CN109270978B - Low dropout linear voltage stabilizing circuit, voltage regulation rate compensation unit and method - Google Patents
Low dropout linear voltage stabilizing circuit, voltage regulation rate compensation unit and method Download PDFInfo
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- CN109270978B CN109270978B CN201710586854.6A CN201710586854A CN109270978B CN 109270978 B CN109270978 B CN 109270978B CN 201710586854 A CN201710586854 A CN 201710586854A CN 109270978 B CN109270978 B CN 109270978B
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- 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
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
- G05F1/567—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor for temperature compensation
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Abstract
The invention provides a low dropout linear voltage regulator circuit, a voltage regulation rate compensation unit and a method, comprising generating a reference voltage by a reference voltage generation module; detecting the temperature by a temperature sensing module; when the environment temperature exceeds the set temperature, the temperature sensing module compensates the reference voltage generated by the reference voltage generating module, and then the power tube is controlled to adjust the output voltage to compensate the reduction of the output voltage caused by load adjustment. The low dropout linear voltage regulator circuit, the voltage regulation compensation unit and the method of the invention aim at the load regulation phenomenon of the low dropout linear voltage regulator circuit, and compensate the reduction of the output voltage caused by load regulation by increasing the reference voltage, thereby achieving the purpose of improving the circuit performance.
Description
Technical Field
The invention relates to the field of integrated circuit design, in particular to a low dropout linear voltage stabilizing circuit, a voltage regulation rate compensation unit and a method.
Background
Power management is an essential part of mobile portable devices, electric vehicles, power electronics systems. Electric vehicles, mobile phones, computers and various mobile power supply devices all need a power management system to improve the working efficiency and prolong the service life of the devices. However, whether the power is supplied by rectifying (or by an ac adapter) the ac mains or by a battery pack, the supply voltage will vary over a wide range during operation. The output voltages of the various rectifiers are affected not only by mains voltage variations but also by load variations. In order to ensure that the power supply voltage is stable and constant, almost all electronic equipment is supplied with power by a voltage stabilizer. Small precision electronic devices also require a very clean power supply (no ripple, no noise) so as not to affect the proper operation of the electronic device. In order to meet the requirements of precise electronic equipment, a linear voltage regulator is added at the input end of a power supply to ensure the constant voltage of the power supply and realize active noise filtering.
In dc circuits, a low dropout linear regulator is usually used to generate a stable voltage source that can provide a certain current. A conventional low dropout regulator includes a bandgap reference circuit, an operational amplifier, a power transistor, and a feedback network, and cooperates with an external output capacitor and a load resistor to provide a stable voltage. However, when the voltage output end outputs a large current, the output voltage at the voltage output end may drop to some extent due to the internal resistance of the power tube, and the larger the load current is, the more the output voltage drops, which is called as load regulation of the linear regulator.
The load adjustment directly causes the stability of the output voltage to be poor, influences the normal use of the electric device and greatly influences the system efficiency.
Therefore, how to solve the influence of the load regulation phenomenon on the output voltage and improve the power utilization efficiency has become one of the problems to be solved by those skilled in the art.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a low dropout linear voltage regulator, a voltage regulation factor compensation unit and a method thereof, which are used to solve the problem of unstable output voltage caused by the load regulation phenomenon in the prior art.
To achieve the above and other related objects, the present invention provides a voltage adjustment rate compensation unit, comprising:
the device comprises a temperature sensing module, a reference voltage generating module, a comparator and a reference adjusting module;
the temperature sensing module is used for detecting the temperature of the environment where the voltage regulation rate compensation unit is located and outputting corresponding temperature detection voltage;
the reference voltage generation module is used for generating a reference voltage and a detection voltage of the reference voltage;
the comparator is connected with the output ends of the temperature sensing module and the reference voltage generating module, compares the temperature detection voltage with the reference voltage or the detection voltage of the reference voltage, and outputs a comparison result;
the reference adjusting module is connected to the output end of the comparator, adjusts the reference voltage according to the comparison result, and increases the reference voltage when the temperature of the environment where the voltage adjustment rate compensating unit is located exceeds a set temperature, so as to compensate the reduction of the output voltage caused by load adjustment.
Preferably, the temperature sensing module includes a first current source, a second current source, a first triode and a second triode; one end of the first current source is connected with a power supply voltage, the other end of the first current source is connected with an emitting electrode of the first triode, and a connecting node of the first current source and the first triode is used as an output end of the temperature sensing module; the collector electrode of the first triode is grounded, and the base electrode of the first triode is connected with the emitter electrode of the second triode; one end of the second current source is connected with the power supply voltage, and the other end of the second current source is connected with an emitting electrode of the second triode; and the collector and the base of the second triode are grounded.
More preferably, the first current source and the second current source are a first PMOS transistor and a second PMOS transistor, respectively; the source end of the first PMOS tube is connected with the power supply voltage, the drain end of the first PMOS tube is connected with the first triode, and the grid end of the first PMOS tube is connected with a first bias voltage; the source end of the second PMOS tube is connected with the power supply voltage, the drain end of the second PMOS tube is connected with the second triode, and the grid end of the second PMOS tube is connected with the first bias voltage.
Preferably, the reference voltage generating module includes a third current source, a first resistor, a switch, a second resistor, and a third transistor; one end of the third current source is connected with a power supply voltage, the other end of the third current source is connected with one end of the first resistor, and a connection node of the third current source and the first resistor outputs the reference voltage; the other end of the first resistor is connected with one end of the second resistor after passing through the switch, and a connection node of the first resistor and the switch outputs the detection voltage of the reference voltage; the other end of the second resistor is connected with an emitting electrode of the third triode, and a grid electrode and a base electrode of the third triode are grounded.
More preferably, the third current source is a third PMOS transistor, a source terminal of the third PMOS transistor is connected to the power supply voltage, a drain terminal of the third PMOS transistor is connected to the first resistor, and a gate terminal of the third PMOS transistor is connected to the first bias voltage.
More preferably, the switch is a first NMOS transistor, a drain terminal of the first NMOS transistor is connected to the first resistor, a source terminal of the first NMOS transistor is connected to the second resistor, and a gate terminal of the first NMOS transistor is connected to the output terminal of the comparator.
More preferably, the reference adjusting module comprises a compensation resistor connected in parallel with the switch.
More preferably, a positive input terminal of the comparator is connected to the output terminal of the temperature sensing module, and a negative input terminal of the comparator is connected to the output terminal of the reference voltage generating module or an intermediate node between the first resistor and the switch.
To achieve the above and other related objects, the present invention further provides a low dropout linear voltage regulator circuit, comprising:
a power tube, a feedback network, an operational amplifier and a voltage regulation rate compensation unit according to any one of claims 1 to 8;
the source end of the power tube is connected with a power supply voltage, the drain end of the power tube is connected with the feedback network, the grid end of the power tube is connected with the output end of the operational amplifier, and the output voltage is adjusted under the control of the operational amplifier;
the input end of the operational amplifier is connected with the feedback network and the voltage regulation rate compensation unit, and compares the feedback voltage with the reference voltage to generate the control voltage of the power tube, so as to control the output voltage.
Preferably, the feedback network includes a first feedback resistor and a second feedback resistor connected in series, the first feedback resistor and the second feedback resistor are connected between the drain of the power tube and ground, and an intermediate node between the first feedback resistor and the second feedback resistor outputs the feedback voltage.
Preferably, the low dropout linear voltage regulator circuit further comprises an output capacitor and a load resistor connected to an output end of the low dropout linear voltage regulator circuit.
In order to achieve the above and other related objects, the present invention further provides a voltage regulation compensation method, based on the low dropout linear voltage regulator circuit, the voltage regulation compensation method at least includes:
when the load current is small, the ambient temperature is low, a reference voltage is generated, and the reference voltage is compared with the feedback voltage to adjust the power tube to generate a stable output voltage;
the ambient temperature rises as the load current increases, and when the ambient temperature exceeds a set temperature, the reference voltage increases to adjust the power tube to compensate for the drop of the output voltage caused by load adjustment.
Preferably, the ambient temperature is detected, and a corresponding temperature detection voltage is generated, wherein the temperature detection voltage is a negative temperature coefficient voltage.
Preferably, when the ambient temperature is lower than the set temperature, the temperature detection voltage output by the temperature sensing module is higher than the reference voltage or the detection voltage of the reference voltage, the comparator outputs a high level, and the switch short-circuits the compensation resistor; when the environment temperature exceeds the set temperature, the temperature detection voltage output by the temperature sensing module is smaller than the reference voltage or the detection voltage of the reference voltage, the comparator outputs a low level, the switch is switched off, and the compensation resistor is connected in series between the first resistor and the second resistor.
More preferably, when the ambient temperature is less than the set temperature, the reference voltage satisfies the following relation:
Vref≈Vbe+(Rbg1+Rbg2)*I；
vbe is a base-emitter voltage of the third triode, Rbg1 is a resistance value of the first resistor, Rbg2 is a resistance value of the second resistor, and I is a current value of the third current source.
More preferably, when the ambient temperature exceeds the set temperature, the reference voltage satisfies the following relation:
Vref≈Vbe+(Rbg1+Rbg2+Radj1)*I；
vbe is a base-emitter voltage of the third triode, Rbg1 is a resistance value of the first resistor, Rbg2 is a resistance value of the second resistor, Radj1 is a resistance value of the compensation resistor, and I is a current value of the third current source.
As described above, the low dropout linear voltage regulator circuit, the voltage regulation compensation unit and the method of the present invention have the following advantages:
the low dropout linear voltage regulator circuit, the voltage regulation compensation unit and the method of the invention aim at the load regulation phenomenon of the low dropout linear voltage regulator circuit, and compensate the reduction of the output voltage caused by load regulation by increasing the reference voltage, thereby achieving the purpose of improving the circuit performance.
Drawings
Fig. 1 is a schematic structural diagram of a voltage regulation compensation unit according to the present invention.
Fig. 2 is a schematic diagram of the bandgap reference circuit of the present invention.
Fig. 3 is a schematic diagram of the comparator according to the present invention.
FIG. 4 is a schematic diagram of a low dropout linear voltage regulator circuit according to the present invention.
Description of the element reference numerals
1 voltage regulation rate compensation unit
11 temperature sensing module
12 reference voltage generation module
13 comparator
14 benchmark adjustment module
2 operational amplifier
3 feedback network
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Please refer to fig. 1 to 4. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
Example one
As shown in fig. 1, the present invention provides a voltage regulation compensation unit 1, where the voltage regulation compensation unit 1 at least includes:
the temperature sensing module 11, the reference voltage generating module 12, the comparator 13 and the reference adjusting module 14.
As shown in fig. 1, the temperature sensing module 11 detects the temperature of the environment where the voltage adjustment rate compensation unit 1 is located, and outputs a corresponding temperature detection voltage Vtemp.
Specifically, the temperature sensing module 11 includes a first current source, a second current source, a first transistor PNP1, and a second transistor PNP 2. In this embodiment, the first current source is a first PMOS transistor PM1, the second current source is a second PMOS transistor PM2, and other devices capable of realizing the current source function are all applicable to the present invention, and are not limited to this embodiment. More specifically, the source terminal of the first PMOS transistor PM1 is connected to the power supply voltage VDD, the drain terminal is connected to the emitter of the first triode PNP1, and the gate terminal is connected to the first bias voltage Vpb; the collector of the first triode PNP1 is grounded, and the base of the first triode PNP1 is connected with the emitter of the second triode PNP 2; the source end of the second PMOS transistor PM2 is connected to the power supply voltage VDD, the drain end is connected to the emitter of the second triode PNP2, and the gate end is connected to the first bias voltage Vpb; the collector and base of the second transistor PNP2 are connected to ground. The base-emitter voltage (the forward voltage of the PN junction diode) of the triode has a negative temperature coefficient, and the temperature can be detected through the first triode PNP1 and the second triode PNP 2.
Specifically, the first bias voltage Vpb is generated by a bandgap reference circuit, as shown in fig. 2, the bandgap reference circuit includes a fourth PMOS transistor PM4, a fifth PMOS transistor PM5, a second NMOS transistor NM2, a third NMOS transistor NM3, a third resistor R, a fourth triode PNP4, and a fifth triode PNP 5; the source end of the fourth PMOS transistor PM4 is connected to the power supply voltage VDD, the drain end of the fourth PMOS transistor PM4 is connected to the drain end of the second NMOS transistor NM2, and the gate end of the fourth PMOS transistor PM4 is connected to the gate end of the fifth PMOS transistor PM 5; the source end of the second NMOS tube NM2 is connected with the emitter of the fourth triode PNP4, and the grid end is connected with the drain end; the base and collector of the fourth triode PNP4 are grounded; a source end of the fifth PMOS transistor PM5 is connected to the power supply voltage VDD, and a drain end is connected to a gate end and outputs the first bias voltage Vpb; the gate end of the third NMOS transistor NM3 is connected to the gate end of the second NMOS transistor NM2, and the source end of the third NMOS transistor NM3 is connected to the emitter of the fifth triode PNP5 after passing through the third resistor R; the base and collector of the fifth triode PNP5 are grounded; the number ratio of the fourth triode PNP4 to the fifth triode PNP5 is 1: and m is selected. The bandgap reference circuit may be any circuit structure capable of generating a bias voltage in the prior art, and is not limited to this embodiment.
As shown in fig. 1, the reference voltage generation module 12 is used for generating a reference voltage Vref and a detection voltage Vdet of the reference voltage.
Specifically, the reference voltage generating module 12 includes a third current source, a first resistor Rbg1, a switch, a second resistor Rbg2, and a third transistor PNP 3. In this embodiment, the third current source is a third PMOS transistor PM3, and other devices capable of realizing the current source function are all suitable for the present invention, and are not limited to this embodiment; the switch is a first NMOS transistor NM 1. Specifically, the source terminal of the third PMOS transistor PM3 is connected to the power supply voltage VDD, the drain terminal is connected to one terminal of the first resistor Rbg1, and the gate terminal is connected to the first bias voltage Vpb, and a connection node between the third PMOS transistor PM3 and the first resistor Rbg1 outputs the reference voltage Vref; the other end of the first resistor Rbg1 is connected to the drain terminal of the first NMOS transistor NM1, and the connection node of the first resistor Rbg1 and the first NMOS transistor NM1 outputs the detection voltage Vdet of the reference voltage; the source end of the first NMOS transistor NM1 is connected to one end of the second resistor Rbg2, and the gate end is connected to the output end of the comparator 13; the other end of the second resistor Rbg2 is connected with the emitter of the third triode PNP3, and the grid and the base of the third triode PNP3 are grounded.
As shown in fig. 1, the comparator 13 is connected to the output ends of the temperature sensing module 11 and the reference voltage generating module 12, compares the temperature detection voltage Vtemp with the reference voltage Vref or the detection voltage Vdet of the reference voltage, and outputs a comparison result.
Specifically, in this embodiment, the comparator 13 is connected to the temperature detection voltage Vtemp and the detection voltage Vdet of the reference voltage, and in practical use, the comparator can be connected to the temperature detection voltage Vtemp and the reference voltage Vref, which is not limited to this embodiment. More specifically, the comparator 13 has a positive input terminal connected to the output terminal of the temperature sensing module 11 and a negative input terminal connected to the output terminal of the reference voltage generating module 12, compares the temperature detection voltage Vtemp with the detection voltage Vdet of the reference voltage, and outputs a comparison result. In practical use, the same logic can be realized by increasing the polarity of the inverting input terminal of the inverter, which is not described herein.
Specifically, as shown in fig. 3, in the present embodiment, the comparator 13 includes a sixth PMOS transistor PM6, a seventh PMOS transistor PM7, an eighth PMOS transistor PM8, a fourth NMOS transistor NM4, a fifth NMOS transistor NM5, a sixth NMOS transistor NM6, a seventh NMOS transistor NM7, and an inverter. The source end of the sixth PMOS transistor PM6 is connected to the power supply voltage VDD, the drain end of the sixth PMOS transistor PM6 is connected to the drain end of the fourth NMOS transistor NM4, and the gate end of the sixth PMOS transistor PM6 is connected to the drain end; a gate end of the fourth NMOS transistor NM4 is used as a non-inverting input end of the comparator 13, and a source end of the fourth NMOS transistor NM4 is connected to a drain end of the sixth NMOS transistor NM 6; the source end of the sixth NMOS transistor NM6 is grounded, and the gate end is connected to a second bias voltage VNB; the source end of the seventh PMOS transistor PM7 is connected to the power supply voltage VDD, the drain end of the seventh PMOS transistor PM7 is connected to the drain end of the fifth NMOS transistor NM5, and the gate end of the seventh PMOS transistor PM6 is connected to the gate end of the sixth PMOS transistor PM 6; the source end of the fifth NMOS transistor NM5 is connected to the drain end and the gate end of the sixth NMOS transistor NM6 as the inverting input end of the comparator 13; the source end of the eighth PMOS transistor PM8 is connected to the power supply voltage VDD, the drain end of the eighth PMOS transistor PM8 is connected to the drain end of the seventh NMOS transistor NM7, and the gate end of the eighth PMOS transistor PM7 is connected to the drain end of the seventh PMOS transistor PM 7; the source end of the seventh NMOS transistor NM7 is grounded, and the gate end is connected to the second bias voltage VNB; the inverter is connected to the drain terminal of the eighth PMOS transistor PM 8.
As shown in fig. 1, the reference adjusting module 14 is connected to the output end of the comparator 13, adjusts the reference voltage Vref according to the comparison result, and increases the reference voltage Vref when the temperature of the environment where the voltage adjustment rate compensation unit 1 is located exceeds a set temperature, so as to compensate for the drop of the output voltage caused by load adjustment.
Specifically, in this embodiment, the reference adjustment module 14 includes a compensation resistor Radj1 connected in parallel with the first NMOSNM 1.
Example two
The invention also provides a low dropout linear voltage regulator circuit, which at least comprises:
the power transistor PM9, the feedback network 3, the operational amplifier 2, the voltage regulation compensation unit 1, the output capacitor Cout, and the load resistor Rload.
As shown in fig. 4, the source terminal of the power transistor PM9 is connected to the power supply voltage VDD, the drain terminal is connected to the feedback network 3, and the gate terminal is connected to the output terminal of the operational amplifier 2, and the output voltage Vout is adjusted under the control of the operational amplifier 2.
Specifically, the power transistor PM9 is a PMOS transistor, and different types of power transistors can be arranged according to needs in actual use, which is not limited to this embodiment.
Specifically, the feedback network 3 includes a first feedback resistor Rfb1 and a second feedback resistor Rfb2 connected in series, the first feedback resistor Rfb1 and the second feedback resistor Rfb2 are connected between the drain of the power transistor PM9 and the ground, and a feedback voltage Vfb is output at an intermediate node between the first feedback resistor Rfb1 and the second feedback resistor Rfb 2.
As shown in fig. 4, the input terminal of the operational amplifier 2 is connected to the feedback network 3 and the voltage regulation compensation unit 1, and compares the feedback voltage Vref and the reference voltage Vref to generate the control voltage of the power transistor PM9, so as to control the output voltage Vout.
Specifically, the structure and the operation principle of the voltage adjustment rate compensation unit 1 are as described above, and are not repeated herein.
Specifically, in this embodiment, the non-inverting input terminal of the operational amplifier 2 is connected to the feedback network 3, and the inverting input terminal is connected to the voltage regulation compensation unit 1; when the feedback voltage Vfb is greater than the reference voltage Vref, the operational amplifier 2 outputs a high level, and when the feedback voltage Vfb is less than the reference voltage Vref, the operational amplifier 2 outputs a low level. In practical applications, signals connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier 2 may be interchanged, and the same logic relationship is realized by adding an inverter, which is not limited to this embodiment.
As shown in fig. 4, the output capacitor Cout and the load resistor Rload are connected to the output end of the low dropout linear voltage regulator circuit.
Specifically, in this embodiment, the upper plate of the output capacitor Cout is connected to the drain of the power transistor PM9, and the lower plate is grounded, so as to stabilize the output voltage Vout. One end of the load resistor Rload is connected with the drain end of the power tube PM9, and the other end is grounded.
EXAMPLE III
The invention also provides a voltage regulation rate compensation method, based on the low dropout linear voltage regulator circuit, the voltage regulation rate compensation method at least comprises the following steps:
when the load current is small, the ambient temperature is low, a reference voltage is generated, and the reference voltage is compared with the feedback voltage to adjust the power tube to generate a stable output voltage;
the ambient temperature rises as the load current increases, and when the ambient temperature exceeds a set temperature, the reference voltage increases to adjust the power tube to compensate for the drop of the output voltage caused by load adjustment.
The set temperature can be set according to a specific circuit structure and a required load current, which are not described herein in detail.
Specifically, as shown in fig. 4, when the load current is small, the load current acts on the feedback network 3, and the corresponding feedback voltage Vfb is obtained.
At this time, the reference voltage generating module 12 generates the reference voltage Vref, specifically, as shown in fig. 1, the first bias voltage Vpb is applied to the third PMOS transistor PM3 to form a current source, and the current source flows through the first resistor Rbg1, the first NMOS transistor NM1 (the first NMOS transistor NM1 is turned on, and the compensation resistor Radj1 is shorted), the second resistor Rbg2, and the third transistor PNP 3; as can be seen from fig. 2, the current source satisfies the following relation: i ═ Vt × ln (m) ]/R, where Vt is a Thermal voltage (Thermal voltage) of the transistor, m is a number ratio of the five transistor PNP5 to the fourth transistor PNP4, and R is a resistance value of the third resistor R; the drain terminal of the third PMOS transistor PM3 outputs the reference voltage Vref, and the following relationship is satisfied: vref ≈ Vbe + (Rbg1+ Rbg2)/R × Vt × ln (m), where Vbe is a base-emitter voltage of the third triode PNP3, Rbg1 is a resistance value of the first resistor Rbg1, and Rbg2 is a resistance value of the second resistor Rbg 2; a connection node of the first resistor Rbg1 and the first NMOS transistor NM1 outputs a detection voltage Vdet of the reference voltage.
The temperature sensing module 11 detects a temperature of an environment where the low dropout linear voltage regulator circuit is located, specifically, as shown in fig. 1, the first bias voltage Vpb acts on the first PMOS transistor PM1 and the second PMOS transistor PM2 to form a current source, and the current source flows through the first triode PNP1 and the second triode PNP2 to generate the temperature detection voltage Vtemp, and the temperature detection voltage Vtemp also has a negative temperature coefficient because a base-emitter voltage (a forward voltage of a PN junction diode) of the triode has a negative temperature coefficient. The temperature detection voltage Vtemp satisfies the following relational expression: vtemp is 2 × Vbe, where Vbe is the base-emitter voltages of the first transistor PNP1 and the second transistor PNP2, and in this embodiment, the device parameters of the first transistor PNP1 and the second transistor PNP2 are completely the same.
The comparator 13 compares the detection voltage Vdet of the reference voltage with the temperature detection voltage Vtemp, and in practical application, the reference voltage Vref may be compared with the temperature detection voltage Vtemp, which is not limited in this embodiment. Because the load current ratio is small and does not have a large influence on the environment where the low dropout linear voltage regulator circuit is located, the temperature detection voltage Vtemp does not influence the output result of the comparator 13, the comparator 13 outputs a high level, the first NMOS transistor NM1 is still in a conducting state, and the reference voltage Vref remains unchanged.
As shown in fig. 4, the operational amplifier 2 compares the feedback voltage Vfb with the reference voltage Vref, and controls the power transistor PM9 to obtain a stable output voltage Vout.
Specifically, as shown in fig. 4, when the load current increases, the temperature of the environment where the low dropout linear voltage regulator circuit is located may increase due to the existence of the package thermal resistance θ j. As shown in fig. 1, the temperature detection voltage Vtemp decreases with the increase of temperature under the action of negative temperature characteristics, when the temperature detection voltage Vtemp is smaller than the detection voltage Vdet of the reference voltage, the output result of the comparator 13 jumps to a low level, the first NMOS transistor NM1 is turned off, the compensation resistor Radj1 is connected in series between the first resistor Rbg1 and the second resistor Rbg2, and the reference voltage Vref is compensated when the current output by the current source is constant, and at this time, the reference voltage Vref satisfies the following relationship: vref ≈ Vbe + (Rbg1+ Rbg2+ Radj1)/R × Vt × ln (m), and the increased portion of the reference voltage Vref is the voltage drop of the current source acting on the compensation resistor Radj 1.
As shown in fig. 4, the operational amplifier 2 compares the feedback voltage Vfb with the reference voltage Vref, and controls the power transistor PM9 to compensate for the drop of the output voltage Vout caused by load adjustment, so as to stabilize the output voltage Vout.
The low dropout linear voltage regulator circuit, the voltage regulation compensation unit and the method of the invention aim at the load regulation phenomenon of the low dropout linear voltage regulator circuit, and compensate the reduction of the output voltage caused by load regulation by increasing the reference voltage, thereby achieving the purpose of improving the circuit performance.
In summary, the present invention provides a low dropout linear voltage regulator, a voltage regulation compensation unit and a method thereof, including: generating a reference voltage by a reference voltage generating module; detecting the temperature by a temperature sensing module; when the environment temperature exceeds the set temperature, the temperature sensing module compensates the reference voltage generated by the reference voltage generating module, and then the power tube is controlled to adjust the output voltage to compensate the reduction of the output voltage caused by load adjustment. The low dropout linear voltage regulator circuit, the voltage regulation compensation unit and the method of the invention aim at the load regulation phenomenon of the low dropout linear voltage regulator circuit, and compensate the reduction of the output voltage caused by load regulation by increasing the reference voltage, thereby achieving the purpose of improving the circuit performance. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (16)
1. A voltage regulation rate compensation unit is applied to a low dropout linear voltage regulator circuit, and is characterized by at least comprising:
the device comprises a temperature sensing module, a reference voltage generating module, a comparator and a reference adjusting module;
the temperature sensing module is used for detecting the temperature of the environment where the voltage regulation rate compensation unit is located and outputting corresponding temperature detection voltage;
the reference voltage generation module is used for generating a reference voltage and a detection voltage of the reference voltage;
the comparator is connected with the output ends of the temperature sensing module and the reference voltage generating module, compares the temperature detection voltage with the reference voltage or the detection voltage of the reference voltage, and outputs a comparison result;
the reference adjusting module is connected to the output end of the comparator, adjusts the reference voltage according to the comparison result, increases the reference voltage when the temperature of the environment where the voltage adjustment rate compensating unit is located exceeds a set temperature, and uses the reference voltage as the reference input of the low dropout linear voltage stabilizing circuit so as to compensate the reduction of the output voltage of the low dropout linear voltage stabilizing circuit caused by load adjustment.
2. The voltage regulation rate compensation unit of claim 1, wherein: the temperature sensing module comprises a first current source, a second current source, a first triode and a second triode; one end of the first current source is connected with a power supply voltage, the other end of the first current source is connected with an emitting electrode of the first triode, and a connecting node of the first current source and the first triode is used as an output end of the temperature sensing module; the collector electrode of the first triode is grounded, and the base electrode of the first triode is connected with the emitter electrode of the second triode; one end of the second current source is connected with the power supply voltage, and the other end of the second current source is connected with an emitting electrode of the second triode; and the collector and the base of the second triode are grounded.
3. The voltage regulation rate compensation unit of claim 2, wherein: the first current source and the second current source are respectively a first PMOS tube and a second PMOS tube; the source end of the first PMOS tube is connected with the power supply voltage, the drain end of the first PMOS tube is connected with the first triode, and the grid end of the first PMOS tube is connected with a first bias voltage; the source end of the second PMOS tube is connected with the power supply voltage, the drain end of the second PMOS tube is connected with the second triode, and the grid end of the second PMOS tube is connected with the first bias voltage.
4. The voltage regulation rate compensation unit of claim 1, wherein: the reference voltage generating module comprises a third current source, a first resistor, a switch, a second resistor and a third triode; one end of the third current source is connected with a power supply voltage, the other end of the third current source is connected with one end of the first resistor, and a connection node of the third current source and the first resistor outputs the reference voltage; the other end of the first resistor is connected with one end of the second resistor after passing through the switch, and a connection node of the first resistor and the switch outputs the detection voltage of the reference voltage; the other end of the second resistor is connected with an emitting electrode of the third triode, and a grid electrode and a base electrode of the third triode are grounded.
5. The voltage regulation rate compensation unit of claim 4, wherein: the third current source is a third PMOS tube, the source end of the third PMOS tube is connected with the power voltage, the drain end of the third PMOS tube is connected with the first resistor, and the gate end of the third PMOS tube is connected with the first bias voltage.
6. The voltage regulation rate compensation unit of claim 4, wherein: the switch is a first NMOS tube, the drain end of the first NMOS tube is connected with the first resistor, the source end of the first NMOS tube is connected with the second resistor, and the grid end of the first NMOS tube is connected with the output end of the comparator.
7. The voltage regulation rate compensation unit of claim 4, wherein: the reference adjustment module includes a compensation resistor in parallel with the switch.
8. The voltage regulation rate compensation unit of claim 4, wherein: and the positive phase input end of the comparator is connected with the output end of the temperature sensing module, and the negative phase input end of the comparator is connected with the output end of the reference voltage generating module.
9. A low dropout linear voltage regulator circuit, comprising at least:
a power tube, a feedback network, an operational amplifier and a voltage regulation rate compensation unit according to any one of claims 1 to 8;
the source end of the power tube is connected with a power supply voltage, the drain end of the power tube is connected with the feedback network, the grid end of the power tube is connected with the output end of the operational amplifier, and the output voltage is adjusted under the control of the operational amplifier;
the input end of the operational amplifier is connected with the feedback network and the voltage regulation rate compensation unit, and compares the feedback voltage with the reference voltage to generate the control voltage of the power tube, so as to control the output voltage.
10. The low dropout linear voltage regulator circuit of claim 9, wherein: the feedback network comprises a first feedback resistor and a second feedback resistor which are connected in series, the first feedback resistor and the second feedback resistor are connected between the drain end of the power tube and the ground, and the intermediate node of the first feedback resistor and the intermediate node of the second feedback resistor outputs the feedback voltage.
11. The low dropout linear voltage regulator circuit of claim 9, wherein: the low dropout linear voltage regulator circuit further comprises an output capacitor and a load resistor which are connected to the output end of the low dropout linear voltage regulator circuit.
12. A voltage regulation rate compensation method according to any one of claims 9 to 11, wherein the voltage regulation rate compensation method at least comprises:
when the load current is small, the ambient temperature is low, a reference voltage is generated, and the reference voltage is compared with the feedback voltage to adjust the power tube to generate a stable output voltage;
the ambient temperature rises as the load current increases, and when the ambient temperature exceeds a set temperature, the reference voltage increases to adjust the power tube to compensate for the drop of the output voltage caused by load adjustment.
13. The voltage regulation rate compensation method of claim 12, wherein: and detecting the environment temperature and generating corresponding temperature detection voltage, wherein the temperature detection voltage is negative temperature coefficient voltage.
14. The voltage regulation rate compensation method of claim 12, wherein: the reference voltage generating module comprises a third current source, a first resistor, a switch, a second resistor and a third triode; one end of the third current source is connected with a power supply voltage, the other end of the third current source is connected with one end of the first resistor, and a connection node of the third current source and the first resistor outputs the reference voltage; the other end of the first resistor is connected with one end of the second resistor after passing through the switch, and a connection node of the first resistor and the switch outputs the detection voltage of the reference voltage; the other end of the second resistor is connected with an emitting electrode of the third triode, and a grid electrode and a base electrode of the third triode are grounded; then the process of the first step is carried out,
when the environment temperature is lower than the set temperature, the temperature detection voltage output by the temperature sensing module is higher than the reference voltage or the detection voltage of the reference voltage, the comparator outputs a high level, and the switch short-circuits the compensation resistor in the reference adjusting module; when the environment temperature exceeds the set temperature, the temperature detection voltage output by the temperature sensing module is smaller than the reference voltage or the detection voltage of the reference voltage, the comparator outputs a low level, the switch is switched off, and the compensation resistor is connected in series between the first resistor and the second resistor.
15. The voltage regulation rate compensation method of claim 14, wherein: when the environment temperature is lower than the set temperature, the reference voltage satisfies the following relational expression:
Vref≈Vbe+(Rbg1+Rbg2)*I；
vbe is a base-emitter voltage of the third triode, Rbg1 is a resistance value of the first resistor, Rbg2 is a resistance value of the second resistor, and I is a current value of the third current source.
16. The voltage regulation rate compensation method of claim 14, wherein: when the environment temperature exceeds the set temperature, the reference voltage satisfies the following relational expression:
Vref≈Vbe+(Rbg1+Rbg2+Radj1)*I；
vbe is a base-emitter voltage of the third triode, Rbg1 is a resistance value of the first resistor, Rbg2 is a resistance value of the second resistor, Radj1 is a resistance value of the compensation resistor, and I is a current value of the third current source.
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| CN110442179B (en) * | 2019-09-06 | 2024-04-30 | 深圳讯达微电子科技有限公司 | Low-dropout linear voltage regulator capable of eliminating influence of connecting line resistance and elimination method |
| CN112309995B (en) * | 2019-10-30 | 2023-05-30 | 成都华微电子科技股份有限公司 | Ceramic tube shell of voltage regulator, packaging structure and manufacturing method thereof |
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| CN101881986B (en) * | 2010-07-09 | 2011-12-21 | 无锡市晶源微电子有限公司 | Ultralow temperature coefficient band-gap reference circuit based on mixed-mode high-order compensation |
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