WO2022160809A1 - 一种电源切换电路 - Google Patents

一种电源切换电路 Download PDF

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Publication number
WO2022160809A1
WO2022160809A1 PCT/CN2021/126193 CN2021126193W WO2022160809A1 WO 2022160809 A1 WO2022160809 A1 WO 2022160809A1 CN 2021126193 W CN2021126193 W CN 2021126193W WO 2022160809 A1 WO2022160809 A1 WO 2022160809A1
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WIPO (PCT)
Prior art keywords
module
voltage
signal
power
power supply
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Application number
PCT/CN2021/126193
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English (en)
French (fr)
Inventor
郑卫国
项勇
熊中燕
王江涛
万鸿
Original Assignee
泰斗微电子科技有限公司
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Publication of WO2022160809A1 publication Critical patent/WO2022160809A1/zh

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors

Definitions

  • the present application relates to the technical field of power switching, and in particular, to a power switching circuit.
  • the input voltage may be higher than the withstand voltage of the switching device, resulting in damage to the switching device.
  • the two input power supply voltages may be higher than the source-drain voltage that the switching device can withstand, for example, the high-level process node cannot provide a single device with a full-port withstand voltage exceeding 1.8V, which will cause the device to be broken down and eventually the overall circuit will fail. Therefore, the withstand voltage of the power switching circuit cannot be guaranteed.
  • the embodiment of the present application provides a power supply switching circuit, which can effectively solve the problem that the power supply switching circuit in the prior art is broken down due to an excessively high input voltage during the implementation process.
  • the withstand voltage of basic devices that can be provided by integrated circuit technology.
  • An embodiment of the present application provides a power switching circuit, including: a first switch circuit, a second switch circuit, and a switch control module;
  • the first switch circuit is connected between the first power supply and the output node
  • the second switch circuit is connected between the second power supply and the output node
  • Both the first switch circuit and the second switch circuit include a first power selection module and a second power selection module; the switch control module outputs the corresponding output to the first power selection module and the second power selection module.
  • the power supply selection signal is used to control the on-off of the switch circuit, so that one of the first power supply and the second power supply is connected to the output node, and the power supply selection signal includes the first power supply selection signal and the second power supply selection signal;
  • Both the first switch circuit and the second switch circuit further include a first voltage dividing module and a second voltage dividing module, and the first voltage dividing module and the second voltage dividing module are connected to the first power supply between the selection module and the second power supply selection module; the first voltage division module and the second voltage division module are controlled by the voltage division control signal output by the switch control module, and the voltage division control signal includes the first voltage division control signal.
  • a voltage-divided control signal and a second voltage-divided control signal are controlled by the voltage division control signal.
  • the switch control module includes a first switch control module and a second switch control module
  • a first power selection signal for a first power selection module of the first switch circuit is obtained via the first switch control module, the first switch control module being powered by the first power supply;
  • the first power selection signal for the first power selection module of the second switch circuit is obtained via the second switch control module, which is powered by the second power supply.
  • the switch control module includes a third switch control module
  • the second power selection signal for the second power selection module of the first switching circuit and the second power selection signal for the second power selection module of the second switching circuit are obtained via the third switch control module , the third switch control module is powered by the output node.
  • the first voltage divider control signal is derived from the first switch control module to control a first voltage divider module of the first switch circuit, and from the second switch control module to control the first voltage divider module of the second switch circuit;
  • the second voltage divider control signal is derived from the third switch control module to control the second voltage divider module of the first switch circuit and the second voltage divider module of the second switch circuit.
  • the first voltage dividing control signal for the first voltage dividing module and the second voltage dividing control signal for the second voltage dividing module are maintained, respectively corresponding to the corresponding switch control modules.
  • the voltage difference between the supply voltages reaches a preset large voltage difference threshold in magnitude, and does not exceed the breakdown voltage of the corresponding switch module.
  • the N-well potential of the first power selection module in the first switch circuit is connected to the first power supply
  • the N-well potential of the first power selection module in the second switch circuit is connected to the first power supply.
  • the second power supply is connected, and the N-well potential of the second power supply selection module in the first switch circuit and the second switch circuit is connected to the output node.
  • the first power selection module and the first voltage dividing module are connected in series in a manner that their respective parasitic diodes are connected in the same direction, and the second power selection module and the second voltage dividing module are connected to The respective parasitic diodes are connected in series in a co-directional manner, and the first voltage dividing module and the second voltage dividing module are connected in series in a manner in which the respective parasitic diodes are reversely connected.
  • the switch control module is operable to control the first power selection signal of the first power selection module and the first power selection signal of the second power selection module in the switch circuit when the switch circuit is controlled to be turned on.
  • the voltage difference between the two power supply selection signals and the power supply voltages of the corresponding switch control modules respectively reaches a preset turn-on threshold value.
  • the switch control module is operable to control the first power selection signal of the first power selection module and the first power selection signal of the second power selection module in the switch circuit when the switch circuit is turned off.
  • the two power supply selection signals are respectively consistent with the power supply voltage of the corresponding switch control module.
  • the switch control module has a first signal output terminal for outputting the power supply selection signal to a corresponding power supply selection module, and a first signal output terminal for outputting the voltage division control signal to a corresponding voltage division module Two signal output terminals, a third signal output terminal for grounding, a second signal input terminal for receiving a power switching signal, and a first signal input terminal for connecting to a power supply, the power switching signal and the power selection Signals are logically in one-to-one correspondence;
  • the switch control module further includes a low-level input module, a first voltage-limiting protection module, a second voltage-limiting protection module, a high-level output module, a first low-voltage voltage stabilization module, and a second low-voltage voltage stabilization module;
  • the control terminal of the low-level input module is connected to the second signal input terminal, the output terminal of the low-level input module and the first terminal of the first low-voltage voltage regulator module are respectively connected to the third signal the output end is connected, and the input end of the low-level input module is connected with the output end of the first voltage limiting protection module;
  • the second end of the first low voltage voltage stabilization module is connected to the control end of the first voltage limiting protection module, the third end of the first low voltage voltage stabilization module is connected to the first signal input end, and the The input end of the first voltage limiting protection module is connected to the output end of the second voltage limiting protection module;
  • the control end of the second voltage limiting protection module is respectively connected to the second end of the second low voltage voltage stabilizer module and the second signal output end, and the first end of the second low voltage voltage stabilizer module is connected to the second end of the second low voltage voltage stabilizer module.
  • the first signal input end is connected, and the third end of the second low-voltage voltage stabilization module is connected with the third signal output end;
  • the input terminal of the high-level output module is connected to the first signal input terminal, and the output terminal of the high-level output module is respectively connected to the first signal output terminal and the input of the second voltage limiting protection module. end connection.
  • the first low-voltage voltage stabilization module includes a first control module and a first current limiting resistor formed by connecting multiple control devices in series; the positive input terminal of the first control module is connected to the first limiting resistor. One end of the first current limiting resistor is connected to the first signal input end, and the second end of the first low-voltage voltage regulator module is connected to the first control module and the first signal input end. Between a current limiting resistor, the negative output terminal of the first control module is connected to the third signal output terminal;
  • the second low-voltage voltage stabilization module includes a second control module and a second current limiting resistor formed by a plurality of control devices in series; the positive input end of the second control module is connected to the first signal input end, and the second control module is connected to the first signal input end.
  • the negative output end of the second control module is connected to one end of the second current limiting resistor, the other end of the second current limiting resistor is connected to the third signal output end, and the second signal output end is connected to the between the second control module and the second current limiting resistor.
  • the high-level output module is a latch composed of a pair of PMOS transistors, and the source of the PMOS transistors in the latch is connected to the first signal input end, and the latch The drain of the PMOS transistor in the device is connected to the first signal output end.
  • the first voltage limiting protection module includes a first NMOS transistor and a second NMOS transistor
  • the second voltage limiting protection module includes a first PMOS transistor and a second PMOS transistor
  • the gate of the first NMOS transistor and the gate of the second NMOS transistor are respectively connected to the second end of the first low-voltage voltage regulator module, and the gate of the first PMOS transistor and the second PMOS transistor
  • the gate of the transistor is connected to the second signal output terminal respectively;
  • the drain of the first NMOS transistor is connected to the drain of the first PMOS, and the drain of the second NMOS transistor is connected to the second PMOS
  • the drain of the first NMOS transistor is connected; the source of the first NMOS transistor and the source of the second NMOS transistor are respectively connected to the first signal output terminal.
  • a power supply switching circuit disclosed in the embodiments of the present application includes a first switching circuit, a second switching circuit and a switch control module, and the first switching circuit is connected between the first power supply and an output node , the second switch circuit is connected between the second power supply and the output node, the first switch circuit and the second switch circuit both include a first power supply selection module and a second power supply selection module, the switch The control module outputs corresponding power selection signals to the first power selection module and the second power selection module to control the on-off of the switch circuit, so that one of the first power supply and the second power supply is A power source is connected to the output node, the power source selection signal includes a first power source selection signal and a second power source selection signal, and both the first switch circuit and the second switch circuit further include a first voltage divider module and a second voltage divider a voltage dividing module, the first voltage dividing module and the second voltage dividing module are connected between the first power supply selection module and the second power supply selection module; the first voltage dividing
  • the power switching circuit has the ability to select any input to switch to the output, and is not affected by the specific size of the input voltage, which can effectively solve the problem that the switching device is broken down due to the excessive input voltage in the implementation process of the power switching circuit in the prior art. It ensures that the power supply can be switched, and at the same time, it can withstand a withstand voltage higher than that of the basic device that the integrated circuit technology can provide.
  • the first switch control module and the second switch control module are arranged, so that the first power selection signal of the first power selection module for the first switch circuit is obtained through the first power supply, and the first power selection signal for the second switch circuit is obtained through the first power supply.
  • the first power supply selection signal of a power supply selection module is obtained through the second power supply, so that the power supply switching circuit can select one of the two independent power supplies according to the power supply voltage to ensure that the switch is turned on.
  • the second power selection signal of the second power selection module for the first switch circuit and the second switch circuit is obtained from the output node voltage, so as to ensure that the switch module on the isolated switch circuit remains off. Open to prevent the reverse current flowing from the working power supply, and the multiple input power supplies will not be conducted during the entire switching process, or there will be no obvious leakage current, so that the power supplies are isolated from each other.
  • the first voltage dividing module of the first switching circuit, the second voltage dividing module of the first switching circuit, the first voltage dividing module of the second switching circuit, and the second voltage dividing module of the second switch circuit follow the first voltage dividing module respectively.
  • the voltage of the first power supply, the output node, the second power supply and the output node changes, and is not affected by the state of the power selection module, so as to realize the sharing of the excess voltage in the branches, ensuring that each branch will not break down due to overvoltage, nor There will be no poor conduction.
  • the above embodiment maintains a relatively stable negative voltage difference between the control terminal voltages of the first voltage dividing module and the second voltage dividing module and the corresponding voltages followed, so that when the branch needs to be turned on, the voltage dividing module When the branch needs to be disconnected, the voltage shared by the voltage divider module is relatively large. Therefore, when the two input voltages change arbitrarily in a large range, it is ensured that each branch will not break down due to overvoltage. There will be no poor conduction.
  • the first power supply selection module and the first voltage divider module, the second power supply selection module and the second voltage divider module are connected in series in a way that their parasitic diodes are connected in the same direction, and the first voltage divider module and the second voltage divider module are connected in series. Connected in series with their parasitic diodes connected in reverse, preventing the reverse flow of current, enabling more free choice of supply voltage, regardless of whether one supply voltage exceeds the other by one diode drop or more, ensuring that switch isolation. Second, if one of the power supplies fails, it prevents the other power supply from delivering current to the failed power supply that could damage the working power supply.
  • the control terminal voltage of the power selection module on the switch circuit is controlled to be lower than the corresponding power supply voltage to the required turn-on threshold, so that the voltage across the power selection module is turned on.
  • the difference is close to zero, enabling complete turn-on while reducing device power consumption.
  • the control terminal voltage of the power selection module on the switch circuit is controlled to be consistent with the corresponding power supply voltage. At this time, it is protected by the adjacent voltage divider module and will not exceed the power supply to the adjacent voltage.
  • the difference between the control terminal voltages of the voltage divider module can protect the disconnection voltage and prevent the device from being broken down.
  • the required power switching control of the first power selection module and the second power selection module is realized by converting the low-level power switching signal to a level suitable for the power supply of each switch control module. Secondly, by applying each low-voltage voltage regulator module to generate a relatively low level with a specific voltage difference, output to the control terminals of the first voltage divider module and the second voltage divider module, and control the second voltage limiting protection module through this level, The lowest voltage corresponding to the power selection signal is not lower than the corresponding voltage of the voltage dividing control signal, so as to share the excess voltage of the withstand voltage part of a single device in the switching circuit.
  • FIG. 1 is a schematic structural diagram of a power switching circuit according to an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a level conversion circuit provided by an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of a switch control module provided by an embodiment of the present application.
  • the power switching circuit includes: a first switch circuit, a second switch circuit, and a switch control module;
  • the first switch circuit is connected between the first power supply and the output node
  • the second switch circuit is connected between the second power supply and the output node
  • Both the first switch circuit and the second switch circuit include a first power selection module and a second power selection module; the switch control module outputs the corresponding output to the first power selection module and the second power selection module.
  • the power supply selection signal is used to control the on-off of the switch circuit, so that one of the first power supply and the second power supply is connected to the output node, and the power supply selection signal includes the first power supply selection signal and the second power supply selection signal;
  • Both the first switch circuit and the second switch circuit further include a first voltage dividing module and a second voltage dividing module, and the first voltage dividing module and the second voltage dividing module are connected to the first power supply between the selection module and the second power supply selection module; the first voltage division module and the second voltage division module are controlled by the voltage division control signal output by the switch control module, and the voltage division control signal includes the first voltage division control signal.
  • a voltage-divided control signal and a second voltage-divided control signal are controlled by the voltage division control signal.
  • the first power supply selection module and the second power supply selection module are used to control the on or off of the switch circuits where they are located.
  • the first The voltage module and the second voltage divider module are used to share the excess voltage.
  • the two voltage divider modules are arranged between the two power source selection modules, so that after the power source selection module turns on or off the switch circuit, the voltage divider modules share the excess voltage.
  • the first power selection module, the second power selection module, the first voltage dividing module and the second voltage dividing module are all switch tubes.
  • the switch tube is preferably a PMOS tube, which is just an example device, the first power selection module, the second power selection module, the first voltage dividing module and the second voltage dividing module can also include any other suitable switching devices, including any other types of transistors. Since the voltage of the control terminal (gate) of the NMOS tube of the conventional process is not lower than the voltage of the switch terminal (ie the source and the drain), when it is turned off at the same time, it needs to be higher than a threshold value to be turned on, that is, the NMOS tube The gate needs to work at a voltage higher than or equal to the source and drain voltages. However, the highest voltage in the actual circuit is generally the input power supply voltage, which is inconvenient to provide a higher voltage unless an additional boost circuit is used. Therefore, the switch tube usually uses a PMOS tube as the first power supply selection module, the second power supply selection module, and the first power supply selection module. The first voltage dividing module and the second voltage dividing module have strong practicability and are easy to operate.
  • this embodiment is provided with a first power supply selection module, a second power supply selection module, a first voltage dividing module and a second voltage dividing module.
  • a branch between the two input power supplies A (first power supply) and B (second power supply) to the output node C, and three nodes A1, A1, A2, A3, B1, B2, B3 nodes are set in sequence on the BC branch (second switch circuit), and four switches are placed in order from A to C between the three nodes of the AC branch to control the on-off switch Devices T1 (first power supply selection module), T2 (first voltage divider module), T3 (second voltage divider module), T4 (second power supply selection module), between the three nodes of the BC branch from B to C sequentially places four switches for controlling on-off switching devices T5 (first power supply selection module), T6 (first voltage divider module), T7 (second voltage divider module), and T8 (second power supply selection module).
  • the output node C switches to the voltage of the input power supply A, at which point the BC branch is disconnected.
  • the output C switches to the voltage of the input B, at which point the AC branch is disconnected.
  • the eight switching devices of the AC and BC branches are implemented by PMOS transistors, among which T1 and T4 are used to control the on-off of the AC branch.
  • the switching devices T2 and T3 are used for Share the excess voltage; the switching devices T5 and T8 are used to control the on-off of the BC branch, and the switching devices T6 and T7 are used to share the excess voltage when the voltage difference between the BCs is higher than that of a single switch tube.
  • the switch control module is used to generate a first power source selection signal for controlling the first power source selection module of the first switch circuit and the second switch circuit, a second power source selection signal for controlling the second power source selection module, and a first power source selection signal for controlling the first power source selection module.
  • the switch control module can be multiple control circuits or chips that generate different control signals, or can be one control circuit that can generate different control signals.
  • the power switching circuit of the present application is capable of selecting one of the two independent power sources so that a voltage is supplied to the output node.
  • the switch control circuit provides a power source selection signal for each power source selection module, and a voltage division control signal for each voltage divider module. In this way, the control terminals (gates) of the modules on each switch circuit are individually controlled by the power source selection signal and the voltage division control signal generated by the switch control circuit.
  • a power supply switching circuit provided by an embodiment of the present application includes: a first switch circuit, a second switch circuit and a switch control module, the first switch circuit is connected between a first power supply and an output node, and the second switch The circuit is connected between the second power source and the output node, the first switch circuit and the second switch circuit each include a first power source selection module and a second power source selection module, and the switch control module reports to the first power source selection module.
  • a power source selection module and the second power source selection module output corresponding power source selection signals to control the on-off of the switch circuit, so that one of the first power source and the second power source is connected to the output node connection
  • the power supply selection signal includes a first power supply selection signal and a second power supply selection signal
  • the first switch circuit and the second switch circuit both further include a first voltage divider module and a second voltage divider module
  • the The first voltage divider module and the second voltage divider module are connected between the first power supply selection module and the second power supply selection module, and the first voltage divider module and the second voltage divider module are connected by the same
  • the voltage division control signal output by the switch control module is controlled, and the voltage division control signal includes a first voltage division control signal and a second voltage division control signal, so that one of the two input power sources is connected to the output node to realize the first Switching between a power supply and a second power supply, at the same time, the excess input voltage is shared by the first voltage divider module and the second voltage divider module,
  • the ability to select any input to switch to output is not affected by the specific size of the input voltage, which can effectively solve the problem that the switching device is broken down due to excessive input voltage in the implementation process of the power switching circuit in the prior art, and ensures the power supply At the same time of switching, it can withstand voltages higher than that of basic devices provided by integrated circuit technology.
  • the switch control module includes a first switch control module and a second switch control module;
  • a first power selection signal for a first power selection module of the first switch circuit is obtained via the first switch control module, the first switch control module being powered by the first power supply;
  • the first power selection signal for the first power selection module of the second switch circuit is obtained via the second switch control module, which is powered by the second power supply.
  • the first switch control module CON1 is controlled by the first power supply A to control the on-off of the first power supply selection module T1 of the first switch circuit AC
  • the second switch control module CON2 is controlled by the second power supply B , to control the on-off of the first power selection module T5 of the first switch circuit BC. Therefore, by arranging the first switch control module and the second switch control module, the first power source selection signal of the first power source selection module for the first switch circuit is obtained through the first power source, and the first power source selection signal for the second switch circuit is obtained through the first power source.
  • the first power source selection signal of the power source selection module is obtained through the second power source, so that the power source switching circuit can select one of the two independent power sources according to the power source voltage to ensure that the switch is turned on.
  • the switch control module includes a third switch control module
  • the second power selection signal for the second power selection module of the first switching circuit and the second power selection signal for the second power selection module of the second switching circuit are obtained via the third switch control module , the third switch control module is powered by the output node.
  • the control terminal voltage of the second power supply selection module (the second power supply selection signal) is obtained by the output node instead of the first power supply or the second power supply.
  • the voltage of the node C is the voltage of the power supply B at this time, and the source of the switching device T4 is connected to the node C, which ensures that the switching device T4 is switched when the circuit transmits power from the power supply B. remain disconnected regardless of the supply voltage used. Therefore, in this embodiment, the first switch control module CON3 is controlled by the output node C, and controls the on-off of the second power selection module T4 of the first switch circuit AC and the second power selection module T8 of the second switch circuit BC.
  • the third switch module, the second power selection signal for switching devices T4 and T8 is obtained from the output node voltage, ensuring that the power selection module on the isolated switch circuit remains disconnected, preventing reverse current flowing from the working power supply. At the same time, the multiple input power supplies will not be turned on during the entire switching process, or there will be no obvious leakage current, so that the power supplies are isolated from each other.
  • each switch circuit adopts at least two power supply selection modules for controlling the on-off of the circuit, so as to prevent the input voltage from being greatly different from the output voltage (the output voltage is another input voltage at this time), if the switch When the gate voltage of the device is as high as the lower input voltage, and the other input voltage is higher, the switching device still has a source-gate voltage difference, and the switching device cannot be completely turned off.
  • the first voltage divider control signal is derived from the first switch control module to control the first voltage divider module of the first switch circuit, and is derived from the a second switch control module to control the first voltage divider module of the second switch circuit;
  • the second voltage divider control signal is derived from the third switch control module to control the second voltage divider module of the first switch circuit and the second voltage divider module of the second switch circuit.
  • the switch control module includes a first switch control module, a second switch control module and a third switch control module.
  • the module CON1 is powered by the A input voltage, outputs the first power supply selection signal to the control terminal of the switching device T1, and outputs the first voltage division control signal to the control terminal of the switching device T2;
  • the module CON2 is powered by the B input voltage, and the switch
  • the control terminal of the device T5 outputs the first power supply selection signal, and outputs the first voltage division control signal to the control terminal of the switching device T6;
  • the module CON3 is powered by the output C terminal voltage, and outputs different second voltages to the control terminals of the switching devices T4 and T8.
  • the power supply selection signal outputs different second voltage division control signals to the control terminals of the switching devices T3 and T7.
  • the first voltage divider module of the first switch circuit, the second voltage divider module of the first switch circuit, the first voltage divider module of the second switch circuit, and the second voltage divider module of the second switch circuit respectively follow the first voltage divider module of the second switch circuit.
  • the voltage of the first power supply, the output node, the second power supply and the output node changes, and is not affected by the state of the power selection module, so as to realize the sharing of the excess voltage in the branches, ensuring that each branch will not break down due to overvoltage, nor There will be no poor conduction.
  • the first voltage division control signal for the first voltage division module and the second voltage division control signal for the second voltage division module are maintained, respectively.
  • the voltage difference with the power supply voltage of the corresponding switch control module reaches a preset large voltage difference threshold in magnitude, and does not exceed the breakdown voltage of the corresponding switch module.
  • a relatively stable negative voltage difference is maintained between the control terminal voltages of the first voltage dividing module and the second voltage dividing module and the corresponding voltages followed, and the absolute value of the voltage difference can be as large as possible, But it does not exceed the limit value of single-tube breakdown voltage.
  • the voltages of the control terminals of each voltage dividing module are not necessarily fixed, as long as each power supply selection module can be protected from breakdown, which is not limited in this application. Exemplarily, when the branch AC is turned on, the switching devices T1 and T4 are turned on at the same time.
  • the voltages of the control terminals of the switching devices T2 and T3 are fixed by a voltage threshold lower than the following voltage, and the switching devices T2 and T3 are turned on. And its on-resistance is very small.
  • the switching devices T2 and T3 are not set, the switching devices T1 and T4 are easily broken down. Specifically, the switching device T1 is turned off, and if the voltage of the node A1 is too low, the switching device T1 may be broken down because the withstand voltage is too high.
  • the switching device T2 protects the switching device T1 from being broken down and shares the excess voltage.
  • the control terminal voltage of the first voltage divider module and the second voltage divider module in this embodiment can be used to correspond to the corresponding It is solved by maintaining a relatively stable negative voltage difference between the following voltages.
  • this embodiment is suitable for the situation where the input voltage changes in a large range, and while ensuring the correct on-off of the switch, it can withstand a withstand voltage higher than that of the basic device provided by the integrated circuit process.
  • the key to sharing the possible high voltage is to realize the reasonable control of the control terminal of the series switch.
  • a relatively stable negative voltage difference is maintained between the control terminal voltages of the first voltage dividing module and the second voltage dividing module and the corresponding voltages followed, so that when the branch needs to be turned on, the The on-resistance of the voltage divider module is small.
  • the voltage shared by the voltage divider module is relatively large, realizing the characteristics of low resistance when on and small leakage when disconnected. Therefore, when the two input voltages are arbitrary In the case of large-scale changes, it is ensured that each branch will not be over-voltage breakdown, nor will the conduction be blocked.
  • each branch is provided with a first power supply selection module, a second power supply selection module, a first voltage divider module and a second voltage divider module. If the input voltage exceeds 2 times the withstand voltage of the PMOS tube, it is necessary to add more PMOS pairs for power selection (composed of a first power selection module and a second power selection module) and a PMOS pair for voltage division (composed of the first power selection module and the second power supply selection module).
  • a voltage divider module and a second voltage divider module are formed).
  • the PMOS pair for power supply selection and the PMOS pair for voltage division are connected in series between switching devices T2 and T3 (or switching devices T6 and T7 ).
  • the first voltage dividing module and the second voltage dividing module of the branch may be selected to be reduced.
  • the N-well potential of the first power selection module in the first switch circuit is connected to the first power supply
  • the N-well potential of the first power selection module in the second switch circuit is connected to the first power supply.
  • the second power supply is connected, and the N-well potential of the second power supply selection module in the first switch circuit and the second switch circuit is connected to the output node.
  • the N-well potential of the switching device T1 is connected to the A input voltage
  • the N-well potential of the switching device T4 is connected to the node output node C voltage
  • the N-well potential of T5 is connected to the B input voltage
  • the N-well potential of T8 is connected to Output point C voltage.
  • the first power selection module and the first voltage dividing module are connected in series in a manner that their respective parasitic diodes are connected in the same direction, and the second power selection module and the second voltage dividing module are connected to The respective parasitic diodes are connected in series in a co-directional manner, and the first voltage dividing module and the second voltage dividing module are connected in series in a manner in which the respective parasitic diodes are reversely connected.
  • the N-well potential of T2 is connected to the voltage of node A1
  • the N-well potential of T3 is connected to the voltage of node A3
  • the N-well potential of T6 is connected to the voltage of node B1
  • the N-well potential of T7 is connected to node B3. Therefore, in this embodiment, the first power supply selection module and the first voltage divider module, the second power supply selection module and the second voltage divider module are connected in series in a way that their parasitic diodes are connected in the same direction, and the first voltage divider module and the second voltage divider module are connected in series.
  • the voltage modules are connected in series with their parasitic diodes connected in reverse, preventing the reverse flow of current and enabling a more free choice of supply voltage, regardless of whether one supply voltage exceeds the other by one diode drop or more, Switch isolation is guaranteed. Second, if one of the power supplies fails, it prevents the other power supply from delivering current to the failed power supply that could damage the working power supply.
  • the switch control module is operable to control a first power source selection signal of a first power source selection module in the switch circuit when a switch circuit is controlled to be turned on
  • the voltage difference between the second power supply selection signal and the second power supply selection signal of the second power supply selection module and the power supply voltage of the corresponding switch control module respectively reaches the preset conduction threshold value in magnitude.
  • the voltages at the control terminals of the switching devices T1 , T4 , T5 , and T8 are generated by each control module, and vary according to the required switching state of the power supply.
  • the gate voltage of the switching device T1 is controlled to be lower than the voltage of the corresponding node A to the required threshold value (not exceeding the gate breakdown voltage) , the switching device T1 is turned on, and the voltage difference across the source and drain of the switching device T1 is close to zero, and the on-resistance is small.
  • the gate voltage of the switching device T4 is controlled to be lower than the voltage of the corresponding node C, so that the AC is turned on.
  • the gate voltage of the control switching device T5 is lower than the voltage of the corresponding node B to the required threshold value (not exceeding the gate voltage). breakdown voltage), the switching device T5 is turned on, and the voltage difference across the source and drain of the switching device T5 is close to zero, and the on-resistance is small.
  • the gate voltage of the switching device T8 is controlled to be lower than the voltage of the corresponding node C, so that BC is turned on.
  • the control terminal voltage of the power selection module on the switch circuit is controlled to be lower than the corresponding power supply voltage to the required turn-on threshold, so that when the switch circuit is turned on, the two The terminal voltage difference is close to zero, achieving complete turn-on and reducing power consumption of the device.
  • the switch control module is operable to control the first power selection signal of the first power selection module in the switch circuit when the switch circuit is turned off. and the second power supply selection signal of the second power supply selection module, which are respectively consistent with the power supply voltage of the corresponding switch control module.
  • the control terminal voltage of the power selection module on the switch circuit is controlled to be consistent with the corresponding power supply voltage. At this time, it is protected by the adjacent voltage divider module and will not exceed the power supply The difference between the control terminal voltages of the adjacent voltage divider modules, so as to realize the protection of the disconnection voltage and prevent the device from being broken down.
  • the switch control module completes the control logic from the input signal (power switching signal, generally low level) to the target level
  • the conversion of the signal (power selection signal) to achieve the above conversion, a level conversion circuit can be set in the switch control module.
  • the switch control module has a first signal output terminal for outputting the power supply selection signal to a corresponding power supply selection module, and a second signal output for outputting the voltage division control signal to a corresponding voltage division module terminal, the third signal output terminal for grounding, the second signal input terminal for receiving the power switching signal and the first signal input terminal for connecting the power supply, the power switching signal and the power selection signal are logically connected one-to-one correspondence;
  • the switch control module further includes a low-level input module, a first voltage-limiting protection module, a second voltage-limiting protection module, a high-level output module, a first low-voltage voltage stabilization module, and a second low-voltage voltage stabilization module;
  • the control terminal of the low-level input module is connected to the second signal input terminal, the output terminal of the low-level input module and the first terminal of the first low-voltage voltage regulator module are respectively connected to the third signal the output end is connected, and the input end of the low-level input module is connected with the output end of the first voltage limiting protection module;
  • the second end of the first low voltage voltage stabilization module is connected to the control end of the first voltage limiting protection module, the third end of the first low voltage voltage stabilization module is connected to the first signal input end, and the The input end of the first voltage limiting protection module is connected to the output end of the second voltage limiting protection module;
  • the control end of the second voltage limiting protection module is respectively connected to the second end of the second low voltage voltage stabilizer module and the second signal output end, and the first end of the second low voltage voltage stabilizer module is connected to the second end of the second low voltage voltage stabilizer module.
  • the first signal input end is connected, and the third end of the second low-voltage voltage stabilization module is connected with the third signal output end;
  • the input terminal of the high-level output module is connected to the first signal input terminal, and the output terminal of the high-level output module is respectively connected to the first signal output terminal and the input of the second voltage limiting protection module. end connection.
  • the switch control modules CON1 , CON2 , and CON3 include the above-mentioned level conversion circuit.
  • the level conversion circuit a low-level power switching signal is received, and the power switching signal is level-converted to generate a high-level signal adapted to the power supply of the switch control module, that is, the aforementioned Power selection signal.
  • the low level range is 0 ⁇ 0.9V
  • the high level range is 1.5 ⁇ 3.3V.
  • a relatively low level (voltage division control signal) with a specific voltage difference is generated by applying a step-down circuit (connection module). More specifically, please refer to FIG.
  • the first low-voltage voltage stabilization module stably generates a Vrefn voltage (ie, the signal REF_n) that is positive relative to VSS, and this signal is applied to the control terminal of the isolation MOS transistor (ie, the first voltage-limiting protection module).
  • the second low-voltage voltage regulator module stably generates a negative -Vrefp voltage relative to VDD (ie, the signal REF_p, the voltage division control signal), which is applied to the control end of the isolation MOS tube (ie, the second voltage-limiting protection module), to
  • the above-mentioned isolation MOS transistor can separate various circuits from VDD to VSS into two parts, the upper and lower parts, and respectively realize voltage limiting protection.
  • the signal REF_p is transmitted to the control terminals of the first voltage dividing module and the second voltage dividing module, so as to share the excess voltage in the switching circuit that exceeds the withstand voltage part of a single device.
  • the second voltage limiting protection module by setting the second voltage limiting protection module, the lowest voltage of the power selection signals SEL_h and SEL_hb is limited, and the lowest voltage of the power selection signal is not lower than the voltage of the voltage dividing control signal, so that high voltage resistance is realized.
  • the low-level input module receives the low-level power switching signals SEL and SEL_b, converts the power switching signal to a level suitable for the power supply of each switch control module, and performs all switching operations on the switching devices T1, T4, T5, and T8.
  • the required power switching control is used to output the power selection signals SEL_h, SEL_hb from the high-level output module.
  • the power switching signal is a control signal obtained by the switch control module after logic control, and the level conversion circuit needs to generate a control signal suitable for the level of each module on the switch circuit.
  • the power switching signal corresponds to the power selection signal and is logically consistent, while the power switching signal is a low level signal, and the power selection signal is a corresponding high level signal.
  • FIG. 3 is a schematic structural diagram of a switch control module provided by an embodiment of the present application
  • FIG. 3( a ) is the first switch control module CON1 .
  • the first power selection module of the first power supply selection module outputs the first power supply selection signal SEL_h, and outputs the first voltage division control signal REF_p to the first voltage division module of the first switch circuit.
  • FIG. 3(b) shows the third switch control module CON3, which outputs the second power selection signal SEL_h to the second power selection module of the first switch circuit, and outputs the second power selection signal SEL_hb to the second power selection module of the second switch circuit , outputting the second voltage dividing control signal REF_p to the second voltage dividing module of the first switch circuit and outputting the second voltage dividing control signal REF_p to the second voltage dividing module of the second switch circuit.
  • FIG. 3( c ) shows the second switch control module CON2 , which outputs the first power source selection signal SEL_hb to the first power source selection module of the second switch circuit, and outputs the first voltage divider control to the first voltage divider module of the second switch circuit Signal REF_p.
  • the first low-voltage voltage stabilization module includes a first control module and a first current limiting resistor formed by connecting a plurality of control devices in series;
  • the positive input end of a control module is connected to one end of the first current limiting resistor, the other end of the first current limiting resistor is connected to the first signal input end, and the second The terminal is connected between the first control module and the first current limiting resistor, and the negative output terminal of the first control module is connected to the third signal output terminal;
  • the second low-voltage voltage stabilization module includes a second control module and a second current limiting resistor formed by a plurality of control devices in series; the positive input end of the second control module is connected to the first signal input end, and the second control module is connected to the first signal input end.
  • the negative output end of the second control module is connected to one end of the second current limiting resistor, the other end of the second current limiting resistor is connected to the third signal output end, and the second signal output end is connected to the between the second control module and the second current limiting resistor.
  • the high-level output module is a latch composed of a pair of PMOS transistors, and the source of the PMOS transistors in the latch is connected to the first signal input end, and the latch The drain of the PMOS transistor in the device is connected to the first signal output end.
  • the high-level output module is a latch composed of a pair of PMOS transistors (T9, T10) powered by the aforementioned voltage (possibly high voltage), and the drain of the latch PMOS transistor outputs a pair of differential signals ( SEL_h, SEL_hb), where the high level is up to the supply voltage and the low level is limited by the mid-bias voltage.
  • the first voltage limiting protection module includes a first NMOS transistor and a second NMOS transistor
  • the second voltage limiting protection module includes a first PMOS transistor and a second PMOS transistor
  • the gate of the first NMOS transistor and the gate of the second NMOS transistor are respectively connected to the second end of the first low-voltage voltage regulator module, and the gate of the first PMOS transistor and the second PMOS transistor
  • the gate of the transistor is connected to the second signal output terminal respectively;
  • the drain of the first NMOS transistor is connected to the drain of the first PMOS, and the drain of the second NMOS transistor is connected to the second PMOS
  • the drain of the first NMOS transistor is connected; the source of the first NMOS transistor and the source of the second NMOS transistor are respectively connected to the first signal output terminal.
  • the low-level input module includes control devices T15 and T16
  • the first voltage limiting protection module includes a first NMOS transistor T13 and a second NMOS transistor T14
  • the second voltage limiting protection module includes a first PMOS transistor T11 and a second PMOS transistor T12
  • the first low-voltage voltage regulator module includes a first control module and a first current limiting resistor R1 formed by a plurality of diodes D1 in series
  • the second low-voltage voltage regulator module includes a plurality of diodes D2 in series. flow resistor R2.
  • the gates of control devices T15 and T16 input power switching signals, the sources of T15 and T16 are grounded, the drain of T15 is connected to the source of T13, the drain of T16 is connected to the source of T14, and the drain of T13 is connected to the source of T13.
  • the drain of T11 is connected, and the drain of T14 is connected to the drain of T12.
  • the gates of T13 and T14 are connected between the first control module and the first current limiting resistor R1, so that the signal REF_n and its controlled T13 and T14 can protect T15 and T16 from 0 ⁇ Vrefn after sharing part of the excess voltage. within the voltage range.
  • T11 and T12 are connected between the second control module and the second current limiting resistor R2, so that the signal REF_p and its controlled T11 and T12 can protect T9 and T10 from working at Vrefp ⁇ VDD after sharing part of the excess voltage. within the voltage range.
  • VDD-VSS is greater than the working voltage of T9 ⁇ T16, as long as it is less than twice the working voltage, all T9 ⁇ T16 can guarantee safe operation.
  • the number of diodes in the first low-voltage voltage regulator module and the second low-voltage voltage regulator module is determined by the withstand voltage value of the switching devices T1 ⁇ T8, that is, select as many diodes as possible, and the series voltage does not exceed the withstand voltage.
  • the voltage value is realized to reduce the voltage, and the current limiting resistor R1 provides the working current.
  • various ways can be selected, such as using a MOS transistor instead of a diode, using a MOS transistor instead of a resistor, etc., which is not limited in this application.
  • the required power switching control of the first power selection module and the second power selection module is realized by converting the low-level power switching signal to a level suitable for the power supply of each switch control module. .
  • each low-voltage voltage regulator module to generate a relatively low level with a specific voltage difference, output to the control terminals of the first voltage divider module and the second voltage divider module, and control the second voltage limiting protection module through this level,
  • the lowest voltage corresponding to the power selection signal is not lower than the corresponding voltage of the voltage dividing control signal, so as to share the excess voltage of the withstand voltage part of a single device in the switching circuit.

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Abstract

本申请公开了一种电源切换电路，包括：第一开关电路、第二开关电路和开关控制模块；第一开关电路和第二开关电路均包括第一电源选择模块和第二电源选择模块；开关控制模块向第一电源选择模块和第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得第一电源和所述第二电源中的其中一个电源与输出节点连接；第一开关电路和第二开关电路均还包括第一分压模块和第二分压模块，第一分压模块和第二分压模块连接于第一电源选择模块和第二电源选择模块之间；第一分压模块和第二分压模块由开关控制模块输出的分压控制信号控制。本申请能有效解决现有技术中电源切换电路在实现过程中因输入电压过高导致开关器件被击穿的问题。

Description

一种电源切换电路
本申请要求于2021年01月28日提交中国专利局、申请号为202110119975.6，名称为“一种电源切换电路”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电源切换技术领域，尤其涉及一种电源切换电路。
 背景技术
电子电路需要电源供电才能工作，部分关键电路使用多于一路的电源来供电，以保证该部分电路的供电不间断。常规工作时由主电源供电，备用电源作为备份平常处于待命状态，一旦主电源主动关闭或被动丢失时，就切换到备用电源，确保关键部分电路仍然正常工作。目前，在主备电源切换电路的实现过程中存在以下问题：输入电压可能高于开关器件耐受电压，导致开关器件损坏。其中，由于输入的两个电源电压可能高于开关器件能承受的源漏电压，比如高阶工艺节点并不能提供全端口耐压超过1.8V的单个器件，造成器件被击穿最终整体电路失效。因此，无法保证电源切换电路的耐压性。
 技术问题
本申请实施例提供一种电源切换电路，能有效解决现有技术中电源切换电路在实现过程中因输入电压过高导致开关器件被击穿的问题，保证了电源切换的同时，能够耐受高于集成电路工艺能提供的基本器件的耐压。
 技术解决方案
本申请一实施例提供一种电源切换电路，包括：第一开关电路、第二开关电路和开关控制模块；
所述第一开关电路连接于第一电源与输出节点之间，所述第二开关电路连接于第二电源与所述输出节点之间；
所述第一开关电路和所述第二开关电路均包括第一电源选择模块和第二电源选择模块；所述开关控制模块向所述第一电源选择模块和所述第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得所述第一电源和所述第二电源中的其中一个电源与所述输出节点连接，所述电源选择信号包括第一电源选择信号和第二电源选择信号；
所述第一开关电路和所述第二开关电路均还包括第一分压模块和第二分压模块，所述第一分压模块和所述第二分压模块连接于所述第一电源选择模块和所述第二电源选择模块之间；所述第一分压模块和所述第二分压模块由所述开关控制模块输出的分压控制信号控制，所述分压控制信号包括第一分压控制信号和第二分压控制信号。
在一些实施例中，所述开关控制模块包括第一开关控制模块及第二开关控制模块；
用于所述第一开关电路的第一电源选择模块的第一电源选择信号经由所述第一开关控制模块获得，所述第一开关控制模块由所述第一电源供电；
用于所述第二开关电路的第一电源选择模块的第一电源选择信号经由所述第二开关控制模块获得，所述第二开关控制模块由所述第二电源供电。
在一些实施例中，所述开关控制模块包括第三开关控制模块；
用于所述第一开关电路的第二电源选择模块的第二电源选择信号以及用于所述第二开关电路的第二电源选择模块的第二电源选择信号经由所述第三开关控制模块获得，所述第三开关控制模块由所述输出节点供电。
在一些实施例中，所述第一分压控制信号源自于所述第一开关控制模块以控制所述第一开关电路的第一分压模块，以及源自于所述第二开关控制模块以控制所述第二开关电路的第一分压模块；
所述第二分压控制信号源自于所述第三开关控制模块以控制所述第一开关电路的第二分压模块和所述第二开关电路的第二分压模块。
在一些实施例中，保持用于所述第一分压模块的第一分压控制信号及用于所述第二分压模块的第二分压控制信号，分别与各自对应的开关控制模块的供电电压之间的电压差在大小上达到预设的大电压差阈值，且不超过对应开关模块的击穿电压。
在一些实施例中，所述第一开关电路中的第一电源选择模块的N阱电位与所述第一电源连接，所述第二开关电路中的第一电源选择模块的N阱电位与所述第二电源连接，所述第一开关电路和所述第二开关电路中的第二电源选择模块的N阱电位与所述输出节点连接。
在一些实施例中，所述第一电源选择模块和所述第一分压模块以各自的寄生二极管同向连接的方式串联连接，所述第二电源选择模块和所述第二分压模块以各自的寄生二极管同向连接的方式串联连接，以及所述第一分压模块和所述第二分压模块以各自的寄生二极管反向连接的方式串联连接。
在一些实施例中，所述开关控制模块能够操作，以当控制一开关电路导通时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压之间的电压差在大小上达到预设的导通门限值。
在一些实施例中，所述开关控制模块能够操作，以当控制一开关电路断开时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压保持一致。
在一些实施例中，所述开关控制模块具有用于向相应的电源选择模块输出所述电源选择信号的第一信号输出端，用于向相应的分压模块输出所述分压控制信号的第二信号输出端，用于接地的第三信号输出端，用于接收电源切换信号的第二信号输入端以及用于连接供电电源的第一信号输入端，所述电源切换信号与所述电源选择信号在逻辑上一一对应；
所述开关控制模块还包括低电平输入模块、第一限压保护模块、第二限压保护模块、高电平输出模块、第一低压稳压模块和第二低压稳压模块；
所述低电平输入模块的控制端与所述第二信号输入端连接，所述低电平输入模块的输出端、所述第一低压稳压模块的第一端分别与所述第三信号输出端连接，所述低电平输入模块的输入端与所述第一限压保护模块的输出端连接；
所述第一低压稳压模块的第二端与所述第一限压保护模块的控制端连接，所述第一低压稳压模块的第三端与所述第一信号输入端连接，所述第一限压保护模块的输入端与所述第二限压保护模块的输出端连接；
所述第二限压保护模块的控制端分别与所述第二低压稳压模块的第二端、所述第二信号输出端连接，所述第二低压稳压模块的第一端与所述第一信号输入端连接，所述第二低压稳压模块的第三端与所述第三信号输出端连接；
所述高电平输出模块的输入端与所述第一信号输入端连接，所述高电平输出模块的输出端分别与所述第一信号输出端、所述第二限压保护模块的输入端连接。
在一些实施例中，所述第一低压稳压模块包括由多个控制器件串联构成的第一控制模块和第一限流电阻；所述第一控制模块的正极输入端与所述第一限流电阻的一端连接，所述第一限流电阻的另一端与所述第一信号输入端连接，所述第一低压稳压模块的第二端连接在所述第一控制模块和所述第一限流电阻之间，所述第一控制模块的负极输出端与所述第三信号输出端连接；
所述第二低压稳压模块包括由多个控制器件串联构成的第二控制模块和第二限流电阻；所述第二控制模块的正极输入端与所述第一信号输入端连接，所述第二控制模块的负极输出端与所述第二限流电阻的一端连接，所述第二限流电阻的另一端与所述第三信号输出端连接，所述第二信号输出端连接在所述第二控制模块和所述第二限流电阻之间。
在一些实施例中，所述高电平输出模块为由一对PMOS管组成的锁存器，所述锁存器中PMOS管的源极与所述第一信号输入端连接，所述锁存器中PMOS管的漏极与所述第一信号输出端连接。
在一些实施例中，所述第一限压保护模块包括第一NMOS管和第二NMOS管，所述第二限压保护模块包括第一PMOS管和第二PMOS管；
所述第一NMOS管的栅极、所述第二NMOS管的栅极分别与所述第一低压稳压模块的第二端连接，所述第一PMOS管的栅极、所述第二PMOS管的栅极分别与所述第二信号输出端连接；所述第一NMOS管的漏极与所述第一PMOS的漏极连接，所述第二NMOS管的漏极与所述第二PMOS的漏极连接；所述第一NMOS管的源极、所述第二NMOS管的源极分别与所述第一信号输出端连接。
 有益效果
相比于现有技术，本申请实施例公开的一种电源切换电路，包括第一开关电路、第二开关电路和开关控制模块，所述第一开关电路连接于第一电源与输出节点之间，所述第二开关电路连接于第二电源与所述输出节点之间，所述第一开关电路和所述第二开关电路均包括第一电源选择模块和第二电源选择模块，所述开关控制模块向所述第一电源选择模块和所述第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得所述第一电源和所述第二电源中的其中一个电源与所述输出节点连接，所述电源选择信号包括第一电源选择信号和第二电源选择信号，所述第一开关电路和所述第二开关电路均还包括第一分压模块和第二分压模块，所述第一分压模块和所述第二分压模块连接于所述第一电源选择模块和所述第二电源选择模块之间；所述第一分压模块和所述第二分压模块由所述开关控制模块输出的分压控制信号控制，所述分压控制信号包括第一分压控制信号和第二分压控制信号，这样通过两路输入电源中的一路电源连接于输出节点，实现第一电源和第二电源之间的切换，同时通过第一分压模块和第二分压模块分担超额输入电压，并通过精确地控制该分压模块各自分担的电压，实现了该电源切换电路具有选择任意输入切换到输出的能力，不会受到输入电压具体大小的影响，能有效解决现有技术中电源切换电路在实现过程中因输入电压过高导致开关器件被击穿的问题，保证了电源切换的同时，能够耐受高于集成电路工艺能提供的基本器件的耐压。
上述实施例通过设置第一开关控制模块和第二开关控制模块，使得用于第一开关电路的第一电源选择模块的第一电源选择信号经由第一电源获得，用于第二开关电路的第一电源选择模块的第一电源选择信号经由第二电源获得，这样电源切换电路能够根据电源电压选择两个独立的电源中的一个电源，保证开关导通。
上述实施例通过设置第三开关模块，用于第一开关电路和第二开关电路的第二电源选择模块的第二电源选择信号由输出节点电压获得，保证隔离的开关电路上的开关模块保持断开，防止从工作电源流出的反向电流，同时输入的多个电源之间在切换全过程中都不会之间导通，或不会出现明显的泄漏电流，实现电源相互隔离。
上述实施例通过第一开关电路的第一分压模块、第一开关电路的第二分压模块、第二开关电路的第一分压模块及第二开关电路的第二分压模块分别跟随第一电源、输出节点、第二电源、输出节点的电压而变化，不受电源选择模块的状态而变化，实现分担支路中的超额电压，保证了各支路既不会超压击穿，也不会导通不畅。
上述实施例通过将第一分压模块和第二分压模块的控制端电压与相应所跟随的电压之间保持相对稳定的负电压差，以使得在支路需要导通时，该分压模块的导通电阻较小，在支路需要断开时，该分压模块分担的电压较大，因此当两个输入电压任意大范围变化时，保证了各支路既不会超压击穿，也不会导通不畅。
上述实施例通过第一电源选择模块和第一分压模块、第二电源选择模块和第二分压模块以其寄生二极管同向连接的方式串联连接，第一分压模块和第二分压模块以其寄生二极管反向连接的方式串联连接，从而阻止电流的反向流动，实现更自由地选择电源电压，而与一个电源电压是否超过另一个电源电压一个二极管压降或更多无关，保证了开关隔离。其次，如果其中一个电源发生故障，则防止另一个电源将电流输送到故障电源从而可能损坏工作电源。
上述实施例通过在开关电路需要导通时，控制该开关电路上的电源选择模块的控制端电压低于相应供电电压至所需要的导通门限值，使得导通时电源选择模块两端压差接近于零，实现导通彻底，同时降低了器件功耗。
上述实施例通过在开关电路需要断开时，控制该开关电路上的电源选择模块的控制端电压与相应供电电压保持一致，此时受到相邻分压模块的保护，不会超过电源到相邻分压模块的控制端电压之差，从而实现对断开电压进行保护，防止器件被击穿。
上述实施例通过将该低电平的电源切换信号转换到各开关控制模块供电相适配的电平，实现对第一电源选择模块和第二电源选择模块进行所需的电源切换控制。其次，通过应用各低压稳压模块产生具有特定电压差的相对低电平，输出给第一分压模块和第二分压模块的控制端，并通过该电平控制第二限压保护模块，使得电源选择信号相应的最低电压不低于分压控制信号相应的电压，实现分担开关电路中单个器件耐压部分的多余电压。
 附图说明
图1是本申请一实施例提供的一种电源切换电路的结构示意图；
图2是本申请一实施例提供的电平转换电路的结构示意图；
图3是本申请一实施例提供的开关控制模块的结构示意图。
 本发明的实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
参见图1，是本申请一实施例提供的一种电源切换电路的结构示意图，所述电源切换电路，包括：第一开关电路、第二开关电路和开关控制模块；
所述第一开关电路连接于第一电源与输出节点之间，所述第二开关电路连接于第二电源与所述输出节点之间；
所述第一开关电路和所述第二开关电路均包括第一电源选择模块和第二电源选择模块；所述开关控制模块向所述第一电源选择模块和所述第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得所述第一电源和所述第二电源中的其中一个电源与所述输出节点连接，所述电源选择信号包括第一电源选择信号和第二电源选择信号；
所述第一开关电路和所述第二开关电路均还包括第一分压模块和第二分压模块，所述第一分压模块和所述第二分压模块连接于所述第一电源选择模块和所述第二电源选择模块之间；所述第一分压模块和所述第二分压模块由所述开关控制模块输出的分压控制信号控制，所述分压控制信号包括第一分压控制信号和第二分压控制信号。
在本申请中，第一电源选择模块和第二电源选择模块，用于控制所在开关电路的导通或断开，当该开关电路之间出现高于单个模块器件的电压差时，第一分压模块和第二分压模块用于分担超额电压。两个分压模块设置于两个电源选择模块之间，这使得在电源选择模块导通或断开该开关电路后，分压模块分担超额电压。其中，第一电源选择模块、第二电源选择模块、第一分压模块和第二分压模块均为开关管。该开关管优选为PMOS管，这只是示例性器件，该第一电源选择模块、第二电源选择模块、第一分压模块和第二分压模块可以同样包括任何其他合适的开关器件，包括任何其他类型的晶体管。由于常规工艺的NMOS管的控制端（栅极）电压不低于开关端（即源极和漏极）电压，当持平时断开时，需高于一个门限值才能导通，即NMOS管栅极需要工作在高于或等于源、漏端电压。但实际电路中最高电压一般就是输入电源电压，不方便提供更高的电压，除非采用额外的升压电路，因此该开关管通常采用PMOS管作为第一电源选择模块、第二电源选择模块、第一分压模块和第二分压模块，具有较强的实用性，便于操作。
示例性的，请参见图1，本实施例设置有一个第一电源选择模块、一个第二电源选择模块、一个第一分压模块和一个第二分压模块。具体的，A（第一电源）、B（第二电源）两个输入电源到输出节点C之间各有一条支路，在AC支路（第一开关电路）上顺序设置3个节点A1、A2、A3，在BC支路（第二开关电路）上顺序设置B1、B2、B3节点，在AC支路的三个节点之间从A到C依次放置四个开关用于控制通断的开关器件T1（第一电源选择模块）、T2（第一分压模块）、T3（第二分压模块）、T4（第二电源选择模块），在BC支路的三个节点之间从B到C依次放置四个开关用于控制通断的开关器件T5（第一电源选择模块）、T6（第一分压模块）、T7（第二分压模块）、T8（第二电源选择模块）。当AC支路保持导通时，输出节点C切换到输入电源A的电压，此时BC支路断开。当BC支路保持导通时，输出C切换到输入B的电压，此时AC支路断开。AC、BC支路的八个开关器件采用PMOS管实现，其中T1、T4用于控制AC支路的通断，当AC之间出现高于单个开关管的电压差时开关器件T2、T3用于分担超额电压；开关器件T5、T8用于控制BC支路的通断，当BC之间出现高于单个开关管的电压差时开关器件T6、T7用于分担超额电压。
开关控制模块用于生成控制所述第一开关电路和所述第二开关电路的第一电源选择模块的第一电源选择信号、控制第二电源选择模块的第二电源选择信号、控制第一分压模块的第一分压控制信号和第二分压模块的第二分压控制信号。开关控制模块可以为多个生成不同控制信号的控制电路或芯片，也可以为一个能够生成不同控制信号的控制电路。本申请的电源切换电路能够选择两个独立电源中的一个电源，使得向输出节点提供电压。开关控制电路提供用于各电源选择模块的电源选择信号，以及用于各分压模块的分压控制信号。这样各开关电路上的模块的控制端（栅极）分别通过由开关控制电路产生的电源选择信号和分压控制信号来单独控制。
本申请实施例提供的一种电源切换电路，包括：第一开关电路、第二开关电路和开关控制模块，所述第一开关电路连接于第一电源与输出节点之间，所述第二开关电路连接于第二电源与所述输出节点之间，所述第一开关电路和所述第二开关电路均包括第一电源选择模块和第二电源选择模块，所述开关控制模块向所述第一电源选择模块和所述第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得所述第一电源和所述第二电源中的其中一个电源与所述输出节点连接，所述电源选择信号包括第一电源选择信号和第二电源选择信号，所述第一开关电路和所述第二开关电路均还包括第一分压模块和第二分压模块，所述第一分压模块和所述第二分压模块连接于所述第一电源选择模块和所述第二电源选择模块之间，所述第一分压模块和所述第二分压模块由所述开关控制模块输出的分压控制信号控制，所述分压控制信号包括第一分压控制信号和第二分压控制信号，这样通过两路输入电源中的一路电源连接于输出节点，实现第一电源和第二电源之间的切换，同时通过第一分压模块和第二分压模块分担超额输入电压，并通过精确地控制该分压模块各自分担的电压，实现了该电源切换电路具有选择任意输入切换到输出的能力，不会受到输入电压具体大小的影响，能有效解决现有技术中电源切换电路在实现过程中因输入电压过高导致开关器件被击穿的问题，保证了电源切换的同时，能够耐受高于集成电路工艺能提供的基本器件的耐压。
在一些实施例中，请参见图1，所述开关控制模块包括第一开关控制模块及第二开关控制模块；
用于所述第一开关电路的第一电源选择模块的第一电源选择信号经由所述第一开关控制模块获得，所述第一开关控制模块由所述第一电源供电；
用于所述第二开关电路的第一电源选择模块的第一电源选择信号经由所述第二开关控制模块获得，所述第二开关控制模块由所述第二电源供电。
在本实施例中，第一开关控制模块CON1受控于第一电源A，控制第一开关电路AC的第一电源选择模块T1的通断，第二开关控制模块CON2受控于第二电源B，控制第一开关电路BC的第一电源选择模块T5的通断。因此，通过设置第一开关控制模块和第二开关控制模块，使得用于第一开关电路的第一电源选择模块的第一电源选择信号经由第一电源获得，用于第二开关电路的第一电源选择模块的第一电源选择信号经由第二电源获得，这样电源切换电路能够根据电源电压选择两个独立电源中的一个电源，保证开关导通。
在一些实施例中，请参见图1，所述开关控制模块包括第三开关控制模块；
用于所述第一开关电路的第二电源选择模块的第二电源选择信号以及用于所述第二开关电路的第二电源选择模块的第二电源选择信号经由所述第三开关控制模块获得，所述第三开关控制模块由所述输出节点供电。
在本实施例中，第二电源选择模块的控制端电压（第二电源选择信号）由输出节点获得，而不是由第一电源或第二电源获得。示例性的，在支路AC截止，支路BC导通时，此时节点C的电压为电源B电压，开关器件T4源极连接节点C，确保了电路在从电源B输送功率时开关器件T4保持断开，而不考虑所使用的电源电压。因此，本实施例第一开关控制模块CON3受控于输出节点C，控制第一开关电路AC的第二电源选择模块T4和第二开关电路BC的第二电源选择模块T8的通断，通过设置第三开关模块，用于开关器件T4和T8的第二电源选择信号由输出节点电压获得，保证隔离的开关电路上的电源选择模块保持断开，防止从工作电源流出的反向电流。同时，输入的多个电源之间在切换全过程中都不会之间导通，或不会出现明显的泄漏电流，实现电源相互隔离。
在本申请中，每个开关电路采用至少两个用于控制电路通断的电源选择模块，以防止输入电压与输出电压（此时输出电压为另外一个输入电压）存在较大差异时，若开关器件的栅极电压高到其中较低的输入电压，则另一个输入电压又较高时，开关器件仍然存在源极栅极电压差，开关器件无法彻底关断。
在一些实施例中，请参见图1，所述第一分压控制信号源自于所述第一开关控制模块以控制所述第一开关电路的第一分压模块，以及源自于所述第二开关控制模块以控制所述第二开关电路的第一分压模块；
所述第二分压控制信号源自于所述第三开关控制模块以控制所述第一开关电路的第二分压模块和所述第二开关电路的第二分压模块。
在本实施例中，开关控制模块包括第一开关控制模块、第二开关控制模块和第三开关控制模块。图1中模块CON1由A输入电压供电，对开关器件T1的控制端输出第一电源选择信号，对开关器件T2的控制端输出第一分压控制信号；模块CON2由B输入电压供电，对开关器件T5的控制端输出第一电源选择信号，对开关器件T6的控制端输出第一分压控制信号；模块CON3由输出C端电压供电，对开关器件T4、T8的控制端输出不同的第二电源选择信号，对开关器件T3、T7的控制端输出不同的第二分压控制信号。本实施例通过第一开关电路的第一分压模块、第一开关电路的第二分压模块、第二开关电路的第一分压模块及第二开关电路的第二分压模块分别跟随第一电源、输出节点、第二电源、输出节点的电压而变化，不受电源选择模块的状态而变化，实现分担支路中的超额电压，保证了各支路既不会超压击穿，也不会导通不畅。
在上述实施例的基础上，在一些实施例中，保持用于所述第一分压模块的第一分压控制信号及用于所述第二分压模块的第二分压控制信号，分别与各自对应的开关控制模块的供电电压之间的电压差在大小上达到预设的大电压差阈值，且不超过对应开关模块的击穿电压。
需要说明的是，本实施例中第一分压模块和第二分压模块的控制端电压与相应所跟随的电压之间保持相对稳定的负电压差，该电压差的绝对值可以尽量大、但不超过单管击穿电压的极限值。可选的，本实施例中各分压模块的控制端电压不一定固定不变，只要能保护各电源选择模块不击穿即可，本申请不对此作出限定。示例性的，当支路AC导通时，开关器件T1、T4同时导通，此时开关器件T2、T3的控制端电压固定比其跟随电压低一电压阈值，开关器件T2、T3导通，且其导通电阻很小。当支路AC断开，且节点A电压大于节点C电压（此时为节点B电压）时，若不设置开关器件T2、T3，则开关器件T1、T4易被击穿。具体的，开关器件T1断开，若节点A1的电压过低，则开关器件T1可能因耐压过高而被击穿。因此，通过控制开关器件T2的控制端电压，使得节点A1电压不低于开关器件T2的控制端电压，开关器件T2的导通电阻变大，处于高阻的半导通状态，上述设定的电压差决定了分担的电压值。因此，开关器件T2保护了开关器件T1不被击穿，分担了超额电压。
优选的，若输入电压若大范围变化，比如0V-3.3V连续变化，用于高压情形下用于分担电压的防击穿功能，在低输入电压情形下有可能变成导通不彻底的障碍，反之若为保证低输入时有较低导通电阻可能造成高输入时不能很好分担高压，则可采用本实施例中第一分压模块和第二分压模块的控制端电压与相应所跟随的电压之间保持相对稳定的负电压差的方式来解决。因此，本实施例适用于输入电压大范围变化的情形，保证开关通断正确的同时，能够耐受高于集成电路工艺能提供的基本器件的耐压，其通过采用多个低压开关器件串联来共同分担可能出现的高电压，关键是实现了串联开关的控制端的合理控制。
因此，本实施例通过将第一分压模块和第二分压模块的控制端电压与相应所跟随的电压之间保持相对稳定的负电压差，以使得在支路需要导通时，该分压模块的导通电阻较小，在支路需要断开时，该分压模块分担的电压较大，实现了导通时电阻小，断开时泄漏小的特性，因此当两个输入电压任意大范围变化时，保证了各支路既不会超压击穿，也不会导通不畅。
在本申请中，若输入电压为2倍PMOS管耐压，此时各支路上设置一个第一电源选择模块、一个第二电源选择模块、一个第一分压模块和一个第二分压模块。若输入电压超过2倍PMOS管耐压，则需要增加更多级用于电源选择的PMOS对（由第一电源选择模块和第二电源选择模块构成）和用于分压的PMOS对（由第一分压模块和第二分压模块构成）。其中，请参见图1，若需要增加更多级模块，则在开关器件T2、T3（或开关器件T6、T7）之间串联该用于电源选择的PMOS对和用于分压的PMOS对。可选的，若某个输入电压不会超高，则可能选择减少该支路的第一分压模块和第二分压模块。
在一些实施例中，所述第一开关电路中的第一电源选择模块的N阱电位与所述第一电源连接，所述第二开关电路中的第一电源选择模块的N阱电位与所述第二电源连接，所述第一开关电路和所述第二开关电路中的第二电源选择模块的N阱电位与所述输出节点连接。
具体的，请参见图1，开关器件T1的N阱电位接A输入电压，开关器件T4的N阱电位接节点输出节点C电压；T5的N阱电位接B输入电压，T8的N阱电位接输出点C电压。这样，通过控制开关器件T1、T4、T5、T8的栅极电压，根据该开关器件的栅源电压来控制其导通电阻，以实现该开关器件开断的控制。
在一些实施例中，所述第一电源选择模块和所述第一分压模块以各自的寄生二极管同向连接的方式串联连接，所述第二电源选择模块和所述第二分压模块以各自的寄生二极管同向连接的方式串联连接，以及所述第一分压模块和所述第二分压模块以各自的寄生二极管反向连接的方式串联连接。
具体的，请参见图1， T2的N阱电位接节点A1电压，T3的N阱电位接节点A3电压； T6的N阱电位接节点B1电压，T7的N阱电位接节点B3。因此，本实施例通过第一电源选择模块和第一分压模块、第二电源选择模块和第二分压模块以其寄生二极管同向连接的方式串联连接，第一分压模块和第二分压模块以其寄生二极管反向连接的方式串联连接，从而阻止电流的反向流动，实现更自由地选择电源电压，而与一个电源电压是否超过另一个电源电压一个二极管压降或更多无关，保证了开关隔离。其次，如果其中一个电源发生故障，则防止另一个电源将电流输送到故障电源从而可能损坏工作电源。
在上述实施例的基础上，在一些实施例中，所述开关控制模块能够操作，以当控制一开关电路导通时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压之间的电压差在大小上达到预设的导通门限值。
示例性的，请参见图1，开关器件T1、T4、T5、T8控制端电压由各控制模块产生，依据所需的电源切换状态而变化。当AC需要导通时，由于开关器件T1源极与节点A连接，此时控制开关器件T1栅极电压低于相应节点A电压，至所需要的门限值（不超过栅极击穿电压），则开关器件T1导通，且开关器件T1源漏两端压差接近于零，导通电阻较小。同时，控制开关器件T4栅极电压低于相应节点C电压，使得AC导通。同理的，当BC需要导通时，由于开关器件T5源极与节点B连接，此时控制开关器件T5栅极电压低于相应节点B电压，至所需要的门限值（不超过栅极击穿电压），则开关器件T5导通，且开关器件T5源漏两端压差接近于零，导通电阻较小。同时，控制开关器件T8栅极电压低于相应节点C电压，使得BC导通。
因此，本实施例通过在开关电路需要导通时，控制该开关电路上的电源选择模块的控制端电压低于相应供电电压至所需要的导通门限值，使得导通时电源选择模块两端压差接近于零，实现导通彻底，同时降低了器件功耗。
在上述实施例的基础上，在一些实施例中，所述开关控制模块能够操作，以当控制一开关电路断开时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压保持一致。
示例性的，请参见图1，当AC需要断开时，由于开关器件T1源极与节点A连接，此时控制开关器件T1栅极电压与相应节点A电压保持一致，则开关器件T1截止，控制开关器件T4栅极电压与相应节点C电压保持一致，则开关器件T4截止，T1两端电压受到相邻的开关器件T2保护，不会超过电源到临近T2栅极电压之差，从而对断开电压进行了保护，防止击穿，使得AC断开。
因此，本实施例通过在开关电路需要断开时，控制该开关电路上的电源选择模块的控制端电压与相应供电电压保持一致，此时受到相邻分压模块的保护，不会超过电源到相邻分压模块的控制端电压之差，从而实现对断开电压进行保护，防止器件被击穿。
在一些实施例中，参见图2，是本申请一实施例提供的电平转换电路的结构示意图，开关控制模块完成控制逻辑由输入信号（电源切换信号，一般为低电平）到目标电平信号（电源选择信号）的转换，实现上述转换可在开关控制模块中设置电平转换电路。
具体的，所述开关控制模块具有用于向相应的电源选择模块输出所述电源选择信号的第一信号输出端，用于向相应的分压模块输出所述分压控制信号的第二信号输出端，用于接地的第三信号输出端，用于接收电源切换信号的第二信号输入端以及用于连接供电电源的第一信号输入端，所述电源切换信号与所述电源选择信号在逻辑上一一对应；
所述开关控制模块还包括低电平输入模块、第一限压保护模块、第二限压保护模块、高电平输出模块、第一低压稳压模块和第二低压稳压模块；
所述低电平输入模块的控制端与所述第二信号输入端连接，所述低电平输入模块的输出端、所述第一低压稳压模块的第一端分别与所述第三信号输出端连接，所述低电平输入模块的输入端与所述第一限压保护模块的输出端连接；
所述第一低压稳压模块的第二端与所述第一限压保护模块的控制端连接，所述第一低压稳压模块的第三端与所述第一信号输入端连接，所述第一限压保护模块的输入端与所述第二限压保护模块的输出端连接；
所述第二限压保护模块的控制端分别与所述第二低压稳压模块的第二端、所述第二信号输出端连接，所述第二低压稳压模块的第一端与所述第一信号输入端连接，所述第二低压稳压模块的第三端与所述第三信号输出端连接；
所述高电平输出模块的输入端与所述第一信号输入端连接，所述高电平输出模块的输出端分别与所述第一信号输出端、所述第二限压保护模块的输入端连接。
示例性的，如图1中开关控制模块CON1、CON2、CON3包括上述电平转换电路。具体的，在该电平转换电路中，接收低电平的电源切换信号，对该电源切换信号进行电平转换，以生成与开关控制模块供电相适配的高电平信号，即前述中的电源选择信号。其中，低电平范围如0~0.9V，高电平范围如1.5~3.3V。此外，通过应用降压电路（连接模块）产生具有特定电压差的相对低电平（分压控制信号）。更具体的，请参见图2，第一低压稳压模块稳定产生相对VSS正向的Vrefn电压（即信号REF_n），该信号被运用到隔离MOS管（即第一限压保护模块）的控制端；第二低压稳压模块稳定产生相对VDD负向的-Vrefp电压（即信号REF_p，分压控制信号），该信号被运用到隔离MOS管（即第二限压保护模块）的控制端，以使得上述隔离MOS管能将从VDD到VSS的各种电路分隔为上下两部分，分别实现限压保护。同时，向第一分压模块和第二分压模块的控制端传输信号REF_p，以分担开关电路中超过单个器件耐压部分的多余电压。其中，通过设置第二限压保护模块，限制了电源选择信号SEL_h、SEL_hb的最低电压，且电源选择信号的最低电压不低于分压控制信号的电压，实现了耐高压。其次，低电平输入模块接收低电平的电源切换信号SEL、SEL_b，将该电源切换信号转换到各开关控制模块供电相适配的电平，对开关器件T1、T4、T5、T8进行所需的电源切换控制，以从高电平输出模块输出电源选择信号SEL_h、SEL_hb。其中，电源切换信号为开关控制模块经逻辑控制后获得的控制信号，需经该电平转换电路生成适用于开关电路上各模块的电平的控制信号。电源切换信号与电源选择信号相对应，逻辑上相一致，而电源切换信号为低电平信号，电源选择信号为相应的高电平信号。
因此，基于图2中电平转换模块的结构，参见图3，是本申请一实施例提供的开关控制模块的结构示意图，图3（a）为第一开关控制模块CON1，向第一开关电路的第一电源选择模块输出第一电源选择信号SEL_h，以及向第一开关电路的第一分压模块输出第一分压控制信号REF_p。图3（b）为第三开关控制模块CON3，向第一开关电路的第二电源选择模块输出第二电源选择信号SEL_h，向第二开关电路的第二电源选择模块输出第二电源选择信号SEL_hb，向第一开关电路的第二分压模块输出第二分压控制信号REF_p以及向第二开关电路的第二分压模块输出第二分压控制信号REF_p。图3（c）为第二开关控制模块CON2，向第二开关电路的第一电源选择模块输出第一电源选择信号SEL_hb，以及向第二开关电路的第一分压模块输出第一分压控制信号REF_p。
在上述实施例的基础上，在一些实施例中，请参见图2，所述第一低压稳压模块包括由多个控制器件串联构成的第一控制模块和第一限流电阻；所述第一控制模块的正极输入端与所述第一限流电阻的一端连接，所述第一限流电阻的另一端与所述第一信号输入端连接，所述第一低压稳压模块的第二端连接在所述第一控制模块和所述第一限流电阻之间，所述第一控制模块的负极输出端与所述第三信号输出端连接；
所述第二低压稳压模块包括由多个控制器件串联构成的第二控制模块和第二限流电阻；所述第二控制模块的正极输入端与所述第一信号输入端连接，所述第二控制模块的负极输出端与所述第二限流电阻的一端连接，所述第二限流电阻的另一端与所述第三信号输出端连接，所述第二信号输出端连接在所述第二控制模块和所述第二限流电阻之间。
在一些实施例中，所述高电平输出模块为由一对PMOS管组成的锁存器，所述锁存器中PMOS管的源极与所述第一信号输入端连接，所述锁存器中PMOS管的漏极与所述第一信号输出端连接。
在本实施例中，高电平输出模块为一对PMOS管（T9、T10）组成的锁存器由前述电压供电（可能是高压），锁存器PMOS管的漏极输出一对差分信号（SEL_h、SEL_hb），其中高电平高达电源电压，低电平受限于中间偏置电压。
在一些实施例中，所述第一限压保护模块包括第一NMOS管和第二NMOS管，所述第二限压保护模块包括第一PMOS管和第二PMOS管；
所述第一NMOS管的栅极、所述第二NMOS管的栅极分别与所述第一低压稳压模块的第二端连接，所述第一PMOS管的栅极、所述第二PMOS管的栅极分别与所述第二信号输出端连接；所述第一NMOS管的漏极与所述第一PMOS的漏极连接，所述第二NMOS管的漏极与所述第二PMOS的漏极连接；所述第一NMOS管的源极、所述第二NMOS管的源极分别与所述第一信号输出端连接。
具体的，请参见图2，各开关控制模块的供电电源VDD，地电源VSS。低电平输入模块包括控制器件T15和T16，第一限压保护模块包括第一NMOS管T13和第二NMOS管T14，第二限压保护模块包括第一PMOS管T11和第二PMOS管T12，第一低压稳压模块包括多个二极管D1串联而成的第一控制模块和第一限流电阻R1，第二低压稳压模块包括多个二极管D2串联而成的第二控制模块和第二限流电阻R2。控制器件T15、T16的栅极输入电源切换信号，T15、T16的源极接地，T15的漏极分别与T13的源极连接，T16的漏极分别与T14的源极连接，T13的漏极与T11的漏极连接，T14的漏极与T12的漏极连接。T13、T14的栅极连接在第一控制模块和第一限流电阻R1之间，使得信号REF_n及其控制的T13、T14通过分担部分多余电压后，可以保护T15、T16处于0~Vrefn的工作电压范围内。T11、T12的栅极连接在第二控制模块和第二限流电阻R2之间，使得信号REF_p及其控制的T11、T12通过分担部分多余电压后，可以保护T9、T10处于Vrefp~VDD的工作电压范围内。此外，即使VDD-VSS大于T9~T16的工作电压，只要小于两倍工作电压，则T9~T16全部都可以保证安全运行。
需要说明的是，第一低压稳压模块和第二低压稳压模块中的二极管数量由开关器件T1~T8的耐压值决定，即选择尽量多的这一串二极管，并且串联电压不超过耐压值，实现降压，限流电阻R1提供工作电流。为了实现REF_p电压，可以选择多种方式实现，比如使用MOS管代替二极管，使用MOS管代替电阻等，本申请不对此作限定。
因此，本申请实施例通过将该低电平的电源切换信号转换到各开关控制模块供电相适配的电平，实现对第一电源选择模块和第二电源选择模块进行所需的电源切换控制。其次，通过应用各低压稳压模块产生具有特定电压差的相对低电平，输出给第一分压模块和第二分压模块的控制端，并通过该电平控制第二限压保护模块，使得电源选择信号相应的最低电压不低于分压控制信号相应的电压，实现分担开关电路中单个器件耐压部分的多余电压。
以上所述是本申请的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本申请原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本申请的保护范围。

Claims (13)

  1. 一种电源切换电路，其特征在于，包括：第一开关电路、第二开关电路和开关控制模块；
    所述第一开关电路连接于第一电源与输出节点之间，所述第二开关电路连接于第二电源与所述输出节点之间；
    所述第一开关电路和所述第二开关电路均包括第一电源选择模块和第二电源选择模块；所述开关控制模块向所述第一电源选择模块和所述第二电源选择模块输出相应的电源选择信号，以控制所在开关电路的通断，使得所述第一电源和所述第二电源中的其中一个电源与所述输出节点连接，所述电源选择信号包括第一电源选择信号和第二电源选择信号；
    所述第一开关电路和所述第二开关电路均还包括第一分压模块和第二分压模块，所述第一分压模块和所述第二分压模块连接于所述第一电源选择模块和所述第二电源选择模块之间；所述第一分压模块和所述第二分压模块由所述开关控制模块输出的分压控制信号控制，所述分压控制信号包括第一分压控制信号和第二分压控制信号。
  2. 如权利要求1所述的电源切换电路，其特征在于，所述开关控制模块包括第一开关控制模块及第二开关控制模块；
    用于所述第一开关电路的第一电源选择模块的第一电源选择信号经由所述第一开关控制模块获得，所述第一开关控制模块由所述第一电源供电；
    用于所述第二开关电路的第一电源选择模块的第一电源选择信号经由所述第二开关控制模块获得，所述第二开关控制模块由所述第二电源供电。
  3. 如权利要求2所述的电源切换电路，其特征在于，所述开关控制模块包括第三开关控制模块；
    用于所述第一开关电路的第二电源选择模块的第二电源选择信号以及用于所述第二开关电路的第二电源选择模块的第二电源选择信号经由所述第三开关控制模块获得，所述第三开关控制模块由所述输出节点供电。
  4. 如权利要求3所述的电源切换电路，其特征在于，所述第一分压控制信号源自于所述第一开关控制模块以控制所述第一开关电路的第一分压模块，以及源自于所述第二开关控制模块以控制所述第二开关电路的第一分压模块；
    所述第二分压控制信号源自于所述第三开关控制模块以控制所述第一开关电路的第二分压模块和所述第二开关电路的第二分压模块。
  5. 如权利要求4所述的电源切换电路，其特征在于，保持用于所述第一分压模块的第一分压控制信号及用于所述第二分压模块的第二分压控制信号，分别与各自对应的开关控制模块的供电电压之间的电压差在大小上达到预设的大电压差阈值，且不超过对应开关模块的击穿电压。
  6. 如权利要求1所述的电源切换电路，其特征在于，所述第一开关电路中的第一电源选择模块的N阱电位与所述第一电源连接，所述第二开关电路中的第一电源选择模块的N阱电位与所述第二电源连接，所述第一开关电路和所述第二开关电路中的第二电源选择模块的N阱电位与所述输出节点连接。
  7. 如权利要求6所述的电源切换电路，其特征在于，所述第一电源选择模块和所述第一分压模块以各自的寄生二极管同向连接的方式串联连接，所述第二电源选择模块和所述第二分压模块以各自的寄生二极管同向连接的方式串联连接，以及所述第一分压模块和所述第二分压模块以各自的寄生二极管反向连接的方式串联连接。
  8. 如权利要求6所述的电源切换电路，其特征在于，所述开关控制模块能够操作，以当控制一开关电路导通时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压之间的电压差在大小上达到预设的导通门限值。
  9. 如权利要求6所述的电源切换电路，其特征在于，所述开关控制模块能够操作，以当控制一开关电路断开时，则控制该开关电路中的第一电源选择模块的第一电源选择信号和第二电源选择模块的第二电源选择信号，分别与其对应的开关控制模块的供电电压保持一致。
  10. 如权利要求1所述的电源切换电路，其特征在于，所述开关控制模块具有用于向相应的电源选择模块输出所述电源选择信号的第一信号输出端，用于向相应的分压模块输出所述分压控制信号的第二信号输出端，用于接地的第三信号输出端，用于接收电源切换信号的第二信号输入端以及用于连接供电电源的第一信号输入端，所述电源切换信号与所述电源选择信号在逻辑上一一对应；
    所述开关控制模块还包括低电平输入模块、第一限压保护模块、第二限压保护模块、高电平输出模块、第一低压稳压模块和第二低压稳压模块；
    所述低电平输入模块的控制端与所述第二信号输入端连接，所述低电平输入模块的输出端、所述第一低压稳压模块的第一端分别与所述第三信号输出端连接，所述低电平输入模块的输入端与所述第一限压保护模块的输出端连接；
    所述第一低压稳压模块的第二端与所述第一限压保护模块的控制端连接，所述第一低压稳压模块的第三端与所述第一信号输入端连接，所述第一限压保护模块的输入端与所述第二限压保护模块的输出端连接；
    所述第二限压保护模块的控制端分别与所述第二低压稳压模块的第二端、所述第二信号输出端连接，所述第二低压稳压模块的第一端与所述第一信号输入端连接，所述第二低压稳压模块的第三端与所述第三信号输出端连接；
    所述高电平输出模块的输入端与所述第一信号输入端连接，所述高电平输出模块的输出端分别与所述第一信号输出端、所述第二限压保护模块的输入端连接。
  11. 如权利要求10所述的电源切换电路，其特征在于，所述第一低压稳压模块包括由多个控制器件串联构成的第一控制模块和第一限流电阻；所述第一控制模块的正极输入端与所述第一限流电阻的一端连接，所述第一限流电阻的另一端与所述第一信号输入端连接，所述第一低压稳压模块的第二端连接在所述第一控制模块和所述第一限流电阻之间，所述第一控制模块的负极输出端与所述第三信号输出端连接；
    所述第二低压稳压模块包括由多个控制器件串联构成的第二控制模块和第二限流电阻；所述第二控制模块的正极输入端与所述第一信号输入端连接，所述第二控制模块的负极输出端与所述第二限流电阻的一端连接，所述第二限流电阻的另一端与所述第三信号输出端连接，所述第二信号输出端连接在所述第二控制模块和所述第二限流电阻之间。
  12. 如权利要求10所述的电源切换电路，其特征在于，所述高电平输出模块为由一对PMOS管组成的锁存器，所述锁存器中PMOS管的源极与所述第一信号输入端连接，所述锁存器中PMOS管的漏极与所述第一信号输出端连接。
  13. 如权利要求10所述的电源切换电路，其特征在于，所述第一限压保护模块包括第一NMOS管和第二NMOS管，所述第二限压保护模块包括第一PMOS管和第二PMOS管；
    所述第一NMOS管的栅极、所述第二NMOS管的栅极分别与所述第一低压稳压模块的第二端连接，所述第一PMOS管的栅极、所述第二PMOS管的栅极分别与所述第二信号输出端连接；所述第一NMOS管的漏极与所述第一PMOS的漏极连接，所述第二NMOS管的漏极与所述第二PMOS的漏极连接；所述第一NMOS管的源极、所述第二NMOS管的源极分别与所述第一信号输出端连接。
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