CN110556910A - power supply switching circuit, power supply system and vehicle - Google Patents
power supply switching circuit, power supply system and vehicle Download PDFInfo
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- CN110556910A CN110556910A CN201810551290.7A CN201810551290A CN110556910A CN 110556910 A CN110556910 A CN 110556910A CN 201810551290 A CN201810551290 A CN 201810551290A CN 110556910 A CN110556910 A CN 110556910A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
- B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
- B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/92—Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Stand-By Power Supply Arrangements (AREA)
Abstract
The invention provides a power supply switching circuit, a power supply system and a vehicle.A detection module is connected with a low-voltage power supply and used for detecting whether the voltage of the low-voltage power supply is greater than an undervoltage reference voltage or not, and a switching module is respectively connected with the detection module, the low-voltage power supply and a backup power supply and used for supplying power through the low-voltage power supply when the voltage of the low-voltage power supply is greater than the undervoltage reference voltage and switching to the backup power supply when the voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage. According to the power supply switching circuit, the power supply system and the vehicle, only the backup power supply or the low-voltage power supply is in a power supply state at the same time by detecting the voltage of the low-voltage power supply, when the low-voltage power supply is under-voltage or power-down, the backup power supply can provide a normal power supply requirement, the switching power supply of the low-voltage power supply and the backup power supply can be accurately controlled, and the utilization rate of the low-voltage power supply is improved.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to a power supply switching circuit, a power supply system and a vehicle.
Background
with the wide application of new energy vehicles, the safety requirements of the new energy vehicles are higher and higher, and when the new energy vehicles run normally, the low-voltage power supply is disconnected or under-voltage due to some reason, even cables fall off, and the like, so that the phenomena of open circuit, short circuit and the like at the low-voltage end are caused, the motor torque and the rotating speed are out of control, the new energy vehicles suddenly lose power, and serious potential safety hazards are brought to drivers.
At present, in order to solve the problem of low-voltage power supply caused by low-voltage disconnection and other reasons, the low-voltage power supply is maintained only by a support capacitor at a power output end, but the low-voltage power supply is limited by the influence of capacitance volume and price, the capacitance value of the support capacitor cannot be very large, the maintenance time of the support capacitor can only be several milliseconds, and in the time period, a system cannot complete fault processing work and cannot execute corresponding torque control work.
However, the switching between the backup power supply and the low-voltage power supply is realized by adopting the diode, the switching can be realized only when the voltage of the low-voltage power supply is lower than the voltage of the backup power supply, although the voltage of the low-voltage power supply is lower than the voltage of the backup power supply, the voltage of the low-voltage power supply does not reach the undervoltage reference voltage of the low-voltage power supply, at this time, the low-voltage power supply can still supply power to the low-voltage power supply system, and if the switching mode of the diode is adopted, the voltage of the backup power supply can be introduced into the low-voltage power supply system in advance.
Disclosure of Invention
in view of this, the present invention provides a power switching circuit to accurately control the switching power supply between a low voltage power supply and a backup power supply, so as to improve the utilization rate of the low voltage power supply.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a power supply switching circuit comprises a detection module and a switching module;
the detection module is connected with the low-voltage power supply and used for detecting whether the voltage of the low-voltage power supply is greater than the under-voltage reference voltage or not;
The switching module is respectively connected with the detection module, the low-voltage power supply and the backup power supply and is used for supplying power through the low-voltage power supply when the voltage of the low-voltage power supply is greater than the undervoltage reference voltage and switching to the backup power supply to supply power when the voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage;
When the voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage, the switching module is conducted with the backup power supply, and the switching module is not conducted with the low-voltage power supply.
furthermore, the detection module comprises a low-voltage power supply voltage detection circuit and an under-voltage detection unit connected with the low-voltage power supply voltage detection circuit;
The low-voltage power supply voltage detection circuit is used for detecting the low-voltage power supply voltage of the low-voltage power supply;
The undervoltage detection unit is used for detecting whether the low-voltage power supply voltage is greater than the undervoltage reference voltage.
further, the under-voltage detection unit includes an under-voltage detection circuit and/or a control unit.
Further, when the under-voltage detection unit includes an under-voltage detection circuit or a control unit, the switching module includes a not gate circuit, a first switch component and a second switch component;
The input end of the NOT gate circuit and the first switch component are respectively connected with the output end of the undervoltage detection circuit, or respectively connected with the output end of the control unit;
the output end of the NOT gate circuit is connected with the second switch component;
The first switch assembly is also connected with the low-voltage power supply;
The second switch assembly is also connected to the backup power supply.
Further, when the undervoltage detection unit comprises an undervoltage detection circuit and a control unit, the switching module comprises an and gate circuit, a not gate circuit, a first switch component and a second switch component;
The first input end of the AND-gate circuit is connected with the output end of the control unit, the second input end of the AND-gate circuit is connected with the output end of the undervoltage detection circuit, and the output end of the AND-gate circuit is connected with the input end of the NOT-gate circuit and the first switch component;
the output end of the NOT gate circuit is connected with the second switch component;
The first switch assembly is also connected with the low-voltage power supply;
The second switch assembly is also connected to the backup power supply.
Further, the first switch component comprises a first transistor and a diode, and when the first transistor is turned on, the diode is in a closed state; the second switching component includes a second transistor.
further, the low-voltage power supply voltage detection circuit includes: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first capacitor, a second capacitor, a third capacitor and a first amplifier;
The first end of the first resistor is connected with a ground terminal, and the second end of the first resistor is connected with the first end of the second resistor;
the second end of the second resistor is connected with the inverting input end of the first amplifier;
The first end of the third resistor is connected with the low-voltage power supply, and the second end of the third resistor is connected with the first end of the fourth resistor;
the second end of the fourth resistor is connected with the non-inverting input end of the first amplifier;
a first end of the fifth resistor is connected with the ground terminal, and a second end of the fifth resistor is connected with a second end of the fourth resistor;
A first end of the sixth resistor is connected with the output end of the first amplifier, and a second end of the sixth resistor is connected with the voltage detection end;
A first end of the seventh resistor is connected with a second end of the second resistor, and a second end of the seventh resistor is connected with a first end of the first capacitor;
The second end of the first capacitor is connected with the grounding end;
A first end of the second capacitor is connected with a first end of the seventh resistor, and a second end of the second capacitor is connected with a second end of the seventh resistor;
a first power end of the first amplifier is connected with a first power supply, and a second power end of the first amplifier is connected with the grounding end;
The first end of the third capacitor is connected with the grounding end, and the second end of the third capacitor is connected with the first power supply.
further, the brown-out detection circuit includes: the circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a fourth capacitor, a fifth capacitor and a second amplifier;
a first end of the eighth resistor is connected with the under-voltage reference voltage end, and a second end of the eighth resistor is connected with the inverting input end of the second amplifier;
A first end of the ninth resistor is connected with the voltage detection end, and a second end of the ninth resistor is connected with a non-inverting input end of the second amplifier;
A first end of the tenth resistor is connected with a second end of the ninth resistor, and a second end of the tenth resistor is connected with an output end of the second amplifier;
a first end of the eleventh resistor is connected with the output end of the second amplifier, and a second end of the eleventh resistor is connected with the first power supply;
a first end of the fourth capacitor is connected with the output end of the second amplifier, and a second end of the fourth capacitor is connected with the grounding end;
a first power terminal of the second amplifier is connected to the first power supply, and a second power terminal of the second amplifier is connected to the ground terminal;
The first end of the fifth capacitor is connected with the grounding end, and the second end of the fifth capacitor is connected with the first power supply.
compared with the prior art, the power supply switching circuit has the following advantages:
(1) The power supply switching circuit provided by the invention supplies power through the low-voltage power supply when the low-voltage power supply voltage of the low-voltage power supply is greater than the undervoltage reference voltage, switches to the backup power supply to supply power when the low-voltage power supply voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage, only the backup power supply or the low-voltage power supply is in a power supply state at the same time by detecting the voltage of the low-voltage power supply, and after the low-voltage power supply is undervoltage or power-down, the backup power supply can provide a normal power supply requirement, can accurately control the switching power supply of the low-voltage power supply and the.
(2) The power supply switching circuit controls the first switch component and the second switch component to be opened or closed through the AND gate circuit and the NOT gate circuit, or controls the first switch component and the second switch component to be opened or closed only through the NOT gate circuit so as to control the low-voltage power supply or the backup power supply to supply power, effectively ensures that the low-voltage power supply and the backup power supply cannot supply power at the same time, and replaces a diode in the prior art through the switching module so as to reduce the conduction loss of the diode and reduce the output power consumption of the whole circuit.
(3) according to the power supply switching circuit, when the first transistor in the first switch component is conducted, the diode in the first switch component is in the off state, and current passes through the first transistor and does not pass through the diode, so that the output power consumption of the whole circuit can be effectively reduced.
(4) The power supply switching circuit disclosed by the invention realizes the control of the first switch component and the second switch component through the low-voltage power supply voltage detection circuit, the undervoltage detection circuit and the control unit, and can still be switched to a backup power supply to supply power when the undervoltage detection circuit or the control unit is damaged, so that the redundant backup effect is realized, and the normal operation of system power supply is effectively ensured.
Another objective of the present invention is to provide a power supply system to accurately control the switching power supply between the low voltage power supply and the backup power supply, so as to improve the utilization rate of the low voltage power supply.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a power supply system comprises a low-voltage power supply, a backup power supply and the power supply switching circuit.
the power supply system and the power switching circuit have the same advantages compared with the prior art, and are not described herein again.
Another objective of the present invention is to provide a vehicle, so as to accurately control the switching power supply between the low voltage power supply and the backup power supply, thereby improving the utilization rate of the low voltage power supply.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
A vehicle comprises the power supply system.
The vehicle and the power supply system have the same advantages compared with the prior art, and are not described in detail herein.
Drawings
the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
Fig. 1 is a schematic diagram of a power switching circuit according to an embodiment of the invention;
Fig. 2 is a circuit diagram of a first power switching circuit according to an embodiment of the invention;
FIG. 3 is a circuit diagram of a second power switching circuit according to an embodiment of the invention;
FIG. 4 is a circuit diagram of a third power switching circuit according to an embodiment of the invention;
FIG. 5 is a circuit diagram of a low voltage power supply voltage detection circuit according to an embodiment of the present invention;
fig. 6 is a circuit diagram of an under-voltage detection circuit according to an embodiment of the invention.
Detailed Description
it should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Example one
Referring to fig. 1, a schematic diagram of a power switching circuit according to an embodiment of the invention is shown.
The embodiment of the invention provides a power supply switching circuit 1, which comprises a detection module 11 and a switching module 12; the detection module 11 is connected with the low-voltage power supply 2 and is used for detecting whether the low-voltage power supply voltage LV of the low-voltage power supply 2 is greater than the under-voltage reference voltage REF or not; the switching module 12 is respectively connected to the detection module 11, the low-voltage power supply 2 and the backup power supply 3, and is configured to supply power through the low-voltage power supply 2 when the low-voltage power supply voltage LV is greater than the under-voltage reference voltage REF, and switch to the backup power supply 3 to supply power when the low-voltage power supply voltage LV is less than or equal to the under-voltage reference voltage REF.
when the low-voltage power supply voltage LV is greater than the under-voltage reference voltage REF, the switching module 12 is not connected to the backup power supply 3, the switching module 12 is connected to the low-voltage power supply 2, and when the low-voltage power supply voltage LV is less than or equal to the under-voltage reference voltage REF, the switching module 12 is connected to the backup power supply 3, and the switching module 12 is not connected to the low-voltage power supply 2.
therefore, only the backup power supply 3 or the low-voltage power supply 2 is in a power supply state at the same time, and when the low-voltage power supply 2 is under-voltage or power-down, the backup power supply 3 can provide a normal power supply requirement.
referring to fig. 2-4, circuit diagrams of three power switching circuits of embodiments of the invention are shown.
In the embodiment of the present invention, the detection module 11 includes a low-voltage power supply voltage detection circuit 111 and an under-voltage detection unit 112 connected to the low-voltage power supply voltage detection circuit 111; a low-voltage power supply voltage detection circuit 111 for detecting a low-voltage power supply voltage LV of the low-voltage power supply 2; and a brown-out detection unit 112, configured to detect whether the low-voltage power supply voltage LV is greater than the brown-out reference voltage REF.
the low-voltage power supply voltage detection circuit 111 detects the low-voltage power supply voltage LV of the low-voltage power supply 2, the undervoltage detection unit 112 compares the low-voltage power supply voltage LV with the undervoltage reference voltage REF, when the low-voltage power supply voltage LV is larger than the undervoltage reference voltage REF, the low-voltage power supply 2 can also normally supply power, when the low-voltage power supply voltage LV is smaller than or equal to the undervoltage reference voltage REF, the undervoltage or power failure of the low-voltage power supply 2 is determined, the power supply is switched to the backup power supply 3, and the normal operation.
the brown-out detection unit 112 includes a brown-out detection circuit 1121 and/or a control unit 1122.
As shown in fig. 2 and fig. 3, when the undervoltage detection unit 112 includes the undervoltage detection circuit 1121 or the control unit 1122, the switching module 12 includes a not-gate circuit G1, a first switch component 121, and a second switch component 122; the input end of the not-gate circuit G1 and the first switch element 121 are respectively connected to the output end of the under-voltage detection circuit 1121, or are respectively connected to the output end of the control unit 1122; the output end of the not gate circuit G1 is connected with the second switch component 122; the first switch assembly 121 is also connected to the low voltage power supply 2; the second switching assembly 122 is also connected to the backup power supply 3.
As shown in fig. 2, the undervoltage detection unit 112 includes an undervoltage detection circuit 1121, an input terminal of the undervoltage detection circuit 1121 is connected to the low-voltage power supply voltage detection circuit 111, and an input terminal of the not-gate circuit G1 and the first switch element 121 are respectively connected to an output terminal of the undervoltage detection circuit 1121.
The low-voltage power supply voltage detection circuit 111 detects a low-voltage power supply voltage LV of the low-voltage power supply 2, the undervoltage detection circuit 1121 compares the low-voltage power supply voltage LV with an undervoltage reference voltage REF, when the low-voltage power supply voltage LV is greater than the undervoltage reference voltage REF, at this time, the low-voltage power supply 2 is not undervoltage, the input end of the not-gate circuit G1 is at a high level, the first switch component 121 is turned on, the load 4 is powered through the low-voltage power supply 2, meanwhile, because the input end of the not-gate circuit G1 is at a high level, after operation, the output end of the not-gate circuit G1 is at a low level, the second switch component 122 is in a closed state, and the backup power; when the undervoltage detection circuit 1121 detects that the low-voltage power supply voltage LV is less than or equal to the undervoltage reference voltage REF, at this time, the low-voltage power supply 2 is in an undervoltage state, the input terminal of the not-gate circuit G1 is at a low level, the first switch component 121 is turned off, and meanwhile, since the input terminal of the not-gate circuit G1 is at a low level, after operation, the output terminal of the not-gate circuit G1 is at a high level, and the second switch component 122 is turned on, and is switched to the backup power supply 3 to supply power to the load 4.
as shown in fig. 3, the under-voltage detection unit 112 includes a control unit 1122, an input terminal of the control unit 1122 is connected to the low-voltage power supply voltage detection circuit 111, and an input terminal of the not-gate circuit G1 and the first switch element 121 are respectively connected to an output terminal of the control unit 1122.
The low-voltage power supply voltage detection circuit 111 detects a low-voltage power supply voltage LV of the low-voltage power supply 2, an under-voltage reference voltage REF is stored in the control unit 1122, the low-voltage power supply voltage LV and the under-voltage reference voltage REF are compared, the subsequent working process is similar to the above description, except that the comparison method of the low-voltage power supply voltage LV and the under-voltage reference voltage REF is different, fig. 2 is compared through the under-voltage detection circuit 1121, and belongs to a method for hardware detection, and the method has the characteristics of high response speed and high precision, fig. 3 is compared through the control unit 1122, and belongs to a method for software detection, and the subsequent working process is not repeated herein.
The Control Unit 1122 may be an MCU (Micro Control Unit).
as shown in fig. 4, when the brown-out detection unit 112 includes the brown-out detection circuit 1121 and the control unit 1122, the switching module 12 includes an and circuit G2, a not circuit G1, a first switch component 121, and a second switch component 122; a first input end of the and circuit G2 is connected to the output end of the control unit 1122, a second input end of the and circuit G2 is connected to the output end of the undervoltage detection circuit 1121, an output end of the and circuit G2 is connected to the input end of the nand circuit G1 and the first switch element 121; the output end of the not gate circuit G1 is connected with the second switch component 122; the first switch assembly 121 is also connected to the low voltage power supply 2; the second switching assembly 122 is also connected to the backup power supply 3.
the low-voltage power supply voltage detection circuit 111 detects a low-voltage power supply voltage LV of the low-voltage power supply 2, the under-voltage detection circuit 1121 compares the low-voltage power supply voltage LV with an under-voltage reference voltage REF, and meanwhile, the control unit 1122 compares the low-voltage power supply voltage LV with the under-voltage reference voltage REF, when the under-voltage detection circuit 1121 and the control unit 1122 detect that the low-voltage power supply voltage LV is greater than the under-voltage reference voltage REF, the first input terminal and the second input terminal of the and circuit G2 are both at a high level, after processing, the output terminal of the and circuit G2 is at a high level, the first switch component 121 is controlled to be turned on, the load 4 is supplied with power through the low-voltage power supply 2, meanwhile, since the output terminal of the and circuit G2 is at a high level, the input terminal of the not circuit G1 is also at a high level, after operation, the output terminal of the not, the backup power supply 3 does not supply power to the load 4; when the undervoltage detection circuit 1121 and/or the control unit 1122 detects that the low-voltage power supply voltage LV is less than or equal to the undervoltage reference voltage REF, after the operation of the and circuit G2, the output terminal of the and circuit G2 is at a low level, and the first switch element 121 is turned off, meanwhile, since the output terminal of the and circuit G2 is at a low level, the input terminal of the not circuit G1 is also at a low level, after the operation, the output terminal of the not circuit G1 is at a high level, and the second switch element 122 is turned on, and is switched to the backup power supply 3 to supply power to the load 4.
the control of the first switch component 121 and the second switch component 122 is realized through the low-voltage power supply voltage detection circuit 111, the undervoltage detection circuit 1121 and the control unit 1122 together, when the undervoltage detection circuit 1121 fails, for example, a certain device in a hardware circuit fails, the control unit 1122 can still switch to the backup power supply 3 for supplying power, when the control unit 1122 fails, for example, software cannot detect the magnitude relation between the low-voltage power supply voltage LV and the undervoltage reference voltage REF due to a precision problem and the like, the undervoltage detection circuit 1121 can still switch to the backup power supply 3 for supplying power, so that a redundant backup effect is achieved, and the normal operation of system power supply is effectively ensured.
As can be seen from the above analysis, when the second switch element 122 is turned on, the first switch element 121 is in the off state, and thus, when the power supply is switched to the backup power supply 3, the current does not flow back to the low voltage power supply.
In the embodiment of the present invention, the first switch assembly 121 includes a first transistor M1 and a diode D1, and when the first transistor M1 is turned on, the diode D1 is in an off state; the second switching component 122 includes a second transistor M2.
The first transistor M1 may be an N-type transistor or a P-type transistor, and the second transistor M2 may also be an N-type transistor or a P-type transistor.
The specific working process is as follows: the low-voltage power supply 2 is firstly powered on, the diode D1 in the first switch component 121 is turned on, the power is supplied to the load 4 through the diode D1, when the load 4 is powered on, the low-voltage power supply voltage LV of the low-voltage power supply 2 is detected through the low-voltage power supply voltage detection circuit 111, when the undervoltage detection unit 112 detects that the low-voltage power supply voltage LV is greater than the undervoltage reference voltage REF, the first transistor M1 in the first switch component 121 is turned on, the power is supplied to the load 4 through the first transistor M1, at this time, the diode D1 is in a closed state, and the output power consumption of the whole circuit is effectively reduced; when the undervoltage detection unit 112 detects that the low-voltage power voltage LV is smaller than or equal to the undervoltage reference voltage REF, the first transistor M1 of the first switch element 121 is turned off, and the second transistor M2 of the second switch element 122 is turned on, so as to switch to the backup power supply 3 to supply power to the load 4.
It should be noted that, when the low-voltage power supply 2 supplies power to the load 4, the voltage output by the low-voltage power supply 2 may be filtered by the first filter circuit 51 to filter out interference signals and the like in the low-voltage power supply 2, and the low-voltage power supply voltage LV filtered by the first filter circuit 51 is detected by the low-voltage power supply voltage detection circuit 111; correspondingly, when the backup power supply 3 supplies power to the load 4, the voltage output by the backup power supply 3 may also be filtered by the second filter circuit 61 to filter out interference signals and the like in the backup power supply 3.
In addition, in practical applications, the load 4 includes a plurality of loads that need to be powered, such as a load a, a load B, and a load C, and the low-voltage power supply 2 and the first switch component 121 are used to supply power to the load a in the load 4, or the backup power supply 3 and the second switch component 122 are used to supply power to the load a in the load 4, the low-voltage power supply voltage LV obtained by filtering processing by the first filter circuit 51 is converted into a low-voltage direct current that can be used by the load B in the load 4 through the first DCDC module 52, and correspondingly, the backup power supply voltage obtained by filtering processing by the second filter circuit 61 is converted into a low-voltage direct current that can be used by the load C in the load 4 through the second DCDC module 62.
When the low-voltage power supply 2 is under-voltage or power-down, the detection module 11 and the switching module 12 can switch to the backup power supply 3 to supply power to the load A, at the moment, the backup power supply 3 supplies power to the load C, the backup power supply 3 is switched to supply power to the load A, buffer time is provided for the subsequent load 4 to execute corresponding torque control work, the load 4 is maintained in a safe working range, and the load 4 is prevented from being directly stopped to enable the torque and the rotating speed of the motor to be out of control.
it should be noted that, in the foregoing, when the low-voltage power supply voltage LV is greater than the under-voltage reference voltage REF, the low-voltage power supply 2 supplies power to the load 4, and when the low-voltage power supply voltage LV is less than or equal to the under-voltage reference voltage REF, the backup power supply 3 is switched to supply power to the load 4, where an object of power supply specifically refers to the load a in the load 4.
referring to fig. 5, a circuit diagram of a low voltage power supply voltage detection circuit according to an embodiment of the present invention is shown.
In the embodiment of the present invention, the low-voltage power supply voltage detection circuit 111 includes: the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a first amplifier F1.
A first end of the first resistor R1 is connected to the ground GND, and a second end of the first resistor R1 is connected to a first end of the second resistor R2; a second end of the second resistor R2 is connected to the inverting input of the first amplifier F1; a first end of the third resistor R3 is connected with the low-voltage power supply 2, and a second end of the third resistor R3 is connected with a first end of the fourth resistor R4; a second end of the fourth resistor R4 is connected to the non-inverting input of the first amplifier F1; a first end of the fifth resistor R5 is connected to the ground GND, and a second end of the fifth resistor R5 is connected to a second end of the fourth resistor R4; a first end of the sixth resistor R6 is connected with the output end of the first amplifier F1, and a second end of the sixth resistor R6 is connected with the voltage detection end DP 1; a first end of the seventh resistor R7 is connected with a second end of the second resistor R2, and a second end of the seventh resistor R7 is connected with a first end of the first capacitor C1; the second end of the first capacitor C1 is connected to the ground GND; a first end of the second capacitor C2 is connected with a first end of the seventh resistor R7, and a second end of the second capacitor C2 is connected with a second end of the seventh resistor R7; the first power supply terminal of the first amplifier F1 is connected to the first power supply VDD, and the second power supply terminal of the first amplifier F1 is connected to the ground terminal GND; a first terminal of the third capacitor C3 is connected to the ground GND, and a second terminal of the third capacitor C3 is connected to the first power VDD.
It should be noted that LV in fig. 5 is the low-voltage power supply voltage output by the low-voltage power supply 2, and the specific voltage value of the low-voltage power supply voltage LV of the low-voltage power supply 2 is detected at the voltage detection terminal DP1 by the low-voltage power supply voltage detection circuit 111.
referring to fig. 6, a circuit diagram of an under-voltage detection circuit according to an embodiment of the present invention is shown.
the under-voltage detection circuit 1121 includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a fourth capacitor C4, a fifth capacitor C5 and a second amplifier F2.
A first end of the eighth resistor R8 is connected to the under-voltage reference voltage terminal LUV _ REF, and a second end of the eighth resistor R8 is connected to the inverting input terminal of the second amplifier F2; a first end of the ninth resistor R9 is connected to the voltage detection end DP1, and a second end of the ninth resistor R9 is connected to the non-inverting input end of the second amplifier F2; a first end of the tenth resistor R10 is connected to a second end of the ninth resistor R9, and a second end of the tenth resistor R10 is connected to an output terminal of the second amplifier F2; a first end of the eleventh resistor R11 is connected to the output end of the second amplifier F2, and a second end of the eleventh resistor R11 is connected to the first power supply VDD; a first end of the fourth capacitor C4 is connected to the output end of the second amplifier F2, and a second end of the fourth capacitor C4 is connected to the ground GND; the first power supply terminal of the second amplifier F2 is connected to the first power supply VDD, and the second power supply terminal of the second amplifier F2 is connected to the ground terminal GND; a first terminal of the fifth capacitor C5 is connected to the ground GND, and a second terminal of the fifth capacitor C5 is connected to the first power VDD.
The undervoltage reference voltage REF inputted from the undervoltage reference voltage terminal LUV _ REF is compared with the low-voltage power supply voltage LV detected by the voltage detection terminal DP1 by the undervoltage detection circuit 1121, the magnitude relation between the undervoltage reference voltage REF and the low-voltage power supply voltage LV is detected by the undervoltage detection point DP1_ UV, and the undervoltage detection point DP1_ UV is connected to the second input terminal of the and gate circuit G2, or the input terminal of the nand gate circuit G1 is connected to the first switch element 121, when the low-voltage power supply voltage LV is greater than the undervoltage reference voltage REF, the detection result of the undervoltage detection point DP1_ UV is 1, which is a high-level signal, and when the low-voltage power supply voltage LV is less than or equal to the undervoltage reference voltage REF, the detection result of the undervoltage detection point DP1_ UV is.
The first power supply VDD is typically 5V.
compared with the prior art, the power supply switching circuit has the following advantages:
(1) The power supply switching circuit provided by the invention supplies power through the low-voltage power supply when the low-voltage power supply voltage of the low-voltage power supply is greater than the undervoltage reference voltage, switches to the backup power supply to supply power when the low-voltage power supply voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage, only the backup power supply or the low-voltage power supply is in a power supply state at the same time by detecting the voltage of the low-voltage power supply, and after the low-voltage power supply is undervoltage or power-down, the backup power supply can provide a normal power supply requirement, can accurately control the switching power supply of the low-voltage power supply and the.
(2) the power supply switching circuit controls the first switch component and the second switch component to be opened or closed through the AND gate circuit and the NOT gate circuit, or controls the first switch component and the second switch component to be opened or closed only through the NOT gate circuit so as to control the low-voltage power supply or the backup power supply to supply power, effectively ensures that the low-voltage power supply and the backup power supply cannot supply power at the same time, and replaces a diode in the prior art through the switching module so as to reduce the conduction loss of the diode and reduce the output power consumption of the whole circuit.
(3) According to the power supply switching circuit, when the first transistor in the first switch component is conducted, the diode in the first switch component is in the off state, and current passes through the first transistor and does not pass through the diode, so that the output power consumption of the whole circuit can be effectively reduced.
(4) The power supply switching circuit disclosed by the invention realizes the control of the first switch component and the second switch component through the low-voltage power supply voltage detection circuit, the undervoltage detection circuit and the control unit, and can still be switched to a backup power supply to supply power when the undervoltage detection circuit or the control unit is damaged, so that the redundant backup effect is realized, and the normal operation of system power supply is effectively ensured.
example two
The embodiment of the invention provides a power supply system, which comprises a low-voltage power supply 2, a backup power supply 3 and the power supply switching circuit 1.
for a detailed description of the power switching circuit 1, reference may be made to embodiment one, and details of the embodiment of the present invention are not repeated herein.
The power supply system and the power switching circuit have the same advantages as the prior art, and are not described herein again.
EXAMPLE III
the embodiment of the invention provides a vehicle comprising the power supply system.
The power supply system comprises a low-voltage power supply 2, a backup power supply 3 and the power supply switching circuit 1.
The advantages of the vehicle and the power supply system are the same as those of the prior art, and are not described herein again.
The power supply switching circuit is not only applied to vehicles, but also applied to any circuit system adopting dual power supplies for power supply.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. a power supply switching circuit is characterized by comprising a detection module and a switching module;
the detection module is connected with the low-voltage power supply and used for detecting whether the voltage of the low-voltage power supply is greater than the under-voltage reference voltage or not;
the switching module is respectively connected with the detection module, the low-voltage power supply and the backup power supply and is used for supplying power through the low-voltage power supply when the voltage of the low-voltage power supply is greater than the undervoltage reference voltage and switching to the backup power supply to supply power when the voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage;
When the voltage of the low-voltage power supply is less than or equal to the undervoltage reference voltage, the switching module is conducted with the backup power supply, and the switching module is not conducted with the low-voltage power supply.
2. The power switching circuit according to claim 1, wherein the detection module comprises a low-voltage power supply voltage detection circuit and an under-voltage detection unit connected to the low-voltage power supply voltage detection circuit;
the low-voltage power supply voltage detection circuit is used for detecting the low-voltage power supply voltage of the low-voltage power supply;
The undervoltage detection unit is used for detecting whether the low-voltage power supply voltage is greater than the undervoltage reference voltage.
3. The power switching circuit of claim 2, wherein the brown-out detection unit comprises a brown-out detection circuit and/or a control unit.
4. the power switching circuit of claim 3, wherein when the under-voltage detection unit comprises an under-voltage detection circuit or a control unit, the switching module comprises a NOT circuit, a first switch component and a second switch component;
the input end of the NOT gate circuit and the first switch component are respectively connected with the output end of the undervoltage detection circuit, or respectively connected with the output end of the control unit;
the output end of the NOT gate circuit is connected with the second switch component;
the first switch assembly is also connected with the low-voltage power supply;
The second switch assembly is also connected to the backup power supply.
5. The power switching circuit according to claim 3, wherein when the under-voltage detection unit comprises an under-voltage detection circuit and a control unit, the switching module comprises an AND gate circuit, a NOT gate circuit, a first switch component and a second switch component;
the first input end of the AND-gate circuit is connected with the output end of the control unit, the second input end of the AND-gate circuit is connected with the output end of the undervoltage detection circuit, and the output end of the AND-gate circuit is connected with the input end of the NOT-gate circuit and the first switch component;
the output end of the NOT gate circuit is connected with the second switch component;
the first switch assembly is also connected with the low-voltage power supply;
The second switch assembly is also connected to the backup power supply.
6. The power switching circuit according to claim 4 or 5, wherein the first switching component comprises a first transistor and a diode, the diode being in an off state when the first transistor is turned on; the second switching component includes a second transistor.
7. The power switching circuit of claim 3, wherein the low voltage supply voltage detection circuit comprises: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first capacitor, a second capacitor, a third capacitor and a first amplifier;
the first end of the first resistor is connected with a ground terminal, and the second end of the first resistor is connected with the first end of the second resistor;
The second end of the second resistor is connected with the inverting input end of the first amplifier;
the first end of the third resistor is connected with the low-voltage power supply, and the second end of the third resistor is connected with the first end of the fourth resistor;
The second end of the fourth resistor is connected with the non-inverting input end of the first amplifier;
a first end of the fifth resistor is connected with the ground terminal, and a second end of the fifth resistor is connected with a second end of the fourth resistor;
a first end of the sixth resistor is connected with the output end of the first amplifier, and a second end of the sixth resistor is connected with the voltage detection end;
a first end of the seventh resistor is connected with a second end of the second resistor, and a second end of the seventh resistor is connected with a first end of the first capacitor;
The second end of the first capacitor is connected with the grounding end;
A first end of the second capacitor is connected with a first end of the seventh resistor, and a second end of the second capacitor is connected with a second end of the seventh resistor;
A first power end of the first amplifier is connected with a first power supply, and a second power end of the first amplifier is connected with the grounding end;
The first end of the third capacitor is connected with the grounding end, and the second end of the third capacitor is connected with the first power supply.
8. The power switching circuit of claim 7, wherein the brown-out detection circuit comprises: the circuit comprises an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a fourth capacitor, a fifth capacitor and a second amplifier;
A first end of the eighth resistor is connected with the under-voltage reference voltage end, and a second end of the eighth resistor is connected with the inverting input end of the second amplifier;
A first end of the ninth resistor is connected with the voltage detection end, and a second end of the ninth resistor is connected with a non-inverting input end of the second amplifier;
A first end of the tenth resistor is connected with a second end of the ninth resistor, and a second end of the tenth resistor is connected with an output end of the second amplifier;
a first end of the eleventh resistor is connected with the output end of the second amplifier, and a second end of the eleventh resistor is connected with the first power supply;
A first end of the fourth capacitor is connected with the output end of the second amplifier, and a second end of the fourth capacitor is connected with the grounding end;
a first power terminal of the second amplifier is connected to the first power supply, and a second power terminal of the second amplifier is connected to the ground terminal;
the first end of the fifth capacitor is connected with the grounding end, and the second end of the fifth capacitor is connected with the first power supply.
9. a power supply system comprising a low voltage power supply, a backup power supply, and a power switching circuit as claimed in any one of claims 1 to 8.
10. A vehicle characterized by comprising the power supply system according to claim 9.
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| CN201810551290.7A CN110556910A (en) | 2018-05-31 | 2018-05-31 | power supply switching circuit, power supply system and vehicle |
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| CN201810551290.7A CN110556910A (en) | 2018-05-31 | 2018-05-31 | power supply switching circuit, power supply system and vehicle |
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