronic device to simplify the circuit structure and save chip pin packaging resources.

[0006] In a first aspect, an embodiment of the present invention provides a multi-phase DC-DC converter, comprising:

[0007] N power stage units, each of the power stage units is connected in parallel, and the power stage units are used to perform power conversion on an input voltage, wherein N is an integer greater than or equal to 2;

[0008] N control circuits, corresponding one to one with the N power stage units, for generating a pulse width modulation signal according to the voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit;

[0009] In which, the voltage error signals of the N control circuits are configured as the same signal; the current error signals of the power stage units corresponding to the N control circuits are determined respectively according to the current sampling signal and the current reference signal of the corresponding power stage circuit, and the value of the current reference signal is determined by the value of the voltage error signal to achieve current balancing of the N power stage units.

[0010] In a second aspect, an embodiment of the present invention provides a control circuit for controlling a power stage unit, the control circuit comprising:

[0011] Voltage error signal pin, used to transmit voltage error signal;

[0012] a current balancing module, configured to output a current reference signal based on the voltage error signal according to a predetermined corresponding relationship;

[0013] a first error amplifier, configured to determine a current error signal according to an output current sampling signal of a corresponding power stage unit and the current reference signal;

[0014] The second error amplifier is used to receive the output voltage sampling signal and output the voltage error signal.

[0015] In a third aspect, an embodiment of the present invention provides an electronic device, comprising the multi-phase DC-DC converter as described in the first aspect.

[0016] The technical solution of an embodiment of the present invention is to provide N control circuits in a multiphase DC-DC converter having N parallel power stage units, each of which generates a pulse-width modulation signal based on a voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit. The voltage error signals of the N control circuits are identical, and the current error signals are determined based on the current sampling signal and current reference signal of the corresponding power stage circuit, respectively. The value of the current reference signal is determined by the value of the voltage error signal. As a result, the voltage error signal pins can be reused between different control circuits to achieve current sharing among the phases of the multiphase DC-DC converter, simplifying the circuit structure and conserving chip pin packaging resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0018] Figure 1 is a circuit diagram of a multi-phase DC-DC converter of the prior art;

[0019] Figure 2 is a schematic diagram of an electronic device according to an embodiment of the present invention;

[0020] Figure 3 is a function diagram of a current balance relationship according to an embodiment of the present invention;

[0021] Figure 4 is a circuit diagram of another implementation of the slave control circuit of an embodiment of the present invention;

[0022] Figure 5 Schematic diagram of a specific implementation of a multi-phase DC-DC converter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present application is described below based on the following embodiments, but the present application is not limited to these embodiments. In the detailed description of the present application below, certain specific details are described in detail. Those skilled in the art can fully understand the present application without the description of these details. To avoid obscuring the essence of the present application, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0024] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0025] Unless the context clearly requires otherwise, words like “include”, “comprising” and the like throughout this application should be interpreted as including rather than exclusive or exhaustive; that is, as meaning “including but not limited to”.

[0026] In the description of this application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance. In addition, in the description of this application, unless otherwise specified, "plurality" means two or more.

[0027] Figure 1 is a circuit diagram of a multi-phase DC-DC converter in the prior art, such as Figure 1 As shown, the multi-phase DC-DC converter includes N power stage units 11', 12'...1 N ', N control circuits 21', 22'...2 N ', wherein the N power stage units are connected in parallel to each other and are used to power the load 3'. Specifically, the output current Iout(i)' of the N power stage units is used to power the load 3'. i 'Includes voltage error signal pin 2 i 1', pulse width modulation signal generator 2 i2', a first error amplifier EA1' and a second error amplifier EA2'. Specifically, the control circuit includes a main control circuit, and the other control circuits are slave control circuits. Specifically, the control circuit 21' is taken as the main control circuit as an example. The main control circuit 21' samples the output signal of the corresponding power stage unit through the current sampling circuit 51' to obtain the output current sampling signal Vcs(0)' of the main phase. The other control circuits 2 i 'Through the current sampling circuit 5 i 'Sampling the output signal of the corresponding power stage unit to obtain the output current sampling signal Vcs(i) of the slave phase. At the same time, the error amplifier EA2' in the master control circuit 21' generates a voltage error signal COMP(0)' based on the output voltage sampling signal FB' and the voltage reference signal REF'. Among them, the master control circuit 21' and each slave control circuit 2 i ' are based on the current error signal ERROR(i) output by the first error amplifier EA1' and the voltage error signal COMP(0)' generated by the error amplifier EA2' in the main control circuit 21' to control each power stage unit 1' to generate the output current Iout(1)'~Iout(N)'. Regarding the current error signal, specifically, each slave control circuit 2 i 'According to the current sampling signal Vcs(0)' obtained by the main control circuit 21 and the slave control circuit 2 i 'Through the current sampling circuit 5 i The current sampling signal Vcs(i)' sampled from the corresponding power stage unit is passed through the error amplifier EA1' to generate a current error signal ERROR(i)'. The current error signal ERROR(i)' is used to adjust the pulse width modulation signal PWM(i)' of the corresponding slave control circuit. The pulse width modulation signal PWM(i)' is used to adjust the output current of each power stage unit to be equal to the output current Iout(1)' of the power stage unit corresponding to the master control circuit 21'. This achieves current sharing between the various power stage circuits.

[0028] When current sharing is achieved by the above method, for the master control circuit 21', since it is necessary to provide the slave control circuit 2 i 'Transmit Vcs(0)', so it is necessary to set an additional pin to transmit the current sampling signal Vcs(0)'. i ', it also requires a pin to receive the main phase current sampling signal Vcs(0)' from the main control circuit, so as to achieve current sharing among the various power stage units.

[0029] However, since additional pins are required for both the master and slave control circuits, this consumes the chip's pin packaging resources and complicates the circuit structure. Therefore, a solution is needed that can achieve output current sharing for each power stage without requiring additional pins, thereby reducing the consumption of pin packaging resources and lowering the cost of the DC-DC converter.

[0030] Figure 2 Schematic diagram of an electronic device according to an embodiment of the present invention. Figure 2 As shown, the electronic device includes a multi-phase DC-DC converter and a load 3, wherein the multi-phase DC-DC converter includes N power stage units 11, 12...1 N , control circuit 21, 22...2 N , the N power stage units are connected in parallel, and the N control circuits correspond to the N power stage units one by one, and are used to control the operation of the corresponding power stage units. Specifically, a pulse width modulation signal is generated according to the voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit. Wherein, N is a positive integer greater than or equal to 2. In some embodiments, the N control circuits include a master control circuit, and the remaining N-1 control circuits are slave control circuits. In the following, the control circuit 21 is specifically used as the master control circuit, and the other control circuits 2 i It is to be understood that the control circuit 2 i Any one of them can be used as the main control circuit, and its principle is the same as when the control circuit 21 is used as the main control circuit. In the embodiment of the present invention, i is a positive integer greater than or equal to 2. The main control circuit 21 is used to control the first power stage unit, and each slave control circuit 2 i They are used to control the second to Nth power stage units respectively. Wherein, the multi-phase DC-DC converter is realized by N power stage units 1 i To supply power to the load 3, the master control circuit 21 and N-1 slave control circuits 2 i Used to control N power stage units 1 respectively i The output current is obtained by the multi-phase DC-DC converter. i is a positive integer greater than or equal to 2. The multi-phase DC-DC converter further includes an output voltage sampling circuit 4 and a first capacitor C1. The output voltage sampling circuit 4 is formed by a first resistor R1 and a second resistor R2 connected in series. The output voltage sampling circuit 4 is connected in parallel with the load 3 to obtain an output voltage sampling signal FB based on the voltage across the load 3. The first capacitor C1 is connected in parallel with the load 3 to stabilize the voltage across the load 3.

[0031] N power stage units 1 i Connected in parallel, the power stage unit 1 iIt is used to convert the input voltage Vin into power to supply power to the load 3. N power stage units 1 are connected in parallel to supply power to the load 3, thereby achieving the effect of superposition of multiple currents and increasing the output voltage.

[0032] A power stage unit is a core module in an electronic system that implements power conversion, amplification, and drive functions. Its core function is to process input electrical energy or signal power in a targeted manner to meet the power requirements of the load. In embodiments of the present invention, the power stage unit is specifically a power electronic power stage unit, which focuses on electrical energy conversion and is commonly found in devices such as inverters and chargers. In one example, the power stage unit can be a switching converter. By combining a power switch with an energy storage element such as an inductor, the power storage element is controlled to switch between receiving electrical energy from the input and outputting electrical energy to the output. Power conversion is achieved by utilizing the energy storage element's property of preventing voltage or current changes. The power stage unit used in this embodiment can be a direct-flow switching converter, such as a buck converter, a boost converter, or a buck-boost converter, or an isolated converter, such as a flyback converter. The load can also be various functional circuits requiring a relatively high current range, such as a DC motor, a semiconductor light source, other types of light sources, or a heating device.

[0033] Specifically, each control circuit 2 i Includes voltage error signal pin 2 i 1. Current balancing module 2 i 2. First error amplifier EA1, second error amplifier EA2 and pulse width modulation (PWM) signal generator 2 i 3. The voltage error signal pins of each control circuit are coupled together. The voltage error signal is configured as a divided voltage error signal generated by a master control circuit among the N control circuits and transmitted to N-1 slave control circuits.

[0034] The working states of the master control circuit and the slave control circuit are described below respectively. It should be understood that in the embodiment of the present invention, the structures of the master control circuit and the slave control circuit are the same. In a specific application scenario, which control circuit serves as the master control circuit can be set according to actual needs.

[0035] Specifically, the main control circuit 21 is connected to the first power stage unit 11 and is configured to control the output current Iout(1) of the power stage unit 11. The main control circuit 21 can be implemented as an integrated circuit. The main control circuit 21 includes a voltage error signal pin 211, a current balancing module 212, a first error amplifier EA1, a second error amplifier EA2, and a pulse width modulation signal generator 213.

[0036] The second error amplifier EA2 is configured to input and output voltage sampling signals FB, and output a voltage error signal COMP(0) based on the output voltage sampling signal FB and a predetermined voltage reference signal REF. Specifically, in an embodiment of the present invention, the voltage error signal is configured as a divided voltage error signal generated by the master control circuit and transmitted to N-1 slave control circuits. One input terminal of the second error amplifier EA2 is connected to the output voltage sampling circuit 51, specifically to the common terminal of the first resistor R1 and the second resistor R2, to receive the output voltage sampling signal FB. The voltage sampling signal FB obtained by the above method is the voltage generated by the voltage across the load 3 after being divided by the first resistor R1 and the second resistor R2. Therefore, the voltage sampling signal FB is proportional to the voltage value Vout across the load 3 and can be used to reflect the voltage value across the load. The error amplifier is an electronic device used to accurately adjust the output in a feedback control system. Its core principle is to compare the difference between the reference signal and the actual output signal, amplify the error, and drive the actuator to make the system output approach the reference value. Specifically, an error signal is first obtained by subtracting the reference signal and the output signal through a subtractor, and then the error amplifier performs high-gain amplification on the signal to improve the control sensitivity, and the amplified error signal is used as a control variable to adjust the system output. In an embodiment of the present invention, the voltage error signal COMP(0) output by the second error amplifier EA2 is used as one of the input signals of the pulse width modulation signal generator 213 to control the pulse width modulation signal generator 213 to generate a pulse width modulation signal, thereby controlling the output current Iout(1) of the corresponding power stage unit 11. The voltage error signal pin 211 is connected to the output end of the second error amplifier EA2 and is configured to output the voltage error signal COMP(0). The current balancing module 212 is connected to the voltage error signal pin 211 and is configured to receive the voltage error signal COMP(0) and output a current reference signal VCS_REF based on the voltage error signal according to a predetermined current balance correspondence. Specifically, the predetermined relationship satisfies the current balancing requirement of the N power stage units, so that the current error signal ERROR(0) can be generated based on the current reference signal VCS_REF in the subsequent process to control the output current Iout(1) of the power stage unit.

[0037] In some embodiments, when the voltage error signal is within a first voltage value range determined by a lower threshold and an upper threshold, the current reference signal is in direct proportion to the voltage error signal; when the voltage error signal is less than the lower threshold, the current reference signal is maintained at a first reference value; and when the voltage error signal is greater than the upper threshold, the current reference signal is maintained at a second reference value. Figure 3As shown, the upper threshold of the voltage error signal is 2V, and the lower threshold is 0.8V. When the voltage error signal is within a first voltage range determined by the lower and upper thresholds, that is, between 0.8V and 2V, this segment of the function is a linear function, meaning that the current reference signal is directly proportional to the voltage error signal. When the voltage error signal is less than the lower threshold, that is, less than 0.8V, the current reference signal is maintained at a first reference value, specifically 0. When the voltage error signal is greater than the upper threshold, that is, greater than 2V, the current reference signal is maintained at a second reference value, specifically 50mV. Thus, through a predetermined piecewise functional relationship, the current balancing module 212 generates a current reference signal based on the voltage error signal.

[0038] It should be understood that the current balancing modules in each control circuit correspond to the same current balancing curve, which represents the relationship between the voltage error signal and the current reference signal. Therefore, the upper threshold, lower threshold, first reference value, and second reference value can be set to other values ​​based on actual needs. Furthermore, in addition to the aforementioned functional relationship, other functional relationships between the current reference signal and the voltage error signal can also be determined based on actual needs.

[0039] After obtaining the current reference signal, in some embodiments, the DC-DC converter is further configured to control at least one power stage circuit to not work according to the current reference signal. Specifically, the smaller the value of the current reference signal, the more power stage circuits are controlled to not work. Specifically, when the current reference signal is small, it indicates that the current required by the load is relatively small. At this time, it is not necessary for all power stage circuits to supply power to the load in order for the load to work normally. Therefore, part of the power stage circuits can be turned off to reduce switching losses. Specifically, the smaller the current reference signal, the fewer the power stage circuits that need to work. Figure 3As shown, when the current reference signal is lower than the first threshold value Vth(1), the power level unit corresponding to one of the slave control circuits is turned off. As an example, it can be the power level unit corresponding to the first slave control circuit. When the current reference signal is lower than the second threshold value Vth(2), the power level units corresponding to two of the slave control circuits are turned off. As an example, it can be based on turning off the power level unit corresponding to the first slave control circuit and then turning off the power level unit corresponding to the second slave control circuit. Similarly, when the current reference signal is lower than the upper threshold value Vth(N), the power level units corresponding to N of the slave control circuits are turned off. As an example, it can be based on turning off the power level units corresponding to the first N-1 slave control circuits and then turning off the power level unit corresponding to the Nth slave control circuit. At this time, only the power level unit corresponding to the master control circuit is working to achieve power supply. Through the above design, the number of power level units supplying power to the load is adjusted according to the power supply situation of the load, thereby achieving resource saving.

[0040] like Figure 2 As shown, the other input terminal of the first error amplifier EA1 is connected to the current sampling circuit 51, and the current sampling circuit 51 is connected to the output terminal of the power stage unit to output the current sampling signal Vcs(0). The first error amplifier EA1 outputs the current error signal ERROR(0) based on the current reference signal VCS_REF and the current sampling signal Vcs(0), and the current error signal ERROR(0) is used to control the pulse width modulation signal generator 213. Specifically, the pulse width modulation signal generator 213 is connected to the output terminal of the first error amplifier EA1 to receive the current error signal ERROR(0), and the pulse width modulation signal generator 213 is also connected to the output terminal of the second error amplifier EA2 to receive the voltage error signal COMP(0). The pulse width modulation signal generator 213 is configured to output the pulse width modulation signal PWM(0) according to the voltage error signal COMP(0) and the current error signal ERROR(0), wherein the pulse width modulation signal PWM(0) is used to control the output current Iout(1) of the first power stage unit.

[0041] Specifically, the pulse width modulation signal generator 213 is an electronic device or circuit module that accurately adjusts the output power, voltage or current by precisely controlling the width of the electrical signal pulse. Its working principle is based on a square wave signal with a fixed frequency. By adjusting the duration ratio of the high level and the low level in a cycle (i.e., the duty cycle), the average output value is controlled, wherein the duty cycle is the ratio of the high level time in a cycle to the cycle. Among them, the core parameters of the pulse width modulation signal generator include frequency, duty cycle and resolution. In the power management of the embodiment of the present invention, the pulse width modulation signal generator is used to achieve efficient voltage conversion, and its advantages are high efficiency and energy saving, precise control, and strong anti-interference ability.

[0042] In some embodiments, the main control circuit further includes a control switch S1, wherein the control switch S1 is connected between the second error amplifier EA2 and the voltage error signal pin 211. The control switch S1 in the main control circuit is turned on.

[0043] N-1 slave control circuits 22, 23...2 N The slave control circuit 22 is connected to the second, third, ..., Nth power stage unit, respectively, where N is an integer greater than or equal to 2. In the embodiment of the present invention, the slave control circuit 22 connected to the second power stage unit is used as an example. Specifically, the structure of the slave control circuit is the same as that of the master control circuit. N , the remaining slave control circuits are indicated by ellipsis in the figure. It should be understood that the structures of the other slave control circuits are the same as the structure of the slave control circuit 22, and therefore the specific working principles are also the same. Specifically, the slave control circuit can be implemented by an integrated circuit. i The circuit is used to determine the voltage error signal COMP(i) and the current error signal ERROR(i) of the branch of the corresponding power stage unit, so as to control the operation of the corresponding power stage unit according to the voltage error signal COMP(i) and the current error signal ERROR(i). Specifically, for the i-1th (i is a positive integer greater than or equal to 2) slave control circuit 2 i , the slave control circuit 2 i Includes voltage error signal pin 2 i 1. Current balancing module 2 i 2. First error amplifier EA1, second error amplifier EA2, pulse width modulation signal generator 2 i 3. The following takes the first slave control circuit as an example for explanation.

[0044] Specifically, since the voltage error signal pin 221 is coupled to the voltage error signal pin 211 in the main control circuit, the voltage error signal pin 221 is used to receive and output the voltage error signal sent by the voltage error signal pin 211 in the control circuit. Since the voltage error signal COMP(1) is obtained from the voltage error signal pin 211, the value of COMP(1) is the same as COMP(0). The current balancing module 222 is connected to the voltage error signal pin 221 and is used to output the current reference signal VCS_REF based on the voltage error signal COMP(1) according to a predetermined current balance correspondence. The other input end of the first error amplifier EA1 is connected to the output end of the first power stage unit to obtain the current sampling signal Vcs(1). The first error amplifier EA1 obtains an output current error signal ERROR(1) based on the current reference signal VCS_REF and the current sampling signal. The current error signal ERROR(1) is used to control the pulse width modulation generator 223. The pulse width modulation generator 223 is connected to the output end of the first error amplifier EA1 to receive the current error signal ERROR(1), and the output end of the second error amplifier EA2 to receive the voltage error signal COMP(1). The pulse width modulation generator 223 is configured to output a pulse width modulation signal PWM(0) according to the voltage error signal COMP(0) and the current error signal ERROR(0). The pulse width modulation signal is used to control the output current of the second power stage unit.

[0045] In some embodiments, the slave control circuit 22 further includes a control switch S2. The second error amplifier EA2 receives the output voltage sampling signal and outputs the voltage error signal. Specifically, the second error amplifier EA2 receives the output voltage sampling signal and outputs the voltage error signal based on the output voltage sampling signal and a predetermined voltage reference signal. The control switch S2 is connected between the second error amplifier EA2 and the voltage error signal pin 221. The voltage error signal pin 221 is connected to the voltage error signal input terminal of the pulse width modulation signal generator 223. The control switch S2 of the slave control circuit 223 is turned off.

[0046] Figure 4 FIG. 1 is a circuit diagram of another implementation of the slave control circuit according to an embodiment of the present invention, such as Figure 4As shown, the slave control circuit includes a voltage error signal pin 21, a current balancing module 22, a first error amplifier EA1, and a pulse-width modulation signal generator 23. Specifically, since the slave control circuit receives the current error signal from the master control circuit via the voltage error signal pin 21, there is no need for a second error amplifier EA2 to generate the voltage error signal. Therefore, the second error amplifier EA2 can be omitted from the slave control circuit. The voltage error signal pin 21 is connected to the voltage error signal pin of the master control circuit to receive a voltage signal. The current balancing module 22 is configured to output a current reference signal based on the voltage error signal according to a predetermined current balancing relationship. One input terminal of the first error amplifier EA1 is connected to the current balancing module 22 to receive the current reference signal, and the other input terminal receives the output current sampling signal of the corresponding power stage circuit. The current balancing module 22 determines the current error signal based on the output current sampling signal and the current reference signal. The pulse-width modulation signal generator 23 is configured to output a pulse-width modulation signal for controlling the power stage unit based on the voltage error signal and the current error signal, thereby controlling the output current of the power stage circuit.

[0047] Specifically, in the practical application of the embodiment of the present invention, since the slave control circuit does not need to use the second error amplifier EA2, when forming the DC-DC converter, the slave control circuit can be Figure 2 The chip integrated in the slave control circuit is consistent with the master control circuit; it can also be Figure 4 The chip integrated with the control circuit in the device can save resources.

[0048] The following is an explanation of the principle of current sharing of the entire multi-phase DC-DC converter. Specifically, when the control circuit 21 is used as the master control circuit, for the master control circuit and N-1 slave control circuits, the control switch S1 of the master control circuit is turned on, and the control switches Si of each slave control circuit are turned off, and the pulse width modulation signal generator 2 i 3 is used to control the corresponding power stage unit, specifically, each pulse width modulation signal generator 2 i3 takes the voltage error signal and the current error signal as inputs to generate a pulse width modulation signal for controlling the power stage units. Regarding the voltage error signal, for the master control circuit, its voltage error signal is determined by the second error amplifier EA2 based on a predetermined voltage reference signal and an output voltage sampling signal. For the slave control circuit, its voltage error signal is obtained via a voltage error signal pin. The voltage error signal pin of the slave control circuit is connected to the voltage error signal pin of the master control circuit to obtain the voltage error signal output by the master control circuit 21. Both the master and slave control circuits use the output of the first error amplifier EA1 as the current error signal. One input of each first error amplifier EA1 is connected to the output of the corresponding power stage unit to obtain the current sampling signal, and the other input is connected to a current balancing module. The current balancing module is connected to the voltage error signal pin to receive the voltage error signal as input and output a current reference signal based on a predetermined correspondence between the voltage error signal and the current reference signal. The first error amplifier EA1 outputs the current error signal based on the current reference signal and the current sampling signal. Thus, by reusing the voltage error signal pin, current sharing is achieved between the outputs of each power stage unit without adding additional pins.

[0049] In an embodiment of the present invention, N control circuits are provided in a multiphase DC-DC converter having N parallel-connected power stage units, each of which generates a pulse-width modulation signal based on a voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit. The voltage error signals of the N control circuits are identical, and the current error signals are determined based on the current sampling signal and current reference signal of the corresponding power stage circuit, respectively. The value of the current reference signal is determined by the value of the voltage error signal. As a result, the voltage error signal pins can be reused between different control circuits to achieve current sharing among the phases of the multiphase DC-DC converter, simplifying the circuit structure and conserving chip pin packaging resources.

[0050] Figure 5 Schematic diagram of a specific implementation of a multi-phase DC-DC converter according to an embodiment of the present invention. Figure 5 As shown, the multi-phase DC-DC converter includes N power stage units 11, 12...1 N , control circuit 21, 22 ... 2 N-1 Wherein, the N power stage units 11, 12...1 N Used to power the load 3. Wherein, the control circuit 2 iThe multi-phase DC-DC converter includes a voltage error signal pin 21, a current balancing module 22, a pulse width modulation signal generator 23, a first error amplifier EA1, and a second error amplifier EA2. The multi-phase DC-DC converter further includes an output voltage sampling circuit 4, which includes a first resistor R1 and a second resistor R2 connected in series. The multi-phase DC-DC converter further includes a first capacitor C1 for stabilizing the voltage across the load 3. For the current sampling circuit, this embodiment uses a resistor R i ' and input interface 5 i To achieve this together. Among them, through the resistor R i 'Connected to the output end of the power stage unit and converts the current signal into a current sampling signal according to Ohm's law, and transmits the current signal to the input interface 5 i The current sampling signal is used as the input of the first error amplifier EA1.

[0051] In addition, in this embodiment, each control circuit 2 i The control switch is turned on. At this time, the voltage error signal is configured as the average value of all the divided voltage error signals of the N control circuits. According to the voltage error signal at this time, based on Figure 2 The same principle as the embodiment of the present invention can also realize the control of the power stage unit, thereby realizing the current sharing among the power stage units.

[0052] In an embodiment of the present invention, N control circuits are provided in a multiphase DC-DC converter having N parallel-connected power stage units, each of which generates a pulse-width modulation signal based on a voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit. The voltage error signals of the N control circuits are identical, and the current error signals are determined based on the current sampling signal and current reference signal of the corresponding power stage circuit, respectively. The value of the current reference signal is determined by the value of the voltage error signal. As a result, the voltage error signal pins can be reused between different control circuits to achieve current sharing among the phases of the multiphase DC-DC converter, simplifying the circuit structure and conserving chip pin packaging resources.

[0053] The foregoing is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application are intended to be within the scope of protection of the present application.

Claims

1. A multiphase DC-DC converter, characterized in that: include: N power stage units, each of the power stage units is connected in parallel, and the power stage units are used to perform power conversion on an input voltage, wherein N is an integer greater than or equal to 2; N control circuits, corresponding one to one with the N power stage units, for generating a pulse width modulation signal according to the voltage error signal and the current error signal of the corresponding power stage unit to control the operation of the corresponding power stage unit; In which, the voltage error signals of the N control circuits are configured as the same signal; the current error signals of the power stage units corresponding to the N control circuits are determined respectively according to the current sampling signal and the current reference signal of the corresponding power stage circuit, and the value of the current reference signal is determined by the value of the voltage error signal to achieve current balancing of the N power stage units.

2. The multiphase DC-DC converter according to claim 1, wherein: Each of the control circuits has a voltage error signal pin for transmitting the voltage error signal, and the voltage error signal pins of the N control circuits are coupled together.

3. The multiphase DC-DC converter according to claim 2, wherein: The voltage error signal is configured as a divided voltage error signal generated by a master control circuit among the N control circuits and transmitted to N-1 slave control circuits.

4. The multiphase DC-DC converter according to claim 2, wherein: The voltage error signal is configured as an average value of all divided voltage error signals of the N control circuits.

5. The multi-phase DC-DC converter according to claim 1, wherein: The current reference signal and the voltage error signal form a predetermined relationship, and the predetermined relationship satisfies a current balancing requirement of N power stage units.

6. The multi-phase DC-DC converter according to claim 5, characterized in that: When the voltage error signal is within a first voltage value range determined by a lower threshold and an upper threshold, the current reference signal is in direct proportion to the voltage error signal; When the voltage error signal is less than the lower threshold, the current reference signal is maintained at a first reference value; When the voltage error signal is greater than the upper threshold, the current reference signal is maintained at a second reference value.

7. The multi-phase DC-DC converter according to claim 1, wherein: The current reference signal is generated based on a predetermined piecewise functional relationship with the voltage error signal.

8. The multiphase DC-DC converter according to claim 1, wherein: The phase DC-DC converter further controls at least one power stage circuit to not operate according to the current reference signal.

9. The multi-phase DC-DC converter according to claim 8, characterized in that: The smaller the value of the current reference signal is, the greater the number of the power stage circuits that are controlled to be inoperative.

10. The multi-phase DC-DC converter according to claim 1, wherein: Each of the control circuits comprises: The first error amplifier is configured to determine the current error signal according to the output current sampling signal of the corresponding power stage unit and the current reference signal.

11. The multi-phase DC-DC converter according to claim 3, wherein: Each of the control circuits comprises: a second error amplifier, configured to determine the divided voltage error signal according to the output voltage sampling signal and a predetermined voltage reference signal; a control switch connected between the output terminal of the second error amplifier and the voltage error signal pin; The control switch in the master control circuit is turned on, and the control switch in the slave control circuit is turned off.

12. The multi-phase DC-DC converter according to claim 4, wherein: Each of the control circuits includes: a second error amplifier for determining the divided voltage error signal based on the output voltage sampling signal and a predetermined voltage reference signal; a control switch connected between the output terminal of the second error amplifier and the voltage error signal pin; The control switches in the N control circuits are all turned on.

13. A control circuit for controlling a power stage unit, characterized in that: The control circuit comprises: Voltage error signal pin, used to transmit voltage error signal; a current balancing module, configured to output a current reference signal based on the voltage error signal according to a predetermined corresponding relationship; a first error amplifier, configured to determine a current error signal according to an output current sampling signal of a corresponding power stage unit and the current reference signal; a pulse width modulation signal generator configured to generate a pulse width modulation signal for controlling the power stage unit according to the voltage error signal and the current error signal; The voltage error signal is received from the voltage error signal pin or generated by a second error amplifier.

14. The control circuit according to claim 13, wherein: The voltage error signal pin and the voltage error signal pins of other control circuits are coupled together.

15. The control circuit according to claim 13, wherein: The control circuit further includes: a control switch connected between the output terminal of the second error amplifier and the voltage error signal pin; wherein the second error amplifier is used to generate the voltage error signal according to the output voltage sampling signal and a predetermined voltage reference signal; When the control circuit is configured as a master control circuit, the control switch is turned on, and when the control circuit is configured as a slave control circuit, the control switch is turned off.

16. The control circuit according to claim 13, wherein: The control circuit further includes: a control switch connected between the output terminal of the second error amplifier and the voltage error signal pin; wherein the second error amplifier is used to generate the voltage error signal according to the output voltage sampling signal and a predetermined voltage reference signal; The control switch is in an on state.

17. The control circuit according to claim 13, wherein: The current reference signal and the voltage error signal form a predetermined relationship, and the predetermined relationship satisfies a requirement of system current balance.

18. An electronic device, characterized in that: The electronic device includes the multi-phase DC-DC converter according to any one of claims 1 to 12.

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