Capacitive buck-boost circuit, chip and electronic equipment

Abstract

The invention discloses a capacitive buck-boost circuit, a chip and electronic equipment. The capacitive buck-boost circuit comprises a first switch path and a second switch path, a plurality of switch tubes are arranged in the capacitive buck-boost circuit, and the first switch path and the second switch path are both connected to the transfer capacitor; in the first switching path, in the switching process of a switching tube connected with the transfer capacitor between on and off, the transfer capacitor and the first voltage stabilizing capacitor are switched between charging and discharging, so that power supply voltage input externally is reduced through the first switching path, and first output voltage is output; in the second switching path, in the switching process of a switching tube connected with the transfer capacitor between the on state and the off state, the transfer capacitor is charged by using the externally input power supply voltage, and then the externally input power supply voltage and the transfer capacitor are driven to charge the second voltage stabilizing capacitor together. The boost circuit boosts the externally input power supply voltage and outputs a second output voltage.

Description

Technical Field

[0001] The present application relates to the technical field of charge pumps, and in particular to a capacitive step-up and step-down circuit, a chip and an electronic device. Background Art

[0002] The step-down module in the chip uses either a charge pump or a linear regulator; a charge pump, also known as a switched capacitor voltage converter, is a DC-DC converter that uses so-called "flying" or "pumping" capacitors to store energy. Charge pump chips add linear regulation or charge pump modulation to reduce voltage, reducing input current and power loss when the input voltage is high.

[0003] When a linear regulator is used for voltage conversion, as the input-output voltage difference increases, the temperature rises significantly and the voltage conversion efficiency is low. Among them, the linear regulator can only step down the voltage and has low efficiency.

[0004] When a charge pump (with a built-in switched capacitor voltage conversion circuit) is used for dual power supply output, at least two transfer capacitors are often required to convert two power supply voltage outputs, resulting in at least twice the capacitor drive loss.

[0005] The Chinese invention patent with patent application number CN202111149312.5 discloses a multi-port fast charging circuit. It does not use a DCDC converter and realizes multi-port fast charging with the simplest circuit structure, providing a low-cost multi-port fast charging solution. The circuit function recorded in the cited patent is: when at least two voltage output ports request the same fast charging voltage, the controller controls the ACDC converter to provide the requested voltage to the voltage output port, including the standard for ordinary charging or the standard for fast charging; in the Chinese invention patent with patent application number CN202111149312.5, although at least two voltage output ports are respectively connected to the first charging device and the second charging device, when the charging voltage supported by the second charging device is inconsistent with the charging voltage supported by the first charging device, the controller controls the ACDC converter to provide the maximum voltage applicable to both the first charging device and the second charging device, and cannot provide two different charging voltages for the two charging devices respectively. Moreover, more capacitors and inductors will be used in the aforementioned ACDC converter. In addition to the increase in volume, cost is also a problem. Summary of the invention

[0006] This application discloses a capacitive step-up and step-down circuit, a chip and an electronic device. The specific technical solution is as follows A capacitive buck-boost circuit, the capacitive buck-boost circuit includes a first switch path and a second switch path; the capacitive buck-boost circuit is used to connect a transfer capacitor, a first voltage-stabilizing capacitor and a second voltage-stabilizing capacitor, a plurality of switch tubes are arranged inside the capacitive buck-boost circuit, and the first switch path and the second switch path are both connected to the transfer capacitor; the first switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the first voltage-stabilizing capacitor; in the first switch path, when the switch tube connected to the transfer capacitor switches between on and off, the transfer capacitor and the first voltage-stabilizing capacitor switch between charging and discharging, so as to step down the external input power supply voltage through the first switch path to output a first output voltage; the second switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the second voltage-stabilizing capacitor; in the second switch path, when the switch tube connected to the transfer capacitor switches between on and off, the transfer capacitor is charged with the external input power supply voltage, and then the external input power supply voltage and the transfer capacitor are driven to charge the second voltage-stabilizing capacitor together, so as to step up the external input power supply voltage to output a second output voltage; wherein the first output voltage is less than the second output voltage.

[0007] In summary, the capacitive buck-boost circuit disclosed in the present application is based on the transfer capacitor to transfer charge in the first switch path and the second switch path respectively, and output a corresponding voltage through the first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor respectively, to obtain output voltages of different sizes, wherein the voltage output from the first voltage-stabilizing capacitor is less than the power supply voltage, and the voltage output from the second voltage-stabilizing capacitor is greater than the power supply voltage. Compared with the prior art, in addition to the voltage-stabilizing capacitor originally required by the charge pump system, the present application uses a capacitor to transfer charge to achieve the output of two different voltages, that is, a charge pump design for dual voltage conversion can be realized through a single capacitor, reducing the number of circuit port designs and reducing costs.

[0008] Further, in the first switch path, the switch tube connected to the transfer capacitor includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the switch tube connected to the transfer capacitor switches between on and off in a manner that includes: when the first switch tube and the fourth switch tube are both on, and the second switch tube and the third switch tube are both off, the transfer capacitor and the first voltage stabilizing capacitor are charged in sequence by the power supply voltage; then, the first switch tube and the fourth switch tube are driven to be off, and the second switch tube and the third switch tube are driven to be on, so that the transfer capacitor and the first voltage stabilizing capacitor are discharged to the outside to output the first output voltage. Thus, when the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are controlled to switch between on and off, the auxiliary transfer capacitor and the first voltage stabilizing capacitor are switched between charging and discharging, so as to reduce the input power supply voltage to the first output voltage.

[0009] Furthermore, when the first switch tube and the fourth switch tube are both turned off, and the second switch tube and the third switch tube are both turned on, the transfer capacitor and the first voltage stabilizing capacitor are discharged to the outside, while the transfer capacitor charges the first voltage stabilizing capacitor, so that when the third switch tube and the fourth switch tube are both turned off, the first switch path is discharged to the outside by the first voltage stabilizing capacitor alone, and the output first output voltage is less than the power supply voltage. As the first stabilizing capacitor continues to discharge, the output voltage gradually drops below the power supply voltage.

[0010] Furthermore, the switch tube shared by the second switch path and the first charge and discharge path includes a first switch tube and a second switch tube; in the second switch path, the switch tube connected to the transfer capacitor includes a first switch tube, a second switch tube, a fifth switch tube and a sixth switch tube; the way in which the switch tube connected to the transfer capacitor switches between on and off includes: when the first switch tube and the second switch tube are both on and the other switch tubes are all off, the transfer capacitor is charged by the power supply voltage until the voltage charged by the transfer capacitor reaches a preset reference voltage, and then, the first switch tube and the second switch tube are driven to be turned off, and the fifth switch tube and the sixth switch tube are driven to be turned on, and the sum of the power supply voltage and the preset reference voltage reached by the transfer capacitor is transmitted to the second voltage stabilizing capacitor, and then the second output voltage is output to the outside through the discharge of the second voltage stabilizing capacitor; wherein the sum of the power supply voltage and the preset reference voltage is greater than or equal to the second output voltage, and the second output voltage is greater than the power supply voltage. In summary, when the first switch tube, the second switch tube, the fifth switch tube and the sixth switch tube are controlled to switch between on and off, the transfer capacitor switches between charging and discharging, and the charging voltage of the auxiliary transfer capacitor and the power supply voltage form a power supply series connection, accumulating the second output voltage for the second voltage stabilizing capacitor, thereby boosting the power supply voltage through the second switch path and the transfer capacitor.

[0011] Further, the first transmission end of the first switch tube is used to connect the power supply voltage, the second transmission end of the first switch tube is connected to the first transmission end of the sixth switch tube, the second transmission end of the sixth switch tube is connected to one end of the second voltage stabilizing capacitor, the other end of the second voltage stabilizing capacitor is grounded, the first transmission end of the first switch tube is connected to the first transmission end of the fifth switch tube, the second transmission end of the fifth switch tube is connected to the first transmission end of the second switch tube, and the second transmission end of the second switch tube is grounded, so as to connect to form the second switch path; wherein, the connection end of the second transmission end of the first switch tube and the first transmission end of the sixth switch tube is connected to one end of the transfer capacitor, and the connection end of the second transmission end of the fifth switch tube and the first transmission end of the second switch tube is connected to the other end of the transfer capacitor; wherein, the connection end between the second transmission end of the sixth switch tube and one end of the second voltage stabilizing capacitor is used to output the second output voltage. Thus, the charge and discharge path between the transfer capacitor and the second voltage stabilizing capacitor is connected through the first switch tube, the second switch tube, the fifth switch tube and the sixth switch tube, and an output voltage greater than the power supply voltage is obtained.

[0012] Further, the first transmission end of the first switch tube is used to connect the power supply voltage, the second transmission end of the first switch tube is connected to the first transmission end of the third switch tube, the first transmission end of the fourth switch tube is connected to the first transmission end of the second switch tube, and the second transmission end of the fourth switch tube is connected to the second transmission end of the third switch tube, so as to form the first switch path; wherein the connection end of the second transmission end of the first switch tube and the first transmission end of the third switch tube is connected to one end of the transfer capacitor, and the connection end of the first transmission end of the fourth switch tube and the first transmission end of the second switch tube is connected to the other end of the transfer capacitor; wherein the connection end of the second transmission end of the fourth switch tube and the second transmission end of the third switch tube is connected to one end of the first voltage stabilizing capacitor, and the other end of the first voltage stabilizing capacitor is grounded; the connection end of the second transmission end of the fourth switch tube and the second transmission end of the third switch tube is used to output the first output voltage. Thus, the charge and discharge path between the transfer capacitor and the first voltage stabilizing capacitor is connected through the first switch tube, the second switch tube, the third switch tube and the fourth switch tube, and an output voltage less than the power supply voltage is obtained.

[0013] Furthermore, the capacitive buck-boost circuit also includes a comparator; the comparator is used to output a voltage for turning on the first switch tube when the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is less than the preset reference voltage, so that the power supply voltage charges the transfer capacitor through the first switch tube, and increases the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor until the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, so that the transfer capacitor is charged to the preset reference voltage; the comparator is used to output a voltage for turning off the first switch tube when the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, so that the power supply voltage stops charging the transfer capacitor through the first switch tube. In summary, when the voltage at the connection end between the first switch tube and the transfer capacitor is small, the first switch tube is turned on to charge the transfer capacitor.

[0014] Furthermore, when the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, the comparator outputs a voltage for turning off the first switch tube, driving the first switch tube to turn off, and then when the first switch tube and the fourth switch tube are both turned off and the second switch tube and the third switch tube are both turned on, the transfer capacitor charges the first voltage stabilizing capacitor, making the first output voltage equal to the preset reference voltage. Thus, the comparator is used to step down the input power supply voltage in the first switch path.

[0015] Furthermore, the positive input terminal of the comparator is connected to the second transmission terminal of the first switch tube, and the negative input terminal of the comparator is used to input the preset reference voltage; the output terminal of the comparator is connected to the control terminal of the first switch tube. Therefore, the voltage on the transfer capacitor can be accurately controlled based on the predetermined preset reference voltage. Based on this, the present application uses a comparator to control the switch tube to assist in boosting the voltage on the transfer capacitor to the preset reference voltage input by the comparator, and then connects the power supply voltage in series to charge and discharge the second voltage stabilizing capacitor to complete the final boost.

[0016] A chip, wherein the capacitive step-up and step-down circuit is arranged inside the chip. The chip disclosed in the present application performs charge transfer in a first switch path and a second switch path respectively based on a transfer capacitor, and outputs a corresponding voltage through a first voltage-stabilizing capacitor and a second voltage-stabilizing capacitor respectively, to obtain output voltages of different magnitudes. Compared with the prior art, in addition to the voltage-stabilizing capacitor originally required by the charge pump system, the chip of the present application performs charge transfer through a capacitor to realize the output of two different power supply voltages, that is, the charge pump chip design that can realize dual voltage conversion through a single capacitor reduces the number of chip pins, reduces the peripheral complexity, and reduces the cost at the same time.

[0017] An electronic device, the electronic device includes a transfer capacitor, a first voltage-stabilizing capacitor, a second voltage-stabilizing capacitor and the chip, the chip is respectively provided with a signal input terminal, a first charging terminal, a second charging terminal, a first signal output terminal and a second signal output terminal; the signal input terminal is used to input the power supply voltage, the transfer capacitor is connected to the first charging terminal and the second charging terminal in parallel, the first signal output terminal is grounded through the first voltage-stabilizing capacitor, and the second signal output terminal is grounded through the second voltage-stabilizing capacitor; or, the electronic device includes a transfer capacitor, a first voltage-stabilizing capacitor, a second voltage-stabilizing capacitor and the capacitive buck-boost circuit. In summary, the two voltage-stabilizing capacitors (the aforementioned first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor) connected to the capacitive buck-boost circuit provided in the electronic device are connected to the switch paths connected to each other through the same transfer capacitor, and the first voltage-stabilizing capacitor is used to output the buck voltage when charging and discharging the transfer capacitor, and the second voltage-stabilizing capacitor is used to output the boost voltage. Compared with the prior art, there is no need to add a DCDC converter (direct current-to-direct current voltage converter) to realize voltage conversion, the circuit structure is simplified and the additional power is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present application discloses a connection diagram between a capacitive buck-boost circuit and a transfer capacitor C1 , a first reference capacitor C2 , and a second reference capacitor C3 . DETAILED DESCRIPTION

[0019] The specific implementation methods of the present application are further described below in conjunction with the accompanying drawings. In the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0020] The charge pump uses capacitors as switches and energy storage elements. The basic principle of the charge pump is to charge the capacitor, remove the capacitor from the charging circuit to isolate the charged charge, and then connect it to another circuit to transfer the isolated charge. The charge pump is applied to the DC-DC voltage converter to add linear adjustment or charge pump modulation. Compared with the use of linear regulators for voltage conversion, it improves the voltage conversion efficiency and reduces the circuit temperature rise; however, as a power supply circuit that improves the level conversion efficiency, when dual power supply applications are used, the charge pump often requires at least two transfer capacitors to achieve two power outputs, which is not conducive to controlling the circuit manufacturing cost.

[0021] In response to the aforementioned technical defects, the present application discloses a capacitive buck-boost circuit, which includes a first switch path and a second switch path. The capacitive buck-boost circuit is used to connect a transfer capacitor, a first voltage stabilizing capacitor and a second voltage stabilizing capacitor. A plurality of switch tubes are arranged inside the capacitive buck-boost circuit, and the first switch path and the second switch path are both connected to the transfer capacitor; each charge and discharge path completes charge transfer through the same transfer capacitor to charge and discharge the first voltage stabilizing capacitor or the second voltage stabilizing capacitor, and based on the number and connection method of the switch tubes arranged in each charge and discharge path, the first switch path and the second switch path output different voltages through the transfer capacitor, the first voltage stabilizing capacitor and the second voltage stabilizing capacitor respectively.

[0022] The first switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the first voltage-stabilizing capacitor, forming a charge-discharge path required between the transfer capacitor and the first voltage-stabilizing capacitor; in the first switch path, the switch tube connected to the transfer capacitor switches between on and off, and the transfer capacitor and the first voltage-stabilizing capacitor switch between charging and discharging, which involves the first group of switch tubes being on and the second group of switch tubes being off. The transfer capacitor is responsible for transferring charge through the on switch tubes, driving the external input power supply voltage to charge the transfer capacitor and the first voltage-stabilizing capacitor. After the transfer capacitor and the first voltage-stabilizing capacitor are charged, the first group of switch tubes are turned off and the second group of switch tubes are turned on, and then the transfer capacitor and the first voltage-stabilizing capacitor are allowed to discharge, so as to step down the external input power supply voltage through the first switch path and output the first output voltage. Among them, the transfer capacitor divides part of the voltage from the power supply voltage charging, causing the first output voltage to be less than the power supply voltage, thereby reducing the input current and power loss when the voltage input to the first switch path is high.

[0023] The second switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the second voltage-stabilizing capacitor, forming a charge-discharge path required between the transfer capacitor and the second voltage-stabilizing voltage; in the second switch path, the switch tube connected to the transfer capacitor uses the external input power supply voltage to charge the transfer capacitor during the process of switching between on and off, preferably controlling the charging voltage of the transfer capacitor to be greater than or equal to the preset reference voltage, and then driving the external input power supply voltage and the transfer capacitor to charge the second voltage-stabilizing capacitor together (equivalent to discharging the transfer capacitor), so that the charging voltage of the second voltage-stabilizing capacitor or the external discharge voltage is greater than the power supply voltage, so as to boost the external input power supply voltage to output the second output voltage. Wherein, the maximum value of the second output voltage is the sum of the external input power supply voltage and the discharge voltage of the transfer capacitor, causing the second output voltage to be greater than the power supply voltage, so that a different output voltage is obtained in the second switch path from that generated by the first switch path.

[0024] In summary, the capacitive buck-boost circuit disclosed in the present application is based on the transfer capacitor to transfer charge in the first switch path and the second switch path respectively, and output a corresponding voltage through the first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor respectively, to obtain output voltages of different sizes, wherein the voltage output from the first voltage-stabilizing capacitor is less than the power supply voltage, and the voltage output from the second voltage-stabilizing capacitor is greater than the power supply voltage. Compared with the prior art, in addition to the voltage-stabilizing capacitor originally required by the charge pump system, the present application uses a capacitor to transfer charge to achieve the output of two different voltages, that is, a charge pump design for dual voltage conversion can be realized through a single capacitor, reducing the number of circuit port designs and reducing costs.

[0025] As an embodiment, in the first switch path, if Figure 1 As shown, the switch tubes connected to the transfer capacitor include a first switch tube SW1, a second switch tube SW2, a third switch tube SW3 and a fourth switch tube SW4; the switch tube connected to the transfer capacitor C1 switches between on and off in the following manner: when the first switch tube SW1 and the fourth switch tube SW4 are both on, and the second switch tube SW2 and the third switch tube SW3 are both off, the transfer capacitor C1 and the first voltage stabilizing capacitor C2 are charged in sequence through the power supply voltage Vin, that is, in the connection path of the first switch tube SW1, the transfer capacitor C1, the fourth switch tube SW4 and the first voltage stabilizing capacitor C2, the transfer capacitor C1 and the first voltage stabilizing capacitor C2 are charged in sequence, and there is charge transfer between the transfer capacitor C1 and the first voltage stabilizing capacitor C2; the transfer capacitor C1 and the first voltage stabilizing capacitor C2 are charged separately. They are charged to a certain voltage respectively, and the voltages obtained by each charging are all lower than the power supply voltage Vin. Then, they start to discharge to the outside respectively. It is necessary to drive the first switch tube SW1 and the fourth switch tube SW4 to be turned off, and drive the second switch tube SW2 and the third switch tube SW3 to be turned on, so that the transfer capacitor C1 and the first voltage stabilizing capacitor C2 are discharged to the outside to output the first output voltage Vout1. It is regarded that the first output voltage Vout1 is output by the positive electrode of the first voltage stabilizing capacitor C2. Therefore, when the first switch tube SW1, the second switch tube SW2, the third switch tube SW3 and the fourth switch tube SW4 are controlled to switch between on and off, the auxiliary transfer capacitor and the first voltage stabilizing capacitor are switched between charging and discharging, so as to reduce the input power supply voltage Vin to the first output voltage Vout1.

[0026] In the above embodiment, combined with Figure 1It can be known that when the first switch tube SW1 and the fourth switch tube SW4 are both turned off, and the second switch tube SW1 and the third switch tube SW3 are both turned on, the transfer capacitor C1 and the first voltage-stabilizing capacitor C2 are discharged to the outside. Since the fourth switch tube SW4 is turned on, the transfer capacitor C1 charges the first voltage-stabilizing capacitor C2, so that once the third switch tube SW3 and the fourth switch tube SW4 are both turned off, the paths between the first voltage-stabilizing capacitor C2 and the external switch tubes and capacitors are disconnected. At this time, the first voltage-stabilizing capacitor C2 has been allocated a part of the voltage of the power supply voltage Vin when the first switch tube SW1 and the fourth switch tube SW4 are both turned off and the second switch tube SW1 and the third switch tube SW3 are both turned on. Then, the first switch path is discharged to the outside by the first voltage-stabilizing capacitor C2 alone, and the output first output voltage Vout1 is less than the power supply voltage Vin. As the first voltage-stabilizing capacitor C2 is continuously discharged, the output voltage gradually drops below the power supply voltage Vin.

[0027] As an embodiment, the switch tube shared by the second switch path and the first switch path includes a first switch tube and a second switch tube; in the second switch path, Figure 1As shown, the switch tubes connected to the transfer capacitor include a first switch tube SW1, a second switch tube SW2, a fifth switch tube SW5 and a sixth switch tube SW6; the switch tube connected to the transfer capacitor C1 is switched between on and off in the following manner: when the first switch tube SW1 and the second switch tube SW2 are both on and the other switch tubes are all off, the power supply voltage Vin is driven to charge the transfer capacitor C1 until the voltage charged by the transfer capacitor C1 reaches a preset reference voltage Vref. The voltage charged by the transfer capacitor C1 is regarded as the voltage of the U1 terminal. Because the U2 terminal is grounded through the second switch tube SW2, it can float at a certain error relative to the preset reference voltage Vref in some charging implementation scenarios. Then, the first switch tube SW1 and the second switch tube SW2 are driven to be turned off, and the fifth switch tube SW5 and the sixth switch tube SW6 are driven to be turned on, and the power supply voltage Vin is connected in series to the transfer capacitor C1 through the fifth switch tube SW5 to form a power supply series connection, and based on the turned-on fifth switch tube SW5 and the sixth switch tube SW6, the sum of the power supply voltage Vin and the preset reference voltage Vref charged to the transfer capacitor C1 is transmitted to the second voltage stabilizing capacitor C3, and then the second output voltage Vout2 is outputted externally through the discharge of the second voltage stabilizing capacitor C3, wherein the sum of the power supply voltage and the preset reference voltage is greater than or equal to the second output voltage, and the second output voltage is greater than the power supply voltage. In summary, when the first switch tube, the second switch tube, the fifth switch tube and the sixth switch tube are controlled to switch between on and off, the charging voltage of the auxiliary transfer capacitor and the power supply voltage form a power supply series connection during the switching process between charging and discharging of the transfer capacitor, and the second output voltage is accumulated for the second voltage stabilizing capacitor, thereby boosting the power supply voltage through the second switch path and the transfer capacitor.

[0028] Regarding the specific connection structure of the second switch path (including the connection relationship between the transfer capacitor and the second stabilizing capacitor), as shown in FIG. Figure 1As shown, the first transmission end of the first switch tube SW1 is used to connect the power supply voltage Vin, the second transmission end of the first switch tube SW1 is connected to the first transmission end of the sixth switch tube SW6, the second transmission end of the sixth switch tube SW6 is connected to one end of the second voltage stabilizing capacitor C3, the other end of the second voltage stabilizing capacitor C3 is grounded, the first transmission end of the first switch tube SW1 is connected to the first transmission end of the fifth switch tube SW5, the second transmission end of the fifth switch tube SW5 is connected to the first transmission end of the second switch tube SW2, and the second transmission end of the second switch tube SW2 is grounded, so as to form the second switch path. Specifically, with regard to the connection between the second switch path and the second voltage stabilizing capacitor, according to the working principle disclosed in the above embodiment, it can be divided into: driving the first switch tube SW1 and the second switch tube SW2 to be turned on and the other switch tubes to be turned off, or driving the first switch tube SW1 and the second switch tube SW2 to be turned off and driving the fifth switch tube SW5 and the sixth switch tube SW6 to be turned on, so that the second voltage stabilizing capacitor C3 obtains a voltage greater than the power supply voltage Vin.

[0029] Regarding the connection between the second switch path and the transfer capacitor C1, the connection end U1 between the second transmission end of the first switch tube SW1 and the first transmission end of the sixth switch tube SW6 is connected to one end of the transfer capacitor C1, and the connection end U2 between the second transmission end of the fifth switch tube SW5 and the first transmission end of the second switch tube SW2 is connected to the other end of the transfer capacitor C1; the connection end between the second transmission end of the sixth switch tube SW6 and one end of the second voltage stabilizing capacitor C3 is used to output the second output voltage Vout, so that the charge and discharge path between the transfer capacitor C1 and the second voltage stabilizing capacitor C3 is connected through the first switch tube, the second switch tube, the fifth switch tube and the sixth switch tube, so as to obtain an output voltage greater than the power supply voltage Vin.

[0030] For the specific connection structure of the first switch path (including the connection relationship between the transfer capacitor and the first voltage stabilizing capacitor), as shown in FIG. Figure 1As shown, the first transmission end of the first switch tube SW1 is used to connect the power supply voltage Vin, the second transmission end of the first switch tube SW1 is connected to the first transmission end of the third switch tube SW3, the first transmission end of the fourth switch tube SW4 is connected to the first transmission end of the second switch tube SW2, and the second transmission end of the fourth switch tube SW4 is connected to the second transmission end of the third switch tube SW3, so as to be connected to form the first switch path. Specifically, it involves the connection between the first switch path and the first voltage stabilizing capacitor. According to the working principle disclosed in the embodiment corresponding to the aforementioned first switch path, it can be divided into: the case where the first switch tube SW1 and the fourth switch tube SW4 are both turned on and the second switch tube SW2 and the third switch tube SW3 are both turned off, the first switch tube SW1 and the fourth switch tube SW4 are driven to be turned off and the second switch tube SW2 and the third switch tube SW3 are driven to be turned on, and the first switch tube SW1 and the fourth switch tube SW4 are driven to be turned off and the second switch tube SW1 and the third switch tube SW3 are both turned on.

[0031] For the connection between the first switch path and the transfer capacitor C1, as shown in FIG. Figure 1 As shown, the connection end between the second transmission end of the first switch tube SW1 and the first transmission end of the third switch tube SW3 is connected to one end U1 of the transfer capacitor C1, and the connection end between the first transmission end of the fourth switch tube SW4 and the first transmission end of the second switch tube SW2 is connected to the other end U2 of the transfer capacitor C1; the connection end between the second transmission end of the fourth switch tube SW4 and the second transmission end of the third switch tube SW3 is connected to one end of the first voltage stabilizing capacitor C2, and the other end of the first voltage stabilizing capacitor C2 is grounded; the connection end between the second transmission end of the fourth switch tube SW4 and the second transmission end of the third switch tube SW3 is used to output the first output voltage Vout1. Thus, the charge and discharge path between the transfer capacitor C1 and the first voltage stabilizing capacitor C2 is connected through the first switch tube SW1, the second switch tube SW2, the third switch tube SW3 and the fourth switch tube SW4, and an output voltage less than the power supply voltage Vin is obtained.

[0032] In order to turn on the first switch tube to charge the transfer capacitor when the voltage at the connection terminal between the first switch tube and the transfer capacitor is small, the capacitive buck-boost circuit further includes a comparator; specifically, Figure 1As shown, the comparator CMP is used to output a voltage for turning on the first switch tube SW1 when the voltage at the connection terminal U1 between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1 is less than the preset reference voltage Vref, so that the power supply voltage Vin charges the transfer capacitor C1 through the first switch tube SW1, and increases the voltage at the connection terminal U1 between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1, until the voltage at the connection terminal U1 between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1 is greater than or equal to the preset reference voltage Vref, thereby realizing that the transfer capacitor C1 is charged to reach the preset reference voltage Vref.

[0033] The comparator CMP is used to output a voltage for turning off the first switch tube SW1 when the voltage at the connection end between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1 is greater than or equal to the preset reference voltage Vref, so that the power supply voltage Vin stops charging the transfer capacitor C1 through the first switch tube SW1.

[0034] In some embodiments, Figure 1 As shown, when the comparator CMP outputs a voltage for turning on the first switch tube SW1, the first switch tube SW1 is driven to turn on. If the first switch tube SW1 and the fourth switch tube SW4 are both turned on and the second switch tube SW2 and the third switch tube SW3 are both turned off, the voltage at the connection end U1 between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1 increases during the process of the transfer capacitor C1 and the first voltage stabilizing capacitor C2 being charged, until it increases to a value greater than or equal to the preset reference voltage Vref. The comparator CMP outputs a voltage for turning off the first switch tube SW1, driving the first switch tube SW1 to turn off. Then, when the first switch tube SW1 and the fourth switch tube SW4 are both turned off and the second switch tube SW2 and the third switch tube SW3 are both turned on, the transfer capacitor C1 charges the first voltage stabilizing capacitor C2, so that the first output voltage Vout1 is equal to the preset reference voltage Vref. Thus, the comparator is used to complete the step-down of the input power supply voltage in the first switch path.

[0035] In other embodiments, Figure 1As shown, when the voltage at the connection terminal U1 is less than the preset reference voltage Vref, the first switch tube and the second switch tube are both turned on and the other switch tubes are all turned off. At this time, the power supply voltage Vin charges the transfer capacitor C1, and the voltage of the connection terminal U1 between the second transmission end of the first switch tube SW1 and one end of the transfer capacitor C1 increases until it increases to be greater than or equal to the preset reference voltage Vref. At this time, the voltage charged by the transfer capacitor C1 is equal to the preset reference voltage Vref, and the comparator CMP outputs a voltage for turning off the first switch tube SW1, driving the first switch tube SW1 to turn off, and then when the first switch tube SW1 and the second switch tube SW2 are both turned off and the fifth switch tube SW5 and the sixth switch tube SW6 are both turned on, the voltage charged by the transfer capacitor C1 and the power supply voltage Vin are used together to charge the second voltage stabilizing capacitor C3, so that the connection end of the second voltage stabilizing capacitor and the sixth switch tube outputs the second output voltage Vout2, which is equal to the sum of the preset reference voltage Vref and the power supply voltage Vin.

[0036] In the capacitive buck-boost circuit, the positive input terminal + of the comparator CMP is connected to the second transmission terminal of the first switch tube SW1, and the positive input terminal + of the comparator CMP inputs the voltage at the connection terminal U1 between the second transmission terminal of the first switch tube SW1 and one end of the transfer capacitor C1; the negative input terminal - of the comparator CMP is used to input the preset reference voltage Vref; the output terminal of the comparator CMP is connected to the control terminal of the first switch tube SW1. After the level of the enable terminal EN of the comparator CMP is valid, the voltage of its positive input terminal and the voltage of its negative input terminal are compared. When the voltage at the connection terminal U1 is greater than the preset reference voltage Vref, the first switch tube SW1 is turned off, and the voltage at the connection terminal U1 stops charging the transfer capacitor; when the voltage at the connection terminal U1 is less than the preset reference voltage Vref, the first switch tube SW1 is turned on, and the voltage at the connection terminal U1 continues to charge the transfer capacitor until the voltage at the connection terminal U1 is greater than or equal to the preset reference voltage Vref. Therefore, the voltage on the transfer capacitor C1 can be accurately controlled based on the predetermined Vref. It should be noted that when all the switch tubes are PMOS tubes, the first transmission end of the switch tube is the source end, and the second transmission end of the switch tube is the drain end.

[0037] In combination with the aforementioned embodiment of the first switch path, it can be known that the present application uses the first switch tube SW1 and the second switch tube SW2 to charge the transfer capacitor C1, wherein the first switch tube SW1 is controlled by the comparator CMP. When the first switch tube SW1 and the second switch tube SW2 are driven to be turned on, if the voltage output to the U1 end is less than the preset reference voltage Vref, the transfer capacitor C1 will continue to be charged until the voltage at the U1 end is greater than or equal to the preset reference voltage Vref; therefore, the present application uses a comparator to control the switch tube to assist in boosting the voltage on the transfer capacitor to the preset reference voltage of the comparator input, and then connects the power supply voltage in series to charge and discharge the second voltage stabilizing capacitor to complete the final boost.

[0038] As an embodiment of first boosting and then reducing the voltage, combined with Figure 1It can be known that when the voltage at the connection terminal U1 of the second transmission terminal of the first switch tube SW1 and one end of the transfer capacitor C1 is less than the preset reference voltage Vref, the voltage at the output terminal of the comparator CMP turns on the first switch tube SW1, and at the same time, drives the second switch tube SW2 to turn on, and drives other switch tubes to turn off, then the transfer capacitor C1 is charged by the power supply voltage Vin until the voltage at the U1 end of the transfer capacitor C1 becomes the preset reference voltage Vref; then the fifth switch tube and the sixth switch tube are both driven to turn on, and the second switch tube and the first switch tube are both driven to turn off, so that the transfer capacitor transmits the sum of Vin and Vref to the third voltage stabilizing capacitor C3, and at the same time, the third voltage stabilizing capacitor is discharged to the outside, and the second output voltage Vout2 is output to the outside, which is greater than Vin; when the second switch path is discharged through the second voltage stabilizing capacitor C3 and the transfer capacitor C1, and the second output voltage Vout2 is output to the outside, the second transmission terminal of the first switch tube SW1 and the transfer capacitor C1 are connected. When the voltage at the connection terminal U1 of one end of the transfer capacitor C1 decreases and the voltage at the connection terminal U1 is less than the preset reference voltage Vref, the voltage at the output terminal of the comparator CMP turns on the first switch tube SW1, and at the same time, drives the fourth switch tube SW4 to turn on, and also drives the second switch tube and the third switch tube to turn off, and also drives the fifth switch tube and the sixth switch tube to turn off. At this time, the transfer capacitor C1 and the first voltage-stabilizing capacitor C2 are charged by the power supply voltage Vin until the voltage at the U1 end of the transfer capacitor C1 becomes greater than or equal to the preset reference voltage Vref, and the first switch tube SW1 is driven to turn off by the output terminal of the comparator CMP, and at the same time, the fourth switch tube SW4 is turned off, and the second switch tube SW2 and the third switch tube SW3 are driven to turn on, and the transfer capacitor C1 and the first voltage-stabilizing capacitor C2 are both discharged to the outside. At the same time, the transfer capacitor C1 also charges the first voltage-stabilizing capacitor C2, so that the first voltage-stabilizing capacitor C2 finally outputs the first output voltage Vout. Schematically, the input Vin of the capacitive buck-boost circuit is 24V. If two output voltages are to be generated, one output voltage is a low voltage of 6~8V and the other output voltage is a high voltage of 30V, then by setting Vref to 6V, two output voltages can be generated, corresponding to Figure 1 Vout1 is 6V, and the other one corresponds to Figure 1 Vout2 is the sum of 24V (Vin) and 6V (Vref). Therefore, the two voltage-stabilizing capacitors (the aforementioned first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor) connected to the capacitive buck-boost circuit are connected to switch paths connected by the same transfer capacitor, and the first voltage-stabilizing capacitor is used to output the buck voltage when charging and discharging the transfer capacitor, and the second voltage-stabilizing capacitor is used to output the boost voltage. Compared with the prior art, there is no need to add a DCDC converter (DC-DC voltage converter) to achieve voltage conversion, the circuit structure is simplified, and the additional power is reduced.

[0039] Based on the above embodiments, the present application discloses a chip, in which the capacitive boost / step-up circuit is arranged. Figure 1 As shown, the signal input end of the chip is the first transmission end of the first switch tube SW1 to input Vin, the connection end U1 of the second transmission end of the first switch tube SW1 and the first transmission end of the third switch tube SW3 is the first charging end of the chip, the connection end U2 of the first transmission end of the fourth switch tube SW4 and the first transmission end of the second switch tube SW2 is the second charging end of the chip, the connection end of the second transmission end of the fourth switch tube SW4 and the second transmission end of the third switch tube SW3 is the first signal output end of the chip to output the first output voltage Vout1, and the second transmission end of the sixth switch tube SW6 is the second signal output end of the chip to output the second output voltage Vout2. The first charging end U1 of the chip and the second charging end U2 of the chip are used to connect the transfer capacitor C1, the first signal output end of the chip is grounded through the first voltage stabilizing capacitor C2, and the second signal output end of the chip is grounded through the second voltage stabilizing capacitor C3. The chip disclosed in the present application performs charge transfer in the first switch path and the second switch path based on the transfer capacitor, and outputs a corresponding voltage through the first voltage stabilizing capacitor and the second voltage stabilizing capacitor, respectively, to obtain output voltages of different sizes. Compared with the prior art, in addition to the voltage-stabilizing capacitor originally required by the charge pump system, the chip of the present application uses a capacitor to perform charge transfer to achieve the output of two different power supply voltages, that is, a charge pump chip design that can achieve dual voltage conversion through a single capacitor, reduces the number of chip pins, reduces peripheral complexity, and reduces costs.

[0040] Based on the above embodiments, the present application discloses an electronic device, which includes a transfer capacitor, a first voltage-stabilizing capacitor, a second voltage-stabilizing capacitor and the chip, wherein the chip is respectively provided with a signal input terminal, a first charging terminal, a second charging terminal, a first signal output terminal and a second signal output terminal; the signal input terminal is used to input the power supply voltage, the transfer capacitor is connected to the first charging terminal and the second charging terminal in parallel, the first signal output terminal is grounded through the first voltage-stabilizing capacitor, and the second signal output terminal is grounded through the second voltage-stabilizing capacitor. It should be noted that the connection nodes between the various components and modules integrated in the chip mentioned above are all arranged in the chip and can be connected to the relevant pins of the chip. On the basis that the prior art buck-boost circuit (including the charge pump) has the first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor, only one transfer capacitor needs to be coupled to realize two different voltage outputs, which reduces the complexity of the chip periphery and reduces the cost of the circuit equipment.

[0041] Alternatively, the electronic device disclosed in the present application includes a transfer capacitor, a first voltage-stabilizing capacitor, a second voltage-stabilizing capacitor, and the capacitive buck-boost circuit. The electronic device provided in the embodiment of the present application has the same beneficial effects as the capacitive buck-boost circuit provided in the embodiment of the present application, which will not be repeated here. Compared with the dual power supply application of the prior art, which requires at least two transfer capacitors to achieve dual power supply output, the present application uses a transfer capacitor to perform charge transfer to achieve the output of two power supplies.

[0042] In summary, the two voltage-stabilizing capacitors (the aforementioned first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor) connected to the capacitive buck-boost circuit in the electronic device are connected to switch paths connected via the same transfer capacitor, and the first voltage-stabilizing capacitor is used to output a buck voltage when charging and discharging the transfer capacitor, and the second voltage-stabilizing capacitor is used to output a boost voltage. Compared with the prior art, there is no need to add a DCDC converter (DC-DC voltage converter) to achieve voltage conversion, the circuit structure is simplified, and the additional power is reduced.

[0043] The units or modules described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units or modules, that is, they may be located in one place, or they may be distributed over multiple units or modules. Some or all of the units or modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0044] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A capacitive step-up / step-down circuit, characterized in that: The capacitive buck-boost circuit includes a first switch path and a second switch path; The capacitive buck-boost circuit is used to connect the transfer capacitor, the first voltage stabilizing capacitor and the second voltage stabilizing capacitor. A plurality of switch tubes are arranged inside the capacitive buck-boost circuit. The first switch path and the second switch path are both connected to the transfer capacitor. The first switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the first voltage stabilizing capacitor; In the first switch path, when the switch connected to the transfer capacitor is switched between on and off, the transfer capacitor and the first voltage stabilizing capacitor are switched between charging and discharging, so as to step down the external input power supply voltage through the first switch path to output a first output voltage; The second switch path includes a switch tube connected to the transfer capacitor and a switch tube connected to the second voltage stabilizing capacitor; In the second switch path, when the switch connected to the transfer capacitor is switched between on and off, the transfer capacitor is charged by the external power supply voltage, and then the external power supply voltage and the transfer capacitor are driven to charge the second voltage stabilizing capacitor together, so as to boost the external power supply voltage to output the second output voltage; The first output voltage is smaller than the second output voltage.

2. The capacitive boost-boost circuit according to claim 1, characterized in that: In the first switch path, the switch tubes connected to the transfer capacitor include a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; The switching mode of the switch connected to the transfer capacitor between on and off includes: When the first switch tube and the fourth switch tube are both turned on, and the second switch tube and the third switch tube are both turned off, the transfer capacitor and the first voltage stabilizing capacitor are charged in sequence through the power supply voltage; then, the first switch tube and the fourth switch tube are driven to be turned off, and the second switch tube and the third switch tube are driven to be turned on, so that the transfer capacitor and the first voltage stabilizing capacitor are discharged to the outside to output the first output voltage.

3. The capacitive boost-boost circuit according to claim 2, characterized in that: When the first switch tube and the fourth switch tube are both turned off, and the second switch tube and the third switch tube are both turned on, the transfer capacitor and the first voltage stabilizing capacitor are discharged to the outside, and the transfer capacitor charges the first voltage stabilizing capacitor. When the third switch tube and the fourth switch tube are both turned off, the first switch path is discharged to the outside by the first voltage stabilizing capacitor alone.

4. The capacitive boost-boost circuit according to claim 2, characterized in that: The switch tube shared by the second switch path and the first charge and discharge path includes a first switch tube and a second switch tube; In the second switch path, the switch tubes connected to the transfer capacitor include a first switch tube, a second switch tube, a fifth switch tube and a sixth switch tube; The switching mode of the switch connected to the transfer capacitor between on and off includes: When the first switch tube and the second switch tube are both turned on and the other switch tubes are turned off, the transfer capacitor is charged by the power supply voltage until the voltage charged by the transfer capacitor reaches a preset reference voltage, and then the first switch tube and the second switch tube are driven to be turned off, and the fifth switch tube and the sixth switch tube are driven to be turned on, and the sum of the power supply voltage and the preset reference voltage charged by the transfer capacitor is transmitted to the second voltage stabilizing capacitor, and then the second output voltage is outputted externally through the discharge of the second voltage stabilizing capacitor; wherein the sum of the power supply voltage and the preset reference voltage is greater than or equal to the second output voltage, and the second output voltage is greater than the power supply voltage.

5. The capacitive boost-boost circuit according to claim 4, characterized in that: The first transmission end of the first switch tube is used to connect the power supply voltage, the second transmission end of the first switch tube is connected to the first transmission end of the sixth switch tube, the second transmission end of the sixth switch tube is connected to one end of the second voltage stabilizing capacitor, the other end of the second voltage stabilizing capacitor is grounded, the first transmission end of the first switch tube is connected to the first transmission end of the fifth switch tube, the second transmission end of the fifth switch tube is connected to the first transmission end of the second switch tube, and the second transmission end of the second switch tube is grounded, so as to form the second switch path; Wherein, a connection end between the second transmission end of the first switch tube and the first transmission end of the sixth switch tube is connected to one end of the transfer capacitor, and a connection end between the second transmission end of the fifth switch tube and the first transmission end of the second switch tube is connected to the other end of the transfer capacitor; Wherein, the connection end between the second transmission end of the sixth switch tube and one end of the second voltage-stabilizing capacitor is used to output the second output voltage.

6. The capacitive boost-boost circuit according to claim 4, characterized in that: The first transmission end of the first switch tube is used to connect the power supply voltage, the second transmission end of the first switch tube is connected to the first transmission end of the third switch tube, the first transmission end of the fourth switch tube is connected to the first transmission end of the second switch tube, and the second transmission end of the fourth switch tube is connected to the second transmission end of the third switch tube, so as to form the first switch path; Wherein, a connection end between the second transmission end of the first switch tube and the first transmission end of the third switch tube is connected to one end of the transfer capacitor, and a connection end between the first transmission end of the fourth switch tube and the first transmission end of the second switch tube is connected to the other end of the transfer capacitor; Among them, the connecting end of the second transmission end of the fourth switch tube and the second transmission end of the third switch tube is connected to one end of the first voltage-stabilizing capacitor, and the other end of the first voltage-stabilizing capacitor is grounded; the connecting end of the second transmission end of the fourth switch tube and the second transmission end of the third switch tube is used to output the first output voltage.

7. The capacitive boost-boost circuit according to claim 5, characterized in that: The capacitive buck-boost circuit also includes a comparator; a comparator, configured to output a voltage for turning on the first switch tube when the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is less than the preset reference voltage, so that the power supply voltage charges the transfer capacitor through the first switch tube, and increases the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor, until the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, so that the transfer capacitor is charged to reach the preset reference voltage; A comparator is used to output a voltage for shutting off the first switch tube when the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, so that the power supply voltage stops charging the transfer capacitor through the first switch tube.

8. The capacitive boost-boost circuit according to claim 7, characterized in that: When the voltage at the connection end between the second transmission end of the first switch tube and one end of the transfer capacitor is greater than or equal to the preset reference voltage, the comparator outputs a voltage used to turn off the first switch tube, driving the first switch tube to turn off, and then when the first switch tube and the fourth switch tube are both turned off and the second switch tube and the third switch tube are both turned on, the transfer capacitor charges the first voltage stabilizing capacitor to make the first output voltage equal to the preset reference voltage.

9. The capacitive boost / step-up circuit according to claim 7, characterized in that: The positive input terminal of the comparator is connected to the second transmission terminal of the first switch tube, and the negative input terminal of the comparator is used to input the preset reference voltage; The output end of the comparator is connected to the control end of the first switch tube.

10. A chip, characterized in that: The capacitive boost / step-up circuit according to any one of claims 1 to 9 is arranged inside the chip.

11. An electronic device, characterized in that: The electronic device comprises a transfer capacitor, a first voltage-stabilizing capacitor, a second voltage-stabilizing capacitor and the chip according to claim 10, wherein the chip is respectively provided with a signal input terminal, a first charging terminal, a second charging terminal, a first signal output terminal and a second signal output terminal; the signal input terminal is used to input the power supply voltage, the transfer capacitor is connected in parallel to the first charging terminal and the second charging terminal, the first signal output terminal is grounded through the first voltage-stabilizing capacitor, and the second signal output terminal is grounded through the second voltage-stabilizing capacitor; Alternatively, the electronic device includes a transfer capacitor, a first voltage stabilizing capacitor, a second voltage stabilizing capacitor, and the capacitive buck-boost circuit according to any one of claims 1 to 9.

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