CN111897387A - Linear low-dropout voltage conversion circuit and working method thereof, power supply device and working method thereof - Google Patents

Linear low-dropout voltage conversion circuit and working method thereof, power supply device and working method thereof Download PDF

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Publication number
CN111897387A
CN111897387A CN202010790781.4A CN202010790781A CN111897387A CN 111897387 A CN111897387 A CN 111897387A CN 202010790781 A CN202010790781 A CN 202010790781A CN 111897387 A CN111897387 A CN 111897387A
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China
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voltage
port
power supply
circuit
electrically connected
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CN202010790781.4A
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Chinese (zh)
Inventor
邓琴
李进
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Zhuhai Smart Ware Technology Co ltd
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Zhuhai Smart Ware Technology Co ltd
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Priority to CN202010790781.4A priority Critical patent/CN111897387A/en
Publication of CN111897387A publication Critical patent/CN111897387A/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • 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
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/10—Control circuit supply, e.g. means for supplying power to the control circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0045—Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention provides a linear low dropout voltage conversion circuit and a working method thereof, a power supply device and a working method thereof. The method comprises the following steps: acquiring a first detection signal of a first port voltage detection circuit, a second detection signal of a second port voltage detection circuit and a comparison signal of a relative voltage comparison circuit; acquiring voltage states of the first power supply port and the second power supply port according to the first detection signal, the second detection signal and the comparison signal; and controlling the first control switch or the second control switch to be conducted according to the voltage state. The linear low dropout voltage conversion circuit can effectively improve the conversion efficiency of the low dropout linear voltage regulator.

Description

Linear low-dropout voltage conversion circuit and working method thereof, power supply device and working method thereof
Technical Field
The invention relates to the technical field of power management, in particular to a linear low dropout voltage conversion circuit, a working method of the linear low dropout voltage conversion circuit, a power supply device applying the linear low dropout voltage conversion circuit and a working method of the power supply device.
Background
With the development of mobile electronic devices, the endurance requirements of the devices are higher and higher, and the market has strong demands on power supply systems, efficiency and self-power consumption. In some existing electronic devices, such as a mobile power supply or a charger, a micro control unit is added to perform some intelligent control, because the power consumption of the micro control unit is usually only dozens of milliamperes, and meanwhile, in order to consider the cost, the micro control unit generally uses a low dropout regulator (LDO) to supply power. As shown in fig. 1, in a specific scenario, the input terminal of the low dropout regulator 10 is fixed, for example, connected to a common power supply terminal of a mobile power supply, and the output terminal of the low dropout regulator 10 supplies power to the micro control unit 20 and the charge and discharge control circuit 30. The conversion efficiency of the low dropout linear regulator is equal to the division of the output voltage by the input voltage, and when the input and output voltage difference is large, the low dropout linear regulator has the problem of low conversion efficiency. Therefore, the conventional solution has a problem of low conversion efficiency.
Disclosure of Invention
The first objective of the present invention is to provide a linear low dropout voltage converting circuit for effectively improving the conversion efficiency of a low dropout linear voltage regulator.
The second objective of the present invention is to provide an operating method of a linear low dropout voltage converting circuit, which effectively improves the conversion efficiency of a low dropout linear voltage regulator.
The third objective of the present invention is to provide a power supply apparatus for effectively improving the conversion efficiency of the low dropout linear regulator.
The fourth objective of the present invention is to provide an operating method of a power supply apparatus for effectively improving the conversion efficiency of a low dropout linear regulator.
In order to achieve the first object, the present invention provides a linear low dropout voltage converting circuit, which comprises a first power port, a second power port, a first port voltage detecting circuit, a second port voltage detecting circuit, a relative voltage comparing circuit, a path selecting circuit, a first control switch, a second control switch and a low dropout linear regulator, wherein a first input terminal of the relative voltage comparing circuit is electrically connected to the first power port, a second input terminal of the relative voltage comparing circuit is electrically connected to the second power port, an output terminal of the relative voltage comparing circuit is electrically connected to the path selecting circuit, an input terminal of the first port voltage detecting circuit is electrically connected to the first power port, an output terminal of the first port voltage detecting circuit is electrically connected to the path selecting circuit, an input terminal of the second port voltage detecting circuit is electrically connected to the second power port, and an output terminal of the second port voltage detecting circuit is electrically connected to the path selecting circuit, the control end of the first control switch and the control end of the second control switch are both electrically connected with the access selection circuit, the low dropout linear regulator is electrically connected with the first power supply port through the first control switch, and the low dropout linear regulator is electrically connected with the second power supply port through the second control switch.
According to the scheme, the linear low dropout voltage conversion circuit can detect the voltage states of the first power supply port and the second power supply port through the relative voltage comparison circuit, the first port voltage detection circuit and the second port voltage detection circuit, and the path selection circuit can control the first control switch and the second control switch according to the voltage states, so that the paths for conducting the first power supply port or the second power supply port and the low dropout linear regulator are selected, the power supply input of the low dropout linear regulator is adjusted according to the voltage states of the first power supply port and the second power supply port, the voltage difference between the input end and the output end of the low dropout linear regulator is reduced, and the conversion efficiency of the low dropout linear regulator is improved.
In a further scheme, the first port voltage detection circuit comprises a first comparator, a first input end of the first comparator is electrically connected with the first power port, a second input end of the first comparator is electrically connected with the reference voltage end, and an output end of the first comparator is electrically connected with the path selection circuit.
Therefore, the first port voltage detection circuit detects the first power supply port through the first comparator by using the first comparator, so as to determine the relation between the voltage of the first power supply port and the target output voltage of the low dropout linear regulator.
In a further scheme, the second port voltage detection circuit comprises a second comparator, a first input end of the second comparator is electrically connected with the second power port, a second input end of the second comparator is electrically connected with the reference voltage end, and an output end of the second comparator is electrically connected with the path selection circuit.
Therefore, the second port voltage detection circuit detects the second power port through the second comparator by using the second comparator, so as to determine the relationship between the voltage of the second power port and the target output voltage of the low dropout linear regulator.
In a further aspect, the relative voltage comparison circuit includes a third comparator, a first input terminal of the third comparator is electrically connected to the first power port, and a second terminal of the third comparator is electrically connected to the second power port.
Therefore, the relative voltage comparison circuit can determine the magnitude relation between the voltage of the first power supply port and the voltage of the second power supply port by arranging the third comparator, so that the path selection circuit controls the first control switch and the second control switch.
In a further scheme, the relative voltage comparison circuit further comprises a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor and a fourth voltage dividing resistor; the first end of the first divider resistor is electrically connected with the first power supply port, the second end of the first divider resistor is electrically connected with the first end of the second divider resistor, the second end of the second divider resistor is grounded, and a branch between the second end of the first divider resistor and the first end of the second divider resistor is electrically connected with the first input end of the third comparator; the first end of the third voltage-dividing resistor is electrically connected with the second power supply port, the second end of the third voltage-dividing resistor is electrically connected with the first end of the fourth voltage-dividing resistor, the second end of the fourth voltage-dividing resistor is grounded, and a branch between the second end of the third voltage-dividing resistor and the first end of the fourth voltage-dividing resistor is electrically connected with the second input end of the third comparator; the resistance ratio of the first voltage dividing resistor to the second voltage dividing resistor is equal to the resistance ratio of the third voltage dividing resistor to the fourth voltage dividing resistor.
Therefore, a first voltage-dividing resistor and a second voltage-dividing resistor are arranged between the first power supply port and the first input end of the third comparator, and a third voltage-dividing resistor and a fourth voltage-dividing resistor are arranged between the second power supply port and the second input end of the third comparator, so that the third comparator can be prevented from being damaged due to overlarge voltages of the first power supply port and the second power supply port. Meanwhile, the resistance ratio of the first divider resistor to the second divider resistor is equal to the resistance ratio of the third divider resistor to the fourth divider resistor, so that the voltages of the first input end and the second input end can represent the real voltages of the first power supply port and the second power supply port.
In a further scheme, the first control switch and the second control switch are both MOS switch tubes.
Therefore, the first control switch and the second control switch both adopt MOS switch tubes, so that the circuit can be conveniently realized, and the control sensitivity is improved.
In order to achieve the second object, the operating method of the linear low dropout voltage converting circuit of the present invention comprises: acquiring a first detection signal of a first port voltage detection circuit, a second detection signal of a second port voltage detection circuit and a comparison signal of a relative voltage comparison circuit; acquiring voltage states of the first power supply port and the second power supply port according to the first detection signal, the second detection signal and the comparison signal; and controlling the first control switch or the second control switch to be conducted according to the voltage state.
According to the scheme, the working method of the linear low dropout voltage conversion circuit can detect the voltage states of the first power supply port and the second power supply port, and can control the first control switch and the second control switch according to the voltage states, so that a passage for conducting the first power supply port or the second power supply port and the low dropout linear regulator is selected, the power supply input of the low dropout linear regulator is adjusted according to the voltage states of the first power supply port and the second power supply port, the voltage difference between the input end and the output end of the low dropout linear regulator is reduced, and the conversion efficiency of the low dropout linear regulator is improved.
In a further aspect, the step of controlling the first control switch or the second control switch to be turned on according to the voltage state includes: if the first voltage of the first power supply port and the second voltage of the second power supply port are both greater than the target output voltage of the low dropout linear regulator, controlling the minimum voltage one of the first power supply port and the second power supply port to be conducted with the low dropout linear regulator; if the first voltage is greater than the target output voltage and the second voltage is less than the target output voltage, controlling the first power supply port to be conducted with the low dropout regulator; if the first voltage is less than the target output voltage and the second voltage is greater than the target output voltage, controlling the second power supply port to be conducted with the low dropout regulator; and if the first voltage of the first power supply port and the second voltage of the second power supply port are both smaller than the target output voltage of the low dropout linear regulator, controlling the maximum voltage of the first power supply port and the second power supply port to be conducted with the low dropout linear regulator.
Therefore, when the voltages of the first power supply port and the second power supply port are higher than the target output voltage, the lower voltage of the first power supply port and the second power supply port is selected as the input source of the low dropout linear regulator when the low dropout linear regulator is supplied with power, the voltage difference of input and output can be reduced, and the efficiency of the LDO is improved. If only one power supply port is higher than the target output voltage, the power supply port is selected as the input source of the low dropout linear regulator, so that the output stability of the low dropout linear regulator can be ensured. In addition, when the voltage of the low dropout regulator and the target output voltage are both lower than the target output voltage, the higher voltage of the low dropout regulator and the target output voltage is selected as the input source of the low dropout regulator, so that the output voltage of the low dropout regulator can be maintained at the higher voltage, and the work of a system can be better maintained.
In order to achieve the third object, the present invention provides a power supply device, which is provided with a linear low dropout voltage converting circuit, wherein the linear low dropout voltage converting circuit is applied to the linear low dropout voltage converting circuit.
In order to achieve the fourth object, the present invention provides a method for operating a power supply apparatus, which uses the above-mentioned method for operating a linear low dropout voltage converter circuit.
Drawings
Fig. 1 is a schematic block circuit diagram of a conventional power supply apparatus.
Fig. 2 is a schematic block circuit diagram of an embodiment of the power supply apparatus of the present invention.
Fig. 3 is a schematic circuit block diagram of a first port voltage detection circuit in an embodiment of the power supply apparatus of the present invention.
Fig. 4 is a schematic circuit block diagram of a second port voltage detection circuit in an embodiment of the power supply apparatus of the present invention.
Fig. 5 is a schematic block diagram of a relative voltage comparison circuit in an embodiment of the power supply apparatus of the present invention.
Fig. 6 is a schematic block diagram of a power control circuit in an embodiment of the power supply apparatus of the present invention.
Fig. 7 is a schematic block circuit diagram of another power control circuit in an embodiment of the power supply apparatus of the present invention.
The invention is further explained with reference to the drawings and the embodiments.
Detailed Description
As shown in fig. 2, the power supply device of the present embodiment is provided with a power supply control circuit 1 and a linear low dropout voltage converting circuit, wherein the power supply control circuit 1 is used for controlling an input-output power supply. The linear low dropout voltage conversion circuit is used for outputting a stable voltage to supply power to other circuit modules in the power supply device. The power supply device may be a mobile power supply, an in-vehicle charger, an adapter, a wireless charger, a dc-dc converter, or the like.
The linear low-dropout voltage conversion circuit comprises a first power port VP1, a second power port VP2, a first port voltage detection circuit 2, a second port voltage detection circuit 3, a relative voltage comparison circuit 4, a path selection circuit 5, a first control switch K1, a second control switch K2 and a low-dropout linear regulator 6, wherein a first input end of the relative voltage comparison circuit 4 is electrically connected with the first power port VP1, a second input end of the relative voltage comparison circuit 4 is electrically connected with the second power port VP2, an output end of the relative voltage comparison circuit 4 is electrically connected with the path selection circuit 5, an input end of the first port voltage detection circuit 2 is electrically connected with the first power port VP1, an output end of the first port voltage detection circuit 2 is electrically connected with the path selection circuit 5, an input end of the second port voltage detection circuit 3 is electrically connected with the second power port VP2, the output end of the second port voltage detection circuit 3 is electrically connected with the path selection circuit 5, the control end of the first control switch K1 and the control end of the second control switch K2 are both electrically connected with the path selection circuit 5, the low dropout regulator 6 is electrically connected with the first power port VP1 through the first control switch K1, and the low dropout regulator 6 is electrically connected with the second power port VP2 through the second control switch K2.
The first power port VP1 and the second power port VP2 may be USB-A, Micro-B, Type-C, Lightning or other types of universal interfaces. The first power port VP1 and the second power port VP2 may be used as power input ports to receive power from an external power source, or may be used as power output ports to supply power to an external device. For example, the first power port VP1 is a power input port, the second power port VP2 is a power output port, and the first power port VP1 outputs a power voltage to the second power port VP2 through the power control circuit 1 to supply power to the system.
The first port voltage detection circuit 2 is configured to detect the voltage of the first power supply port VP 1. In this embodiment, referring to fig. 3, the first port voltage detection circuit 2 includes a first comparator 21, a first input terminal of the first comparator 21 is electrically connected to the first power port VP1, a second input terminal of the first comparator 21 is electrically connected to the reference voltage terminal Vref, and an output terminal of the first comparator 21 is electrically connected to the path selection circuit 5. The voltage of the reference voltage terminal Vref is set according to the target output voltage of the low dropout regulator 6. The first port voltage detection circuit 2 is further provided with a voltage division resistor R1 and a voltage division resistor R2, a first end of the voltage division resistor R1 is electrically connected with the first power port VP1, a second end of the voltage division resistor R1 is electrically connected with a first end of the voltage division resistor R2, a second end of the voltage division resistor R2 is grounded, and a branch between the second end of the voltage division resistor R1 and the first end of the voltage division resistor R2 is electrically connected with a first input end of the first comparator 21.
The second port voltage detection circuit 3 is configured to detect the voltage of the second power supply port VP 2. In this embodiment, referring to fig. 4, the second port voltage detection circuit 3 includes a second comparator 31, a first input terminal of the second comparator 31 is electrically connected to the second power port VP2, a second input terminal of the second comparator 31 is electrically connected to the reference voltage terminal Vref, and an output terminal of the second comparator 31 is electrically connected to the path selection circuit 5. The voltage of the reference voltage terminal Vref is set according to the target output voltage of the low dropout regulator 6. The second port voltage detection circuit 3 is further provided with a voltage division resistor R3 and a voltage division resistor R4, a first end of the voltage division resistor R3 is electrically connected with the second power port VP2, a second end of the voltage division resistor R3 is electrically connected with a first end of the voltage division resistor R4, a second end of the voltage division resistor R4 is grounded, and a branch between the second end of the voltage division resistor R3 and the first end of the voltage division resistor R4 is electrically connected with a first input end of the second comparator 31.
In an alternative embodiment, when the first port voltage detection circuit 2 and the second port voltage detection circuit 3 are provided, the comparison threshold may be set. The comparison threshold can be set with a margin DeltaV and a hysteresis quantity VHYSNamely, the voltage of the first power supply port VP1 and the voltage detection determination threshold of the second power supply port VP2 are the sum of the target output voltage of the low dropout linear regulator 6 and Δ V. Wherein. The margin Δ V is set to ensure that the input voltage of the low dropout regulator 6 is sufficiently high, and to ensure that the output of the low dropout regulator 6 is stabilized at the target output voltage within the load range. Setting hysteresis quantity VHYSThe reason is to prevent the voltage of the first power port VP1 and the second power port VP2 from having ripples and glitches due to fluctuations in system power consumption, so that the comparison result of the first power port VP1 and the second power port VP2 is switched back and forth, resulting in output ripples. The setting of Δ V is determined by the internal resistance of the power tube of the low dropout regulator 6 and the maximum load current, and it is ensured that the target output voltage can be stably output in the low dropout regulator 6. If the internal resistance of the power tube of the low dropout linear regulator 6 is Ron and the maximum load current is ILoad, the delta V is larger than or equal to Iload multiplied by Ron. In the overlap hysteresis quantity VHYSThen, the comparison rising threshold of the first power port VP1 and the second power port VP2 is Vr ═ the target output voltage + Δ V + VHYSThe falling threshold is Vf — target output voltage + Δ V. When the voltage of the first power port VP1 or the voltage of the second power port VP2 is in the boosted voltage state, if the voltage of the first power port VP1 is equal to orThe voltage of the second power port VP2 is higher than Vr, and the associated comparator outputs a high level. When the voltage of the first power port VP1 or the voltage of the second power port VP2 is in a reduced voltage state, the associated comparator outputs a low level when the voltage of the first power port VP1 or the voltage of the second power port VP2 is lower than Vf.
The relative voltage comparison circuit 4 is used for comparing the voltage of the first power supply port VP1 with the voltage of the second power supply port VP 2. In this embodiment, referring to fig. 5, the relative voltage comparing circuit 4 includes a third comparator 41, a first input terminal of the third comparator 41 is electrically connected to the first power port VP1, and a second terminal of the third comparator 41 is electrically connected to the second power port VP 2. The relative voltage comparison circuit 4 further includes a voltage division resistor R5, a voltage division resistor R6, a voltage division resistor R7, and a voltage division resistor R8. The first end of the voltage dividing resistor R5 is electrically connected with the first power port VP1, the second end of the voltage dividing resistor R5 is electrically connected with the first end of the voltage dividing resistor R6, the second end of the voltage dividing resistor R6 is grounded, and the branch between the second end of the voltage dividing resistor R5 and the first end of the voltage dividing resistor R6 is electrically connected with the first input end of the third comparator 41. The first end of the voltage dividing resistor R7 is electrically connected with the second power port VP2, the second end of the voltage dividing resistor R7 is electrically connected with the first end of the voltage dividing resistor R8, the second end of the voltage dividing resistor R8 is grounded, and a branch between the second end of the voltage dividing resistor R7 and the first end of the voltage dividing resistor R8 is electrically connected with the second input end of the third comparator 41. The resistance ratio of the voltage dividing resistor R5 to the voltage dividing resistor R6 is equal to the resistance ratio of the voltage dividing resistor R7 to the voltage dividing resistor R8.
The path selection circuit 5 is configured to obtain detection results of the first port voltage detection circuit 2, the second port voltage detection circuit 3, and the relative voltage comparison circuit 4, and output control signals corresponding to the first control switch K1 and the second control switch K2 by performing logical operation on the detection results, so as to select a path for turning on the first power port VP1 or the second power port VP2 and the low dropout regulator 6. The path selection circuit 5 can be realized by a single chip microcomputer or a combinational logic circuit.
The power control circuit 1 is electrically connected to the first power port VP1 and the second power port VP2, respectively, the power control circuit 1 is used to control input and output power, and the power control circuit 1 may be provided according to actual requirements of an applied device.
Referring to fig. 6, fig. 6 is a schematic block diagram of the power control circuit 1 in the charging circuit. The power control circuit 1 includes a MOS switch transistor M1, a MOS switch transistor M2, an inductor L, a current detection resistor R9, and a charging control circuit 11, where the charging control circuit 11 controls the switching states of the MOS switch transistor M1 and the MOS switch transistor M2 to implement a charging control function, which is a known technology of a person skilled in the art and is not described herein again.
Referring to fig. 7, fig. 7 is a schematic block diagram of a circuit of the power control circuit 1 in the buck-boost dc converter. The power supply control circuit 1 comprises a MOS switch tube ML1, a MOS switch tube ML2, a MOS switch tube MR1, a MOS switch tube MR2, an inductor L2, a current detection resistor R10, a current detection resistor R11 and a buck-boost control circuit 12, wherein the buck-boost control circuit 12 realizes the buck-boost function by controlling the switching states of the MOS switch tube ML1, the MOS switch tube ML2, the MOS switch tube MR1 and the MOS switch tube MR 2.
As can also be seen from fig. 6 and 7, the first control switch K1 and the second control switch K2 are MOS switch transistors. Of course, the first control switch K1 and the second control switch K2 are implemented by components having a pass switch function, and may be provided as needed.
For better illustration of the present invention, the operation method of the linear low dropout voltage converting circuit of the present invention will be described in detail. The working method is applied to a path selection circuit 5 in a linear low-dropout voltage conversion circuit.
In this embodiment, when the linear low dropout voltage converting circuit operates, first, the first detection signal of the first port voltage detecting circuit 2, the second detection signal of the second port voltage detecting circuit 3, and the comparison signal of the relative voltage comparing circuit 4 are obtained. The first port voltage detection circuit 2 outputs a high level when the voltage of the first power supply port VP1 is greater than the reference voltage, and otherwise outputs a low level by comparing the voltage of the first power supply port VP1 with the reference voltage of the reference voltage terminal Vref. The second port voltage detection circuit 3 compares the voltage of the second power port VP2 with the reference voltage of the reference voltage terminal Vref, and when the voltage of the second power port VP2 is greater than the reference voltage, the second comparator 31 outputs a high level, otherwise, outputs a low level. The relative voltage comparison circuit 4 compares the voltage of the first power port VP1 with the voltage of the second power port VP2, and when the voltage of the first power port VP1 is greater than the voltage of the second power port VP2, the third comparator 41 outputs a high level, otherwise, outputs a low level.
Next, the voltage states of the first power port VP1 and the second power port VP2 are obtained from the first detection signal, the second detection signal, and the comparison signal. The first and second detection signals can determine whether the voltage of the first power port VP1 and the voltage of the second power port VP2 exceed the target output voltage of the differential voltage regulator 6, and the comparison signal can determine the voltage between the voltage of the first power port VP1 and the voltage of the second power port VP 2.
After the voltage state is acquired, the first control switch K1 or the second control switch K2 is controlled to be turned on according to the voltage state. After the voltage state is obtained, a path between the first power port VP1 or the second power port VP2 and the low dropout regulator 6 needs to be selectively turned on, so that the input-output voltage difference of the low dropout regulator 6 is small, and the conversion efficiency is improved.
In this embodiment, the step of controlling the first control switch K1 or the second control switch K2 to be turned on according to the voltage status includes: if the first voltage of the first power supply port VP1 and the second voltage of the second power supply port VP2 are both greater than the target output voltage of the low dropout linear regulator 6, controlling the minimum voltage of the first power supply port VP1 and the second power supply port VP2 to be conducted with the low dropout linear regulator 6; if the first voltage is greater than the target output voltage and the second voltage is less than the target output voltage, controlling the first power port VP1 to be connected with the low dropout regulator 6; if the first voltage is less than the target output voltage and the second voltage is greater than the target output voltage, controlling the second power port VP2 to be connected with the low dropout regulator 6; if the first voltage of the first power port VP1 and the second voltage of the second power port VP2 are both less than the target output voltage of the low dropout linear regulator 6, the maximum voltage of the first power port VP1 and the second power port VP2 is controlled to be turned on with the low dropout linear regulator 6. If the voltages of the first power supply port VP1 and the second power supply port VP2 are higher than the target output voltage, the lower voltage of the two is selected as the input source of the low dropout regulator 6 when supplying power to the low dropout regulator 6, so that the voltage difference between the input end and the output end of the low dropout regulator 6 can be reduced, and the conversion efficiency of the low dropout regulator 6 is improved. If only one power supply port is higher than the target output voltage, the power supply port is selected as the input source of the low dropout regulator 6, so that the output stability of the low dropout regulator 6 can be ensured. In addition, when both voltages are lower than the target output voltage, the higher voltage is selected as the input source of the low dropout regulator 6, so that the output voltage of the low dropout regulator 6 can be maintained at the higher voltage, and the operation of the system can be maintained better.
Therefore, the linear low dropout voltage conversion circuit can control the first control switch and the second control switch according to the voltage states by detecting the voltage states of the first power port and the second power port, so as to select a passage for conducting the first power port or the second power port and the low dropout linear regulator, thereby realizing the purpose of adjusting the power input of the low dropout linear regulator according to the voltage states of the first power port and the second power port, reducing the voltage difference between the input end and the output end of the low dropout linear regulator and improving the conversion efficiency of the low dropout linear regulator.
It should be noted that the above is only a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept also fall within the protection scope of the present invention.

Claims (10)

1. A linear low dropout voltage converting circuit, characterized in that: the circuit comprises a first power port, a second power port, a first port voltage detection circuit, a second port voltage detection circuit, a relative voltage comparison circuit, a path selection circuit, a first control switch, a second control switch and a low-dropout linear regulator, wherein a first input end of the relative voltage comparison circuit is electrically connected with the first power port, a second input end of the relative voltage comparison circuit is electrically connected with the second power port, an output end of the relative voltage comparison circuit is electrically connected with the path selection circuit, an input end of the first port voltage detection circuit is electrically connected with the first power port, an output end of the first port voltage detection circuit is electrically connected with the path selection circuit, an input end of the second port voltage detection circuit is electrically connected with the second power port, and an output end of the second port voltage detection circuit is electrically connected with the path selection circuit, the control end of the first control switch and the control end of the second control switch are electrically connected with the access selection circuit, the low-dropout linear regulator is electrically connected with the first power supply port through the first control switch, and the low-dropout linear regulator is electrically connected with the second power supply port through the second control switch.
2. The linear low dropout voltage converting circuit according to claim 1, wherein:
the first port voltage detection circuit comprises a first comparator, a first input end of the first comparator is electrically connected with the first power port, a second input end of the first comparator is electrically connected with the reference voltage end, and an output end of the first comparator is electrically connected with the path selection circuit.
3. The linear low dropout voltage converting circuit of claim 2, wherein:
the second port voltage detection circuit comprises a second comparator, a first input end of the second comparator is electrically connected with the second power port, a second input end of the second comparator is electrically connected with the reference voltage end, and an output end of the second comparator is electrically connected with the path selection circuit.
4. The linear low dropout voltage converting circuit according to any one of claims 1 to 3, wherein:
the relative voltage comparison circuit comprises a third comparator, wherein a first input end of the third comparator is electrically connected with the first power supply port, and a second end of the third comparator is electrically connected with the second power supply port.
5. The linear low dropout voltage converting circuit of claim 4, wherein:
the relative voltage comparison circuit further comprises a first voltage division resistor, a second voltage division resistor, a third voltage division resistor and a fourth voltage division resistor;
a first end of the first voltage-dividing resistor is electrically connected with the first power supply port, a second end of the first voltage-dividing resistor is electrically connected with a first end of the second voltage-dividing resistor, a second end of the second voltage-dividing resistor is grounded, and a branch between the second end of the first voltage-dividing resistor and the first end of the second voltage-dividing resistor is electrically connected with a first input end of the third comparator;
a first end of the third voltage-dividing resistor is electrically connected with the second power supply port, a second end of the third voltage-dividing resistor is electrically connected with a first end of the fourth voltage-dividing resistor, a second end of the fourth voltage-dividing resistor is grounded, and a branch between the second end of the third voltage-dividing resistor and the first end of the fourth voltage-dividing resistor is electrically connected with a second input end of the third comparator;
the resistance ratio of the first voltage dividing resistor to the second voltage dividing resistor is equal to the resistance ratio of the third voltage dividing resistor to the fourth voltage dividing resistor.
6. The linear low dropout voltage converting circuit according to any one of claims 1 to 3, wherein:
the first control switch and the second control switch are both MOS switch tubes.
7. An operating method of a linear low dropout voltage converting circuit, which is applied to a path selecting circuit in the linear low dropout voltage converting circuit of any one of claims 1 to 5, is characterized in that: the working method comprises the following steps:
acquiring a first detection signal of the first port voltage detection circuit, a second detection signal of the second port voltage detection circuit and a comparison signal of the relative voltage comparison circuit;
acquiring voltage states of the first power supply port and the second power supply port according to the first detection signal, the second detection signal and the comparison signal;
and controlling the first control switch or the second control switch to be conducted according to the voltage state.
8. The method of operating a linear low dropout voltage converting circuit according to claim 7, wherein:
the step of controlling the first control switch or the second control switch to be conducted according to the voltage state comprises the following steps:
if the first voltage of the first power supply port and the second voltage of the second power supply port are both greater than the target output voltage of the low dropout regulator, controlling the minimum voltage of the first power supply port and the second power supply port to be conducted with the low dropout regulator;
if the first voltage is greater than the target output voltage and the second voltage is less than the target output voltage, controlling the first power supply port to be conducted with the low dropout regulator;
if the first voltage is less than the target output voltage and the second voltage is greater than the target output voltage, controlling the second power supply port to be conducted with the low dropout regulator;
and if the first voltage of the first power supply port and the second voltage of the second power supply port are both smaller than the target output voltage of the low dropout linear regulator, controlling the maximum voltage of the first power supply port and the second power supply port to be conducted with the low dropout linear regulator.
9. A power supply device is provided with a linear low dropout voltage conversion circuit, and is characterized in that:
the linear low dropout voltage converting circuit applies the linear low dropout voltage converting circuit of any one of claims 1 to 6.
10. A method of operating a power supply device, applied to the power supply device according to claim 9, characterized in that: the method applies the operation method of the linear low dropout voltage conversion circuit according to any one of claims 7 to 8.
CN202010790781.4A 2020-08-07 2020-08-07 Linear low-dropout voltage conversion circuit and working method thereof, power supply device and working method thereof Pending CN111897387A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113012611A (en) * 2021-02-26 2021-06-22 深圳市华星光电半导体显示技术有限公司 Voltage detection circuit, display device and display driving method thereof
WO2023071833A1 (en) * 2021-11-01 2023-05-04 深圳飞骧科技股份有限公司 Multi-voltage domain-based power supply planning circuit, radio frequency amplifier and chip

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0717333A1 (en) * 1994-12-16 1996-06-19 STMicroelectronics S.A. Supply voltage selection circuit for a voltage controller
CN1310504A (en) * 2000-02-22 2001-08-29 富士通株式会社 DC-DC transfer circuit, power selection circuit and equipment
CN102591391A (en) * 2011-01-10 2012-07-18 英飞凌科技股份有限公司 Voltage regulator
CN203204489U (en) * 2013-04-26 2013-09-18 无锡中星微电子有限公司 Low-dropout regulator with multi-power input
CN104102260A (en) * 2013-04-03 2014-10-15 国民技术股份有限公司 Dual-power supply system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0717333A1 (en) * 1994-12-16 1996-06-19 STMicroelectronics S.A. Supply voltage selection circuit for a voltage controller
CN1310504A (en) * 2000-02-22 2001-08-29 富士通株式会社 DC-DC transfer circuit, power selection circuit and equipment
CN102591391A (en) * 2011-01-10 2012-07-18 英飞凌科技股份有限公司 Voltage regulator
CN104102260A (en) * 2013-04-03 2014-10-15 国民技术股份有限公司 Dual-power supply system
CN203204489U (en) * 2013-04-26 2013-09-18 无锡中星微电子有限公司 Low-dropout regulator with multi-power input

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113012611A (en) * 2021-02-26 2021-06-22 深圳市华星光电半导体显示技术有限公司 Voltage detection circuit, display device and display driving method thereof
WO2023071833A1 (en) * 2021-11-01 2023-05-04 深圳飞骧科技股份有限公司 Multi-voltage domain-based power supply planning circuit, radio frequency amplifier and chip

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Application publication date: 20201106