A charge pump control circuit and motor driving chip

Abstract

This application discloses a charge pump control circuit and a motor drive chip. The circuit includes a sampling module, a conversion module, and a control module. The sampling module receives the power supply voltage and the output voltage of the charge pump, and outputs a current signal to characterize the voltage difference between the power supply voltage and the output voltage. The input terminal of the conversion module is connected to the output terminal of the sampling module, and the conversion module converts the current signal into a voltage signal. The input terminal of the control module is connected to the output terminal of the conversion module, and the control module generates a control signal based on the voltage signal and a preset reference voltage, and outputs it to the clock control terminal of the charge pump to adjust the output voltage so that the voltage difference is maintained at the target voltage difference.

Description

Technical Field

[0001] This application relates to the field of motor drive chip technology, and in particular to a charge pump control circuit and a motor drive chip. Background Technology

[0002] In fields such as motor driver chips, a voltage higher than the source voltage needs to be applied to the gate of a high-side power transistor to drive it. Related technologies typically employ an on-chip charge pump circuit to drive the high-side power transistor, which pumps the voltage to the required level through the charging and discharging of a capacitor. However, to achieve a stable output voltage, traditional charge pump feedback control schemes generally rely on an external voltage divider resistor network to sample the output voltage. These voltage divider resistors need to withstand high voltages and maintain accuracy, occupying a significant amount of chip area in integrated circuits and substantially increasing manufacturing costs. Summary of the Invention

[0003] This application aims to propose a charge pump control circuit and a motor drive chip, which can solve the problems of large chip area and high manufacturing cost of motor drive chips.

[0004] In a first aspect, embodiments of this application provide a charge pump control circuit, applied to a charge pump, the circuit comprising:

[0005] A sampling module is used to receive the power supply voltage and the output voltage of the charge pump, and output a current signal to characterize the voltage difference between the power supply voltage and the output voltage;

[0006] A conversion module, the input of which is connected to the output of the sampling module, is used to convert the current signal into a voltage signal;

[0007] The control module has its input terminal connected to the output terminal of the conversion module. The control module is used to generate a control signal based on the voltage signal and a preset reference voltage and output it to the clock control terminal of the charge pump to adjust the output voltage so that the pressure difference is maintained at the target pressure difference.

[0008] According to some embodiments of this application, the sampling module includes:

[0009] A differential input unit, wherein the input terminal of the differential input unit is used to receive the power supply voltage and the output voltage of the charge pump, and convert the voltage difference into the current signal;

[0010] A current mirror unit is connected to the differential input unit, and the current mirror unit is used to keep the currents of the two differential branches of the differential input unit equal;

[0011] A clamping protection unit is provided, which is connected to the differential input unit and the current mirror unit respectively. The clamping protection unit is used to clamp the input terminals of the differential input unit and the current mirror unit to protect the differential input unit and the current mirror unit.

[0012] According to some embodiments of this application, the differential input unit includes:

[0013] A first resistor, the first terminal of which is used to receive the power supply voltage.

[0014] The first MOSFET is connected to the source of the first MOSFET, and the drain of the first MOSFET is connected to the input of the conversion module.

[0015] The second MOSFET has its gate connected to the gate of the first MOSFET, and its source connected to the input terminal of the conversion module.

[0016] The second resistor has a first end for receiving the output voltage of the charge pump, and a second end connected to the source of the second MOS transistor.

[0017] According to some embodiments of this application, the conversion module includes:

[0018] The third MOS transistor has its gate connected to the drain of the seventh MOS transistor, its drain connected to the second terminal of the second resistor, and its source connected to the input terminal of the control module.

[0019] According to some embodiments of this application, the conversion module further includes:

[0020] The third resistor, the first end of which is connected to the source of the third MOS transistor;

[0021] The fourth resistor has its first end connected to the second end of the third resistor, and its second end is grounded.

[0022] According to some embodiments of this application, the current mirror unit includes:

[0023] The fourth MOS transistor has its drain connected to the output terminal of the clamping protection unit, its gate connected to the bias voltage terminal, and its source grounded.

[0024] The fifth MOS transistor has its drain connected to the output terminal of the clamping protection unit, its gate connected to the bias voltage terminal, and its source grounded.

[0025] According to some embodiments of this application, the clamping protection unit includes:

[0026] The sixth MOS transistor, the source of which is connected to the differential input unit;

[0027] The seventh MOS transistor has its source connected to the differential input unit and its gate connected to the gate of the sixth MOS transistor.

[0028] The eighth MOS transistor has its drain connected to the drain of the seventh MOS transistor, its gate connected to the clamping voltage terminal, and its source connected to the current mirror unit.

[0029] The ninth MOS transistor has its drain connected to the drain of the sixth MOS transistor, its gate connected to the clamping voltage terminal, and its source connected to the current mirror unit.

[0030] According to some embodiments of this application, the control module includes:

[0031] The comparator has its non-inverting input connected to the output of the conversion module, its inverting input used to input the reference voltage, and its output connected to the clock control terminal of the charge pump.

[0032] According to some embodiments of this application, the control module further includes:

[0033] Hysteresis control unit, which is connected between the output of the comparator and the conversion module.

[0034] Secondly, embodiments of this application provide a motor drive chip, including the charge pump control circuit described above.

[0035] In this embodiment, a sampling module receives the power supply voltage and the charge pump output voltage, and directly converts the voltage difference between them into a current signal characterizing the voltage difference. A conversion module then converts the current signal into a voltage signal, and a control module compares the voltage signal with a preset reference voltage. Finally, a control signal is generated to precisely adjust the operating state of the charge pump, dynamically maintaining the voltage difference between the power supply voltage and the charge pump output voltage at the target voltage difference, thus providing a stable and reliable gate-source drive voltage for the high-side power transistor. Compared to traditional solutions, this embodiment eliminates the external voltage divider resistor network, significantly reducing chip area and manufacturing costs.

[0036] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0037] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0038] Figure 1 A circuit diagram of an embodiment of the charge pump control circuit provided in this application;

[0039] Figure 2 This is a schematic diagram of the structure of an embodiment of the motor driver chip provided in this application;

[0040] Figure 3 The waveform diagram of the charge pump in the embodiment of the motor drive chip provided in this application.

[0041] Figure label:

[0042] Sampling module 100, conversion module 200, control module 300. Detailed Implementation

[0043] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0044] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0046] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0047] The following is based on Figures 1 to 3 This application describes a charge pump control circuit and a motor drive chip provided in an embodiment.

[0048] This application provides a charge pump control circuit, which is applied to a charge pump, such as... Figure 1 As shown, the circuit includes:

[0049] The sampling module 100 is used to receive the power supply voltage and the output voltage of the charge pump, and output a current signal to characterize the voltage difference between the power supply voltage and the output voltage.

[0050] The conversion module 200 has its input terminal connected to the output terminal of the sampling module 100. The conversion module 200 is used to convert the current signal into a voltage signal.

[0051] The control module 300 has its input terminal connected to the output terminal of the conversion module 200. The control module 300 generates a control signal based on the voltage signal and a preset reference voltage and outputs it to the clock control terminal of the charge pump to adjust the output voltage so that the pressure difference is maintained at the target pressure difference.

[0052] In this embodiment, the sampling module 100 receives the power supply voltage and the charge pump output voltage, and directly converts the voltage difference between the two into a current signal characterizing the voltage difference. Then, the conversion module 200 converts the current signal into a voltage signal, and the control module 300 compares the voltage signal with a preset reference voltage. Finally, a control signal is generated to precisely adjust the operating state of the charge pump, dynamically maintaining the voltage difference between the power supply voltage and the charge pump output voltage at the target voltage difference, providing a stable and reliable gate-source drive voltage for the high-side power transistor. Compared with traditional solutions, this embodiment eliminates the external voltage divider resistor network, greatly reducing the chip area and lowering manufacturing costs.

[0053] In some embodiments of this application, the sampling module 100 includes:

[0054] The differential input unit receives the power supply voltage and the output voltage of the charge pump at its input terminal and converts the voltage difference into a current signal.

[0055] The current mirror unit is connected to the differential input unit and is used to keep the currents of the two differential branches of the differential input unit equal.

[0056] The clamping protection unit is connected to the differential input unit and the current mirror unit respectively. The clamping protection unit is used to clamp the input terminals of the differential input unit and the current mirror unit to protect the differential input unit and the current mirror unit.

[0057] In this embodiment, the differential input unit directly receives and converts the voltage difference between the power supply voltage and the charge pump output voltage, eliminating the need for a traditional external voltage divider network and fundamentally reducing the chip area. Then, the current mirror unit forces precise current matching between the two differential branches, ensuring the linearity and accuracy of the voltage difference conversion into a current signal. Simultaneously, the clamping protection unit performs multi-stage voltage clamping on the input terminals of the differential input unit and the current mirror unit, safely limiting the potential to a low voltage range. This allows the use of high-performance, low-voltage devices, achieving the advantages of low power consumption and small area while withstanding high-voltage input, thus realizing the control objective of stably maintaining the target voltage difference under full duty cycle operation of the high-side power transistor.

[0058] In some embodiments of this application, the differential input unit includes:

[0059] First resistor (e.g.) Figure 1 In the first resistor R1, the first terminal is used to receive the power supply voltage.

[0060] First MOSFET (e.g.) Figure 1 M1 in the first resistor is connected to the source of the first MOSFET, and the drain of the first MOSFET is connected to the input of the conversion module 200.

[0061] Second MOSFET (such as) Figure 1 In the M2), the gate of the second MOSFET is connected to the gate of the first MOSFET, and the source of the second MOSFET is connected to the input terminal of the conversion module 200;

[0062] Second resistor (such as) Figure 1 In the second resistor R2), the first end of the second resistor is used to receive the output voltage of the charge pump, and the second end of the second resistor is connected to the source of the second MOS transistor.

[0063] In this embodiment, a symmetrical common-gate differential structure is formed by a first resistor and a first MOSFET, and a second resistor and a second MOSFET. Both the first and second MOSFETs are NMOS transistors. The first resistor and the source of the first MOSFET are connected in series to form a differential branch for sampling the power supply voltage, and the second resistor and the source of the second MOSFET are connected in series to form a differential branch for sampling the charge pump output voltage. The gates of the first and second MOSFETs are connected together to form a differential pair. The high voltage difference between the power supply voltage and the charge pump output voltage is directly converted into two matched current signals. This achieves voltage difference sampling without the need for external voltage divider resistors, and the high voltage input can be withstood through the inherent characteristics of the common-gate structure. At the same time, the symmetrical differential branch design ensures accurate matching of the current signals, providing a basis for the subsequent current mirror unit to achieve equal current in the two differential branches, thus realizing stable and reliable high-precision voltage difference detection.

[0064] In some embodiments of this application, the conversion module 200 includes:

[0065] Third MOSFET (such as) Figure 1 In the M9 section, the gate of the third MOSFET is connected to the drain of the seventh MOSFET, the drain of the third MOSFET is connected to the second terminal of the second resistor, and the source of the third MOSFET is connected to the input terminal of the control module 300.

[0066] In this embodiment, by connecting the gate and drain of the third MOSFET to the drains of the first and second MOSFETs in the differential input unit, respectively, and connecting the source of the third MOSFET as the output terminal to the control module 300, a precise current summation and voltage conversion path is constructed. The third MOSFET and the sampling module 100 together form a negative feedback loop, forcing the current flowing through its channel to be precisely equal to the current value determined by the voltage difference between the power supply voltage and the charge pump output voltage. This linearly converts the current signal representing the voltage difference into a voltage signal on the source of the third MOSFET, achieving not only a high linearity conversion from current signal to voltage signal, but also significantly improving loop stability and anti-interference capability through the negative feedback mechanism.

[0067] In some embodiments of this application, the conversion module 200 further includes:

[0068] Third resistor (such as) Figure 1 R3 in the diagram), the first end of the third resistor is connected to the source of the third MOS transistor;

[0069] Fourth resistor (e.g.) Figure 1 In the circuit, R4), the first end of the fourth resistor is connected to the second end of the third resistor, and the second end of the fourth resistor is grounded.

[0070] In this embodiment, a stable and reliable current-to-voltage conversion network is constructed by connecting a third resistor and a fourth resistor in series between the source of the third MOSFET and ground. This network converts the current signal, which accurately represents the voltage difference between the power supply voltage and the charge pump output voltage, into a corresponding voltage signal. By selecting an appropriate ratio of the third resistor to the fourth resistor, the circuit gain can be flexibly set, thereby establishing an accurate target voltage difference reference.

[0071] In some embodiments of this application, the current mirror unit includes:

[0072] Fourth MOSFET (e.g.) Figure 1 In the M7 section, the drain of the fourth MOSFET is connected to the output terminal of the clamping protection unit, the gate of the fourth MOSFET is connected to the bias voltage terminal, and the source of the fourth MOSFET is grounded.

[0073] Fifth MOSFET (e.g.) Figure 1In the M8 transistor, the drain of the fifth MOSFET is connected to the output terminal of the clamping protection unit, the gate of the fifth MOSFET is connected to the bias voltage terminal, and the source of the fifth MOSFET is grounded.

[0074] In this embodiment, the fourth and fifth MOSFETs constitute a current mirror unit. The gates of the fourth and fifth MOSFETs are interconnected and connected to the bias voltage terminal. The sources of the fourth and fifth MOSFETs are grounded together, and the drains of the fourth and fifth MOSFETs are respectively connected to the output terminal of the clamping protection unit, forming a precise current mirror structure. This forces the two differential branch currents flowing through the first and second MOSFETs to remain dynamically equal, thereby eliminating detection errors caused by device mismatch or process deviations. This ensures the linear conversion accuracy from the voltage difference between the power supply voltage and the charge pump output voltage to the current signal, improving detection accuracy and thus achieving high-precision differential voltage detection without the need for external voltage divider resistors.

[0075] In some embodiments of this application, the clamping protection unit includes:

[0076] The sixth MOSFET (such as Figure 1 In the M3 transistor, the source of the sixth MOS transistor is connected to the differential input unit;

[0077] Seventh MOSFET (e.g.) Figure 1 In the M4 transistor, the source of the seventh MOSFET is connected to the differential input unit, and the gate of the seventh MOSFET is connected to the gate of the sixth MOSFET.

[0078] The eighth MOSFET (e.g.) Figure 1 In the M5, the drain of the eighth MOSFET is connected to the drain of the seventh MOSFET, the gate of the eighth MOSFET is connected to the clamping voltage terminal, and the source of the eighth MOSFET is connected to the current mirror unit.

[0079] Ninth MOSFET (e.g.) Figure 1 In the M6 ​​configuration, the drain of the ninth MOSFET is connected to the drain of the sixth MOSFET, the gate of the ninth MOSFET is connected to the clamping voltage terminal, and the source of the ninth MOSFET is connected to the current mirror unit.

[0080] In this embodiment, the sixth and seventh MOSFETs are respectively connected to the two differential branches of the differential input unit. The gates of the sixth and seventh MOSFETs are interconnected, clamping the voltage input to the differential input unit at a safe potential and effectively blocking the direct impact of high-voltage signals on the differential input unit. The eighth and ninth MOSFETs are connected to the input terminals of the current mirror unit. The clamping voltage received by the upper gates of the eighth and ninth MOSFETs precisely limits the operating potential of the current mirror unit, forming a reliable voltage barrier and significantly improving reliability and service life.

[0081] In some embodiments of this application, the control module 300 includes:

[0082] Comparator (e.g.) Figure 1 The non-inverting input of the comparator (COMP) is connected to the output of the conversion module 200, the inverting input of the comparator is used to input the reference voltage, and the output of the comparator is connected to the clock control terminal of the charge pump.

[0083] In this embodiment, the non-inverting input of the comparator is connected to the output of the conversion module 200 to receive the voltage signal, while the inverting input of the comparator is input with a reference voltage. The comparator compares the amplitude relationship between the voltage signal and the reference voltage in real time and outputs a control signal to the clock control terminal of the charge pump, which directly determines the start and stop state of the charge pump. This achieves closed-loop control of the charge pump's operating state and can dynamically lock the voltage difference between the power supply voltage and the charge pump output voltage to the target voltage difference, thus ensuring the full duty cycle operation of the high-side power transistor.

[0084] In some embodiments of this application, the control module 300 further includes:

[0085] Hysteresis control unit, which is connected between the output of the comparator and the conversion module 200.

[0086] In this embodiment, a hysteresis control unit is added to the control module 300 and connected between the comparator output and the resistor network of the conversion module 200. Specifically, the hysteresis control unit includes a tenth MOSFET (e.g., Figure 1 In the M10 section, the source and drain of the tenth MOSFET are connected in parallel across the fourth resistor, and the gate of the tenth MOSFET is connected to the output of the comparator. The state of the comparator output level controls the conduction and cutoff of the tenth MOSFET: when the charge pump needs to be started, the comparator outputs a low level to turn off the tenth MOSFET. At this time, the equivalent resistance of the conversion module 200 is the series value of the third and fourth resistors, thus using a higher threshold as the target voltage difference; when the charge pump needs to be turned off, the comparator outputs a high level to turn on the tenth MOSFET, short-circuiting the fourth resistor, so that the equivalent resistance of the conversion module 200 is only the third resistor, thus automatically switching to a lower threshold as the target voltage difference. The hysteresis control unit establishes different thresholds as target voltage differences when the charge pump is turned on and off, effectively avoiding output oscillations in critical states and significantly improving stability and anti-interference capability.

[0087] In addition, this application provides a motor drive chip, including the charge pump control circuit described above.

[0088] like Figure 2 As shown, Figure 2This is a schematic diagram of a motor driver chip. The power half-bridge structure includes a high-side bridge arm and a low-side bridge arm. The high-side bridge arm is driven by a high-side driver circuit, and its power supply is provided by a charge pump. The low-side bridge arm is driven by a low-side driver circuit, and its power supply is provided by an internal fixed power supply within the chip. The pulse width modulation signal is generated and output uniformly by the internal drive logic unit.

[0089] The charge pump specifically includes a first diode D3 and a second diode D4, a load capacitor C1, a pump capacitor C2, a first switch M11, a second switch M12, a high-side level shifting circuit, a low-side level shifting circuit, and a non-overlapping clock signal generation unit. The control signal adjusts the transmission path of the clock signal, and then controls the on / off state of the first switch M11 and the second switch M12 via the high-side and low-side level shifting circuits to regulate the output voltage of the charge pump. The corresponding operating waveform of the charge pump is shown below. Figure 3 As shown.

[0090] The motor drive chip provided in this application embodiment can implement the various processes implemented in the above embodiments and achieve the same beneficial effects. To avoid repetition, it will not be described again here.

[0091] Those skilled in the art will understand that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program units, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program units, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0092] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A charge pump control circuit, characterized in that, Applied to a charge pump, the circuit includes: A first resistor, the first end of which is used to receive the power supply voltage; A second resistor, the first end of which is used to receive the output voltage of the charge pump; The first MOSFET has its source connected to the second terminal of the first resistor and its gate connected to the drain of the first MOSFET. The second MOSFET has its source connected to the second terminal of the second resistor, and its gate connected to the gate of the first MOSFET. A third diode, wherein the anode of the third diode is connected to the gate of the second MOS transistor, and the cathode of the third diode is connected to the source of the second MOS transistor; The sixth MOS transistor has its source connected to the drain of the first MOS transistor, and its gate connected to the drain of the sixth MOS transistor. The seventh MOS transistor has its source connected to the drain of the second MOS transistor and its gate connected to the gate of the sixth MOS transistor. A fourth diode, the anode of which is connected to the gate of the seventh MOS transistor, and the cathode of which is connected to the source of the seventh MOS transistor; The eighth MOS transistor has its drain connected to the drain of the seventh MOS transistor, and its gate connected to the clamping voltage terminal. The ninth MOS transistor has its drain connected to the drain of the sixth MOS transistor, and its gate connected to the clamping voltage terminal. The fourth MOS transistor has its drain connected to the source of the eighth MOS transistor, its gate connected to the bias voltage terminal, and its source grounded. The fifth MOS transistor has its drain connected to the source of the ninth MOS transistor, its gate connected to the bias voltage terminal, and its source grounded. The third MOS transistor has its drain connected to the second terminal of the second resistor, and its gate connected to the drain of the seventh MOS transistor. The third resistor, the first end of which is connected to the source of the third MOS transistor; A fourth resistor, the first end of which is connected to the second end of the third resistor, and the second end of the fourth resistor is grounded; The comparator has its non-inverting input connected to the source of the third MOSFET, its inverting input used to input a preset reference voltage, and its output connected to the clock control terminal of the charge pump. The tenth MOS transistor has its drain connected to the first terminal of the fourth resistor, its source connected to the second terminal of the fourth resistor, and its gate connected to the output terminal of the comparator.

2. A motor driver chip, characterized in that, Includes the charge pump control circuit as described in claim 1.

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