CN114785098B

CN114785098B - Drive circuit and power supply chip

Info

Publication number: CN114785098B
Application number: CN202210664119.3A
Authority: CN
Inventors: 李瑞平; 刘彬; 王建虎
Original assignee: Shanghai Xinlong Semiconductor Technology Co ltd Nanjing Branch
Current assignee: Shanghai Xinlong Semiconductor Technology Co ltd Nanjing Branch
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2022-09-09
Anticipated expiration: 2042-06-14
Also published as: CN114785098A

Abstract

The invention provides a driving circuit and a power supply chip. The driving circuit comprises an upper tube driving module and a lower tube driving module, and the power cathode of the upper tube driving module is connected with the power anode of the lower tube driving module. According to the configuration, different electrical characteristics of the PMOS power tube and the NMOS power tube are reasonably utilized, and an intermediate level is introduced, wherein the intermediate level is a reference ground of the upper tube driving module and a power supply of the lower tube driving module, so that two driving currents in a traditional driving mode are skillfully changed into one current, and the influence of the driving current on the overall efficiency of the system is effectively reduced when high voltage is input.

Description

Drive circuit and power supply chip

Technical Field

The invention relates to the technical field of power chips, in particular to a driving circuit and a power chip.

Background

The BUCK type switching power supply control system generally requires two power transistors, one is a power output transistor (hereinafter, referred to as an upper transistor), a PMOS power transistor and an NMOS power transistor can be selected, and the other is a follow current transistor (hereinafter, referred to as a lower transistor), and an NMOS power transistor is adopted. The switching power supply chip needs to design corresponding driving circuits and power supply circuits for the two power tubes. The general driving circuit power supply circuit is powered by input voltage, and the internal linear voltage reduction module reduces the voltage to proper driving voltage for the power tube switch, namely, the whole charging and discharging current path of the GATE end of the power tube flows into GND from the input voltage, and when the input voltage gradually rises, the corresponding power also gradually rises. In high voltage applications, the proportion of this loss to the system loss gradually increases, and has become an important factor affecting the system efficiency.

That is, the prior art has a problem that the energy loss of the driving circuit in the high voltage application is high.

Disclosure of Invention

The invention provides a driving circuit and a power supply chip, and aims to solve the problem that the driving circuit in the prior art has high energy loss in high-voltage application.

In order to solve the above technical problem, the present invention provides a driving circuit for driving a synchronous rectification system, where the driving circuit includes an upper tube driving module and a lower tube driving module, and a power supply cathode of the upper tube driving module is connected to a power supply anode of the lower tube driving module.

Optionally, the cathode of the power supply of the upper tube driving module is connected with the anode of the power supply of the lower tube driving module in a switchable manner; the power supply anode of the upper tube driving module is used for being connected with an external power supply; when a preset condition is met, the cathode of the power supply of the upper tube driving module is communicated with the anode of the power supply of the lower tube driving module; and when the preset condition is not met, the positive electrode of the power supply of the lower tube driving module is disconnected with the negative electrode of the power supply of the upper tube driving module, and the power supply is switched to be used for connecting the same external power supply.

Optionally, the power supply positive electrode of the upper tube driving module is used for being connected with an external power supply; the external power supply is further connected with the first end of the external energy storage capacitor, and the power cathode of the upper tube driving module is used for being connected with the second end of the external energy storage capacitor. The drive circuit further comprises a periodic discharge module, and the periodic discharge module is used for limiting the voltage of the second end of the external energy storage capacitor to a preset interval through charging and discharging.

In order to solve the technical problem, the invention further provides a driving circuit for driving the synchronous rectification system, wherein the driving circuit comprises a periodic discharge module, an upper tube driving module, an input voltage detection module and a lower tube driving module.

The power anode of the upper tube driving module is used for being connected with an external power supply, the external power supply is further connected with the first end of the external energy storage capacitor, and the power cathode of the upper tube driving module is used for being connected with the second end of the external energy storage capacitor.

The periodic discharging module is used for limiting the voltage of the second end of the external energy storage capacitor to a preset interval through charging and discharging.

The input voltage detection module is used for judging the voltage value of the external power supply, and when the voltage value of the external power supply is greater than a first preset voltage, the input voltage detection module outputs a first signal; and when the voltage value of the external power supply is smaller than the first preset voltage, the input voltage detection module outputs a second signal.

The negative electrode of the power supply of the lower tube driving module is grounded; when the first signal is received, the positive electrode of a first power supply of the lower tube driving module is connected with the negative electrode of the power supply of the upper tube driving module, and the positive electrode of a second power supply of the lower tube driving module is disconnected; when the second signal is received, the positive electrode of the first power supply of the lower tube driving module is disconnected, and the positive electrode of the second power supply of the lower tube driving module is used for being connected with the same external power supply.

Optionally, the periodic discharge module includes a level detection submodule and a timing discharge submodule; the level detection submodule is used for detecting an intermediate level, and the intermediate level is the voltage of the second end of the external energy storage capacitor; when the intermediate level is smaller than a second preset voltage, resetting the timing characteristic parameter of the timing discharge submodule; the timing discharge submodule is used for continuously increasing the timing characteristic parameter, and when the timing characteristic parameter exceeds a preset parameter, the timing discharge submodule discharges the energy storage capacitor outside the capacitor so as to reduce the intermediate level.

Optionally, the level detection submodule includes a first triode, a second triode, a third triode, a fourth triode, a fifth triode, a sixth triode, a first constant current source, a first voltage regulator tube, and a first resistor.

The first triode is a PNP triode, an emitting electrode of the first triode is used for being connected with the external power supply, a base electrode of the first triode is connected with a collector electrode of the first triode, the collector electrode of the first triode is connected with the positive electrode of the first constant current source, and the negative electrode of the first constant current source is used for being grounded.

The second triode is a PNP triode, an emitting electrode of the second triode is used for being connected with the external power supply, a base electrode of the second triode is connected with a base electrode of the first triode, a collector electrode of the second triode is connected with a negative electrode of the first voltage-stabilizing tube, and a positive electrode of the first voltage-stabilizing tube is connected with a negative electrode of the power supply of the upper tube driving module through the first resistor.

The third triode is a PNP type triode, an emitting electrode of the third triode is used for being connected with the external power supply, and a base electrode of the third triode is connected with a base electrode of the first triode.

The fourth triode is an NPN type triode, a collector electrode of the fourth triode is connected with a collector electrode of the third triode, a base electrode of the fourth triode is connected with the positive electrode of the first voltage-regulator tube, and an emitting electrode of the fourth triode is connected with the negative electrode of the power supply of the upper tube driving module.

The fifth triode is a PNP type triode, an emitting electrode of the fifth triode is used for being connected with the external power supply, and a base electrode of the fifth triode is connected with a base electrode of the first triode.

The sixth triode is a PNP type triode, an emitting electrode of the sixth triode is connected with a collecting electrode of the fifth triode, a base electrode of the sixth triode is connected with a collecting electrode of the third triode, and the collecting electrode of the sixth triode is used for outputting and resetting the timing characteristic parameter signal.

Optionally, the timing discharging submodule includes a seventh triode, an eighth triode, a ninth triode, a thirteenth triode, an eleventh triode, a twelfth triode, a thirteenth triode, a fourteenth triode, a fifteenth triode, a sixteenth triode, a second constant current source, a timing capacitor, a second resistor, a third resistor, and a fourth resistor.

The seventh triode is a PNP triode, an emitter of the seventh triode is used for connecting an internal power supply, a base of the seventh triode is connected with a collector of the seventh triode, the collector of the seventh triode is connected with the anode of the second constant current source, and the cathode of the second constant current source is used for grounding.

The eighth triode is an NPN type triode, the base of the eighth triode is used for being grounded through the second resistor, the emitter of the eighth triode is used for being grounded, and the base of the eighth triode is also used for receiving the signal for outputting and resetting the timing characteristic parameter.

The first end of the timing capacitor is connected with the collector of the eighth triode, the second end of the timing capacitor is used for grounding, and the voltage value of the timing capacitor is configured as the timing characteristic parameter.

The ninth triode is a PNP type triode, an emitting electrode of the ninth triode is used for being connected with the internal power supply, and a base electrode of the ninth triode is connected with a base electrode of the seventh triode.

The thirteenth polar tube is a PNP type polar tube, an emitting electrode of the thirteenth polar tube is connected with a collector electrode of the ninth polar tube, a base electrode of the thirteenth polar tube is connected with a collector electrode of the eighth polar tube, and the collector electrode of the thirteenth polar tube is grounded.

The eleventh triode is an NPN triode, a collector of the eleventh triode is connected with a collector of the ninth triode, a base of the eleventh triode is connected with a collector of the eleventh triode, and an emitting electrode of the eleventh triode is grounded through the third resistor.

The twelfth triode is a PNP type triode, an emitting electrode of the twelfth triode is used for being connected with the internal power supply, and a base electrode of the twelfth triode is connected with a base electrode of the seventh triode.

The thirteenth triode is an NPN type triode, a collector of the thirteenth triode is connected with a collector of the twelfth triode, a base of the thirteenth triode is connected with an emitter of the eleventh triode, and the emitter of the thirteenth triode is used for being grounded.

The fourteenth triode is a PNP type triode, an emitting electrode of the fourteenth triode is used for being connected with the internal power supply, and a base electrode of the fourteenth triode is connected with a base electrode of the seventh triode.

The fifteenth triode is an NPN type triode, the base of the fifteenth triode is connected with the collector of the twelfth triode, the collector of the fifteenth triode is connected with the collector of the fourteenth triode, and the emitter of the fifteenth triode is used for being grounded.

The sixteenth triode is an NPN triode, a collector of the sixteenth triode is connected with the negative electrode of the power supply of the upper tube driving module, a base of the sixteenth triode is connected with the collector of the fourteenth triode, the base of the sixteenth triode is also used for being grounded through the fourth resistor, and an emitter of the sixteenth triode is used for being grounded.

Optionally, the input voltage detection module includes a seventeenth triode, an eighteenth triode, a nineteenth triode, a twentieth triode, a twenty-first triode, a twenty-second triode, a twenty-third triode, a twenty-fourth triode, a twenty-fifth triode, a twenty-sixth triode, a third constant current source, a second voltage regulator tube, a third voltage regulator tube, a fifth resistor, a sixth resistor and a seventh resistor.

The seventeenth triode is a PNP triode, an emitting electrode of the seventeenth triode is used for being connected with the external power supply, a base electrode of the seventeenth triode is connected with a collector electrode of the seventeenth triode, the collector electrode of the seventeenth triode is connected with the positive electrode of the third constant current source, and the negative electrode of the third constant current source is used for being grounded.

The eighteenth triode, the nineteenth triode, the twenty-first triode, the twenty-third triode and the twenty-fifth triode are PNP type triodes, the eighteenth triode, the nineteenth triode, the twenty-first triode, the twenty-third triode and the projecting pole of the twenty-fifth triode are all used for connecting external power source, the eighteenth triode, the nineteenth triode, the twenty-first triode, the twenty-third triode and the base of the twenty-fifth triode all with the base of the seventeenth triode is connected.

The negative electrode of the second voltage-stabilizing tube is connected with the collector electrode of the eighteenth triode, the positive electrode of the second voltage-stabilizing tube is connected with the negative electrode of the third voltage-stabilizing tube, and the positive electrode of the third voltage-stabilizing tube is grounded through the fifth resistor.

The twenty-third triode is an NPN triode, a collector of the twentieth triode is connected with a collector of the nineteenth triode, a base of the twentieth triode is connected with the positive electrode of the third voltage-regulator tube, and an emitter of the twentieth triode is grounded.

The second triode is an NPN type triode, a collector of the second triode is connected with a collector of the first triode, a base of the second triode is connected with a collector of the nineteenth triode through the sixth resistor, and an emitting electrode of the second triode is used for being grounded.

The twenty-fourth triode is an NPN triode, a collector of the twenty-fourth triode is connected with a collector of the twenty-third triode, a base of the twenty-fourth triode is connected with a collector of the nineteenth triode through the seventh resistor, and an emitting electrode of the twenty-fourth triode is used for being grounded.

The twenty-sixth triode is an NPN type triode, a collector electrode of the twenty-sixth triode is connected with a collector electrode of the twenty-fifth triode, a base electrode of the twenty-sixth triode is connected with a collector electrode of the twenty-third triode, and an emitting electrode of the twenty-sixth triode is used for being grounded.

A collector of the twenty-second triode and a collector of the twenty-sixth triode are configured as an output of the input voltage detection module, a voltage of the collector of the twenty-second triode is a high level and a voltage of the collector of the twenty-sixth triode is a low level and is configured as the first signal, a voltage of the collector of the twenty-second triode is a low level and a voltage of the collector of the twenty-sixth triode is a high level and is configured as the second signal.

Optionally, the lower tube driving module includes a twenty-seventh triode, a twenty-eighth triode, a twenty-ninth triode, a thirty-sixth triode, a thirty-seventh triode, a thirty-eighth triode, a thirty-second triode, a thirty-third triode, a thirty-fourth triode, a thirty-fifth triode, a thirty-sixth triode, a thirty-seventh triode, a thirty-eighth triode, a thirty-ninth triode, a forty-fourth triode, a forty-first triode, a forty-second triode, a forty-third triode, a forty-fourth triode, a forty-fifth triode, a fourth regulator tube, a fifth regulator tube, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a thirteenth resistor.

Wherein the twenty-seventh triode, the twenty-ninth triode, the thirty-first triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all PNP type triodes, emitters of the twenty-seventh triode, the twenty-ninth triode, the thirty-first triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all used for obtaining the external power supply, bases of the twenty-seventh triode, the twenty-ninth triode, the thirty-eleventh triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all used for obtaining a base reference voltage, bases of the twenty-seventh triode, the twenty-ninth triode, the thirty-first triode, the thirty-third triode, the twenty-fifth triode and the thirty-seventh triode are all used for obtaining a base reference voltage, and bases of the twenty-seventh triode, the twenty-ninth triode, the thirty-third triode, The collectors of the thirty-fifth triode and the thirty-seventh triode are used for generating bias current based on the base reference voltage.

The twenty-eighth triode is an NPN type triode, a collector electrode of the twenty-eighth triode is connected with a collector electrode of the twenty-seventh triode, a base electrode of the twenty-eighth triode is used for acquiring a low tube control signal, and an emitting electrode of the twenty-eighth triode is used for being grounded.

The thirty-third triode is an NPN type triode, a collector of the thirty-third triode is connected with a collector of the twenty-ninth triode, a base of the thirty-third triode is connected with a collector of the twenty-seventh triode, and an emitter of the thirty-third triode is used for being grounded.

The thirty-second triode is an NPN type triode, a collector of the thirty-second triode is connected with a collector of the thirty-first triode, a base of the thirty-second triode is connected with a collector of the twenty-ninth triode through the eighth resistor, and an emitter of the thirty-second triode is used for being grounded.

The thirty-fourth triode is an NPN type triode, a collector of the thirty-fourth triode is connected with a collector of the thirty-third triode, a base of the thirty-fourth triode is connected with a collector of the twenty-ninth triode through the ninth resistor, and an emitter of the thirty-fourth triode is used for being grounded.

The thirty-sixth triode is an NPN type triode, a collector of the thirty-sixth triode is connected with a collector of the thirty-fifth triode, a base of the thirty-sixth triode is connected with a collector of the twenty-ninth triode through the tenth resistor, and an emitter of the thirty-sixth triode is used for being grounded.

The thirty-eighth triode is an NPN type triode, a collector of the thirty-eighth triode is connected with a collector of the thirty-seventh triode, a base of the thirty-eighth triode is connected with a collector of the thirty-third triode, and an emitter of the thirty-eighth triode is used for being grounded.

The thirty-ninth triode is an NPN type triode, a collector electrode of the thirty-ninth triode is connected with a collector electrode of the thirty-seventh triode, an emitter electrode of the thirty-ninth triode is connected with a negative electrode of the fifth voltage regulator tube, and a positive electrode of the fifth voltage regulator tube is used for being grounded.

The forty-first triode is an NPN type triode, a collector of the forty-first triode is connected with a collector of the thirty-seventh triode, an emitter of the forty-first triode is connected with a negative electrode of the fourth voltage-stabilizing tube, and a positive electrode of the fourth voltage-stabilizing tube is used for being grounded.

The forty-first triode is an NPN type triode, the base of the forty-first triode is connected with the collector of the thirty-first triode, the emitter of the forty-first triode is connected with the collector of the thirty-fifth triode through the eleventh resistor, and the emitter of the forty-first triode is also used for being grounded through the twelfth resistor.

The forty-second triode is an NPN-type triode, a collector of the forty-second triode is configured as a second power supply positive electrode of the lower tube driving module, a base of the forty-second triode is connected with an emitter of the forty-second triode, an emitter of the forty-second triode is connected with a collector of the forty-first triode, the emitter of the forty-second triode is further used for being grounded through the thirteenth resistor, and the emitter of the forty-second triode is configured as an output end of the lower tube driving module.

The forty-third triode is an NPN type triode, a collector of the forty-third triode is connected with a collector of the forty-first triode, a base of the forty-third triode is connected with an emitter of the forty-first triode, and the emitter of the forty-third triode is used for being grounded.

The forty-fourth triode is an NPN type triode, a collector electrode of the forty-fourth triode is connected with a base electrode of the forty-fourth triode, and the collector electrode of the forty-fourth triode is configured to be a first power supply positive electrode of the lower tube driving module.

The forty-fifth triode is an NPN type triode, a collector of the forty-fifth triode is connected with an emitter of the forty-fourth triode, a base of the forty-fifth triode is connected with an emitter of the thirty-ninth triode, and the emitter of the forty-fifth triode is connected with an emitter of the forty-second triode.

The base of the thirty-ninth triode and the base of the forty-fourth triode are configured as the input end of the down tube driving module, the voltage of the base of the thirty-ninth triode is at a high level and the voltage of the base of the forty-fourth triode is at a low level and is configured as the first signal, and the voltage of the base of the thirty-ninth triode is at a low level and the voltage of the base of the forty-fourth triode is at a high level and is configured as the second signal.

In order to solve the above technical problem, the present invention further provides a power chip including the above driving circuit.

Compared with the prior art, the driving circuit and the power chip provided by the invention have the advantages that the driving circuit comprises the upper tube driving module and the lower tube driving module, and the power cathode of the upper tube driving module is connected with the power anode of the lower tube driving module. According to the configuration, different electrical characteristics of the PMOS power tube and the NMOS power tube are reasonably utilized, and an intermediate level is introduced, wherein the intermediate level is a reference ground of the upper tube driving module and a power supply of the lower tube driving module, so that two driving currents in a traditional driving mode are ingeniously changed into one current, and the influence of the driving current on the overall efficiency of the system is effectively reduced when high voltage is input.

Drawings

It will be appreciated by those skilled in the art that the drawings are provided for a better understanding of the invention and do not constitute any limitation to the scope of the invention. Wherein:

FIG. 1 is a schematic diagram of a driving circuit according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating connection relationships of application scenarios of a driving circuit according to an embodiment of the present invention;

FIG. 3 is a circuit diagram of a driving circuit according to an embodiment of the invention;

FIG. 4 is a waveform diagram of the driving circuit according to an embodiment of the present invention when the driving circuit is at 12V input;

fig. 5 is a waveform diagram of the driving circuit according to an embodiment of the present invention when the driving circuit is in 24V input.

In the drawings:

201-periodic discharge module; 202-an upper tube driving module; 203-input voltage detection module; 204-a lower tube driving module; 5-an external energy storage capacitor; 2011-level detection submodule; 2012-a timed discharge sub-module; 2041-first power supply positive pole; 2042-second supply positive;

10-a power supply circuit; 20-a driver circuit; 30-external power tube; 40-an output circuit; 301-upper tube; 302-lowering a tube; 401-energy storage inductance; 402-an output filter capacitor; 403-load; 101-an input power module; 102-an input filter capacitance; 103-external energy storage capacitance.

Detailed Description

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in greatly simplified form and are not to scale, but are merely intended to facilitate and clarify the explanation of the embodiments of the present invention. Further, the structures illustrated in the drawings are intended to be part of actual structures. In particular, the drawings are intended to show different emphasis, sometimes in different proportions.

As used in this application, the singular forms "a", "an" and "the" include plural referents, the term "or" is generally employed in a sense including "and/or," the terms "a" and "an" are generally employed in a sense including "at least one," the terms "at least two" are generally employed in a sense including "two or more," and the terms "first", "second" and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to the corresponding two parts, which include not only the end points, but also the terms "mounted", "connected" and "connected" should be understood broadly, e.g., as a fixed connection, as a detachable connection, or as an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. Furthermore, as used in the present invention, the disposition of an element with another element generally only means that there is a connection, coupling, fit or driving relationship between the two elements, and the connection, coupling, fit or driving relationship between the two elements may be direct or indirect through intermediate elements, and cannot be understood as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation inside, outside, above, below or to one side of another element, unless the content clearly indicates otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The core idea of the invention is to provide a driving circuit and a power supply chip to solve the problem of high energy loss of the driving circuit in high voltage application in the prior art.

The following description refers to the accompanying drawings.

Referring to fig. 1, the present embodiment provides a driving circuit for driving a synchronous rectification system, where the driving circuit includes a periodic discharge module 201, an upper tube driving module 202, an input voltage detecting module 203, and a lower tube driving module 204. Particularly, the upper transistor of the present embodiment is a PMOS transistor.

Wherein, the power positive pole of going up pipe drive module 202 is used for connecting external power source VCC, external power source VCC still is connected with the first end of outside energy storage electric capacity 5, the power negative pole of going up pipe drive module 202 is used for connecting the second end of outside energy storage electric capacity 5.

The periodic discharging module 201 is configured to limit the voltage at the second end of the external energy-storage capacitor 5 to a preset interval through charging and discharging. So configured, the purpose is to prevent the voltage of the ground reference of the upper tube driving module 202 from becoming high and becoming inoperable. It can be understood that, when the external power VCC is not changed, the preset interval is a fixed interval, but when the external power VCC is changed, in different embodiments, the preset interval may also be a changed interval. Hereinafter, one possible value of the preset interval will be described.

The input voltage detection module 203 is configured to determine a voltage value of the external power VCC, and when the voltage value of the external power VCC is greater than a first preset voltage (for example, 17V), the input voltage detection module 203 outputs a first signal; when the voltage value of the external power VCC is smaller than the first preset voltage, the input voltage detection module 203 outputs a second signal.

The negative electrode of the power supply of the lower tube driving module 204 is used for grounding; when the first signal is received, a first power positive electrode 2041 of the lower tube driving module 204 is connected with a power negative electrode of the upper tube driving module, and a second power positive electrode 2042 of the lower tube driving module 204 is disconnected; when the second signal is received, the first power supply positive electrode 2041 of the lower tube driving module 204 is disconnected, and the second power supply positive electrode 2042 of the lower tube driving module 204 is used for connecting the same external power supply VCC.

So dispose, through one external power source VCC is two drive module power supplies, has reduced the energy loss under the high-voltage condition, has solved the problem that exists among the prior art.

Based on the above embodiments, the following description can be summarized.

The first scheme is as follows: the driving circuit comprises an upper tube driving module 202 and a lower tube driving module 204, wherein the negative electrode of the power supply of the upper tube driving module 202 is connected with the positive electrode of the power supply of the lower tube driving module 204. The connection refers to fixed connection and connection capable of being switched on and off. The fixed connection scheme can be applied to occasions with higher external input voltage and unchanged working conditions; the scheme of the connection capable of being switched on and off can be applied to a general circuit with the working condition changing or serving a plurality of working conditions, and the circuit is suitable for two working conditions of high voltage and low voltage in a switching-on and switching-off mode under different working conditions. In one embodiment, high pressure refers to a condition greater than 17V, and low pressure refers to a condition less than 17V; in other embodiments, the dividing line between high and low pressures is on the same level as 17V.

Scheme II: on the basis of the first scheme, the negative power supply of the upper tube driving module 202 is connected with the positive power supply of the lower tube driving module 204 in an on-off manner; the power supply anode of the upper tube driving module 202 is used for being connected with an external power supply VCC; when a preset condition is met, the cathode of the power supply of the upper tube driving module 202 is communicated with the anode of the power supply of the lower tube driving module 204; when the preset condition is not met, the power anode of the lower tube driving module 204 and the power cathode of the upper tube driving module 202 are disconnected, and the connection is switched to be the same as the external power VCC. In an embodiment, the preset condition is that "the voltage value of the external power source VCC is greater than the first preset voltage", but the preset condition may be set to other conditions according to different actual needs.

The third scheme is as follows: on the basis of the first scheme, the power supply positive electrode of the upper tube driving module 202 is used for being connected with an external power supply VCC; external power source VCC still is connected with the first end of outside energy storage capacitor 5, the power negative pole of top tube drive module 202 is used for connecting the second end of outside energy storage capacitor 5. The driving circuit further includes a periodic discharging module 201, and the periodic discharging module 201 is configured to limit the voltage at the second end of the external energy-storage capacitor 5 to a preset interval through charging and discharging. In this embodiment, the voltage at the negative power supply of the top tube driving module 202 is stabilized by an external capacitor and the periodic discharging module 201, in other embodiments, other schemes may also be used to stabilize the voltage at the negative power supply of the top tube driving module 202, and the scheme is not limited to the scheme using scheme three.

For a complete understanding of the specific logic of the driving circuit 20, one possible way of connecting the periphery of the driving circuit 20 is shown in fig. 2. In fig. 2, 10 is a power circuit, 20 is the driving circuit, 30 is an external power tube, and 40 is an output circuit. DRP is a control signal of a PMOS power transistor (i.e. upper transistor 301), GATEP is a driving signal of the upper transistor 301, DRN is a control signal of an NMOS power transistor (i.e. lower transistor 302), and GATEN is a driving signal of the lower transistor 302. Wherein 301 is a PMOS power transistor, which is a power output tube of the whole system, and 302 is an NMOS power transistor, which is used to provide a freewheeling loop for the inductor 401 during the off period of the PMOS power transistor in 20. 401 is an energy storage inductor, 402 is an output filter capacitor, and 403 is a load. 101 is an input power supply module for providing the external power supply VCC, 102 is an input filter capacitor, and 103 is also the external energy storage capacitor 5.

Specifically, the periodic discharge module 201 includes a level detection sub-module 2011 and a timed discharge sub-module 2012; the level detection sub-module 2011 is configured to detect an intermediate level VC, where the intermediate level VC is a voltage at the second end of the external energy storage capacitor 5; when the intermediate level VC is less than a second preset voltage, resetting the timing characteristic parameter of the timing discharge sub-module 2012; the timing discharge sub-module 2012 is configured to continuously increase the timing characteristic parameter, and when the timing characteristic parameter exceeds a preset parameter, discharge the capacitor external energy storage capacitor 5 to reduce the intermediate level VC. The timing characteristic parameter is a certain electrical parameter of a certain element or a certain module, and the specific selection of the timing characteristic parameter can be set according to different application scenarios, and in an embodiment, the timing characteristic parameter can be a voltage value of a certain capacitor. In other embodiments, other types of implementation circuits can be designed according to the purpose of the periodic discharge module 201.

Referring to fig. 3, in an embodiment, the level detection sub-module 2011 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a sixth transistor Q6, a first constant current source IS1, a first regulator DZ1, and a first resistor R1.

Wherein, first triode Q1 IS PNP type triode, the projecting pole of first triode Q1 IS used for connecting external power source VCC, the base of first triode Q1 IS connected with the collecting electrode of self, the collecting electrode of first triode Q1 with first constant current source IS 1's positive pole IS connected, first constant current source IS 1's negative pole IS used for ground connection.

The second triode Q2 is PNP type triode, the projecting pole of second triode Q2 is used for connecting the external power source VCC, the base of second triode Q2 with the base of first triode Q1 is connected, the collecting electrode of second triode Q2 with first stabilivolt DZ 1's negative pole is connected, first stabilivolt DZ 1's positive pole passes through first resistance R1 with the power negative pole of upper tube drive module 202 is connected.

The third triode Q3 is a PNP type triode, the emitting electrode of the third triode Q3 is used for being connected with the external power supply VCC, the base electrode of the third triode Q3 is connected with the base electrode of the first triode Q1.

The fourth triode Q4 is an NPN type triode, a collector of the fourth triode Q4 is connected to a collector of the third triode Q3, a base of the fourth triode Q4 is connected to the positive electrode of the first voltage regulator DZ1, and an emitter of the fourth triode Q4 is connected to the negative electrode of the power supply of the upper tube driving module 202.

The fifth triode Q5 is a PNP type triode, the emitter of the fifth triode Q5 is used for connecting the external power supply VCC, and the base of the fifth triode Q5 is connected with the base of the first triode Q1.

The sixth triode Q6 is a PNP type triode, an emitter of the sixth triode Q6 is connected to a collector of the fifth triode Q5, a base of the sixth triode Q6 is connected to a collector of the third triode Q3, and the collector of the sixth triode Q6 is used for outputting a signal for resetting the timing characteristic parameter.

So configured, when VCC-VC < VDZ1+ VBE4, Q4 is not turned on. The BASE terminal voltage of Q6 is VCC, and Q6 is also not turned on. When VCC-VC > VDZ1+ VBE4, Q4 is turned on and Q6 is also turned on. The timed discharge submodule 2012 is controlled by the on and off states of Q6. Wherein VDZ1 represents the clamping voltage of the first regulator DZ1, and VBE4 represents the turn-on voltage of the fourth transistor Q4. The second preset voltage is VCC-VDZ1-VBE 4.

The timing discharging submodule 2012 comprises a seventh triode Q7, an eighth triode Q8, a ninth triode Q9, a thirteenth triode Q10, an eleventh triode Q11, a twelfth triode Q12, a thirteenth triode Q13, a fourteenth triode Q14, a fifteenth triode Q15, a sixteenth triode Q16, a second constant current source IS2, a timing capacitor C1, a second resistor R2, a third resistor R3 and a fourth resistor R4.

The seventh triode Q7 IS a PNP triode, an emitter of the seventh triode Q7 IS used for connecting an internal power supply VDD, a base of the seventh triode Q7 IS connected with a collector of the seventh triode Q7, a collector of the seventh triode Q7 IS connected with a positive electrode of the second constant current source IS2, and a negative electrode of the second constant current source IS2 IS used for grounding. The manner of generating the internal power supply VDD can be understood according to the common knowledge in the art, and will not be described herein.

The eighth triode Q8 is an NPN type triode, the base of the eighth triode Q8 is configured to be grounded through the second resistor R2, the emitter of the eighth triode Q8 is configured to be grounded, and the base of the eighth triode Q8 is further configured to receive the output signal for resetting the timing characteristic parameter. In this embodiment, the base of the eighth transistor Q8 is connected to the collector of the sixth transistor Q6.

The first end of the timing capacitor C1 is connected to the collector of the eighth transistor Q8, the second end of the timing capacitor C1 is connected to ground, and the voltage value of the timing capacitor C1 is configured as the timing characteristic parameter.

The ninth triode Q9 is a PNP triode, an emitter of the ninth triode Q9 is used for connecting the internal power supply VDD, and a base of the ninth triode Q9 is connected to a base of the seventh triode Q7.

The thirteenth pole tube Q10 is a PNP type triode, the emitter of the thirteenth pole tube Q10 is connected to the collector of the ninth triode Q9, the base of the thirteenth pole tube Q10 is connected to the collector of the eighth triode Q8, and the collector of the thirteenth pole tube Q10 is grounded.

The eleventh triode Q11 is an NPN type triode, a collector of the eleventh triode Q11 is connected to a collector of the ninth triode Q9, a base of the eleventh triode Q11 is connected to a collector of the eleventh triode Q11, and an emitter of the eleventh triode Q11 is grounded through the third resistor R3.

The twelfth triode Q12 is a PNP type triode, the emitter of the twelfth triode Q12 is used for connecting the internal power supply VDD, and the base of the twelfth triode Q12 is connected with the base of the seventh triode Q7.

The thirteenth triode Q13 is an NPN type triode, a collector of the thirteenth triode Q13 is connected with a collector of the twelfth triode Q12, a base of the thirteenth triode Q13 is connected with an emitter of the eleventh triode Q11, and an emitter of the thirteenth triode Q13 is used for grounding.

The fourteenth triode Q14 is a PNP type triode, an emitter of the fourteenth triode Q14 is used for connecting an internal power supply VDD, and a base of the fourteenth triode Q14 is connected to a base of the seventh triode Q7.

The fifteenth triode Q15 is an NPN type triode, the base of the fifteenth triode Q15 is connected to the collector of the twelfth triode Q12, the collector of the fifteenth triode Q15 is connected to the collector of the fourteenth triode Q14, and the emitter of the fifteenth triode Q15 is used for grounding.

The sixteenth triode Q16 is an NPN-type triode, a collector of the sixteenth triode Q16 is connected to a negative electrode of the power supply of the upper tube driving module 202, a base of the sixteenth triode Q16 is connected to a collector of the fourteenth triode Q14, the base of the sixteenth triode Q16 is further configured to be grounded through the fourth resistor R4, and an emitter of the sixteenth triode Q16 is configured to be grounded.

The timing discharge sub-module 2012 works as follows.

Q8 was on when Q6 was on, and Q8 was off when Q6 was off.

When VCC-VC is larger than VDZ1+ VBE4, Q8 is turned on, the voltage of a C1 upper plate is pulled to the ground, the voltage of an emitter of Q10 is pulled to be 0.7V, at the moment, Q13 is turned off, Q15 is turned on, Q16 is turned off, Q16 stops discharging to the external energy storage capacitor 5, and the voltage of VCC-VC keeps unchanged. At this time, since the PMOS mobility is larger than the NMOS, the area and parasitic capacitance of the PMOS power transistor in general synchronous rectification application are both larger than the NMOS, and the voltage VCC-VC is gradually lowered with the normal switching period.

When VCC-VC is less than VDZ1+ VBE4, Q8 is closed, Q10 charges the upper electrode plate of C1 through the BASE end of the Q10, when the voltage of the upper electrode plate of C1 is 0.7V of the opening voltage of an NPN tube, the voltage of the E end of Q10 is 1.4V, Q13 is opened, Q15 is closed, Q16 is opened, Q16 discharges the external energy storage capacitor 5, and the VC voltage is pulled down.

Then, until VCC-VC is again greater than VDZ1+ VBE4, Q8 is turned on to repeat the above cycle.

The NMOS power tube has the advantages that when the PMOS is started, the voltage of the VC is reduced, the Q16 cannot be started at the first time, when the NMOS power tube is started, the voltage of the VC can be used for supplying power to the NMOS, charges flow from the VC to the GATE end of the NMOS and then flow into the GND from the GATE end of the NMOS, so that the two driving circuits are supplied with power vividly by one path of current, and the loss of the whole system is greatly reduced. In practical application, the parasitic capacitance of the NMOS is smaller than that of the PMOS, and the electric charge quantity required by the NMOS drive is smaller than that of the PMOS, so that a period timing circuit needs to be designed, and the problem that the VC voltage is higher and higher after a plurality of periods until the power supply voltage VCC causes the failure of the whole system is solved.

In this embodiment, the lower limit of the preset interval is VCC-VDZ1-VBE4, and the upper limit of the preset interval is determined by the capacitance parameter of the timing capacitor C1, the base current of the thirteenth diode Q10, and the turn-on voltage of the thirteenth diode Q13. It is understood that the voltage of one capacitor can be maintained in one interval by charging and discharging, and the method is not limited to the specific circuit shown in fig. 3.

The operating logic of the upper tube driving module 202 is as follows: taking VCC as power supply voltage, VC as reference ground and DRP as control signal, when DRP is high, the GATEP output is VC, when DRP is low, the GATEP output is VCC. The specific circuit of the upper tube driving module 202 may be set according to actual needs, and is not described herein.

The input voltage detection module 203 comprises a seventeenth triode Q17, an eighteenth triode Q18, a nineteenth triode Q19, a twentieth triode Q20, a twenty-first triode Q21, a twenty-second triode Q22, a twenty-third triode Q23, a twenty-fourth triode Q24, a twenty-fifth triode Q25, a twenty-sixth triode Q26, a third constant current source IS3, a second voltage regulator DZ2, a third voltage regulator DZ3, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7.

The seventeenth triode Q17 IS a PNP triode, the emitter of the seventeenth triode Q17 IS connected to the external power VCC, the base of the seventeenth triode Q17 IS connected to the collector of the seventeenth triode Q17, the collector of the seventeenth triode Q17 IS connected to the anode of the third constant current source IS3, and the cathode of the third constant current source IS3 IS connected to the ground.

The eighteenth triode Q18, the nineteenth triode Q19, the twenty-first triode Q21, the twenty-third triode Q23 and the twenty-fifth triode Q25 are PNP type triodes, the eighteenth triode Q18, the nineteenth triode Q19, the twenty-first triode Q21, the twenty-third triode Q23 and the twenty-fifth triode Q25 have their emitters all used for connecting the external power source VCC, and the eighteenth triode Q18, the nineteenth triode Q19, the twenty-first triode Q21, the twenty-third triode Q23 and the twenty-fifth triode Q25 have their bases connected to the base of the seventeenth triode Q17.

The negative electrode of the second voltage-regulator tube DZ2 is connected with the collector of the eighteenth triode Q18, the positive electrode of the second voltage-regulator tube DZ2 is connected with the negative electrode of the third voltage-regulator tube DZ3, and the positive electrode of the third voltage-regulator tube DZ3 is grounded through the fifth resistor R5.

The twentieth triode Q20 is an NPN-type triode, a collector of the twentieth triode Q20 is connected to a collector of the nineteenth triode Q19, a base of the twentieth triode Q20 is connected to the anode of the third voltage regulator DZ3, and an emitter of the twentieth triode Q20 is grounded.

The twenty-second triode Q22 is an NPN type triode, a collector of the twenty-second triode Q22 is connected to a collector of the twenty-first triode Q21, a base of the twenty-second triode Q22 is connected to a collector of the nineteenth triode Q19 through the sixth resistor R6, and an emitter of the twenty-second triode Q22 is grounded.

The twenty-fourth triode Q24 is an NPN-type triode, a collector of the twenty-fourth triode Q24 is connected with a collector of the twenty-third triode Q23, a base of the twenty-fourth triode Q24 is connected with a collector of the nineteenth triode Q19 through the seventh resistor R7, and an emitter of the twenty-fourth triode Q24 is used for grounding.

The twenty-sixth triode Q26 is an NPN type triode, a collector of the twenty-sixth triode Q26 is connected with a collector of the twenty-fifth triode Q25, a base of the twenty-sixth triode Q26 is connected with a collector of the twenty-third triode Q23, and an emitter of the twenty-sixth triode Q26 is used for grounding.

The collector of the twenty-second transistor Q22 and the collector of the twenty-sixth transistor Q26 are configured as the output terminal of the input voltage detection module 203, and the voltage DS _ VC of the collector of the twenty-second transistor Q22 is high and the voltage DS _ VIN of the collector of the twenty-sixth transistor Q26 is low are configured as the first signal, and the voltage DS _ VC of the collector of the twenty-second transistor Q22 is low and the voltage DS _ VIN of the collector of the twenty-sixth transistor Q26 is high and configured as the second signal.

The operation logic of the input voltage detection module 203 is as follows: the current mirror IS composed of Q17, Q18, Q19, Q21, Q23 and Q25, and the third constant current source IS3 provides bias current for the current mirror. When VCC is greater than VDZ2+ VDZ3+ VBE20 (wherein VDZ2 is the clamp voltage of the second regulator DZ2, VDZ3 is the clamp voltage of the third regulator DZ3, and VBE20 is the turn-on voltage of the twentieth triode Q20, and in one embodiment, VDZ2+ VDZ3+ VBE20 is 17V), Q20 is turned on, Q22 is turned off, DS _ VC is high level, at this time, Q24 is turned off, Q26 is turned on, and DS _ VIN is low level. When VCC is less than VDZ2+ VDZ3+ VBE20, Q20 is off, Q22 is on, DS _ VC is low, at which time Q24 is on, Q26 is off, and DS _ VIN is high. And the voltage of the two ports is used for signal output, so that the lower tube driving module 204 can work conveniently.

The lower tube driving module 204 includes a twenty-seventh triode Q27, a twenty-eighth triode Q28, a twenty-ninth triode Q29, a thirty-fifth triode Q30, a thirty-eleventh triode Q31, a thirty-second triode Q32, a thirty-third triode Q33, a thirty-fourth triode Q34, a thirty-fifth triode Q35, a thirty-sixth triode Q36, a thirty-seventh triode Q37, a thirty-eighth triode Q38, a thirty-ninth triode Q39, a forty-third triode Q40, a forty-first triode Q41, a forty-second triode Q42, a forty-third triode Q43, a forty-fourth triode Q44, a forty-fifth triode Q45, a fourth voltage regulator DZ4, a fifth voltage regulator DZ5, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a thirteenth resistor R13.

Wherein the twenty-seventh triode Q27, the twenty-ninth triode Q29, the thirty-eleventh triode Q31, the thirty-third triode Q33, the thirty-fifth triode Q35 and the thirty-seventh triode Q37 are PNP type triodes, emitters of the twenty-seventh triode Q27, the twenty-ninth triode Q29, the thirty-eleventh triode Q31, the thirty-third triode Q33, the thirty-fifth triode Q35 and the thirty-seventh triode Q37 are all used for obtaining the external power VCC, bases of the twenty-seventh triode Q27, the twenty-ninth triode Q29, the thirty-eleventh triode Q31, the thirty-third triode Q33, the thirty-fifth triode Q35 and the thirty-seventh triode Q37 are all used for obtaining a base reference voltage, and bases of the twenty-seventh triode Q27, the twenty-ninth triode Q29, the thirty-ninth triode Q29 and the thirty-seventh triode Q393545 are all used for obtaining a base reference voltage, Collectors of the thirty-first transistor Q31, the thirty-third transistor Q33, the thirty-fifth transistor Q35 and the thirty-seventh transistor Q37 are all configured to generate a bias current based on the base reference voltage.

The twenty-eighth triode Q28 is an NPN-type triode, a collector of the twenty-eighth triode Q28 is connected with a collector of the twenty-seventh triode Q27, a base of the twenty-eighth triode Q28 is used for acquiring a down tube control signal DRN, and an emitter of the twenty-eighth triode Q28 is used for grounding.

The thirty-third triode Q30 is an NPN type triode, a collector of the thirty-third triode Q30 is connected to a collector of the twenty-ninth triode Q29, a base of the thirty-third triode Q30 is connected to a collector of the twenty-seventh triode Q27, and an emitter of the thirty-third triode Q30 is connected to ground.

The thirty-second triode Q32 is an NPN type triode, a collector of the thirty-second triode Q32 is connected with a collector of the thirty-first triode Q31, a base of the thirty-second triode Q32 is connected with a collector of the twenty-ninth triode Q29 through the eighth resistor R8, and an emitter of the thirty-second triode Q32 is used for being grounded.

The thirty-fourth triode Q34 is an NPN type triode, a collector of the thirty-fourth triode Q34 is connected to a collector of the thirty-third triode Q33, a base of the thirty-fourth triode Q34 is connected to a collector of the twenty-ninth triode Q29 through the ninth resistor R9, and an emitter of the thirty-fourth triode Q34 is connected to ground.

The thirty-sixth triode Q36 is an NPN type triode, a collector of the thirty-sixth triode Q36 is connected to a collector of the thirty-fifth triode Q35, a base of the thirty-sixth triode Q36 is connected to a collector of the twenty-ninth triode Q29 through the tenth resistor R10, and an emitter of the thirty-sixth triode Q36 is connected to ground.

The thirty-eighth triode Q38 is an NPN type triode, the collector of the thirty-eighth triode Q38 is connected with the collector of the thirty-seventh triode Q37, the base of the thirty-eighth triode Q38 is connected with the collector of the thirty-third triode Q33, and the emitter of the thirty-eighth triode Q38 is grounded.

The thirty-ninth triode Q39 is an NPN triode, the collector of the thirty-ninth triode Q39 is connected with the collector of the thirty-seventh triode Q37, the emitter of the thirty-ninth triode Q39 is connected with the negative electrode of the fifth voltage-stabilizing tube DZ5, and the positive electrode of the fifth voltage-stabilizing tube DZ5 is grounded.

The forty-first triode Q40 is an NPN-type triode, a collector of the forty-first triode Q40 is connected with a collector of the thirty-seventh triode Q37, an emitter of the forty-first triode Q40 is connected with a cathode of the fourth voltage-regulator tube DZ4, and a positive electrode of the fourth voltage-regulator tube DZ4 is used for grounding.

The forty-first transistor Q41 is an NPN-type transistor, the base of the forty-first transistor Q41 is connected to the collector of the thirty-first transistor Q31 (in fig. 3, the DN _ OFF signal is used to indicate the connection relationship therebetween), the emitter of the forty-first transistor Q41 is connected to the collector of the thirty-fifth transistor Q35 through the eleventh resistor R11, and the emitter of the forty-first transistor Q41 is further used to be grounded through the twelfth resistor R12.

The forty-second transistor Q42 is an NPN-type transistor, a collector of the forty-second transistor Q42 is configured as the second power positive electrode 2042 of the down tube driving module 204, a base of the forty-second transistor Q42 is connected to an emitter of the forty-second transistor Q40, an emitter of the forty-second transistor Q42 is connected to a collector of the forty-first transistor Q41, an emitter of the forty-second transistor Q42 is further configured to be grounded through the thirteenth resistor R13, and an emitter of the forty-second transistor Q42 is configured as an output end of the down tube driving module 204.

The forty-third triode Q43 is an NPN type triode, a collector of the forty-third triode Q43 is connected to a collector of the forty-first triode Q41, a base of the forty-third triode Q43 is connected to an emitter of the forty-first triode Q41, and an emitter of the forty-third triode Q43 is grounded.

The forty-fourth transistor Q44 is an NPN transistor, a collector of the forty-fourth transistor Q44 is connected to a base thereof, and a collector of the forty-fourth transistor Q44 is configured as a first power positive electrode 2041 of the lower tube driving module 204.

The forty-fifth triode Q45 is an NPN type triode, the collector of the forty-fifth triode Q45 is connected to the emitter of the forty-fourth triode Q44, the base of the forty-fifth triode Q45 is connected to the emitter of the thirty-ninth triode Q39, and the emitter of the forty-fifth triode Q45 is connected to the emitter of the forty-second triode Q42.

While the base of the thirty-ninth transistor Q39 and the base of the forty-fourth transistor Q40 are configured as inputs to the down tube driver block 204, it is understood that an electrical component may include a plurality of inputs, for example, the base of Q28 of the down tube driver block 204 is also an input for obtaining the down tube control signal DRN. The voltage at the base of the thirty-ninth transistor Q39 is at a high level and the voltage at the base of the forty-fourth transistor Q40 is at a low level and is configured as the first signal, and the voltage at the base of the thirty-ninth transistor Q39 is at a low level and the voltage at the base of the forty-fourth transistor Q40 is at a high level and is configured as the second signal.

The operation logic of the lower tube driving module 204 is as follows.

When VCC is greater than VDZ2+ VDZ3+ VBE20 (typically 17V), DS _ VC is high, and Q38 is turned off, Q37 current drives BASE terminal of Q45 through Q39, at which time NMOS drive power is VC. When VCC is less than VDZ2+ VDZ3+ VBE20 (typically 17V), DS _ VIN is high, and Q38 is turned off, Q37 current drives BASE terminal of Q45 through Q40, at which time NMOS drive supply is VCC.

When DRN is high level, Q28 is turned on, Q30 is turned OFF, Q32, Q34 and Q36 are turned on, Q38 and Q43 are turned OFF, Q43 is turned OFF, DN _ OFF is low level, and Q38 is turned OFF, wherein DZ4 and DZ5 are clamp tubes and are used for limiting the maximum typical value of BASE end maximum level of Q42 and Q45 to be 8.2V. If VCC is greater than 17V, then the current of Q37 drives the BASE end of Q45 through Q39, at this time, Q45 is turned on, the GATEN signal goes from low to high, the GATEN high level is VDZ5-VBE45 (VDZ 5 is the clamp voltage of the fifth voltage regulator tube DZ5, VBE45 is the turn-on voltage of the forty-fifth triode Q45, and the typical value of VDZ5-VBE45 is 7.5V). If VCC is smaller than 17V, then Q37 current drives the BASE port of Q42 through Q40, at this time, Q42 turns on, the GATEN signal goes from low to high, and the GATEN high level is VDZ5-VBE42 (VBE 42 is the turn-on voltage of the forty-second transistor Q42, and a typical value of VDZ5-VBE42 is 7.5V). When DRN goes from high to low, Q28 is off, Q30 is on, at which time Q32, Q34, Q36 are off, Q38 is on, and Q37 current is pulled down to ground. At this time, Q43 is turned on, Q32 is turned OFF, DN _ OFF is high, Q41 is also turned on, GATEN is changed from high to low, and NMOS is turned OFF (Q41 is used to connect the GATE terminal current of part of NMOS to the BASE terminal of Q43, which can increase the collector current of Q43, thereby increasing the NMOS turn-OFF speed). Wherein, R12 and R13 are pull-down resistors, Q44 is a power triode used as a diode connection method, so that when the input voltage is smaller than VDZ2+ VDZ3+ VBE20, DS _ VC is low level, DS _ VIN is high level, the chip input voltage is lower than VDZ1+ VBE4, and Q16 is always turned on. The VC reference voltage is 0V, and if Q44 is not provided, the GATE end of the NMOS forms a discharge loop through Q45 and Q16, and the system loss is increased.

The waveform diagrams of the embodiment shown in fig. 3 under different working conditions are shown in fig. 4 and fig. 5. In the figure, the SW signal is the power output signal of the system, and at a high level, it is desirable that the upper tube 301 is open and the lower tube 302 is closed, and at a low level, it is desirable that the lower tube 302 is open and the upper tube 301 is closed.

As can be seen from fig. 4, when the voltage of the external power VCC is less than 17V (12V in fig. 4), VC rises as the reference ground level of the PMOS driving circuit, and when SW goes low, the NMOS is turned on, and the VC level does not change, that is, the NMOS driving circuit is powered by VCC. When VC is continuously increased, the voltage value of the timing capacitor C1 is also continuously increased, when a time point is reached, the discharge of the external energy storage capacitor 5 is triggered, VC is reduced, when VC is reduced to the second preset voltage, the discharge is stopped, and VC starts to be continuously increased again.

As can be seen from fig. 5, when the input voltage is greater than 17V (24V in fig. 5), SW goes high, i.e., PMOS is turned on, and then VC rises as the voltage of the reference ground level of the PMOS driving circuit, and when SW goes low, NMOS is turned on, and then the level of VC falls, i.e., the level of VC in the switching period is the reference ground of the PMOS driving circuit and also serves as the power supply circuit for NMOS driving, so that one path of current drives two power MOS circuits, the switching loss of the whole system is reduced, and the conversion efficiency of the system is effectively improved. The up and down oscillation process of VC on the overall trend can be understood with reference to the related description of fig. 4.

The embodiment also provides a power supply chip which comprises the driving circuit. The details of the power supply chip can be understood by referring to the common general knowledge in the art, and will not be described herein.

In summary, the present embodiment provides a driving circuit and a power chip. The driving circuit comprises an upper tube driving module and a lower tube driving module, and the power cathode of the upper tube driving module is connected with the power anode of the lower tube driving module. According to the configuration, different electrical characteristics of the PMOS power tube and the NMOS power tube are reasonably utilized, and an intermediate level is introduced, wherein the intermediate level is a reference ground of the upper tube driving module and a power supply of the lower tube driving module, so that two driving currents in a traditional driving mode are ingeniously changed into one current, and the influence of the driving current on the overall efficiency of the system is effectively reduced when high voltage is input.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art according to the above disclosure are within the scope of the present invention.

Claims

1. A driving circuit for driving a synchronous rectification system, the driving circuit comprising a periodic discharge module, an upper tube driving module, an input voltage detecting module, and a lower tube driving module,

the power supply anode of the upper tube driving module is used for connecting an external power supply, the external power supply is also connected with a first end of an external energy storage capacitor, and the power supply cathode of the upper tube driving module is used for connecting a second end of the external energy storage capacitor;

the periodic discharging module is used for limiting the voltage of the second end of the external energy storage capacitor to a preset interval through charging and discharging;

the input voltage detection module is used for judging the voltage value of the external power supply, and when the voltage value of the external power supply is greater than a first preset voltage, the input voltage detection module outputs a first signal; when the voltage value of the external power supply is smaller than the first preset voltage, the input voltage detection module outputs a second signal;

2. The driving circuit of claim 1, wherein the periodic discharge module comprises a level detection sub-module and a timed discharge sub-module; wherein the content of the first and second substances,

the level detection submodule is used for detecting an intermediate level, and the intermediate level is the voltage of the second end of the external energy storage capacitor; when the intermediate level is smaller than a second preset voltage, resetting the timing characteristic parameter of the timing discharge submodule;

the timing discharge submodule is used for continuously increasing the timing characteristic parameter, and when the timing characteristic parameter exceeds a preset parameter, the timing discharge submodule discharges the energy storage capacitor outside the capacitor so as to reduce the intermediate level.

3. The driving circuit of claim 2, wherein the level detection submodule comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a first constant current source, a first voltage regulator and a first resistor; wherein the content of the first and second substances,

the first triode is a PNP triode, an emitting electrode of the first triode is used for being connected with the external power supply, a base electrode of the first triode is connected with a collector electrode of the first triode, the collector electrode of the first triode is connected with the positive electrode of the first constant current source, and the negative electrode of the first constant current source is used for being grounded;

the second triode is a PNP triode, an emitting electrode of the second triode is used for being connected with the external power supply, a base electrode of the second triode is connected with a base electrode of the first triode, a collector electrode of the second triode is connected with a negative electrode of the first voltage-regulator tube, and a positive electrode of the first voltage-regulator tube is connected with a negative electrode of the power supply of the upper tube driving module through the first resistor;

the third triode is a PNP triode, an emitting electrode of the third triode is used for being connected with the external power supply, and a base electrode of the third triode is connected with a base electrode of the first triode;

the fourth triode is an NPN triode, a collector of the fourth triode is connected with a collector of the third triode, a base of the fourth triode is connected with the positive electrode of the first voltage-regulator tube, and an emitter of the fourth triode is connected with the negative electrode of the power supply of the upper tube driving module;

the fifth triode is a PNP triode, an emitting electrode of the fifth triode is used for being connected with the external power supply, and a base electrode of the fifth triode is connected with a base electrode of the first triode;

4. The driving circuit of claim 2, wherein the timing discharge submodule comprises a seventh triode, an eighth triode, a ninth triode, a thirteenth triode, an eleventh triode, a twelfth triode, a thirteenth triode, a fourteenth triode, a fifteenth triode, a sixteenth triode, a second constant current source, a timing capacitor, a second resistor, a third resistor and a fourth resistor; wherein the content of the first and second substances,

the seventh triode is a PNP triode, an emitting electrode of the seventh triode is used for being connected with an internal power supply, a base electrode of the seventh triode is connected with a collector electrode of the seventh triode, the collector electrode of the seventh triode is connected with the positive electrode of the second constant current source, and the negative electrode of the second constant current source is used for being grounded;

the eighth triode is an NPN type triode, the base of the eighth triode is grounded through the second resistor, the emitter of the eighth triode is grounded, and the base of the eighth triode is also used for receiving a signal for resetting the timing characteristic parameter;

a first end of the timing capacitor is connected with a collector of the eighth triode, a second end of the timing capacitor is used for grounding, and a voltage value of the timing capacitor is configured as the timing characteristic parameter;

the ninth triode is a PNP triode, an emitting electrode of the ninth triode is used for being connected with the internal power supply, and a base electrode of the ninth triode is connected with a base electrode of the seventh triode;

the thirteenth polar tube is a PNP type polar tube, an emitting electrode of the thirteenth polar tube is connected with a collector electrode of the ninth polar tube, a base electrode of the thirteenth polar tube is connected with a collector electrode of the eighth polar tube, and the collector electrode of the thirteenth polar tube is grounded;

the eleventh triode is an NPN type triode, a collector of the eleventh triode is connected with a collector of the ninth triode, a base of the eleventh triode is connected with a collector of the eleventh triode, and an emitter of the eleventh triode is grounded through the third resistor;

the twelfth triode is a PNP triode, an emitting electrode of the twelfth triode is used for being connected with the internal power supply, and a base electrode of the twelfth triode is connected with a base electrode of the seventh triode;

the thirteenth triode is an NPN type triode, a collector of the thirteenth triode is connected with a collector of the twelfth triode, a base of the thirteenth triode is connected with an emitter of the eleventh triode, and the emitter of the thirteenth triode is used for being grounded;

the fourteenth triode is a PNP triode, an emitter of the fourteenth triode is used for being connected with the internal power supply, and a base of the fourteenth triode is connected with a base of the seventh triode;

the fifteenth triode is an NPN type triode, the base of the fifteenth triode is connected with the collector of the twelfth triode, the collector of the fifteenth triode is connected with the collector of the fourteenth triode, and the emitter of the fifteenth triode is used for being grounded;

5. The driving circuit according to claim 1, wherein the input voltage detection module comprises a seventeenth triode, an eighteenth triode, a nineteenth triode, a twentieth triode, a twenty-first triode, a twenty-second triode, a twenty-third triode, a twenty-fourth triode, a twenty-fifth triode, a twenty-sixth triode, a third constant current source, a second voltage regulator, a third voltage regulator, a fifth resistor, a sixth resistor and a seventh resistor; wherein, the first and the second end of the pipe are connected with each other,

the seventeenth triode is a PNP triode, an emitting electrode of the seventeenth triode is used for being connected with the external power supply, a base electrode of the seventeenth triode is connected with a collector electrode of the seventeenth triode, the collector electrode of the seventeenth triode is connected with the positive electrode of the third constant current source, and the negative electrode of the third constant current source is used for being grounded;

the emitter electrodes of the eighteenth triode, the nineteenth triode, the twenty-first triode, the twenty-third triode and the twenty-fifth triode are all used for being connected with the external power supply, and the base electrodes of the eighteenth triode, the nineteenth triode, the twenty-first triode, the twenty-third triode and the twenty-fifth triode are all connected with the base electrode of the seventeenth triode;

the negative electrode of the second voltage-stabilizing tube is connected with the collector electrode of the eighteenth triode, the positive electrode of the second voltage-stabilizing tube is connected with the negative electrode of the third voltage-stabilizing tube, and the positive electrode of the third voltage-stabilizing tube is grounded through the fifth resistor;

the twenty-third triode is an NPN triode, a collector of the twentieth triode is connected with a collector of the nineteenth triode, a base of the twentieth triode is connected with the positive electrode of the third voltage-regulator tube, and an emitter of the twentieth triode is grounded;

the second triode is an NPN type triode, a collector of the second triode is connected with a collector of the first triode, a base of the second triode is connected with a collector of the nineteenth triode through the sixth resistor, and an emitter of the second triode is used for being grounded;

the twenty-fourth triode is an NPN type triode, a collector of the twenty-fourth triode is connected with a collector of the twenty-third triode, a base of the twenty-fourth triode is connected with a collector of the nineteenth triode through the seventh resistor, and an emitter of the twenty-fourth triode is used for being grounded;

the twenty-sixth triode is an NPN type triode, a collector electrode of the twenty-sixth triode is connected with a collector electrode of the twenty-fifth triode, a base electrode of the twenty-sixth triode is connected with a collector electrode of the twenty-third triode, and an emitting electrode of the twenty-sixth triode is used for grounding;

the collector of the twenty-second triode and the collector of the twenty-sixth triode are configured as the output end of the input voltage detection module, the voltage of the collector of the twenty-second triode is at a high level and the voltage of the collector of the twenty-sixth triode is at a low level and is configured as the first signal, the voltage of the collector of the twenty-second triode is at a low level and the voltage of the collector of the twenty-sixth triode is at a high level and is configured as the second signal.

6. The driving circuit of claim 1, wherein the down tube driving module comprises a twenty-seventh triode, a twenty-eighth triode, a twenty-ninth triode, a thirty-third triode, a thirty-eleventh triode, a thirty-second triode, a thirty-third triode, a thirty-fourth triode, a thirty-fifth triode, a thirty-sixth triode, a thirty-seventh triode, a thirty-eighth triode, a thirty-ninth triode, a forty-fourth triode, a forty-first triode, a forty-second triode, a forty-third triode, a forty-fourth triode, a forty-fifth triode, a fourth regulator, a fifth regulator, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor and a thirteenth resistor; wherein, the first and the second end of the pipe are connected with each other,

the twenty-seventh triode, the twenty-ninth triode, the thirty-first triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all PNP type triodes, emitters of the twenty-seventh triode, the twenty-ninth triode, the thirty-first triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all used for acquiring the external power supply, bases of the twenty-seventh triode, the twenty-ninth triode, the thirty-eleventh triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all used for acquiring base reference voltages, and collectors of the twenty-seventh triode, the twenty-ninth triode, the thirty-eleventh triode, the thirty-third triode, the thirty-fifth triode and the thirty-seventh triode are all used for referencing the base based on the base Generating a bias current according to the reference voltage;

the twenty-eighth triode is an NPN type triode, a collector of the twenty-eighth triode is connected with a collector of the twenty-seventh triode, a base of the twenty-eighth triode is used for acquiring a low tube control signal, and an emitter of the twenty-eighth triode is used for grounding;

the thirty-third triode is an NPN type triode, a collector of the thirty-third triode is connected with a collector of the twenty-ninth triode, a base of the thirty-third triode is connected with a collector of the twenty-seventh triode, and an emitter of the thirty-third triode is used for being grounded;

the thirty-second triode is an NPN type triode, a collector of the thirty-second triode is connected with a collector of the thirty-first triode, a base of the thirty-second triode is connected with a collector of the twenty-ninth triode through the eighth resistor, and an emitter of the thirty-second triode is used for being grounded;

the thirty-fourth triode is an NPN type triode, a collector of the thirty-fourth triode is connected with a collector of the thirty-third triode, a base of the thirty-fourth triode is connected with a collector of the twenty-ninth triode through the ninth resistor, and an emitter of the thirty-fourth triode is used for being grounded;

the thirty-sixth triode is an NPN type triode, a collector of the thirty-sixth triode is connected with a collector of the thirty-fifth triode, a base of the thirty-sixth triode is connected with a collector of the twenty-ninth triode through the tenth resistor, and an emitter of the thirty-sixth triode is used for being grounded;

the thirty-eighth triode is an NPN type triode, a collector of the thirty-eighth triode is connected with a collector of the thirty-seventh triode, a base of the thirty-eighth triode is connected with a collector of the thirty-third triode, and an emitter of the thirty-eighth triode is used for being grounded;

the thirty-ninth triode is an NPN type triode, a collector of the thirty-ninth triode is connected with a collector of the thirty-seventh triode, an emitter of the thirty-ninth triode is connected with a negative electrode of the fifth voltage regulator tube, and a positive electrode of the fifth voltage regulator tube is used for grounding;

the forty-fourth triode is an NPN type triode, a collector of the forty-fourth triode is connected with a collector of the thirty-seventh triode, an emitter of the forty-fourth triode is connected with a cathode of the fourth voltage-regulator tube, and an anode of the fourth voltage-regulator tube is used for grounding;

the forty-first triode is an NPN type triode, the base of the forty-first triode is connected with the collector of the thirty-first triode, the emitter of the forty-first triode is connected with the collector of the thirty-fifth triode through the eleventh resistor, and the emitter of the forty-first triode is also used for being grounded through the twelfth resistor;

the forty-second triode is an NPN-type triode, a collector of the forty-second triode is configured as a second power supply positive electrode of the lower tube driving module, a base of the forty-second triode is connected with an emitter of the forty-second triode, an emitter of the forty-second triode is connected with a collector of the forty-first triode, the emitter of the forty-second triode is further used for being grounded through the thirteenth resistor, and the emitter of the forty-second triode is configured as an output end of the lower tube driving module;

the forty-third triode is an NPN type triode, a collector of the forty-third triode is connected with a collector of the forty-first triode, a base of the forty-third triode is connected with an emitter of the forty-first triode, and the emitter of the forty-third triode is used for being grounded;

the forty-fourth triode is an NPN type triode, a collector of the forty-fourth triode is connected with a base of the forty-fourth triode, and the collector of the forty-fourth triode is configured to be a first power supply positive electrode of the lower tube driving module;

the forty-fifth triode is an NPN type triode, a collector of the forty-fifth triode is connected with an emitter of the forty-fourth triode, a base of the forty-fifth triode is connected with an emitter of the thirty-ninth triode, and the emitter of the forty-fifth triode is connected with an emitter of the forty-second triode;

the base electrodes of the thirty-ninth and forty-fourth transistors are configured as the input end of the down tube driving module, the voltage of the base electrode of the thirty-ninth transistor is at a high level, the voltage of the base electrode of the forty-fourth transistor is at a low level and is configured as the first signal, and the voltage of the base electrode of the thirty-ninth transistor is at a low level and the voltage of the base electrode of the forty-fourth transistor is at a high level and is configured as the second signal.

7. A power supply chip comprising the drive circuit according to any one of claims 1 to 6.