Unidirectional conductive circuit, power multiplexer and electronic equipment

Abstract

The invention discloses a unidirectional conductive circuit, a power multiplexer and electronic equipment, and relates to the technical field of electronic circuits. The unidirectional conductive circuit comprises a first transistor and a first driving branch, and the first transistor is connected between a first voltage input end and a voltage output end. The first driving branch is connected with a first voltage input end, a voltage output end and a control end of the first transistor, and the first driving branch is configured to output a first driving voltage to the control end of the first transistor. The first driving voltage is adjusted based on the voltage difference between the first input voltage of the first voltage input end and the output voltage of the voltage output end, so that the conduction impedance of the first transistor is adjusted, the voltage difference is kept at a preset voltage difference value when the first input voltage is larger than the output voltage, and the conduction impedance of the second transistor is kept at a preset voltage difference value when the first input voltage is smaller than or equal to the output voltage. The first transistor is turned off. Through the mode, the power supply loss can be reduced, the power supply efficiency can be improved, and stable voltage output can be realized.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic circuits, and in particular to a unidirectional conductive circuit, a power multiplexer and an electronic device. Background Art

[0002] A diode is an electronic component whose main characteristic is that it allows current to flow freely in one direction, while almost completely blocking current in the opposite direction. Therefore, it can be said that a diode is unidirectional. This characteristic enables the diode to play a variety of roles in the circuit, such as rectification and protection of the circuit from reverse voltage damage. The basic structure of a diode is a PN junction composed of a P-type semiconductor and an N-type semiconductor. When a forward voltage is applied to both ends of the diode, that is, the P-type end is connected to the positive pole of the power supply and the N-type end is connected to the negative pole of the power supply, the diode is turned on; conversely, if a reverse voltage is applied, the diode is cut off and current is blocked.

[0003] However, when the diode is forward-conducting, there is a large conduction voltage drop across the diode, such as 0.7V, which results in high losses on the diode and low power supply efficiency when used in power supply circuits. Moreover, the conduction voltage drop increases with the increase of conduction current, which is not conducive to achieving stable voltage output. Summary of the invention

[0004] The embodiments of the present application provide a unidirectional conductive circuit, a power multiplexer and an electronic device, which can reduce power supply loss, improve power supply efficiency, and achieve stable voltage output.

[0005] In a first aspect, an embodiment of the present application provides a unidirectional conductive circuit, comprising: A first transistor connected between the first voltage input terminal and the voltage output terminal; A first driving branch is respectively connected to the first voltage input terminal, the voltage output terminal and the control terminal of the first transistor, and is configured to output a first driving voltage to the control terminal of the first transistor, and adjust the first driving voltage based on a voltage difference between a first input voltage of the first voltage input terminal and an output voltage of the voltage output terminal to adjust the on-resistance of the first transistor, so as to maintain the voltage difference at a preset voltage difference when the first input voltage is greater than the output voltage, and to turn off the first transistor when the first input voltage is less than or equal to the output voltage.

[0006] In one or more embodiments, the first driving branch includes a first resistor, a second resistor, a second transistor, a third transistor, a first current source, and a second current source; The first resistor is connected between the first voltage input terminal and the first end of the non-control terminal of the second transistor, the second resistor is connected between the voltage output terminal and the first end of the non-control terminal of the third transistor, the control terminal of the second transistor is respectively connected to the second end of the non-control terminal of the second transistor and the control terminal of the third transistor, the second end of the non-control terminal of the second transistor is connected to the negative electrode of the first current source, the positive electrode of the first current source and the positive electrode of the second current source are both grounded, and the second end of the non-control terminal of the third transistor is respectively connected to the negative electrode of the second current source and the control terminal of the first transistor; The first driving branch is configured to maintain a difference between a voltage drop across the first resistor caused by a first current output by the first current source and a voltage drop across the second resistor caused by a second current output by the second current source equal to the preset voltage difference.

[0007] In one or more embodiments, a first current output by the first current source is equal to a second current output by the second current source, and the second transistor and the third transistor have the same size.

[0008] In one or more embodiments, the second transistor and the third transistor are both field effect transistors; The control end of the second transistor and the control end of the third transistor are both gates of the field effect transistor, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both sources of the field effect transistor, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both drains of the field effect transistor.

[0009] In one or more embodiments, the second transistor and the third transistor are both bipolar transistors; The control end of the second transistor and the control end of the third transistor are both bases of bipolar transistors, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both emitters of bipolar transistors, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both collectors of bipolar transistors.

[0010] In one or more embodiments, the first driving branch further includes: The bias branch is connected between the control terminal of the second transistor and the ground and is connected to the negative electrode of the first current source, and is configured to form a path between the control terminal of the second transistor and the ground.

[0011] In one or more embodiments, the bias branch includes a fourth transistor and a third resistor; The control end of the fourth transistor is connected to the negative electrode of the first current source, the first end of the non-control end of the fourth transistor is connected to the control end of the second transistor, and the second end of the non-control end of the fourth transistor is grounded through the third resistor.

[0012] In one or more embodiments, the first driving branch further includes: The resistor branch is connected between the first voltage input terminal and the control terminal of the first transistor, and is configured to generate a third current based on the first input voltage, wherein the third current is greater than the current of the control terminals of the second transistor and the third transistor.

[0013] In one or more embodiments, the resistance branch includes a fourth resistor; The fourth resistor is connected between the first voltage input terminal and the control terminal of the second transistor.

[0014] In one or more embodiments, the first driving branch further includes: The output buffer branch is respectively connected to the negative electrode of the second current source, the voltage output end and the control end of the first transistor, and is configured so that the input resistance of the output buffer branch is greater than the output resistance to reduce the output resistance of the first driving branch.

[0015] In one or more embodiments, the output buffer branch includes a fifth resistor and a fifth transistor; The first end of the fifth resistor is connected to the voltage output end, the second end of the fifth resistor is respectively connected to the first end of the non-control end of the fifth transistor and the control end of the first transistor, the control end of the fifth transistor is connected to the negative electrode of the second current source, and the second end of the non-control end of the fifth transistor is grounded.

[0016] In one or more embodiments, the output buffer branch includes a sixth transistor and a seventh transistor; The control end of the sixth transistor is respectively connected to the control end of the seventh transistor and the negative electrode of the second current source, the second end of the non-control end of the sixth transistor is connected to the voltage output end, the first end of the non-control end of the sixth transistor is respectively connected to the first end of the non-control end of the seventh transistor and the control end of the first transistor, and the second end of the non-control end of the seventh transistor is grounded.

[0017] In a second aspect, an embodiment of the present application provides a power multiplexer, including a voltage converter and the unidirectional conductive circuit as described above; The first end of the unidirectional conductive circuit is connected to the first voltage input end, the first voltage input end is used to input a first input voltage, the first end of the voltage converter is connected to the second voltage input end, the second voltage input end is used to input a second input voltage, and the second end of the unidirectional conductive circuit and the second end of the voltage converter are both connected to the voltage output end; The power multiplexer is configured to automatically provide current from the unidirectional conductive circuit to the voltage output terminal when the output voltage of the unidirectional conductive circuit is greater than the preset output voltage of the voltage converter, and to automatically provide current from the voltage converter to the voltage output terminal when the output voltage of the unidirectional conductive circuit is less than the preset output voltage.

[0018] In one or more embodiments, the voltage converter comprises: an eighth transistor connected between the second voltage input terminal and the voltage output terminal; The second driving branch is connected to the voltage output terminal, the reference voltage and the control terminal of the eighth transistor, and is configured to output a second driving voltage to the control terminal of the eighth transistor, and adjust the second driving voltage based on the reference voltage and the output voltage of the voltage output terminal to adjust the on-resistance of the eighth transistor, and provide current to the voltage output terminal to keep the output voltage at the preset output voltage when the output voltage of the unidirectional conductive circuit is less than the preset output voltage; and maintain the eighth transistor off when the output voltage of the unidirectional conductive circuit is greater than the preset output voltage.

[0019] In one or more embodiments, the second driving branch includes a sixth resistor, a seventh resistor and an operational amplifier; The sixth resistor and the seventh resistor are connected in series between the voltage output terminal and the ground, the connection point between the sixth resistor and the seventh resistor is connected to the non-inverting input terminal of the operational amplifier, the reference voltage is input to the inverting input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the control terminal of the eighth transistor, the first terminal of the non-control terminal of the eighth transistor is connected to the second voltage input terminal, and the second terminal of the non-control terminal of the eighth transistor is connected to the voltage output terminal.

[0020] In one or more embodiments, the voltage converter further comprises: An isolation branch is connected between the eighth transistor and the voltage output terminal, and is configured to establish a connection between the eighth transistor and the voltage output terminal when the second input voltage is greater than a preset voltage threshold, and is configured to disconnect the connection between the voltage output terminal and the eighth transistor when the second input voltage is less than the preset voltage threshold.

[0021] In one or more embodiments, the isolation branch comprises a ninth transistor; The control end of the ninth transistor inputs a third driving signal, the first end of the non-control end of the ninth transistor is connected to the voltage output end, and the second end of the non-control end of the ninth transistor is connected to the second end of the non-control end of the eighth transistor; Among them, when the second input voltage is greater than the preset voltage threshold, the third drive signal is at a low level, controlling the ninth transistor to be turned on; when the second input voltage is less than the preset voltage threshold, the third drive signal is at a high level, controlling the ninth transistor to be turned off.

[0022] In one or more embodiments, the power multiplexer further includes a controller, the controller being configured to output a control signal based on a first preset voltage when a voltage difference between the first input voltage and an output voltage of the voltage output terminal is greater than a first preset voltage, wherein the first preset voltage is greater than a preset voltage difference value; The unidirectional conductive circuit also includes a current limiting branch, which is connected between the first transistor and the voltage output terminal. The current limiting branch is configured to adjust the on-resistance based on the control signal so that the current flowing through the first transistor does not exceed a preset current limiting value.

[0023] In one or more embodiments, the current limiting branch includes a tenth transistor; The control end of the tenth transistor is connected to the controller, the first end of the non-control end of the tenth transistor is connected to the first end of the non-control end of the first transistor, and the second end of the non-control end of the tenth transistor is connected to the voltage output end.

[0024] In a third aspect, an embodiment of the present application provides an electronic device, comprising the power multiplexer as described above.

[0025] The beneficial effect of the present application is that the unidirectional conductive circuit of the embodiment of the present application includes a first transistor and a first driving branch. The first transistor is connected between the first voltage input terminal and the voltage output terminal. The first driving branch is respectively connected to the first voltage input terminal, the voltage output terminal and the control terminal of the first transistor. The first driving branch is configured to output a first driving voltage to the control terminal of the first transistor, and adjust the first driving voltage based on the voltage difference between the first input voltage of the first voltage input terminal and the output voltage of the voltage output terminal to adjust the on-resistance of the first transistor, so as to keep the voltage difference as a preset voltage difference when the first input voltage is greater than the output voltage, and turn off the first transistor when the first input voltage is less than or equal to the output voltage. Thus, the above process realizes the function of a diode. Since a transistor is used to conduct current, the voltage difference can be made much smaller than the conduction voltage drop of the diode when it is forward-conducted, which is beneficial to reduce power supply loss and improve power supply efficiency. Moreover, by adjusting the on-resistance of the first transistor, the voltage difference can be maintained stable, thereby achieving a stable voltage output. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplary descriptions are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0027] Figure 1 is a schematic diagram of the structure of a unidirectional conductive circuit provided in an embodiment of the present application; Figure 2 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 1 ; Figure 3 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 2 ; Figure 4 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 3 ; Figure 5 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 4 ; Figure 6 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 5 ; Figure 7 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 6 ; Figure 8 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 7 ; Fig. 9The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 8 ; Fig.10 The circuit structure of the first driving branch provided in the embodiment of the present application is shown in FIG. Figure 9 ; Fig.11 The schematic diagram of the composition block diagram of the power multiplexer provided in the embodiment of the present application is Figure 1 ; Fig.12 The schematic diagram of the composition block diagram of the power multiplexer provided in the embodiment of the present application is Figure 2 ; Fig.13 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 1 ; Fig.14 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 2 ; Fig.15 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 3 ; Fig.16 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 4 ; Fig.17 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 5 ; Fig.18 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 6 ; Fig.19 The circuit structure of the power multiplexer provided in the embodiment of the present application is shown in FIG. Figure 7 ; Fig. 20 yes Fig.19 Schematic diagram of the various signals in the power multiplexer shown. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] It should be noted that, when an element is described as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

[0030] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0031] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a unidirectional conductive circuit provided in an embodiment of the present application. Figure 1 As shown, the unidirectional conductive circuit 100 includes a first transistor M D and the first driving branch 101 .

[0032] Among them, the first transistor M D The first transistor M is connected between the first voltage input terminal VIN1 and the voltage output terminal VOUT. D The first end of the non-control terminal is connected to the voltage output terminal VOUT, and the first transistor M D The second end of the non-control end is connected to the first voltage input end VIN1. The first driving branch 101 is respectively connected to the first voltage input end VIN1, the voltage output end VOUT and the first transistor M D The control end connection.

[0033] In this embodiment, the first transistor M D Taking a P-type field effect transistor (PMOS transistor) as an example, the first transistor M D The control end of the first transistor M is the gate of the PMOS tube. D The first non-control terminal is the source of the PMOS tube. D The second end of the non-control end is the drain of the PMOS tube. Of course, in other embodiments, the first transistor M D It can also be any controllable switch, such as an NMOS tube or an IGBT switch tube. Specifically, the first driving branch 101 is configured to output a first driving voltage V gate To the first transistor M D The first driving voltage V is adjusted based on the voltage difference between the first input voltage (denoted as VI1) of the first voltage input terminal VIN1 and the output voltage VO1 of the voltage output terminal VOUT. gate , to adjust the first transistor M D The on-resistance is such that when the first input voltage VI1 is greater than the output voltage VO1, the voltage difference is maintained at a preset voltage difference (denoted as ΔV), and when the first input voltage VI1 is less than or equal to the output voltage VO1, the first transistor M is turned off. D .

[0034] The preset voltage difference ΔV can be set based on the actual application scenario, and the embodiment of the present application does not impose any specific restrictions on this. It only needs to satisfy that the preset voltage difference ΔV is much smaller than the voltage of the first transistor MD The first driving branch 101 is configured to automatically adjust the first driving voltage V according to the actual voltage difference between the first input voltage VI1 and the output voltage VO1 in real time. gate , to adjust the first transistor M D If the first input voltage VI1 is greater than the output voltage VO1, the actual voltage difference between the first input voltage VI1 and the output voltage VO1 is controlled to be equal to the preset voltage difference ΔV; and if the first input voltage VI1 is less than or equal to the output voltage VO1, the first transistor M is controlled to D Turn off. Thus, the function of unidirectional conduction is realized, that is, the function of a diode is realized. At the same time, by setting the preset voltage difference ΔV to be much smaller than the forward voltage drop of the diode when it is forward-conducting, the actual voltage difference between the first input voltage VI1 and the output voltage VO1 can be much smaller than the forward voltage drop of the diode when it is forward-conducting, which is beneficial to reducing power supply loss and improving power supply efficiency. In addition, by adjusting the first transistor M in a closed loop, D The on-resistance can maintain the voltage difference stable at ΔV, thereby achieving a stable voltage output.

[0035] In some embodiments, Figure 2 As shown, the first driving branch 101 includes a first resistor R1, a second resistor R2, a second transistor (i.e., field effect transistor M2), a third transistor (i.e., field effect transistor M3), a first current source IA1, and a second current source IA2. In this embodiment, the second transistor and the third transistor are both PMOS field effect transistors as an example, wherein the control end of the second transistor and the control end of the third transistor are both gates of the field effect transistor, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both sources of the field effect transistor, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both drains of the field effect transistor.

[0036] Wherein, the first resistor R1 is connected between the first voltage input terminal VIN1 and the source of the field effect transistor M2; the second resistor R2 is connected between the voltage output terminal VOUT and the source of the field effect transistor M3; the gate of the field effect transistor M2 is connected to the drain of the field effect transistor M2 and the gate of the field effect transistor M3 respectively; the drain of the field effect transistor M2 is connected to the negative electrode of the first current source IA1; the positive electrode of the first current source IA1 and the positive electrode of the second current source IA2 are both grounded GND; the drain of the field effect transistor M3 is connected to the negative electrode of the second current source IA2 and the first transistor M D The control terminal is connected to output a first driving voltage V gate To the first transistor M D control terminal.

[0037] Specifically, the first driving branch 101 is configured to maintain the difference between the voltage drop generated by the first current (recorded as current I1) output by the first current source IA1 on the first resistor R1 and the voltage drop generated by the second current (recorded as current I2) output by the second current source IA2 on the second resistor R2 equal to the preset voltage difference ΔV, that is, ΔV=I1*R1-I2*R2. Since the current mirror circuit composed of the field effect transistor M2 and the field effect transistor M3 will ensure that the source voltage of the field effect transistor M2 is equal to the source voltage of the field effect transistor M3, it can be obtained that: VI1-I1*R1=VO1-I2*R2. Therefore, VI1-VO1=I1*R1-I2*R2=ΔV. It can be seen that the required preset voltage difference ΔV can be obtained by simply setting the first resistor R1, the second resistor R2, the first current source IA1 and the second current source IA2 accordingly.

[0038] In some embodiments, the first current I1 output by the first current source IA1 is equal to the second current I2 output by the second current source IA2, that is, I1=I2. In addition, the second transistor and the third transistor have the same size, that is, the size (i.e., width-to-length ratio) of the field effect transistor M2 and the field effect transistor M3 are the same. Then, ΔV=I1*(R1-R2), that is, the preset voltage difference ΔV can be configured by configuring the difference between the resistance values ​​of the first resistor R1 and the second resistor R2.

[0039] Take I1=I2 as an example Figure 1 and Figure 2 The working principle of the combination is explained below.

[0040] When the unidirectional conductive circuit operates in a steady state, the source voltage of the field effect transistor M2 is equal to the source voltage of the field effect transistor M3, and the current flowing through the first resistor R1 and the second resistor R2 is I1. If the load connected to the voltage output terminal VOUT increases (for example, if the output resistance is used to characterize the load, the corresponding output resistance decreases at this time), the voltage of the voltage output terminal VOUT will decrease. Since the gate voltage of the field effect transistor M3 is the same as the gate voltage of the field effect transistor M2, the voltage drop of the voltage output terminal VOUT causes the voltage difference between the source and the gate of the field effect transistor M3 to decrease, so that the field effect transistor M3 is not fully turned on, and the current flowing through the second resistor R2 is reduced to I1-ΔI, and the second current source IA2 will be connected from the first transistor M D The control terminal of the first transistor M draws a current ΔI, causing the first transistor M D The voltage at the control terminal of the first transistor M is reduced. D The first transistor M is more fully turned on. D The on-resistance is reduced, thereby increasing the output voltage VO1 of the voltage output terminal VOUT, forming a negative feedback process to maintain the voltage difference between the first voltage input terminal VIN1 and the voltage output terminal VOUT stable near the preset voltage difference ΔV.

[0041] However, in Figure 2 In the circuit structure shown, the voltage difference between the first voltage input terminal VIN1 and the voltage output terminal VOUT is difficult to stabilize near the preset voltage difference ΔV, possibly due to poor matching between the field effect transistor M2 and the field effect transistor M3.

[0042] Based on this, in some embodiments, the field effect transistor M2 and the field effect transistor M3 can be replaced by bipolar transistors. In this embodiment, the second transistor and the third transistor are PNP transistors as an example. Figure 3 As shown, the second transistor (i.e., bipolar transistor Q2) and the third transistor (i.e., bipolar transistor Q3) are both bipolar transistors. The control end of the second transistor and the control end of the third transistor are both bases of the bipolar transistors, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both emitters of the bipolar transistors, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both collectors of the bipolar transistors.

[0043] Specifically, the matching degree between the bipolar transistor Q2 and the bipolar transistor Q3 during the manufacturing process is better than that between the field effect transistor M2 and the field effect transistor M3, so the use of bipolar transistors Q2 and Q3 to form a current mirror can more accurately maintain the voltage of the emitter of the bipolar transistor Q2 and the emitter of the bipolar transistor Q3 to be equal, and can further ensure that the voltage difference between the first voltage input terminal VIN1 and the voltage output terminal VOUT is more accurately maintained at the preset voltage difference ΔV.

[0044] In some embodiments, Figure 4 As shown, in Figure 3 Based on the circuit structure shown, the first driving branch 101 further includes a bias branch 1011 , wherein the bias branch 1011 is connected between the base of the bipolar transistor Q2 and the ground GND, and is connected to the negative electrode of the first current source IA1 .

[0045] Specifically, the bias branch 1011 is configured to form a path between the base of the bipolar transistor Q2 and the ground GND. That is, the bias branch 1011 is introduced to provide an independent grounding loop for the bias current of the base of the bipolar transistor Q2 and the base of the bipolar transistor Q3, so as to ensure that the first current I1 output by the first current source IA1 and the current flowing through the first resistor R1 are equal, and ensure that the second current I2 output by the second current source IA2 and the current flowing through the second resistor R2 are equal, so that when the first current I1 and the second current I2 are equal, it can ensure that the voltage of the emitter of the bipolar transistor Q2 and the voltage of the emitter of the bipolar transistor Q3 are equal.

[0046] In some embodiments, Figure 5 As shown, the bias branch 1011 includes a fourth transistor M4 and a third resistor R3.

[0047] The control end of the fourth transistor M4 is connected to the negative electrode of the first current source IA1, the first end of the non-control end of the fourth transistor M4 is connected to the base of the bipolar transistor Q2, and the second end of the non-control end of the fourth transistor M4 is grounded GND through the third resistor R3.

[0048] In this embodiment, taking the fourth transistor M4 as a PMOS tube as an example, the control end of the fourth transistor M4 is the gate of the PMOS tube, the first end of the non-control end of the fourth transistor M4 is the source of the PMOS tube, and the second end of the non-control end of the fourth transistor M4 is the drain of the PMOS tube. Of course, in other embodiments, the fourth transistor M4 can also be any controllable switch, such as an NMOS tube or an IGBT switch tube.

[0049] In some embodiments, Figure 6 As shown, in Figure 5 Based on the circuit structure shown, the first driving branch 101 further includes a resistance branch 1012. The resistance branch 1012 is connected between the first voltage input terminal VIN1 and the control terminal of the second transistor.

[0050] Specifically, the resistor branch 1012 is configured to generate a third current based on the first input voltage VI1, wherein the third current is greater than the current of the base of the bipolar transistor Q2 / Q3, and is generally much greater than the current of the base of the bipolar transistor Q2 / Q3, for example, the third current is greater than 100 times the current of the base of the bipolar transistor Q2 / Q3. Subsequently, the influence of the change of the current of the base of the bipolar transistor Q2 / Q3 on the gate bias of the fourth transistor M4 can be further reduced, and the matching accuracy between the first current I1 output by the first current source IA1 and the current flowing through the first resistor R1 and the matching accuracy between the second current I2 output by the second current source IA2 and the current flowing through the second resistor R2 can be further improved.

[0051] In some embodiments, Figure 7 As shown, the resistor branch 1012 includes a fourth resistor R4.

[0052] The fourth resistor R4 is connected between the first voltage input terminal VIN1 and the base of the bipolar transistor Q2.

[0053] In some embodiments, Figure 8 As shown, the first driving branch 101 further includes an output buffer branch 1013 , wherein the output buffer branch 1013 is connected to the negative electrode of the second current source IA2 .

[0054] Specifically, the output buffer branch 1013 is configured such that the input resistance of the output buffer branch 1013 is greater than the output resistance, so as to reduce the output resistance ro of the first driving branch 101. Lower output resistance is conducive to increasing the phase margin of the unidirectional conductive circuit 100 and increasing the response speed.

[0055] Specifically, use Figure 2-Figure 7 The frequency response of the unidirectional conductive circuit 100 of the first driving branch 101 shown in FIG. 1 has two poles. One pole is the frequency response of the capacitor CL (not shown) at the voltage output terminal VOUT, the load RL (not shown) connected to the voltage output terminal VOUT and the first transistor M. D The main pole is determined by the on-resistance Ro of the first driving branch 101, and its frequency fp1=1 / 2pi((RL / / Ro)*CL). The other frequency is determined by the output resistance ro at the output end Vgate of the first driving branch 101 and the first transistor M D The secondary pole is determined by the parasitic gate capacitance Cgd, and its frequency fp2≈1 / 2pi(ro*Cgd). In applications, the frequency of the main pole fp1 is often low and changes with the load. The frequency of the secondary pole can be very close to the frequency of the main pole, resulting in application Figure 2-Figure 7 The unidirectional conductive circuit 100 of the first driving branch 101 shown in the figure has insufficient phase margin, slow transient response speed and the risk of instability. By adding the output buffer branch 1013, the output resistance ro of the first driving branch 101 can be effectively reduced. In addition, the frequency of the secondary pole of the unidirectional conductive circuit 100 is pushed up to be much higher than the frequency of the main pole, so that the phase margin of the unidirectional conductive circuit 100 can be increased and the response speed can be improved.

[0056] In some embodiments, Fig. 9 As shown, the output buffer branch 1013 includes a fifth resistor R5 and a fifth transistor Q5.

[0057] The first end of the fifth resistor R5 is connected to the voltage output terminal VOUT, and the second end of the fifth resistor R5 is connected to the first end of the non-control terminal of the fifth transistor Q5 and the first transistor M1 respectively. D The control end of the fifth transistor Q5 is connected to the negative electrode of the second current source IA2, and the second end of the non-control end of the fifth transistor Q5 is grounded GND.

[0058] In this embodiment, taking the fifth transistor Q5 as a bipolar transistor as an example, the control end of the fifth transistor Q5 is the base of the bipolar transistor, the first end of the non-control end of the fifth transistor Q5 is the emitter of the bipolar transistor, and the second end of the non-control end of the fifth transistor Q5 is the collector of the bipolar transistor. Of course, in other embodiments, the fifth transistor Q5 can also be any controllable switch, such as a MOS tube or an IGBT switch tube.

[0059] Specifically, the fifth resistor R5 and the fifth transistor Q5 form a common collector amplifier circuit. According to the properties of the common collector circuit, its input resistance is large and its output resistance is small. As the output buffer stage of the first driving branch 101, it can effectively reduce the overall output resistance ro of the first driving branch 101, thereby pushing up the frequency of the secondary pole of the unidirectional conductive circuit 100 to make it much greater than the frequency of the main pole, thereby achieving an increase in the phase margin and an improvement in the response speed of the unidirectional conductive circuit 100.

[0060] In practical applications, when the unidirectional conductive circuit 100 operates in a steady state, the emitter voltages of the bipolar transistor Q2 and the bipolar transistor Q3 are equal, and the currents flowing through the first resistor R1 and the second resistor R2 are both I1. If the load connected to the voltage output terminal VOUT increases, the voltage of the voltage output terminal VOUT will decrease. Since the base voltage of the bipolar transistor Q2 is equal to the base voltage of the bipolar transistor Q3, the voltage drop of the voltage output terminal VOUT causes the voltage difference between the emitter and the base of the bipolar transistor Q3 to decrease, making the bipolar transistor Q3 insufficiently turned on, and the current flowing through the second resistor R2 is reduced to I1-ΔI. The second current source IA2 will extract a current ΔI from the base of the fifth transistor Q5, thereby increasing the emitter current of the fifth transistor Q5, causing the first transistor M D The gate voltage of the first transistor M D The first transistor M is more fully turned on. D The on-resistance is reduced, thereby increasing the output voltage VO1 of the voltage output terminal VOUT, forming a negative feedback process to maintain the voltage difference between the first voltage input terminal VIN1 and the voltage output terminal VOUT stable near the preset voltage difference ΔV.

[0061] However, for Fig. 9 In the circuit structure shown, when the first input voltage VI1 of the first voltage input terminal VIN1 drops, such as when the power supply is unplugged from the first voltage input terminal VIN1, in response to the drop of the first input voltage VI1, the base voltage of the bipolar transistor Q3 drops rapidly, the emitter voltage of the bipolar transistor Q3 also drops rapidly, the current on the second resistor R2 increases rapidly, and the bipolar transistor Q5 is turned off. However, due to the first transistor M D The voltage of the control terminal of the first transistor M1 is pulled up only by the fifth resistor R5, and the pull-up speed is very slow. Moreover, when the first input voltage VI1 drops very quickly, the first transistor M2 D The control terminal and the first transistor M D The parasitic capacitance between the non-control terminal and the second terminal can make the first transistor M D The gate voltage of the first transistor M is temporarily pulled down. The above two factors simultaneously causeD The shutdown cannot be completed quickly, resulting in a current flowing from the voltage output terminal VOUT through the first transistor M D The risk of backflow to the first voltage input terminal VIN1.

[0062] Based on this, Fig.10 Another circuit implementation of the output buffer branch 1013 is shown as an example to solve the problem that the current flows from the voltage output terminal VOUT through the first transistor M1. D The problem of backflow to the first voltage input terminal VIN1.

[0063] like Fig.10 As shown, the output buffer branch 1013 includes a sixth transistor Q6 and a seventh transistor Q7.

[0064] The control end of the sixth transistor Q6 is connected to the control end of the seventh transistor Q7 and the negative electrode of the second current source IA2, the second end of the non-control end of the sixth transistor Q6 is connected to the voltage output end VOUT, and the first end of the non-control end of the sixth transistor Q6 is connected to the first end of the non-control end of the seventh transistor Q7 and the first transistor M D The control end of the seventh transistor Q7 is connected, and the second end of the non-control end of the seventh transistor Q7 is grounded GND.

[0065] In this embodiment, the sixth transistor Q6 and the seventh transistor Q7 are bipolar transistors as an example, wherein the sixth transistor Q6 is an NPN transistor and the seventh transistor Q7 is a PNP transistor, then the control end of the sixth transistor Q6 (and the seventh transistor Q7) is the base of the bipolar transistor, the first end of the non-control end of the sixth transistor Q6 (and the seventh transistor Q7) is the emitter of the bipolar transistor, and the second end of the non-control end of the sixth transistor Q6 (and the seventh transistor Q7) is the collector of the bipolar transistor. Of course, in other embodiments, the sixth transistor Q6 and the seventh transistor Q7 can also be any controllable switches, such as MOS transistors or IGBT switch tubes.

[0066] Specifically, when the first input voltage VI1 drops rapidly, the sixth transistor Q6 can be fully turned on in response to the rapid rise of the collector voltage of the bipolar transistor Q2 to quickly raise the voltage of the first transistor M. D The voltage at the control terminal of the first transistor M is driven D The rapid shutdown is performed to prevent the voltage output terminal VOUT from feeding back current to the first voltage input terminal VIN1.

[0067] Please refer to Fig.11 , Fig.11 Schematic diagram of the composition block diagram of the power multiplexer provided in the embodiment of the present application. Fig.11As shown, the power multiplexer 1000 includes the unidirectional conductive circuit 100 and the voltage converter 200 in any embodiment of the present application.

[0068] Among them, the first end of the unidirectional conductive circuit 100 is connected to the first voltage input terminal VIN1, and the first voltage input terminal VIN1 is used to input the first input voltage VI1. The first end of the voltage converter 200 is connected to the second voltage input terminal VIN2, and the second voltage input terminal VIN2 is used to input the second input voltage (referred to as VI2). The second end of the unidirectional conductive circuit 100 and the second end of the voltage converter 200 are both connected to the voltage output terminal VOUT.

[0069] Specifically, the power multiplexer 1000 is configured to automatically provide current to the voltage output terminal VOUT from the unidirectional conductive circuit 100 when the output voltage of the unidirectional conductive circuit 100 is greater than the preset output voltage of the voltage converter 200, and automatically provide current to the voltage output terminal VOUT from the voltage converter 200 when the output voltage of the unidirectional conductive circuit 100 is less than the preset output voltage. The preset output voltage can be set based on the actual application scenario, and the embodiment of the present application does not specifically limit this.

[0070] In some embodiments, the first voltage input terminal VIN1 is configured to be connected to a battery, and the first input voltage VI1 is a voltage provided by the battery; the second voltage input terminal VIN2 is configured to be connected to a DC power supply, and the second input voltage VI2 is a voltage provided by the DC power supply.

[0071] Specifically, the power multiplexer 1000 is used to realize the smooth switching of the power supply of the electrical device from the external DC power supply and the built-in battery, and to realize the mutual isolation between the two power supplies. In this embodiment, the power multiplexer 1000 takes power from the battery first, and supplies power to the electrical device connected to the voltage output terminal VOUT through the unidirectional conductive circuit 100. When the voltage of the battery is too low to support the voltage required by the voltage output terminal VOUT, and the second voltage input terminal VIN2 of the voltage converter 200 is connected to the power supply, the voltage converter 200 converts the voltage of the power supply into a voltage suitable for the electrical device and outputs it to the voltage output terminal VOUT. At the same time, the voltage output by the voltage converter 200 to the voltage output terminal VOUT cannot be fed back to the battery (i.e., the first voltage input terminal VIN1) through the unidirectional conductive circuit 100.

[0072] In some embodiments, voltage converter 200 is configured as a low dropout linear regulator.

[0073] In some embodiments, Fig.12 As shown, the power multiplexer 1000 further includes an output capacitor CL. The output capacitor CL is connected between the voltage output terminal VOUT and the ground GND.

[0074] Please refer to Fig.13 , Fig.13 The circuit structure of the unidirectional conductive circuit 100 and the voltage converter 200 is shown as an example. Figure 1-Figure 12 The structure shown in FIG. D The first non-control terminal is the second terminal of the unidirectional conductive circuit 100 and is connected to the voltage output terminal VOUT. D The second end of the non-control end is the first end of the unidirectional conductive circuit 100 and is connected to the first voltage input end VIN1 .

[0075] like Fig.13 As shown, the voltage converter 200 includes an eighth transistor M L and the second driving branch 201 .

[0076] Among them, the eighth transistor M L The second driving branch 201 is connected between the second voltage input terminal VIN2 and the voltage output terminal VOUT. The second driving branch 201 is connected to the voltage output terminal VOUT, the reference voltage VREF and the eighth transistor M L The control end connection.

[0077] In this embodiment, the eighth transistor M L Taking the PMOS tube as an example, the eighth transistor M L The control end of the eighth transistor M is the gate of the PMOS tube. L The first end of the non-control terminal is the source of the PMOS tube, and is also the first end of the voltage converter 200, and is connected to the second voltage input terminal VIN2. L The second end of the non-control end is the drain of the PMOS tube, and is also the second end of the voltage converter 200, and is connected to the voltage output end VOUT. Of course, in other embodiments, the eighth transistor M L It can also be any controllable switch, such as an NMOS tube or an IGBT switch tube.

[0078] Specifically, the second driving branch 201 is configured to output a second driving voltage to the eighth transistor M. L The control terminal of the eighth transistor M is used to adjust the second driving voltage based on the reference voltage VREF and the output voltage VO1 of the voltage output terminal VOUT to adjust the LThe second driving branch 201 is further configured to provide a current to the voltage output terminal VOUT to keep the output voltage VO1 at the preset output voltage when the output voltage VO1 of the unidirectional conductive circuit 100 is less than the preset output voltage; the second driving branch 201 is further configured to maintain the eighth transistor M when the output voltage VO1 of the unidirectional conductive circuit 100 is greater than the preset output voltage. L Shut down.

[0079] In some embodiments, Fig.14 As shown, the second driving branch 201 includes a sixth resistor R6, a seventh resistor R7 and an operational amplifier U1.

[0080] The sixth resistor R6 and the seventh resistor R7 are connected in series between the voltage output terminal VOUT and the ground GND, the connection point between the sixth resistor R6 and the seventh resistor R7 is connected to the non-inverting input terminal of the operational amplifier U1, the inverting input terminal of the operational amplifier U1 inputs the reference voltage VREF, and the output terminal of the operational amplifier U1 is connected to the eighth transistor M L The control terminal of the eighth transistor M is connected L The first end of the non-control terminal is connected to the second voltage input terminal VIN2, and the eighth transistor M L The second end of the non-control end is connected to the voltage output end VOUT.

[0081] Specifically, the operational amplifier U1 outputs the control signal of the eighth transistor M according to the difference between the voltage at the voltage output terminal VOUT divided by the sixth resistor R6 and the seventh resistor R7 and the reference voltage VREF. L The gate voltage signal (ie, the second driving voltage) of the eighth transistor M is used to adjust the L The on-resistance of the voltage output terminal VOUT is maintained stable. By setting the reference voltage VREF to the voltage VREFO (VREFO=VREF*(R6+R7) / R7) before the reference voltage VREF is divided by the sixth resistor R6 and the seventh resistor R7, which is equal to the lower limit of the output voltage VO1 of the unidirectional conductive circuit 100, the unidirectional conductive circuit 100 preferentially supplies power to the voltage output terminal VOUT. That is, the preset output voltage is configured as the lower limit of the output voltage VO1. When the output voltage VO1 of the unidirectional conductive circuit 100 is less than the lower limit, Fig.14 The voltage converter 200 shown in FIG. 1 automatically provides current to the voltage output terminal VOUT; when the output voltage VO1 of the unidirectional conductive circuit 100 is greater than its lower limit, Fig.14 The voltage converter 200 shown in FIG. 1 automatically controls the eighth transistor M L The unidirectional conductive circuit 100 is turned off, so that only the current is provided to the voltage output terminal VOUT by the unidirectional conductive circuit 100.

[0082] In some embodiments, Fig.15 As shown, the voltage converter 200 further includes an isolation branch 202. The isolation branch 202 is connected to the eighth transistor M L Between the voltage output terminal VOUT.

[0083] Specifically, the isolation branch 202 is configured to establish a state where the eighth transistor M is switched off when the second input voltage VI2 of the second voltage input terminal VIN2 is greater than a preset voltage threshold. L and the voltage output terminal VOUT, and is configured to disconnect the voltage output terminal VOUT from the eighth transistor M when the second input voltage VI2 is less than a preset voltage threshold. L The preset voltage threshold can be set based on the actual application scenario, and the embodiment of the present application does not impose any specific limitation on this.

[0084] In some embodiments, Fig.16 As shown, the isolation branch 202 includes a ninth transistor M RB Among them, the ninth transistor M RB The control terminal inputs the third drive signal , the ninth transistor M RB The first end of the non-control terminal is connected to the voltage output terminal VOUT, and the ninth transistor M RB The second terminal of the non-control terminal is connected to the eighth transistor M L The second end connection is not the control end.

[0085] In this embodiment, the ninth transistor M RB Taking the PMOS tube as an example, the ninth transistor M RB The control end of the ninth transistor M is the gate of the PMOS tube. RB The first end of the non-control end is the source of the PMOS tube, and the ninth transistor M RB The second end of the non-control end is the drain of the PMOS tube. Of course, in other embodiments, the ninth transistor M RB It can also be any controllable switch, such as an NMOS tube or an IGBT switch tube.

[0086] Specifically, when the second input voltage VI2 is greater than the preset voltage threshold, the third drive signal is low level, controlling the ninth transistor M RB is turned on to establish the eighth transistor M L When the second input voltage VI2 is less than the preset voltage threshold, the third drive signal is high level, controlling the ninth transistor M RB The voltage output terminal VOUT is turned off to disconnect the eighth transistor M L The connection between.

[0087] In this embodiment, the ninth transistor M RB The drain of the eighth transistor M L The drain of the ninth transistor M is connected RB The source of the second input voltage VI2 is connected to the voltage output terminal VOUT, and the third driving signal representing that the second input voltage VI2 is less than the preset voltage threshold is Controlling the ninth transistor M RB The gate of the ninth transistor M is used to control RB Specifically, when the second input voltage VI2 is greater than the preset voltage threshold, the third drive signal is low level, when the second input voltage VI2 is less than the preset voltage threshold, the third drive signal When the second input voltage VI2 is input to the power multiplexer 1000 through the second voltage input terminal VIN2, the third driving signal is low level, the ninth transistor M RB When the second input voltage VI2 is disconnected from the second voltage input terminal VIN2, the third driving signal Turning to high level, the ninth transistor M RB In this case, the ninth transistor M RB The parasitic body diode can play a role in isolating the voltage output terminal VOUT and the second voltage input terminal VIN2, so that the voltage of the voltage output terminal VOUT cannot be fed back to the second voltage input terminal VIN2.

[0088] In the following, the first input voltage VI1 is configured as a voltage provided by a battery, and the second input voltage VI2 is configured as a voltage provided by a DC power supply. Fig.16 The principle of the circuit structure shown is explained.

[0089] Specifically, when only the voltage of the battery is input into the unidirectional conductive circuit 100 , the voltage of the battery is used to supply power to the voltage output terminal VOUT through the unidirectional conductive circuit 100 .

[0090] When the battery voltage (denoted as VBATT) input to the unidirectional conductive circuit 100 is sufficient (e.g., VBATT-ΔV>VREFO), and a DC power source is also input to the second voltage input terminal VIN2, since the voltage provided to the voltage output terminal VOUT by the unidirectional conductive circuit 100 is higher than the voltage VREFO before the reference voltage VREF is divided by the sixth resistor R6 and the seventh resistor R7, the first transistor M L In the state of high on-resistance, almost no current flows through the first transistor M L, which can be regarded as being turned off, thus realizing that the battery voltage VBATT is used to power the voltage output terminal VOUT through the unidirectional conductive circuit 100 in priority. Such a setting can also maximize the efficiency of powering the voltage output terminal VOUT, because the second input voltage VI2 inputted by the second voltage input terminal VIN2 is often significantly higher than the battery voltage VBATT and the voltage required by the electrical device connected to the voltage output terminal VOUT, and using the voltage converter 200 to provide voltage to the voltage output terminal VOUT requires the first transistor M L Most of the electrical energy is consumed in the circuit, which will result in low efficiency.

[0091] When the battery voltage input to the unidirectional conductive circuit 100 decreases to a value such that VBATT-ΔV≤VREFO, the voltage converter 200 starts to provide current to the voltage output terminal VOUT, and the first driving branch 101 controls the first transistor M D Thus, the connection between the voltage output terminal VOUT and the first voltage input terminal VIN1 is disconnected, and the first driving branch 101 can quickly turn off the first transistor M. D To prevent the current from flowing back from the voltage output terminal VOUT to the battery terminal VBATT. It should be noted that the first transistor M D The anode of the parasitic diode is connected to the first voltage input terminal VIN1, the cathode of the parasitic diode is connected to the voltage output terminal VOUT, and the first transistor M D In the off state, current can also be prevented from flowing back from the voltage output terminal VOUT to the first voltage input terminal VIN1.

[0092] When the battery is not connected to the first voltage input terminal VIN1 or is seriously low on power, the power multiplexer 1000 automatically uses the voltage converter 200 to provide a suitable voltage to the voltage output terminal VOUT.

[0093] In summary, the power multiplexer 1000 can achieve the optimal configuration of the two power supplies for the voltage output terminal VOUT and the rapid response and smooth transition of the switching process between the two power supplies, and at the same time can achieve mutual isolation between the two power supplies, thereby effectively improving the reliability and power supply efficiency of the two power supplies when powering electrical equipment.

[0094] In some embodiments, Fig.17 As shown, the power multiplexer 1000 further includes a controller 300 , and the unidirectional conductive circuit 100 further includes a current limiting branch 102 .

[0095] The controller 300 is configured to output a control signal based on the voltage difference when the voltage difference between the first input voltage VI1 and the output voltage VO1 of the voltage output terminal VOUT is greater than a first preset voltage, wherein the first preset voltage is greater than the voltage when the voltage difference is a fixed value, that is, the first preset voltage is greater than the preset voltage difference ΔV. The current limiting branch 102 is connected to the first transistor M D The current limiting branch 102 is configured to adjust the on-resistance of the current limiting branch 102 based on the control signal so that the current flowing through the first transistor M D The current does not exceed the preset current limit value. The preset current limit value can be set based on the actual application scenario, and the embodiment of the present application does not make any specific restrictions on this.

[0096] In some embodiments, Fig.19 As shown, the current limiting branch 102 includes a tenth transistor M FB .

[0097] Among them, the tenth transistor M FB The control end of the tenth transistor M is connected to the controller 300. FB The first terminal of the non-control terminal and the first transistor M D The first end of the non-control terminal is connected to the tenth transistor M FB The second end of the non-control end is connected to the voltage output end VOUT.

[0098] In this embodiment, the tenth transistor M FB Taking the PMOS tube as an example, the tenth transistor M FB The control end of the PMOS tube is the gate of the tenth transistor M FB The first end of the non-control end is the source of the PMOS tube, and the tenth transistor M FB The second end of the non-control end is the drain of the PMOS tube. Of course, in other embodiments, the tenth transistor M FB It can also be any controllable switch, such as an NMOS tube or an IGBT switch tube.

[0099] The following combination Fig. 20 The signal pairs in the power multiplexer shown Fig.19 The principle of the circuit structure shown in FIG. Fig. 20 In FIG. 1 , the abscissa is the current Iout flowing through the unidirectional conductive circuit 100 , and the ordinate is the difference between the first input voltage VI1 and the output voltage VO1 .

[0100] Specifically, when the current Iout flowing through the unidirectional conductive circuit 100 is small, such as (Iout is less than Ireg, where Ireg is the maximum current flowing through the unidirectional conductive circuit 100 when the voltage difference is the preset voltage difference ΔV), the unidirectional conductive circuit 100 maintains the voltage difference between the first input voltage VI1 and the output voltage VO1 at the preset voltage difference ΔV. When the current Iout flowing through the unidirectional conductive circuit 100 exceeds Ireg, even if the first driving branch 101 controls the first transistor M D Even if the unidirectional conductive circuit 100 is fully turned on, the voltage difference between the first input voltage VI1 and the output voltage VO1 cannot be controlled within the preset voltage difference ΔV, and this voltage difference increases with the increase of the current Iout. Until the current Iout flowing through the unidirectional conductive circuit 100 reaches the preset current limit value (denoted as Ilim), the controller 300 can adjust the voltage difference between the tenth transistor M1 and the output voltage VO1 according to the voltage difference between the first input voltage VI1 and the output voltage VO1. FB The on-resistance of unidirectional conductive circuit 100 is maintained at the preset current limiting value Ilim.

[0101] An embodiment of the present application further provides an electronic device, which includes the power multiplexer 1000 in any embodiment of the present application.

[0102] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

[0103] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Under the idea of ​​the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. It should be understood by ordinary technicians in this field that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A unidirectional conductive circuit, characterized in that: include: A first transistor connected between the first voltage input terminal and the voltage output terminal; A first driving branch is respectively connected to the first voltage input terminal, the voltage output terminal and the control terminal of the first transistor, and is configured to output a first driving voltage to the control terminal of the first transistor, and adjust the first driving voltage based on a voltage difference between a first input voltage of the first voltage input terminal and an output voltage of the voltage output terminal to adjust the on-resistance of the first transistor, so as to maintain the voltage difference at a preset voltage difference when the first input voltage is greater than the output voltage, and to turn off the first transistor when the first input voltage is less than or equal to the output voltage.

2. The unidirectional conductive circuit according to claim 1, characterized in that: The first driving branch includes a first resistor, a second resistor, a second transistor, a third transistor, a first current source and a second current source; The first resistor is connected between the first voltage input terminal and the first end of the non-control terminal of the second transistor, the second resistor is connected between the voltage output terminal and the first end of the non-control terminal of the third transistor, the control terminal of the second transistor is respectively connected to the second end of the non-control terminal of the second transistor and the control terminal of the third transistor, the second end of the non-control terminal of the second transistor is connected to the negative electrode of the first current source, the positive electrode of the first current source and the positive electrode of the second current source are both grounded, and the second end of the non-control terminal of the third transistor is respectively connected to the negative electrode of the second current source and the control terminal of the first transistor; The first driving branch is configured to maintain a difference between a voltage drop across the first resistor caused by a first current output by the first current source and a voltage drop across the second resistor caused by a second current output by the second current source equal to the preset voltage difference.

3. The unidirectional conductive circuit according to claim 2, characterized in that: A first current output by the first current source is equal to a second current output by the second current source, and the second transistor and the third transistor have the same size.

4. The unidirectional conductive circuit according to claim 2 or 3, characterized in that: The second transistor and the third transistor are both field effect transistors; The control end of the second transistor and the control end of the third transistor are both gates of the field effect transistor, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both sources of the field effect transistor, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both drains of the field effect transistor.

5. The unidirectional conductive circuit according to claim 2 or 3, characterized in that: The second transistor and the third transistor are both bipolar transistors; The control end of the second transistor and the control end of the third transistor are both bases of bipolar transistors, the first end of the non-control end of the second transistor and the first end of the non-control end of the third transistor are both emitters of bipolar transistors, and the second end of the non-control end of the second transistor and the second end of the non-control end of the third transistor are both collectors of bipolar transistors.

6. The unidirectional conductive circuit according to claim 2, characterized in that: The first driving branch further includes: The bias branch is connected between the control terminal of the second transistor and the ground and is connected to the negative electrode of the first current source, and is configured to form a path between the control terminal of the second transistor and the ground.

7. The unidirectional conductive circuit according to claim 6, characterized in that: The bias branch includes a fourth transistor and a third resistor; The control end of the fourth transistor is connected to the negative electrode of the first current source, the first end of the non-control end of the fourth transistor is connected to the control end of the second transistor, and the second end of the non-control end of the fourth transistor is grounded through the third resistor.

8. The unidirectional conductive circuit according to claim 6, characterized in that: The first driving branch further includes: The resistor branch is connected between the first voltage input terminal and the control terminal of the first transistor, and is configured to generate a third current based on the first input voltage, wherein the third current is greater than the current of the control terminals of the second transistor and the third transistor.

9. The unidirectional conductive circuit according to claim 8, characterized in that: The resistance branch includes a fourth resistor; The fourth resistor is connected between the first voltage input terminal and the control terminal of the second transistor.

10. The unidirectional conductive circuit according to claim 2, characterized in that: The first driving branch further includes: The output buffer branch is respectively connected to the negative electrode of the second current source, the voltage output end and the control end of the first transistor, and is configured so that the input resistance of the output buffer branch is greater than the output resistance to reduce the output resistance of the first driving branch.

11. The unidirectional conductive circuit according to claim 10, characterized in that: The output buffer branch includes a fifth resistor and a fifth transistor; The first end of the fifth resistor is connected to the voltage output end, the second end of the fifth resistor is respectively connected to the first end of the non-control end of the fifth transistor and the control end of the first transistor, the control end of the fifth transistor is connected to the negative electrode of the second current source, and the second end of the non-control end of the fifth transistor is grounded.

12. The unidirectional conductive circuit according to claim 10, characterized in that: The output buffer branch includes a sixth transistor and a seventh transistor; The control end of the sixth transistor is respectively connected to the control end of the seventh transistor and the negative electrode of the second current source, the second end of the non-control end of the sixth transistor is connected to the voltage output end, the first end of the non-control end of the sixth transistor is respectively connected to the first end of the non-control end of the seventh transistor and the control end of the first transistor, and the second end of the non-control end of the seventh transistor is grounded.

13. A power multiplexer, characterized in that: A device comprising a voltage converter and a unidirectional conductive circuit as claimed in any one of claims 1 to 12; The first end of the unidirectional conductive circuit is connected to the first voltage input end, the first voltage input end is used to input a first input voltage, the first end of the voltage converter is connected to the second voltage input end, the second voltage input end is used to input a second input voltage, and the second end of the unidirectional conductive circuit and the second end of the voltage converter are both connected to the voltage output end; The power multiplexer is configured to automatically provide current from the unidirectional conductive circuit to the voltage output terminal when the output voltage of the unidirectional conductive circuit is greater than the preset output voltage of the voltage converter, and to automatically provide current from the voltage converter to the voltage output terminal when the output voltage of the unidirectional conductive circuit is less than the preset output voltage.

14. The power multiplexer according to claim 13, characterized in that: The voltage converter comprises: an eighth transistor connected between the second voltage input terminal and the voltage output terminal; The second driving branch is connected to the voltage output terminal, the reference voltage and the control terminal of the eighth transistor, and is configured to output a second driving voltage to the control terminal of the eighth transistor, and adjust the second driving voltage based on the reference voltage and the output voltage of the voltage output terminal to adjust the on-resistance of the eighth transistor, and provide current to the voltage output terminal to keep the output voltage at the preset output voltage when the output voltage of the unidirectional conductive circuit is less than the preset output voltage; and maintain the eighth transistor off when the output voltage of the unidirectional conductive circuit is greater than the preset output voltage.

15. The power multiplexer according to claim 14, characterized in that: The second driving branch includes a sixth resistor, a seventh resistor and an operational amplifier; The sixth resistor and the seventh resistor are connected in series between the voltage output terminal and the ground, the connection point between the sixth resistor and the seventh resistor is connected to the non-inverting input terminal of the operational amplifier, the reference voltage is input to the inverting input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the control terminal of the eighth transistor, the first terminal of the non-control terminal of the eighth transistor is connected to the second voltage input terminal, and the second terminal of the non-control terminal of the eighth transistor is connected to the voltage output terminal.

16. The power multiplexer according to claim 14 or 15, characterized in that: The voltage converter further comprises: An isolation branch is connected between the eighth transistor and the voltage output terminal, and is configured to establish a connection between the eighth transistor and the voltage output terminal when the second input voltage is greater than a preset voltage threshold, and is configured to disconnect the connection between the voltage output terminal and the eighth transistor when the second input voltage is less than the preset voltage threshold.

17. The power multiplexer according to claim 16, characterized in that: The isolation branch includes a ninth transistor; The control end of the ninth transistor inputs a third driving signal, the first end of the non-control end of the ninth transistor is connected to the voltage output end, and the second end of the non-control end of the ninth transistor is connected to the second end of the non-control end of the eighth transistor; Among them, when the second input voltage is greater than the preset voltage threshold, the third drive signal is at a low level, controlling the ninth transistor to be turned on; when the second input voltage is less than the preset voltage threshold, the third drive signal is at a high level, controlling the ninth transistor to be turned off.

18. The power multiplexer according to claim 13, characterized in that: The power multiplexer further includes a controller configured to output a control signal based on a first preset voltage when a voltage difference between the first input voltage and an output voltage of the voltage output terminal is greater than a first preset voltage, wherein the first preset voltage is greater than a preset voltage difference; The unidirectional conductive circuit also includes a current limiting branch, which is connected between the first transistor and the voltage output terminal. The current limiting branch is configured to adjust the on-resistance based on the control signal so that the current flowing through the first transistor does not exceed a preset current limiting value.

19. The power multiplexer according to claim 18, characterized in that: The current limiting branch includes a tenth transistor; The control end of the tenth transistor is connected to the controller, the first end of the non-control end of the tenth transistor is connected to the first end of the non-control end of the first transistor, and the second end of the non-control end of the tenth transistor is connected to the voltage output end.

20. An electronic device, characterized in that: Comprising a power multiplexer as described in any one of claims 13-19.

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