Voltage stabilizing circuit and power supply equipment

Abstract

The invention provides a voltage stabilizing circuit and power supply equipment. The voltage stabilizing circuit comprises a first amplification module, a second amplification module and an output switch tube. A first input end of the first amplification module is connected with an output end of the output switch tube, a second input end of the first amplification module is used for connecting a first reference voltage source, an output end of the first amplification module is connected with an input end of the second amplification module, and an output end of the second amplification module is connected with a control end of the output switch tube. The input end of the output switch tube is used for connecting an input voltage source. The control voltage of the output switch tube is adjusted through the first amplification module and the second amplification module according to the magnitude relationship between the output voltage and the first reference voltage, so that the voltage difference between the control voltage of the output switch tube and the input voltage is regulated and controlled, the output voltage of the output switch tube is adjusted, and the stability of the output voltage is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of electronic circuit technology, and in particular to a voltage stabilizing circuit and a power supply device. Background Art

[0002] Currently, in application scenarios where a power supply voltage needs to be input, a voltage stabilization circuit is usually required to implement a voltage stabilization function and then provide power.

[0003] For traditional voltage stabilization circuits, most of them are equipped with a boost circuit, a buck circuit or a boost-buck circuit to maintain the stability of the output voltage. However, in actual complex systems, the input voltage and output voltage are often unstable. At this time, it is difficult to maintain the stability of the output voltage using traditional voltage stabilization circuits. Summary of the invention

[0004] The embodiments of the present application provide a voltage stabilizing circuit and a power supply device, which can improve the stability of the output voltage when the input voltage and the output voltage change.

[0005] In a first aspect, an embodiment of the present application provides a voltage stabilizing circuit, which includes: a first amplifying module, a second amplifying module and an output switch tube. The first input end of the first amplifying module is connected to the output end of the output switch tube, the second input end of the first amplifying module is used to connect to a first reference voltage source, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the control end of the output switch tube, and the input end of the output switch tube is used to connect to an input voltage source. The first amplifying module outputs a comparison signal to the second amplifying module based on the output voltage of the output switch tube and the first reference voltage of the first reference voltage source. The second amplifying module adjusts the control voltage of the control end of the output switch tube based on the comparison signal. The output switch tube adjusts the output voltage based on the control voltage and the input voltage of the input voltage source.

[0006] In some embodiments, the voltage stabilizing circuit further includes a current limiting module. The input end of the current limiting module is connected to the output switch tube, and the output end of the current limiting module is respectively connected to the output end of the first amplification module and the input end of the second amplification module. The current limiting module is used to obtain the output current of the output switch tube, and adjust the comparison signal based on the output current so that the output current is within a preset current range.

[0007] In some embodiments, the current limiting module includes a current sampling unit, a voltage conversion unit and a comparison unit. The first end of the current sampling unit is respectively connected to the output end of the second amplification module and the control end of the output switch tube, the second end of the current sampling unit is used to connect the input voltage source, the third end of the current sampling unit is connected to the output end of the output switch tube, the voltage conversion unit is respectively connected to the fourth end of the current sampling unit and the first input end of the comparison unit, the second input end of the comparison unit is used to connect the second reference voltage source, and the output end of the comparison unit is respectively connected to the output end of the first amplification module and the input end of the second amplification module. Wherein, the current sampling unit generates a mirror current based on the input voltage, the control voltage and the output voltage. The voltage conversion unit converts the mirror current into a conversion voltage. The comparison unit adjusts the comparison signal based on the second reference voltage of the second reference voltage source and the conversion voltage.

[0008] In some embodiments, the current sampling unit includes a reference current source I B3, a switch tube MP8, a switch tube MP9, and a switch tube MP10. The control end of the switch tube MP8 is respectively connected to the output end of the second amplification module and the control end of the output switch tube, the first end of the switch tube MP8 is used to connect to the input voltage source, the first end of the switch tube MP9 is connected to the output end of the output switch tube, the control end of the switch tube MP9 is respectively connected to the control end of the switch tube MP10, the reference current source I B3, and the second end of the switch tube MP9, the first end of the switch tube MP10 is connected to the second end of the switch tube MP8, and the second end of the switch tube MP10 is connected to the voltage conversion unit.

[0009] In some embodiments, the voltage conversion unit includes a resistor RC, a first end of the resistor RC is respectively connected to the fourth end of the current sampling unit and the first input end of the comparison unit, and a second end of the resistor RC is grounded.

[0010] In some embodiments, the comparison unit includes a comparator and a switch tube MN7. The first input end of the comparator is connected to the voltage conversion unit, the second input end of the comparator is used to connect to the second reference voltage source, the output end of the comparator is connected to the control end of the switch tube MN7, the first end of the switch tube MN7 is used to connect to the input voltage source, and the second end of the switch tube MN7 is respectively connected to the output end of the first amplification module and the input end of the second amplification module.

[0011] In some embodiments, the first amplification module includes a voltage divider unit and an error comparison unit. The input end of the voltage divider unit is connected to the output end of the output switch tube, the output end of the voltage divider unit is connected to the first input end of the error comparison unit, the second input end of the error comparison unit is used to connect the first reference voltage source, and the output end of the error comparison unit is connected to the input end of the second amplification module. The voltage divider unit generates a voltage divider signal to the first input end of the error comparison unit based on the output voltage. The error comparison unit outputs the comparison signal to the second amplification module based on the voltage divider signal and the first reference voltage.

[0012] In some embodiments, the error comparison unit includes a current generating branch and a comparison branch. The current generating branch is respectively connected to the output end of the voltage dividing unit, the first reference voltage source and the comparison branch, and the comparison branch is also connected to the input end of the second amplification module. The current generating branch generates a first current to the comparison branch based on the voltage dividing signal, and generates a second current to the comparison branch based on the first reference voltage. The comparison branch generates the comparison signal based on the magnitude relationship between the first current and the second current.

[0013] In some embodiments, the current generating branch includes a reference current source I B1 , a switch tube MP1 and a switch tube MP2 , and the comparing branch includes a switch tube MN1 , a switch tube MN2 , a switch tube MN3 , a switch tube MN4 , a switch tube MP3 and a switch tube MP4 . The reference current source I B1 is respectively connected to the input voltage source, the first end of the switch tube MP1 and the first end of the switch tube MP2, the control end of the switch tube MP1 is connected to the output end of the voltage dividing unit, the control end of the switch tube MP2 is connected to the first reference voltage, the first end of the switch tube MP3 and the first end of the switch tube MP4 are both connected to the input voltage source, the control end of the switch tube MP3 is respectively connected to the second end of the switch tube MP3, the control end of the switch tube MP4 and the first end of the switch tube MN3, the second end of the switch tube MN3 is respectively connected to the second end of the switch tube MP1 and the first end of the switch tube MN1, the second end of the switch tube MP4 is respectively connected to the first end of the switch tube MN4 and the input end of the second amplification module, the second end of the switch tube MN4 is respectively connected to the second end of the switch tube MP2 and the first end of the switch tube MN2, the control end of the switch tube MN1 and the control end of the switch tube MN2 are both connected to the first voltage, the control end of the switch tube MN3 and the control end of the switch tube MN4 are both connected to the second voltage, and the second end of the switch tube MN1 and the second end of the switch tube MN2 are both grounded.

[0014] In some embodiments, the second amplification module includes a reference current source I B2, a switch tube MP5, a switch tube MN5, a switch tube MP6, and a switch tube MN6. The output end of the first amplification module is respectively connected to the control end of the switch tube MP5 and the control end of the switch tube MP6, the reference current source I B2 is respectively connected to the input voltage source, the first end of the switch tube MN5, the control end of the switch tube MN5, and the control end of the switch tube MN6, the second end of the switch tube MN5 is connected to the first end of the switch tube MP5, the first end of the switch tube MN6 is used to connect to the input voltage source, the second end of the switch tube MN6 is respectively connected to the first end of the switch tube MP6 and the control end of the output switch tube, and the second end of the switch tube MP5 and the second end of the switch tube MP6 are both grounded.

[0015] In a second aspect, the present application provides a power supply device, which includes an input voltage source and a voltage stabilizing circuit as described in any one of the embodiments of the first aspect; the input voltage source is connected to the voltage stabilizing circuit.

[0016] Compared with the prior art, the beneficial effect of the present application is as follows: Different from the prior art, the embodiment of the present application provides a voltage stabilizing circuit and a power supply device, including a first amplifying module, a second amplifying module and an output switch tube. The first input end of the first amplifying module is connected to the output end of the output switch tube, the second input end of the first amplifying module is used to connect to the first reference voltage source, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the control end of the output switch tube, and the input end of the output switch tube is used to connect to the input voltage source. The control voltage of the output switch tube is adjusted according to the magnitude relationship between the output voltage and the first reference voltage through the first amplifying module and the second amplifying module, so as to adjust the voltage difference between the control voltage of the output switch tube and the input voltage, thereby adjusting the output voltage of the output switch tube and improving the stability of the output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements / modules and steps with the same reference numerals in the drawings are represented as similar elements / modules and steps. Unless otherwise specified, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 is a structural block diagram of a voltage stabilizing circuit provided in an embodiment of the present application;

[0019] Figure 2 is a structural block diagram of another voltage stabilizing circuit provided in an embodiment of the present application;

[0020] Figure 3It is a structural diagram of a voltage stabilizing circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The present application is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0022] For ease of understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those generally understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0023] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional module division is performed in the device schematic, in some cases, the module division can be different from that in the device. In addition, the words "first", "second", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0024] In a first aspect, the present application provides a voltage stabilizing circuit. Figure 1 The voltage stabilizing circuit includes: a first amplifying module 10, a second amplifying module 20 and an output switch tube MP7.

[0025] The first input end of the first amplifier module 10 is connected to the output end of the output switch tube MP7, the second input end of the first amplifier module 10 is used to connect the first reference voltage source VREF, the output end of the first amplifier module 10 is connected to the input end of the second amplifier module 20, the output end of the second amplifier module 20 is connected to the control end of the output switch tube MP7, and the input end of the output switch tube MP7 is used to connect the input voltage source VIN. The first amplifier module 10 outputs a comparison signal to the second amplifier module 20 based on the output voltage of the output switch tube MP7 and the first reference voltage of the first reference voltage source VREF. The second amplifier module 20 adjusts the control voltage of the control end of the output switch tube MP7 based on the comparison signal. The output switch tube MP7 adjusts the output voltage based on the control voltage and the input voltage of the input voltage source VIN.

[0026] In some implementations, such as Figure 1As shown, the output switch tube MP7 can be a PMOS tube, the output end of the output switch tube MP7 is the drain of the PMOS tube, the control end of the output switch tube MP7 is the gate of the PMOS tube, and the input end of the output switch tube MP7 is the source of the PMOS tube.

[0027] The first reference voltage is the voltage value of the first reference voltage source VREF, the input voltage is the voltage value of the input voltage source VI N, the control voltage is the voltage value of the control end of the output switch tube MP7, and the output voltage is the voltage value of the output end of the output switch tube MP7. In the voltage stabilizing circuit, the first reference voltage can be preset. When the output voltage is less than the first reference voltage, the first amplification module 10 reduces the amplitude of the comparison signal, and the second amplification module 20 reduces the control voltage when the amplitude of the comparison signal decreases, so that the voltage difference between the control voltage and the input voltage increases, and the conduction capacity of the output switch tube MP7 is improved, and the output switch tube MP7 will increase the output voltage; when the output voltage is greater than the first reference voltage, the first amplification module 10 increases the amplitude of the comparison signal, and the second amplification module 20 increases the control voltage when the amplitude of the comparison signal increases, so that the voltage difference between the control voltage and the input voltage decreases, and the conduction capacity of the output switch tube MP7 is reduced, and the output switch tube MP7 will decrease the output voltage. Usually, the input voltage of the input voltage source VI N is relatively stable.

[0028] It can be seen that in the voltage stabilizing circuit, the magnitude of the control voltage of the output switch tube MP7 is adjusted by the magnitude relationship between the output voltage and the first reference voltage through the first amplifying module 10 and the second amplifying module 20, so as to adjust the magnitude of the voltage difference between the control voltage of the output switch tube MP7 and the input voltage, thereby adjusting the output voltage of the output switch tube MP7 and improving the stability of the output voltage. In addition, the circuit architecture is very simple, and the chip area consumed is very small, which can increase the scope of application.

[0029] In some of these embodiments, see Figure 2 The voltage stabilizing circuit further includes a current limiting module 30. The input end of the current limiting module 30 is connected to the output switch tube MP7, and the output end of the current limiting module 30 is respectively connected to the output end of the first amplifying module 10 and the input end of the second amplifying module 20. The current limiting module 30 is used to obtain the output current of the output switch tube MP7, and adjust the comparison signal based on the output current so that the output current is within a preset current range.

[0030] The output current of the output switch tube MP7 is the current flowing through the first end and the second end of the output switch tube MP7, that is, the current between the source and the drain of the output switch tube MP7. In the voltage stabilizing circuit, a current reference value can be preset, and the current reference value can be the maximum allowable current value of the output current. When the output current is greater than the current reference value, the current limiting module 30 will increase the amplitude of the comparison signal, so that the second amplification module 20 increases the control voltage, thereby reducing the voltage difference between the control voltage and the input voltage, reducing the conduction capacity of the output switch tube MP7, and thus limiting the output current. When the output current is less than or equal to the current reference value, the current limiting module 30 does not adjust the comparison signal, that is, it does not affect the operation of the output switch tube MP7.

[0031] In the voltage stabilizing circuit, by providing the current limiting module 30, the current output by the voltage stabilizing circuit can be made to meet a preset range, thereby avoiding the situation where the circuit fails due to excessive output current.

[0032] In some of these embodiments, see Figure 3 The current limiting module 30 includes a current sampling unit 31, a voltage conversion unit 32 and a comparison unit 33. The first end of the current sampling unit 31 is respectively connected to the output end of the second amplification module 20 and the control end of the output switch tube MP7, the second end of the current sampling unit 31 is used to connect the input voltage source VI N, the third end of the current sampling unit 31 is connected to the output end of the output switch tube MP7, the voltage conversion unit 32 is respectively connected to the fourth end of the current sampling unit 31 and the first input end of the comparison unit 33, the second input end of the comparison unit 33 is used to connect the second reference voltage source VREF_OCP, and the output end of the comparison unit 33 is respectively connected to the output end of the first amplification module 10 and the input end of the second amplification module 20. Among them, the current sampling unit 31 generates a mirror current based on the input voltage, the control voltage VO2 and the output voltage VO. The voltage conversion unit 32 converts the mirror current into a conversion voltage. The comparison unit 33 adjusts the comparison signal VO1 based on the second reference voltage of the second reference voltage source VREF_OCP and the conversion voltage.

[0033] The mirror current generated by the current sampling unit 31 has a certain ratio relationship with the output current of the output switch tube MP7. For example, the ratio may be 1:1, that is, the mirror current is equal to the output current, or the ratio may be 1:1000, that is, the mirror current is not equal to the output current. For example, if the output current is 10mA, the mirror current is 10uA.

[0034] In the voltage stabilizing circuit, the current sampling unit 31 generates a mirror current in a certain proportional relationship with the output current based on the input voltage, the control voltage VO2 and the output voltage VO; then, the mirror current flows through the voltage conversion unit 32, and the voltage conversion unit 32 can generate a conversion voltage to the comparison unit 33, wherein the conversion voltage can be used to characterize the magnitude of the mirror current, and the magnitude of the mirror current has a certain ratio relationship with the magnitude of the output current, so the conversion voltage can characterize the magnitude of the output current; then, the comparison unit 33 adjusts the comparison signal VO1 by comparing the magnitude relationship between the second reference voltage and the conversion voltage, wherein the second reference voltage is used to characterize the magnitude of the current reference value, specifically, when the conversion voltage is greater than the second reference voltage, it means that the output current is greater than the current reference value, and the comparison unit 33 controls the comparison signal VO1 to rise, so that the second amplification module 20 increases the control voltage VO2, thereby reducing the voltage difference between the control voltage VO2 and the input voltage, reducing the conduction capacity of the output switch tube MP7, thereby limiting the output current, and when the conversion voltage is less than or equal to the second reference voltage, it means that the output current is less than or equal to the current reference value, and the comparison unit 33 does not adjust the magnitude of the comparison signal VO1.

[0035] In the voltage stabilizing circuit, a conversion voltage that can characterize the output current is generated by a current sampling unit 31 and a voltage conversion unit 32, and a comparison unit 33 compares the size relationship between the conversion voltage and a second reference voltage to determine whether the current output current exceeds the current reference value. When the current reference value is exceeded, that is, when the conversion voltage is greater than the second reference voltage, the amplitude of the comparison signal VO1 is increased to reduce the conduction capacity of the output switch tube MP7, thereby limiting the output current so that the output current meets a preset range.

[0036] In some of these embodiments, see Figure 3 The current sampling unit 31 includes a reference current source I B3, a switch tube MP8, a switch tube MP9 and a switch tube MP10. The control end of the switch tube MP8 is respectively connected to the output end of the second amplification module 20 and the control end of the output switch tube MP7, the first end of the switch tube MP8 is used to connect to the input voltage source VIN, the first end of the switch tube MP9 is connected to the output end of the output switch tube MP7, the control end of the switch tube MP9 is respectively connected to the control end of the switch tube MP10, the reference current source I B3 and the second end of the switch tube MP9, the first end of the switch tube MP10 is connected to the second end of the switch tube MP8, and the second end of the switch tube MP10 is connected to the voltage conversion unit 32.

[0037] In some implementations, the switch tube MP8, the switch tube MP9 and the switch tube MP10 are all PMOS tubes, the control end of the switch tube MP8 is the gate of the PMOS tube, the first end of the switch tube MP8 is the source of the PMOS tube, the second end of the switch tube MP8 is the drain of the PMOS tube, the control end of the switch tube MP9 is the gate of the PMOS tube, the first end of the switch tube MP9 is the source of the PMOS tube, the second end of the switch tube MP9 is the drain of the PMOS tube, the control end of the switch tube MP10 is the gate of the PMOS tube, the first end of the switch tube MP10 is the source of the PMOS tube, and the second end of the switch tube MP10 is the drain of the PMOS tube.

[0038] The reference current source IB3 can be a constant current source circuit, or a constant current source provided by a previous circuit, which can keep the output reference current constant. The specific circuit structure can refer to the prior art and is not limited here. The reference current source IB3 can provide a current bias for the switch tube MP9 to ensure that the switch tube MP9 is in a normal working state.

[0039] The switch tube MP9 and the switch tube MP10 are input pairs of the current sampling unit 31. The reference current source I B3, the switch tube MP9 and the switch tube MP10 form a common-gate amplifier. When the current flowing through the switch tube MP9 is the same as the current flowing through the switch tube MP10, and the width and length of the switch tube MP9 are the same as those of the switch tube MP10, the voltage between the gate and the source of the switch tube MP9 is equal to the voltage between the gate and the source of the switch tube MP10. Because the gate of the switch tube MP9 is connected to the gate of the switch tube MP10, the source voltage of the switch tube MP9 is equal to the source voltage of the switch tube MP10, so that the drain voltages of the output switch tubes MP7 and MP8 can be clamped to the same voltage.

[0040] In the current sampling unit 31, the switch tube MP8 is a current sampling mirror tube of the output switch tube MP7, and the current flowing through the switch tube MP8 has a certain proportional relationship with the output current of the output switch tube MP7, thereby realizing sampling of the output current. In the present application, the current flowing through the switch tube refers to the current flowing from the first end to the second end of the switch tube.

[0041] In some of these embodiments, see Figure 3 The voltage conversion unit 32 includes a resistor RC. A first end of the resistor RC is respectively connected to the fourth end of the current sampling unit 31 and the first input end of the comparison unit 33, and a second end of the resistor RC is grounded GND.

[0042] In some implementations, see Figure 3The first end of the resistor RC is connected to the second end of the switch tube MP10 and the first input end of the comparison unit 33 respectively. In this way, the mirror current flowing through the switch tube MP8 will flow through the resistor RC, and a conversion voltage is generated at both ends of the resistor RC to the comparison unit 33, thereby realizing the function of converting voltage.

[0043] In some of these embodiments, see Figure 3 The comparison unit 33 includes a comparator OP and a switch tube MN7. The first input end of the comparator OP is connected to the voltage conversion unit 32, the second input end of the comparator OP is used to connect to the second reference voltage source VREF_OCP, the output end of the comparator OP is connected to the control end of the switch tube MN7, the first end of the switch tube MN7 is used to connect to the input voltage source VI N, and the second end of the switch tube MN7 is respectively connected to the output end of the first amplification module 10 and the input end of the second amplification module 20.

[0044] The first input terminal of the comparator OP is a positive input terminal, and the second input terminal is a negative input terminal. The first input terminal of the comparator OP is connected to the first end of the resistor RC. The switch tube MN7 can be an NMOS tube. The control end of the switch tube MN7 is the gate of the NMOS tube. The first end of the switch tube MN7 is the drain of the NMOS tube, and the second end of the switch tube MN7 is the source of the NMOS tube.

[0045] In the voltage stabilizing circuit, when the conversion voltage is greater than the second reference voltage, the output signal of the comparator OP is at a high level, the switch tube MN7 is turned on, and the amplitude of the comparison signal VO1 can be increased. When the conversion voltage is less than the second reference voltage, the output signal of the comparator OP is at a low level, which does not affect the size of the comparison signal VO1. It can be seen that the amplitude of the comparison signal VO1 can be adjusted by the comparator OP and the switch tube MN7.

[0046] In some of these embodiments, see Figure 3 The first amplification module 10 includes a voltage divider unit 11 and an error comparison unit 12. The input end of the voltage divider unit 11 is connected to the output end of the output switch tube MP7, the output end of the voltage divider unit 11 is connected to the first input end of the error comparison unit 12, the second input end of the error comparison unit 12 is used to connect the first reference voltage source VREF, and the output end of the error comparison unit 12 is connected to the input end of the second amplification module 20. The voltage divider unit 11 generates a voltage divider signal to the first input end of the error comparison unit 12 based on the output voltage VO. The error comparison unit 12 outputs a comparison signal VO1 to the second amplification module 20 based on the voltage divider signal and the first reference voltage.

[0047] In some implementations, the voltage divider unit 11 includes a resistor RF1 and a resistor RF2, the first end of the resistor RF1 is connected to the output end of the output switch tube MP7, the second end of the resistor RF1 is respectively connected to the first input end of the error comparison unit 12 and the first end of the resistor RF2, the second end of the resistor RF2 is grounded GND, and the input signal size of the error comparison unit can be adjusted by adjusting the resistance values ​​of the resistor RF1 and the resistor RF2. Among them, the resistance value and number of the resistors in the voltage divider unit 11 can be set according to actual needs and are not limited here.

[0048] In the voltage stabilizing circuit, the magnitude of the first reference voltage may be the amplitude of the voltage-dividing signal corresponding to the output voltage VO at the set stable value. When the voltage-dividing signal is less than the first reference voltage, the error comparison unit 12 reduces the amplitude of the comparison signal VO1; when the voltage-dividing signal is greater than the first reference voltage, the error comparison unit 12 increases the amplitude of the comparison signal VO1. When the voltage-dividing signal is equal to the first reference voltage, the error comparison unit 12 may not adjust the magnitude of the comparison signal VO1.

[0049] In this embodiment, the error comparison unit 12 can adjust the amplitude of the comparison signal VO1 based on processing and analyzing the voltage division signal.

[0050] In some of these embodiments, see Figure 3 , the error comparison unit 12 includes a current generating branch 121 and a comparison branch 122. The current generating branch 121 is respectively connected to the output end of the voltage dividing unit 11, the first reference voltage source VREF and the comparison branch 122, and the comparison branch 122 is also connected to the input end of the second amplification module 20. Among them, the current generating branch 121 generates a first current to the comparison branch 122 based on the voltage dividing signal, and generates a second current to the comparison branch 122 based on the first reference voltage. The comparison branch 122 generates a comparison signal VO1 based on the magnitude relationship between the first current and the second current.

[0051] When the voltage division signal is less than the first reference voltage, the first current will be less than the second current, and the comparison branch 122 reduces the amplitude of the comparison signal VO1; when the voltage division signal is greater than the first reference voltage, the first current will be greater than the second current, and the comparison branch 122 increases the amplitude of the comparison signal VO1.

[0052] In the voltage stabilizing circuit, after the current generating branch 121 generates the first current and the second current, the comparing branch 122 adjusts the amplitude of the comparison signal VO1 by comparing the magnitude relationship between the first current and the second current.

[0053] In some of these embodiments, see Figure 3The current generating branch 121 includes a reference current source I B1, a switch tube MP1 and a switch tube MP2, and the comparing branch 122 includes a switch tube MN1, a switch tube MN2, a switch tube MN3, a switch tube MN4, a switch tube MP3 and a switch tube MP4. The reference current source I B1 is respectively connected to the input voltage source VIN, the first end of the switch tube MP1 and the first end of the switch tube MP2, the control end of the switch tube MP1 is connected to the output end of the voltage dividing unit 11, the control end of the switch tube MP2 is connected to the first reference voltage, the first end of the switch tube MP3 and the first end of the switch tube MP4 are both connected to the input voltage source VIN, the control end of the switch tube MP3 is respectively connected to the second end of the switch tube MP3, the control end of the switch tube MP4 and the first end of the switch tube MN3, the second end of the switch tube MN3 is respectively connected to the second end of the switch tube MP1 and the first end of the switch tube MN1, the second end of the switch tube MP4 is respectively connected to the first end of the switch tube MN4 and the input end of the second amplification module 20, the second end of the switch tube MN4 is respectively connected to the second end of the switch tube MP2 and the first end of the switch tube MN2, the control end of the switch tube MN1 and the control end of the switch tube MN2 are both connected to the first voltage VB1, the control ends of the switch tube MN3 and the switch tube MN4 are both connected to the second voltage VB2, and the second end of the switch tube MN1 and the second end of the switch tube MN2 are both grounded GND.

[0054] In some implementations, the switch tube MP1, the switch tube MP2, the switch tube MP3 and the switch tube MP4 are all PMOS tubes, the switch tube MN1, the switch tube MN2, the switch tube MN3 and the switch tube MN4 are all NMOS tubes, the control end of the switch tube MP1 is the gate of the PMOS tube, the first end of the switch tube MP1 is the source of the PMOS tube, the second end of the switch tube MP1 is the drain of the PMOS tube, the control end of the switch tube MP2 is the gate of the PMOS tube, the first end of the switch tube MP2 is the source of the PMOS tube, the second end of the switch tube MP2 is the drain of the PMOS tube, the control end of the switch tube MP3 is the gate of the PMOS tube, the first end of the switch tube MP3 is the source of the PMOS tube, the second end of the switch tube MP3 is the drain of the PMOS tube, the control end of the switch tube MP4 is the gate of the PMOS tube, and the switch The first end of the switch tube MP4 is the source of the PMOS tube, the second end of the switch tube MP4 is the drain of the PMOS tube, the control end of the switch tube MN1 is the gate of the NMOS tube, the first end of the switch tube MN1 is the drain of the NMOS tube, the second end of the switch tube MN1 is the source of the NMOS tube, the control end of the switch tube MN2 is the gate of the NMOS tube, the first end of the switch tube MN2 is the drain of the NMOS tube, the second end of the switch tube MN2 is the source of the NMOS tube, the control end of the switch tube MN3 is the gate of the NMOS tube, the first end of the switch tube MN3 is the drain of the NMOS tube, the second end of the switch tube MN3 is the source of the NMOS tube, the control end of the switch tube MN4 is the gate of the NMOS tube, the first end of the switch tube MN4 is the drain of the NMOS tube, and the second end of the switch tube MN4 is the source of the NMOS tube.

[0055] The reference current source I B1 can be a constant current source circuit, or a constant current source provided by a previous circuit, which can make the output reference current not change with the voltage change of the input voltage source VIN, that is, the reference current remains constant. Its specific circuit structure can refer to the prior art and is not limited here. The reference current source I B1 provides current bias for the switch tube MP1 and the switch tube MP2 to ensure that the switch tube MP1 and the switch tube MP2 are in normal working state.

[0056] In the voltage stabilizing circuit, if the voltage division signal is less than the first reference voltage VREF, the gate voltage of the switch tube MP1 is lower than the gate voltage of the switch tube MP2, and the current I flowing through the switch tube MP1 is MP1 Greater than the current I flowing through the switch tube MP2 MP2 , due to the current I flowing through the switch tube MN1 MN1 、The current I flowing through the switch tube MN3 MN3 and the current I flowing through the switch tube MP1 MP1 satisfy:

[0057] I MN1 =I MN3+I MP1 ;

[0058] The current I flowing through the switch tube MN2 MN2 、The current I flowing through the switch tube MN4 MN4 and the current I flowing through the switch MP2 MP2 satisfy:

[0059] I MN2 =I MN4 +I MP2 ;

[0060] Because the current I flowing through the switch tube MN1 MN1 and the current I flowing through the switch tube MN2 MN2 equal, so the current I flowing through the switch tube MN4 MN4 Greater than the current I flowing through the switch tube MN3 MN3 , since the current I flowing through the switch tube MN3 MN3 Equal to the current I flowing through the switch tube MP3 MP3 , the switch tube MP4 is a mirror tube of the switch tube MP3, that is, the current I flowing through the switch tube MP4 MP4 Equal to the current I flowing through the switch tube MP3 MP3 Therefore, the current I flowing through the switch tube MN4 MN4 Greater than the current I flowing through the switch tube MP4 MP4 Therefore, the voltage at the first terminal of the switch tube MN4 decreases, that is, the amplitude of the comparison signal VO1 decreases. On the contrary, if the voltage-divided signal is greater than the first reference voltage VREF, the amplitude of the comparison signal VO1 increases.

[0061] It can be seen that in this embodiment, the size of the comparison signal VO1 can be adjusted based on the size of the output voltage VO through the above-mentioned switch tube.

[0062] In some of these embodiments, see Figure 3 The second amplifying module 20 includes a reference current source I B2, a switch tube MP5, a switch tube MN5, a switch tube MP6 and a switch tube MN6. The output end of the first amplifying module 10 is respectively connected to the control end of the switch tube MP5 and the control end of the switch tube MP6, the reference current source I B2 is respectively connected to the input voltage source VIN, the first end of the switch tube MN5, the control end of the switch tube MN5 and the control end of the switch tube MN6, the second end of the switch tube MN5 is connected to the first end of the switch tube MP5, the first end of the switch tube MN6 is used to connect to the input voltage source VIN, the second end of the switch tube MN6 is respectively connected to the first end of the switch tube MP6 and the control end of the output switch tube MP7, and the second end of the switch tube MP5 and the second end of the switch tube MP6 are both grounded GND.

[0063] In some implementations, the switch tube MP5 and the switch tube MP6 are PMOS tubes, the switch tube MN5 and the switch tube MN6 are NMOS tubes, the control end of the switch tube MP5 is the gate of the PMOS tube, the first end of the switch tube MP5 is the source of the PMOS tube, the second end of the switch tube MP5 is the drain of the PMOS tube, the control end of the switch tube MP6 is the gate of the PMOS tube, the first end of the switch tube MP6 is the source of the PMOS tube, the second end of the switch tube MP6 is the drain of the PMOS tube, the control end of the switch tube MN5 is the gate of the NMOS tube, the first end of the switch tube MN5 is the drain of the NMOS tube, the second end of the switch tube MN5 is the source of the NMOS tube, the control end of the switch tube MN6 is the gate of the NMOS tube, the first end of the switch tube MN6 is the drain of the NMOS tube, and the second end of the switch tube MN6 is the source of the NMOS tube.

[0064] The reference current source I B2 can be a constant current source circuit, or a constant current source provided by a previous circuit, which can make the output reference current not change with the voltage change of the input voltage source VIN, that is, the reference current remains constant. Its specific circuit structure can refer to the prior art and is not limited here. The reference current source I B2 provides current bias for the switch tube MN5 and the switch tube MN6 to ensure that the switch tube MN5 and the switch tube MN6 are in a normal working state.

[0065] In this voltage stabilization circuit, the amplitude of the control voltage VO2 is V 02 =V GS_MP5 +V GS_MN5 -V GS_MN6 ≈

[0066] V O1 +V GS_MP6 If the amplitude of the comparison signal VO1 decreases, that is, the gate voltage of the switch tube MP5 and the gate voltage of the switch tube MP6 decrease, then the source voltage of the switch tube MP6 decreases, that is, the control voltage VO2 decreases; if the comparison signal VO1 increases, that is, the gate voltage of the switch tube MP5 and the gate voltage of the switch tube MP6 increase, then the source voltage of the switch tube MP6 increases, that is, the control voltage VO2 increases. Among them, V GS_MP5 is the voltage between the gate and source of the switch tube MP5, V GS_MN5 is the voltage between the gate and source of the switch tube MN5, V GS_MN6 is the voltage between the gate and source of the switch tube MN6, V GS_MP6 is the voltage between the gate and source of the switch tube MP6, V O1 is the amplitude of the comparison signal VO1.

[0067] It can be seen that the switch tube MN5 shifts up the DC voltage of the input signal (comparison signal) passing through the switch tube MP5 so as to accurately control the switch tube MN6, and the switch tube MN6 and the switch tube MP6 form a class AB amplifier, which has strong pull-up and pull-down capabilities for the control voltage VO2, thereby realizing the rapid shutdown and conduction control of the power tube MP7.

[0068] In some of these embodiments, see Figure 3 The voltage stabilizing circuit further includes a clamping module 40, which is connected to the input voltage source VI N, the output end of the first amplifying module 10 and the output end of the second amplifying module 20 respectively.

[0069] In some implementations, the clamping module 40 is respectively connected to the second end of the switch tube MP4, the first end of the switch tube MN4, the control end of the switch tube MP5, and the control end of the switch tube MP6. The clamping module 40 may include a Zener diode. By setting the clamping module 40, the amplitude of the comparison signal VO1 can be clamped relative to the input voltage source VI N, so as to avoid the voltage difference between the comparison signal VO1 and the input voltage source VI N being too large to cause device breakdown, thereby improving the safety and reliability of the voltage stabilization circuit.

[0070] Combine the following Figure 3 The embodiment shown in the figure describes in detail the specific working process of the voltage stabilizing circuit provided by the present application. Before the voltage stabilizing circuit works, the target stable value of the output voltage and the maximum allowable current value of the output current can be preset, and the voltage magnitude of the first reference voltage source VREF and the voltage magnitude of the second reference voltage source VREF_OCP can be determined by corresponding calculation, wherein the target stable value V1 and the first reference voltage source V REF The voltage size satisfies:

[0071] V1=V REF / R RF2 *(R RF1 +R RF2 ).

[0072] When the output voltage VO is lower than the target stable value V1, the voltage signal of the output voltage VO after being divided by the resistors RF1 and RF2 is low, the gate voltage of the switch tube MP1 is lower than the gate voltage of the switch tube MP2 (the first reference voltage VREF), the current flowing through the switch tube MP1 is greater than the current flowing through the switch tube MP2, so that the current flowing through the switch tube MN4 is greater than the current flowing through the switch tube MP4, so the voltage amplitude of the comparison signal VO1 is reduced, that is, the gate voltages of the switch tubes MP5 and MP6 are reduced, so the source voltage of MP6, that is, the amplitude of the control voltage VO2 is reduced, the output switch tube MP7 is more fully turned on, so that the output voltage VO increases. On the contrary, when the output voltage VO is higher than the target stable value V1, the amplitude of the control voltage VO2 increases, the conduction ability of the output switch tube MP7 becomes weaker or even turns off, so that the output voltage VO decreases, and finally the amplitude of the output voltage VO is stabilized at the target stable value V1.

[0073] In addition, when the output current through the switch tube MP7 is less than the maximum allowable current value of the output current, the voltage of the mirror current sampled by the switch tube MP8 flowing through the resistor RC will be less than the second reference voltage source VREF_OCP, then the output of the comparison amplifier OP is low, and the source terminal voltage of the switch tube MN7 is also low, which does not affect the amplitude of the comparison signal VO1, and thus does not limit the current of the output switch tube MP7; on the contrary, when the output current through MP7 is greater than the maximum allowable current value of the output current, the voltage on the resistor RC will be greater than the second reference voltage source VREF_OCP, then the output of the comparison amplifier OP is high, the switch tube MN7 will increase the voltage amplitude of the comparison signal VO1, thereby increasing the amplitude of the control voltage VO2, at this time, the conduction ability of the output switch tube MP7 becomes weaker, limiting the output current, and finally the output current will reach a balance at the maximum allowable current value.

[0074] In summary, the voltage stabilizing circuit can adjust the magnitude of the control voltage of the output switch tube MP7 based on the magnitude relationship between the voltage division signal after the output voltage is divided and the first reference voltage, so as to regulate the output voltage of the output switch tube MP7 and improve the stability of the output voltage. In addition, the voltage stabilizing circuit can regulate the output current of the output switch tube MP7 by comparing the output current with the maximum allowable current value, so as to avoid the LDO current being too large, which may cause the circuit to fail.

[0075] In a second aspect, the present application provides a power supply device, which includes an input voltage source and a voltage stabilizing circuit as described in any one of the embodiments of the first aspect; the input voltage source is connected to the voltage stabilizing circuit. In this embodiment, the voltage stabilizing circuit has the same structure and function as the voltage stabilizing circuit as described in any one of the embodiments of the first aspect, which will not be repeated here. The power supply device can be a voltage stabilizing source, a charger, and other devices.

[0076] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A voltage stabilizing circuit, characterized in that: include: A first amplifying module, a second amplifying module and an output switching tube; The first input end of the first amplifying module is connected to the output end of the output switch tube, the second input end of the first amplifying module is used to connect to a first reference voltage source, the output end of the first amplifying module is connected to the input end of the second amplifying module, the output end of the second amplifying module is connected to the control end of the output switch tube, and the input end of the output switch tube is used to connect to an input voltage source; Wherein, the first amplification module outputs a comparison signal to the second amplification module based on the output voltage of the output switch tube and the first reference voltage of the first reference voltage source; The second amplifying module adjusts the control voltage of the control terminal of the output switch tube based on the comparison signal; The output switch tube adjusts the output voltage based on the control voltage and the input voltage of the input voltage source.

2. The voltage stabilizing circuit according to claim 1, characterized in that: The voltage stabilizing circuit also includes a current limiting module; The input end of the current limiting module is connected to the output switch tube, and the output end of the current limiting module is respectively connected to the output end of the first amplifying module and the input end of the second amplifying module; The current limiting module is used to obtain the output current of the output switch tube, and adjust the comparison signal based on the output current so that the output current is within a preset current range.

3. The voltage stabilizing circuit according to claim 2, characterized in that: The current limiting module includes a current sampling unit, a voltage conversion unit and a comparison unit; The first end of the current sampling unit is respectively connected to the output end of the second amplifying module and the control end of the output switch tube, the second end of the current sampling unit is used to connect the input voltage source, the third end of the current sampling unit is connected to the output end of the output switch tube, the voltage conversion unit is respectively connected to the fourth end of the current sampling unit and the first input end of the comparison unit, the second input end of the comparison unit is used to connect the second reference voltage source, and the output end of the comparison unit is respectively connected to the output end of the first amplifying module and the input end of the second amplifying module; Wherein, the current sampling unit generates a mirror current based on the input voltage, the control voltage and the output voltage; The voltage conversion unit converts the mirror current into a conversion voltage; The comparison unit adjusts the comparison signal based on a second reference voltage of the second reference voltage source and the conversion voltage.

4. The voltage stabilizing circuit according to claim 3, characterized in that: The current sampling unit includes a reference current source IB3, a switch tube MP8, a switch tube MP9 and a switch tube MP10; The control end of the switch tube MP8 is respectively connected to the output end of the second amplifying module and the control end of the output switch tube, the first end of the switch tube MP8 is used to connect to the input voltage source, the first end of the switch tube MP9 is connected to the output end of the output switch tube, the control end of the switch tube MP9 is respectively connected to the control end of the switch tube MP10, the reference current source IB3 and the second end of the switch tube MP9, the first end of the switch tube MP10 is connected to the second end of the switch tube MP8, and the second end of the switch tube MP10 is connected to the voltage conversion unit.

5. The voltage stabilizing circuit according to claim 3, characterized in that: The voltage conversion unit includes a resistor RC; The first end of the resistor RC is respectively connected to the fourth end of the current sampling unit and the first input end of the comparison unit, and the second end of the resistor RC is grounded.

6. The voltage stabilizing circuit according to claim 3, characterized in that: The comparison unit includes a comparator and a switch tube MN7; The first input end of the comparator is connected to the voltage conversion unit, the second input end of the comparator is used to connect to the second reference voltage source, the output end of the comparator is connected to the control end of the switch tube MN7, the first end of the switch tube MN7 is used to connect to the input voltage source, and the second end of the switch tube MN7 is respectively connected to the output end of the first amplification module and the input end of the second amplification module.

7. The voltage stabilizing circuit according to any one of claims 1 to 6, wherein the first amplifying module comprises a voltage dividing unit and an error comparing unit; The input end of the voltage divider unit is connected to the output end of the output switch tube, the output end of the voltage divider unit is connected to the first input end of the error comparison unit, the second input end of the error comparison unit is used to connect to the first reference voltage source, and the output end of the error comparison unit is connected to the input end of the second amplification module; in, The voltage dividing unit generates a voltage dividing signal to the first input terminal of the error comparing unit based on the output voltage; The error comparison unit outputs the comparison signal to the second amplification module based on the voltage division signal and the first reference voltage.

8. The voltage stabilizing circuit according to claim 7, characterized in that: The error comparison unit includes a current generating branch and a comparison branch; The current generating branch is respectively connected to the output end of the voltage dividing unit, the first reference voltage source and the comparing branch, and the comparing branch is also connected to the input end of the second amplifying module; Wherein, the current generating branch generates a first current to the comparing branch based on the voltage division signal, and generates a second current to the comparing branch based on the first reference voltage; The comparison branch generates the comparison signal based on the magnitude relationship between the first current and the second current.

9. The voltage stabilizing circuit according to claim 8, characterized in that: The current generating branch includes a reference current source IB1, a switch tube MP1 and a switch tube MP2, and the comparing branch includes a switch tube MN1, a switch tube MN2, a switch tube MN3, a switch tube MN4, a switch tube MP3 and a switch tube MP4; The reference current source IB1 is respectively connected to the input voltage source, the first end of the switch tube MP1 and the first end of the switch tube MP2, the control end of the switch tube MP1 is connected to the output end of the voltage dividing unit, the control end of the switch tube MP2 is connected to the first reference voltage, the first end of the switch tube MP3 and the first end of the switch tube MP4 are both connected to the input voltage source, the control end of the switch tube MP3 is respectively connected to the second end of the switch tube MP3, the control end of the switch tube MP4 and the first end of the switch tube MN3, the second end of the switch tube MN3 is respectively connected to the second end of the switch tube MP1 and the first end of the switch tube MN1, the second end of the switch tube MP4 is respectively connected to the first end of the switch tube MN4 and the input end of the second amplification module, the second end of the switch tube MN4 is respectively connected to the second end of the switch tube MP2 and the first end of the switch tube MN2, the control end of the switch tube MN1 and the control end of the switch tube MN2 are both connected to the first voltage, the control end of the switch tube MN3 and the control end of the switch tube MN4 are both connected to the second voltage, and the second end of the switch tube MN1 and the second end of the switch tube MN2 are both grounded.

10. The voltage stabilizing circuit according to any one of claims 1 to 6, characterized in that: The second amplification module includes a reference current source IB2, a switch tube MP5, a switch tube MN5, a switch tube MP6 and a switch tube MN6; The output end of the first amplifying module is respectively connected to the control end of the switch tube MP5 and the control end of the switch tube MP6, the reference current source IB2 is respectively connected to the input voltage source, the first end of the switch tube MN5, the control end of the switch tube MN5 and the control end of the switch tube MN6, the second end of the switch tube MN5 is connected to the first end of the switch tube MP5, the first end of the switch tube MN6 is used to connect to the input voltage source, the second end of the switch tube MN6 is respectively connected to the first end of the switch tube MP6 and the control end of the output switch tube, and the second end of the switch tube MP5 and the second end of the switch tube MP6 are both grounded.

11. A power supply device, characterized in that: comprising an input voltage source, and a voltage stabilizing circuit as claimed in any one of claims 1 to 10; The input voltage source is connected to the voltage stabilizing circuit.

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