CN203786597U - Low-dropout linear regulator - Google Patents
Low-dropout linear regulator Download PDFInfo
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- CN203786597U CN203786597U CN201420222022.8U CN201420222022U CN203786597U CN 203786597 U CN203786597 U CN 203786597U CN 201420222022 U CN201420222022 U CN 201420222022U CN 203786597 U CN203786597 U CN 203786597U
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Abstract
The utility model discloses a low-dropout linear regulator which comprises a main circuit path, a sampling resistor network, a charge pump and an operational amplifier, wherein the main circuit path comprises a cascade structure composed of a first transistor and a second transistor which are of contrary conductive types; one end of the main circuit path is used as an input end; the other end of the main circuit path is used as an output end; the sampling resistor network is connected between the output end and the ground and used for providing sampling voltage of output voltage; the charge pump is used for generating first grid voltage and supplying the first grid voltage to the grid of the first transistor; the operational amplifier is used for generating second grid voltage according to sampling voltage and reference voltage and supplying the second grid voltage to the grid of the second transistor; the low-dropout linear regulator disclosed by the utility model is characterized by further comprising a clamping circuit; and the clamping circuit is connected between the output end of the charge pump and the power supply end of the operational amplifier and used for keeping the voltage difference between the first grid voltage and the power supply voltage of the operational amplifier at a constant value. The low-dropout linear regulator disclosed by the utility model is capable of increasing power supply rejection ratio and improving the reliability.
Description
Technical field
The utility model relates to linear voltage regulator, more specifically, relates to low pressure difference linear voltage regulator.
Background technology
Low pressure difference linear voltage regulator (low dropout regulator, is abbreviated as LDO) can provide and power supply and the irrelevant output voltage of environment temperature, has certain load capacity, has been widely used in various power chips.With respect to traditional linear voltage regulator, LDO allows the voltage difference between input end and output terminal less.For example, the input terminal voltage of LDO is the high 1.7V of specific output terminal voltage only, or less.
An important parameter of LDO is Power Supply Rejection Ratio (Power Supply Rejection Ratio, is abbreviated as PSRR), and input terminal voltage changes the ratio changing with output end voltage.If Power Supply Rejection Ratio is larger, LDO also can provide stable output end voltage under the poor situation of power environment.For example, in the time that LDO is used for driving motor, motor will produce low-frequency noise and high frequency noise.Motor produces very large current spikes in the time of work, and then is easy to cause power supply burr.The method that has proposed many raising Power Supply Rejection Ratio in existing LDO, is mainly used in suppressing low-frequency power noise.But existing LDO still may be subject to the adverse effect of high frequency electric source noise.Point power supply burr causes the fluctuation of LDO output end voltage.As a result, the Power Supply Rejection Ratio of LDO is still not good.
Therefore, expect that LDO has high PSRR, to suppress the severe jamming of the output waveform of sharp power supply burr to LDO.
Utility model content
The purpose of this utility model is to provide one can improve Power Supply Rejection Ratio, particularly suppresses the low pressure difference linear voltage regulator of sharp power supply burr.
According to the utility model, a kind of low pressure difference linear voltage regulator is provided, comprises: primary current path, comprises the cascade structure being made up of the first transistor and the transistor seconds of films of opposite conductivity, one end of this primary current path is as input end, and the other end is as output terminal; Sampling resistor network, is connected between output terminal and ground, for the sampled voltage of output voltage is provided; Charge pump, for generation of primary grid voltage, and offers primary grid voltage the grid of the first transistor; And operational amplifier, for producing second grid voltage according to sampled voltage and reference voltage, and second grid voltage is offered to the grid of transistor seconds, it is characterized in that, described low pressure difference linear voltage regulator also comprises clamp circuit, described clamp circuit is connected between electric charge delivery side of pump and the feeder ear of operational amplifier, for the voltage difference between primary grid voltage and the supply voltage of operational amplifier is maintained to steady state value.
Preferably, in described low pressure difference linear voltage regulator, described steady state value is the threshold voltage sum of the first transistor and transistor seconds.
Preferably, described low pressure difference linear voltage regulator also comprises the biasing circuit for supply voltage is provided to operational amplifier, and the supply voltage that this biasing circuit produces is weak relevant to input terminal voltage
Preferably, in described low pressure difference linear voltage regulator, described biasing circuit comprises: be connected in series in successively current source between input end and ground and the 3rd transistor and the 4th transistor of identical conduction type, wherein provide supply voltage at current source and the 3rd transistorized intermediate node.
Preferably, in described low pressure difference linear voltage regulator, the grid of each in described the 3rd transistor and described the 4th transistor and its drain electrode short circuit separately.
Preferably, in described low pressure difference linear voltage regulator, described clamp circuit comprises the 5th transistor, described the 5th transistorized grid and its drain electrode short circuit.
Preferably, in described low pressure difference linear voltage regulator, described clamp circuit also comprises and being connected with the 5th transistor series and the 6th transistor of conduction type, described the 6th transistorized grid and its drain electrode short circuit.
Preferably, in described low pressure difference linear voltage regulator, the 5th transistorized conduction type is identical with the conduction type of the first transistor, and the 6th transistorized conduction type is identical with the conduction type of transistor seconds.
Preferably, in described low pressure difference linear voltage regulator, the 5th transistorized technological parameter is identical with the technological parameter of the first transistor, and the 6th transistorized technological parameter is identical with the technological parameter of transistor seconds.
Preferably, in described low pressure difference linear voltage regulator, described clamp circuit comprises Zener diode, and wherein, the positive pole of described Zener diode is connected with the feeder ear of operational amplifier, and negative pole is connected with electric charge delivery side of pump.
Preferably, in described low pressure difference linear voltage regulator, the first transistor is the one in N-type and P type MOSFET, and transistor seconds is the another kind in N-type and P type MOSFET.
Preferably, in described low pressure difference linear voltage regulator, the 3rd transistor and the 4th transistor are the one in N-type and P type MOSFET.
Preferably, in described low pressure difference linear voltage regulator, the 5th transistor is the one in N-type and P type MOSFET, and the 6th transistor is the another kind in N-type and P type MOSFET.
Preferably, in described low pressure difference linear voltage regulator, sampling resistor network comprises the first resistance and the second resistance that are connected between output terminal and ground, and the sampled voltage of output voltage is provided at the intermediate node of the first resistance and the second resistance.
Preferably, in described low pressure difference linear voltage regulator, sampling resistor network comprises the first resistance being connected between output terminal and ground, and the sampled voltage of output voltage is provided at output terminal.
In low pressure difference linear voltage regulator of the present utility model, due to the buffer action of the first transistor, the output terminal of the low pressure difference linear voltage regulator that the power supply noise of input terminal voltage can not be delivered to via primary current path.
This low pressure difference linear voltage regulator comprises clamp circuit, makes the voltage difference between the gate drive voltage of the first transistor and the gate drive voltage of transistor seconds can maintain steady state value.Under different load currents, this low pressure difference linear voltage regulator can be realized good linear regulation effect.And even if supply voltage, temperature, technological parameter change, this low pressure difference linear voltage regulator also can ensure the normal work of the first transistor and transistor seconds.Low pressure difference linear voltage regulator of the present utility model can significantly improve Power Supply Rejection Ratio and improve its reliability.
In a preferred embodiment, this low pressure difference linear voltage regulator comprises biasing circuit.Due to the buffer action of biasing circuit, the power supply noise of input terminal voltage can be by not being delivered to the output terminal of low pressure difference linear voltage regulator yet via the output of operational amplifier.Therefore, this preferred low pressure difference linear voltage regulator can further improve Power Supply Rejection Ratio.
Brief description of the drawings
By the description to the utility model embodiment referring to accompanying drawing, above-mentioned and other objects of the present utility model, feature and advantage will be more clear, in the accompanying drawings:
Fig. 1 is according to the schematic circuit of the low pressure difference linear voltage regulator of prior art;
Fig. 2 is the schematic circuit as the low pressure difference linear voltage regulator of reference examples of the present utility model;
Fig. 3 is according to the schematic circuit of the low pressure difference linear voltage regulator of embodiment of the present utility model;
Fig. 4 is the first example according to low pressure difference linear voltage regulator of the present utility model;
Fig. 5 is the second example according to low pressure difference linear voltage regulator of the present utility model; And
Fig. 6 is the 3rd example according to low pressure difference linear voltage regulator of the present utility model.
Embodiment
Hereinafter with reference to accompanying drawing, various embodiment of the present utility model is described in more detail.In each accompanying drawing, identical element adopts same or similar Reference numeral to represent.For the sake of clarity, the various piece in accompanying drawing is not drawn in proportion.
Fig. 1 is according to the schematic circuit of the low pressure difference linear voltage regulator LDO of prior art.This LDO is the cascade structure that comprises the first transistor MN1, transistor seconds MP1, and sampling resistor R1 and R2 between transistor seconds MP1 and ground.The intermediate node of transistor seconds MP1 and sampling resistor R1 is as output terminal.
The conductivity type opposite of the first transistor MN1 and transistor seconds MP1.In an example, the first transistor MN1 is N-type MOSFET, and transistor seconds MP1 is P type MOSFET.The drain electrode of the first transistor MN1 is connected to input end, and source electrode connects the source electrode of transistor seconds MP1, and the drain electrode of transistor seconds MP1 is via sampling resistor R1 and R2 ground connection.
The first transistor MN1 is as isolated transistor.Charge pump 101 is connected to the grid of the first transistor MN1, provides grid voltage Vg1 to it.Transistor seconds MP1 is as adjusting transistor, and the variation according to output end voltage falls in its source-drain voltage.The intermediate node of sampling resistor R1 and R2 is connected to the in-phase input end of operational amplifier U01.The inverting input of operational amplifier U01 obtains reference voltage VREF, and the sampled voltage that it is obtained with in-phase input end is compared.The output terminal of operational amplifier U01 is connected to the grid of transistor seconds MP1, provides grid voltage Vg2 to it.
In the time of work, the first transistor MN1 is usually operated at saturation region.Input terminal voltage VCC provides to the drain electrode of transistor seconds MP1 via the first transistor MN1.Therefore, the fluctuation of input terminal voltage VCC only appears at the drain electrode of the first transistor MN1.Due to the buffer action of the first transistor MN1, any low-frequency noise all can not be delivered to the output terminal of transistor seconds MP1.Transistor seconds MP1 is usually operated at linear zone, is fallen and is stablized output by adjustment source-drain voltage.In the time that the sampled voltage of output voltage V LDO is less than reference voltage VREF and further reduces, the output voltage V g2 of operational amplifier output reduces, thereby output voltage is raise.On the contrary, in the time that the sampled voltage of output voltage V LDO is greater than reference voltage VREF and further increases, the output voltage V g2 of operational amplifier output raises, thereby output voltage is reduced.In power supply process, the adjustment of output voltage is carried out continuously, thereby obtains stable output end voltage VLDO.
Although the power supply noise that LDO as shown in Figure 1 can utilize the first transistor MN1 to suppress input terminal voltage VCC is delivered to output terminal via primary current path, but operational amplifier U01 is still powered by input terminal voltage VCC.The fluctuation of input terminal voltage VCC, particularly sharp power supply burr, will affect the output of operational amplifier U01 significantly, makes the grid voltage Vg2 of transistor seconds MP1 occur significantly fluctuation.Under the very large situation of power supply noise, transistor seconds MP1 even may, because sharp power supply burr is closed, make this LDO cisco unity malfunction.
Fig. 2 is the schematic circuit as the LDO of reference examples of the present utility model.On the basis of the LDO of the prior art shown in Fig. 1, change the power supply of operational amplifier U01 into independently power supply or biasing circuit power supply, for example supply voltage is VX.Other aspects of the LDO of this reference examples are identical with the LDO of the prior art shown in Fig. 1.
Owing to adopting independently power supply or biasing circuit power supply, the supply voltage of operational amplifier U01 is weak relevant to input terminal voltage VCC.The fluctuation of input terminal voltage VCC can not be delivered to the output terminal of operational amplifier U01, thereby this voltage fluctuation also can not cause the grid voltage Vg2 of transistor seconds MP1 to occur significantly fluctuation.The power supply noise that the LDO of this reference examples not only suppresses input terminal voltage VCC is delivered to output terminal via primary current path, and the power supply noise that suppresses input terminal voltage VCC is delivered to output terminal via operational amplifier U01, thereby can suppress the power supply burr of low-frequency noise and high frequency.
But, in the LDO of this reference examples, because independently power supply or biasing circuit provide supply voltage VX, the output voltage that operational amplifier U01 produces, the maximal value of the grid voltage Vg2 of transistor seconds MP1 equals supply voltage VX.The size of this supply voltage VX is extremely important to the normal work of LDO.
In order to ensure that the first transistor MN1 and transistor seconds MP1 all can normally work, Vg1 and VX must have a reasonably coupling.If Vg1 is too high with respect to VX, when LDO exports little electric current, operational amplifier U01 must export higher voltage, the grid voltage Vg2 of transistor seconds MP1 is increased, to reduce the electric current in transistor seconds MP1.If due to the restriction of supply voltage VX, the grid voltage Vg2 of transistor seconds MP1 can not be increased to required numerical value, and LDO cannot work the in the situation that of little current loading.Otherwise if Vg1 is too low, the maximum voltage difference of the grid voltage Vg1 of the first transistor MN1 and the grid voltage Vg2 of transistor seconds MP1 is restricted, the output current ability of LDO again can be not enough.
In addition, Vg1 and VX itself also can have very large difference with the variation of VCC, temperature, technological parameter.In this reference examples, adopt charge pump 101 independent of each other and independently power supply Vg1 and VX are provided, may cause the stability of this LDO and reliability not good.In some application, as electronic toy, the supply voltage of battery was worked within the scope of very wide supply voltage with service time.Correspondingly, the voltage difference between Vg1 and VX also can change a lot, and is difficult to meet desirable coupling.Should ensure that LDO can normally work, guarantee that again the contradiction of the load capacity of LDO can become more outstanding.
Fig. 3 is according to the schematic circuit of the LDO of embodiment of the present utility model.The primary current path of this LDO is identical with the LDO according to prior art shown in Fig. 1, comprises the cascade structure of the first transistor MN1, transistor seconds MP1, and sampling resistor R1 and R2 between transistor seconds MP1 and ground.The intermediate node of transistor seconds MP1 and sampling resistor R1 is as output terminal.
The conductivity type opposite of the first transistor MN1 and transistor seconds MP1.In an example, the first transistor MN1 is N-type MOSFET, and transistor seconds MP1 is P type MOSFET.The drain electrode of the first transistor MN1 is connected to input end, and source electrode connects the source electrode of transistor seconds MP1, and the drain electrode of transistor seconds MP1 is via sampling resistor R1 and R2 ground connection.
The first transistor MN1 is as isolated transistor.Charge pump 101 is connected to the grid of the first transistor MN1, provides grid voltage Vg1 to it.Transistor seconds MP1 is as adjusting transistor, and the variation according to output end voltage falls in its source-drain voltage.The intermediate node of sampling resistor R1 and R2 is connected to the in-phase input end of operational amplifier U01.The inverting input of operational amplifier U01 obtains reference voltage VREF, and the sampled voltage that it is obtained with in-phase input end is compared.The output terminal of operational amplifier U01 is connected to the grid of transistor seconds MP1, provides grid voltage Vg2 to it.
In the time of work, the first transistor MN1 is usually operated at saturation region.Input terminal voltage VCC provides to the drain electrode of transistor seconds MP1 via the first transistor MN1.Therefore, the fluctuation of input terminal voltage VCC appears at the drain electrode of the first transistor MN1.Due to the buffer action of the first transistor MN1, any low-frequency noise all can not be delivered to the output terminal of transistor seconds MP1.Transistor seconds MP1 is usually operated at linear zone, is fallen and is stablized output by adjustment source-drain voltage.In the time that the sampled voltage of output voltage V LDO is less than reference voltage VREF and further reduces, the output voltage V g2 of operational amplifier output reduces, thereby output voltage is raise.On the contrary, in the time that the sampled voltage of output voltage V LDO is greater than reference voltage VREF and further increases, the output voltage V g2 of operational amplifier output raises, thereby output voltage is reduced.In power supply process, the adjustment of output voltage is carried out continuously, thereby obtains stable output end voltage VLDO.
Different from the LDO according to prior art shown in Fig. 1, operational amplifier U01 is not directly powered by input terminal voltage VCC.Alternatively, this LDO comprises biasing circuit 102, for giving operational amplifier U01 power supply.Biasing circuit 102 is circuit modules relevant to input terminal voltage VCC, for generation of a voltage VCCD.
This LDO also comprises the clamp circuit 103 being connected between the output terminal of charge pump 101 and the feeder ear of operational amplifier U01.Clamp circuit 103 makes to keep between the output voltage V g1 of charge pump 101 and the output voltage V CCD of biasing circuit 102 constant voltage difference.
In ideal conditions, clamp circuit 103 makes this voltage difference equal the threshold voltage sum of the first transistor MN1 and transistor seconds MP1.In the time that the grid voltage Vg2 of transistor seconds MP1 equals VCCD, the first transistor MN1 conducting, and transistor seconds MP1 enters conducting state just, can carry very little load current.In the time that the grid voltage Vg2 of transistor seconds MP1 equals 0, the first transistor MN1 conducting, and the complete conducting of transistor seconds MP1, can carry maximum load current.
Fig. 4 is the first example according to LDO of the present utility model.In this LDO, sampling resistor R1 and R2 form sampling resistor network, the dividing potential drop of the output voltage V LDO that the voltage that makes the in-phase input end of operational amplifier U01 is LDO on sampling resistor R2.Also,, in the time that the output voltage of LDO is greater than reference voltage VREF, sampling resistor network comprises sampling resistor R1 and R2.
Biasing circuit 102 comprises current source Id, the 3rd transistor MN3 and the 4th transistor MN4 that are connected on successively between input terminal voltage VCC and ground.The 3rd transistor MN3 is identical with the conduction type of the 4th transistor MN4.In an example, the 3rd transistor MN3 and the 4th transistor MN4 are N-type MOSFET.The drain electrode of the 3rd transistor MN3 is connected to current source, and source electrode is connected with the drain electrode of the 4th transistor MN4.The source ground of the 4th transistor MN4.And the equal short circuit of grid of the 3rd transistor MN3 and the 4th transistor MN4 is in its drain electrode separately.Current source Id produces steady current, flow to ground from input end via the 3rd transistor MN3 and the 4th transistor MN4, thereby relevant voltage VCCD a little less than one of the intermediate node place of current source Id and the 3rd transistor MN3 generation and power supply, for giving operational amplifier U01 power supply.In another example, biasing circuit 102 can also comprise the more transistor being connected in series with the 3rd transistor MN3 and the 4th transistor MN4.In another example, the 3rd transistor MN3 and the 4th transistor MN4 can be replaced by Zener diode.
Clamp circuit 103 is included in the 5th transistor MN2 and the 6th transistor MP2 that between the output terminal of charge pump 101 and the feeder ear of operational amplifier U01, are connected in series.The conductivity type opposite of the 5th transistor MN2 and the 6th transistor MP2.In an example, the 5th transistor MN2 is N-type MOSFET, and the 6th transistor MP2 is P type MOSFET.The drain electrode of the 5th transistor MN2 is connected to the output terminal of charge pump 101, and source electrode is connected to the source electrode of the 6th transistor MP2.The drain electrode of the 6th transistor MP2 is connected to the feeder ear of operational amplifier U01.And the equal short circuit of grid of the 5th transistor MN2 and the 6th transistor MP2 is in its drain electrode separately.Charge pump 101 produces the voltage higher than VCC.Then, this voltage is by the 5th transistor MN2 and the 6th transistor MP2 clamp.As a result, voltage VCCD is also as the benchmark of the output voltage V g1 of charge pump 101.The output voltage V g1 of charge pump 101 is associated with the supply voltage VCCD of operational amplifier U01, meets following equation:
Vg1＝VCCD+Vthp+Vthn，
Wherein, Vthn is the threshold voltage of the 5th transistor MN2, and Vthp is the threshold voltage of the 6th transistor MP2.
In this LDO, operational amplifier U01 is powered separately by the biasing circuit that comprises current source Id, the 3rd transistor MN3 and the 4th transistor MN4.Therefore, the fluctuation of input terminal voltage VCC only appears at the drain electrode of the first transistor MN1.Due to the buffer action of the first transistor MN1, the power supply noise of input terminal voltage VCC can not be delivered to via primary current path the output terminal of LDO.Due to the buffer action of biasing circuit, the power supply noise of input terminal voltage VCC also can not be delivered to by affecting the output of operational amplifier U01 the output terminal of LDO.Therefore, LDO of the present utility model can significantly improve Power Supply Rejection Ratio.
Select the first transistor MN1 identical with technological parameter and the temperature characterisitic of the 6th transistor MP2 with the 5th transistor MN2, transistor seconds MP1, make the threshold voltage sum (Vthp+Vthn) of the 5th transistor MN2 and the 6th transistor MP2 be substantially equal to the threshold voltage sum of the first transistor MN1 and transistor seconds MP1.No matter how input terminal voltage VCC, environment temperature and technological parameter change, the voltage difference constant of the supply voltage VCCD of the output voltage V g1 of charge pump 101 and operational amplifier U01, the output voltage V g1 of charge pump 101 is all the time than the supply voltage VCCD of operational amplifier U01 high (Vthp+Vthn).Therefore, can guarantee that the first transistor MN1 and transistor seconds MP1 under any circumstance can normally work.That is to say that this circuit can guarantee that LDO can normally work under these conditions, and output load current to greatest extent.The drain electrode of only having MN1 that whole like this LDO is relevant with power supply VCC.Any fluctuation on VCC all can not be delivered to LDO output.The difference of LDO of the present invention and traditional LDO is the control of MN1 grid voltage.Improve the Power Supply Rejection Ratio of LDO by the path of isolation operational amplifier U01 and VCC, then, by Vg and operational amplifier U01 power supply are associated, can significantly improve the reliability of Power Supply Rejection Ratio and raising LDO.
In alternative embodiment, clamp circuit 103 can comprise a transistor in the first transistor MN1 and transistor seconds MP1.The voltage difference constant of the supply voltage VCCD of the output voltage V g1 of charge pump 101 and operational amplifier U01, is substantially equal to this transistorized threshold voltage.Select this transistorized parameter, make the first transistor M1 be operated in saturation region.
Fig. 5 is the second example according to LDO of the present utility model.In this LDO, sampling resistor network only comprises sampling resistor R2, thereby reference voltage VREF equals output voltage V LDO.
Biasing circuit 102 is identical with the biasing circuit of the LDO in the first example.Biasing circuit 102 produces one and the weak relevant voltage VCCD of power supply, for giving operational amplifier U01 power supply.Clamp circuit 103 is identical with the clamp circuit of the LDO in the first example.Clamp circuit 103 maintains the voltage difference constant of the output voltage V g1 of charge pump 101 and the supply voltage VCCD of operational amplifier U01.
Fig. 6 is the 3rd example according to LDO of the present utility model.In this LDO, biasing circuit 102 is identical with the biasing circuit of the LDO in the first example.Biasing circuit 102 produces one and the weak relevant voltage VCCD of power supply, for giving operational amplifier U01 power supply.
Clamp circuit 103 is included in the Zener diode ZD1 being connected between the output terminal of charge pump 101 and the feeder ear of operational amplifier U01.Particularly, the positive pole of Zener diode ZD1 is connected with the feeder ear of operational amplifier U01, and negative pole is connected with the output terminal of charge pump 101.The supply voltage VCCD of operational amplifier U01 is also as the benchmark of the output voltage V g1 of charge pump 101.The output voltage V g1 of charge pump 101 is associated with the supply voltage VCCD of operational amplifier U01, for example, meets following equation:
Vg1＝VCCD+V
ZD，
Wherein, V
zDfor the voltage breakdown of Zener diode.
Select the voltage breakdown V of Zener diode
zD, make it be substantially equal to the threshold voltage sum (Vthp+Vthn) of the first transistor MN1 and transistor seconds MP1.The voltage difference constant of the supply voltage VCCD of the output voltage V g1 of charge pump 101 and operational amplifier U01, the output voltage V g1 of charge pump 101 is than roughly high (Vthp+Vthn) of the supply voltage VCCD of operational amplifier U01.Therefore, can guarantee that the first transistor MN1 and transistor seconds MP1 under any circumstance can normally work.That is to say that this circuit can guarantee that LDO can normally work under these conditions, and output load current to greatest extent.The drain electrode of only having MN1 that whole like this LDO is relevant with power supply VCC.Any fluctuation on VCC all can not be delivered to LDO output.The difference of LDO of the present invention and traditional LDO is the control of MN1 grid voltage.Improve the Power Supply Rejection Ratio of LDO by the path of isolation operational amplifier U01 and VCC, then, by Vg and operational amplifier U01 power supply are associated, can significantly improve the reliability of Power Supply Rejection Ratio and raising LDO.In the above-described embodiment, each transistorized conduction type has been described.But in alternative example, each in the first to the 6th transistor can be contrary conduction type, correspondingly, needs to exchange the position of its source electrode and drain electrode in the circuit of Fig. 4.In addition, just as understood by the skilled person in the art, above-mentioned current source can be made up of auxiliary transistor, and above-mentioned charge pump can be made up of the DC converter that comprises electric capacity.
According to embodiment of the present utility model as described above, these embodiment do not have all details of detailed descriptionthe, and also not limiting this utility model is only described specific embodiment.Obviously,, according to above description, can make many modifications and variations.These embodiment are chosen and specifically described to this instructions, is in order to explain better principle of the present utility model and practical application, thereby under making, technical field technician can utilize the utility model and the amendment on the utility model basis to use well.The scope that protection domain of the present utility model should be defined with the utility model claim is as the criterion.
Claims (15)
1. a low pressure difference linear voltage regulator, comprising:
Primary current path, comprises the cascade structure being made up of the first transistor and the transistor seconds of films of opposite conductivity, and one end of this primary current path is as input end, and the other end is as output terminal;
Sampling resistor network, is connected between output terminal and ground, for the sampled voltage of output voltage is provided;
Charge pump, for generation of primary grid voltage, and offers primary grid voltage the grid of the first transistor; And
Operational amplifier, for producing second grid voltage according to sampled voltage and reference voltage, and offers second grid voltage the grid of transistor seconds,
It is characterized in that, described low pressure difference linear voltage regulator also comprises clamp circuit, described clamp circuit is connected between electric charge delivery side of pump and the feeder ear of operational amplifier, for the voltage difference between primary grid voltage and the supply voltage of operational amplifier is maintained to steady state value.
2. low pressure difference linear voltage regulator according to claim 1, is characterized in that, described steady state value is the threshold voltage sum of the first transistor and transistor seconds.
3. low pressure difference linear voltage regulator according to claim 1, is characterized in that, also comprises the biasing circuit for supply voltage is provided to operational amplifier, and the supply voltage that this biasing circuit produces is weak relevant to input terminal voltage.
4. low pressure difference linear voltage regulator according to claim 3, it is characterized in that, described biasing circuit comprises: be connected in series in successively current source between input end and ground and the 3rd transistor and the 4th transistor of identical conduction type, wherein provide supply voltage at current source and the 3rd transistorized intermediate node.
5. low pressure difference linear voltage regulator according to claim 4, is characterized in that, the grid of each in described the 3rd transistor and described the 4th transistor and its drain electrode short circuit separately.
6. low pressure difference linear voltage regulator according to claim 1, is characterized in that, described clamp circuit comprises the 5th transistor, described the 5th transistorized grid and its drain electrode short circuit.
7. low pressure difference linear voltage regulator according to claim 6, is characterized in that, described clamp circuit also comprises and being connected with the 5th transistor series and the 6th transistor of conductivity type opposite, described the 6th transistorized grid and its drain electrode short circuit.
8. low pressure difference linear voltage regulator according to claim 7, is characterized in that, the 5th transistorized conduction type is identical with the conduction type of the first transistor, and the 6th transistorized conduction type is identical with the conduction type of transistor seconds.
9. low pressure difference linear voltage regulator according to claim 7, is characterized in that, the 5th transistorized technological parameter is identical with the technological parameter of the first transistor, and the 6th transistorized technological parameter is identical with the technological parameter of transistor seconds.
10. low pressure difference linear voltage regulator according to claim 1, is characterized in that, described clamp circuit comprises Zener diode, and wherein, the positive pole of described Zener diode is connected with the feeder ear of operational amplifier, and negative pole is connected with electric charge delivery side of pump.
11. low pressure difference linear voltage regulators according to claim 1, is characterized in that, the first transistor is the one in N-type and P type MOSFET, and transistor seconds is the another kind in N-type and P type MOSFET.
12. low pressure difference linear voltage regulators according to claim 4, is characterized in that, the 3rd transistor and the 4th transistor are the one in N-type and P type MOSFET.
13. low pressure difference linear voltage regulators according to claim 7, is characterized in that, the 5th transistor is the one in N-type and P type MOSFET, and the 6th transistor is the another kind in N-type and P type MOSFET.
14. low pressure difference linear voltage regulators according to claim 1, it is characterized in that, sampling resistor network comprises the first resistance and the second resistance that are connected between output terminal and ground, and the sampled voltage of output voltage is provided at the intermediate node of the first resistance and the second resistance.
15. low pressure difference linear voltage regulators according to claim 1, is characterized in that, sampling resistor network comprises the first resistance being connected between output terminal and ground, and the sampled voltage of output voltage is provided at output terminal.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103941798A (en) * | 2014-04-30 | 2014-07-23 | 杭州士兰微电子股份有限公司 | Low dropout regulator |
| CN107479619A (en) * | 2016-06-08 | 2017-12-15 | 英飞凌科技股份有限公司 | The Self Adaptive Control of linear voltage regulator |
| CN111198589A (en) * | 2018-11-16 | 2020-05-26 | 力旺电子股份有限公司 | Reference voltage generator and operation method thereof |
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2014
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103941798A (en) * | 2014-04-30 | 2014-07-23 | 杭州士兰微电子股份有限公司 | Low dropout regulator |
| CN103941798B (en) * | 2014-04-30 | 2015-12-02 | 杭州士兰微电子股份有限公司 | Low pressure difference linear voltage regulator |
| CN107479619A (en) * | 2016-06-08 | 2017-12-15 | 英飞凌科技股份有限公司 | The Self Adaptive Control of linear voltage regulator |
| CN107479619B (en) * | 2016-06-08 | 2019-04-26 | 英飞凌科技股份有限公司 | The self adaptive control of linear voltage regulator |
| CN111198589A (en) * | 2018-11-16 | 2020-05-26 | 力旺电子股份有限公司 | Reference voltage generator and operation method thereof |
| US11086349B2 (en) | 2018-11-16 | 2021-08-10 | Ememory Technology Inc. | Reference voltage generator capable of reducing hot carrier stress |
| CN111198589B (en) * | 2018-11-16 | 2021-11-09 | 力旺电子股份有限公司 | Reference voltage generator and operation method thereof |
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