CN213182462U - High-stability low-dropout linear voltage regulator - Google Patents
High-stability low-dropout linear voltage regulator Download PDFInfo
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Abstract
A high-stability low-dropout linear regulator comprises a voltage difference amplifying unit, a mirror image conversion unit, a sampling unit, a first feedback unit and a second feedback unit. The embodiment of the utility model provides a can compare and amplify reference voltage and the voltage signal of sampling unit feedback through the pressure difference amplification unit; the current output by the differential pressure amplification unit can be mirrored and amplified through the mirror image amplification unit, so that the mirror image conversion unit can be controlled to work; the first power supply voltage and the second power supply voltage can be virtually short through the mirror image conversion unit, so that when the second power supply voltage changes, feedback can be carried out through the first feedback unit, errors generated by the second power supply voltage can be further corrected, and the power supply rejection ratio is increased. The feedback signal of the mirror image conversion unit is output to the input end of the mirror image amplification unit through the second feedback unit, so that the number of feedback intermediate links is reduced, and a basis for quick feedback is provided.
Description
Technical Field
The utility model belongs to the electronic circuit field, concretely relates to high stability low dropout linear voltage regulator.
Background
The low dropout regulator is a new generation of integrated circuit regulator, has the advantages of low cost, low output noise, simple circuit structure, small occupied chip area, low power consumption and the like, and is widely applied in numerous fields at present. Conventional linear voltage regulators such as 78xx series chips require that the input voltage be higher than the output voltage by more than 2V to 3V, otherwise they cannot operate normally. However, in some cases, such conditions are obviously too harsh, e.g. 5v to 3.3v, and the pressure difference between input and output is only 1.7v, which is obviously not satisfactory. In response to this situation, low dropout linear regulators have been proposed.
The operation of a low dropout linear regulator generally requires two supply voltages: the feedback loop of the conventional low dropout linear regulator only works in the voltage domain of the first power supply voltage. Therefore, once the second power supply voltage is changed, the output voltage of the low dropout linear regulator is difficult to be corrected, and the stability is difficult to be ensured. In addition, the conventional low dropout linear regulator generally has the problem of slow feedback speed.
The term of art: LDO: english abbreviation of low dropout linear regulator; vgs: the grid of the MOS tube is relative to the voltage of the drain.
SUMMERY OF THE UTILITY MODEL
The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a high stability low dropout linear regulator, the slow problem of output poor stability and feedback circuit feedback speed has been solved.
According to the utility model discloses high stability low dropout regulator, include:
the voltage difference amplifying unit is provided with a grounding end for connecting a ground wire, a power supply voltage end for connecting a first power supply voltage, a reference voltage end, a feedback input end and an output end; the voltage difference amplifying unit is used for amplifying the voltage difference between the reference voltage end and the feedback input end;
the mirror image amplification unit is provided with an input end connected with the output end of the voltage difference amplification unit, a grounding end connected with the ground wire, a power supply voltage end connected with the first power supply voltage, an output end, a feedback input end and a feedback output end; the mirror image amplifying unit is used for amplifying the current mirror image of the input end of the mirror image amplifying unit;
the image conversion unit is provided with an input end connected with the output end of the image amplification unit, a first power supply voltage end connected with the first power supply voltage, a second power supply voltage end used for connecting a second power supply voltage, a grounding end connected with a ground wire, an output end used for providing output voltage, a first feedback output end and a second feedback output end connected with the feedback input end of the image amplification unit; the mirror image conversion unit is used for virtually shortening the second power supply voltage and the first power supply voltage and mirroring the current of the input end of the mirror image conversion unit;
the sampling unit is provided with a first connecting end, a second connecting end and a feedback output end, wherein the first connecting end is connected with the output end of the mirror image conversion unit, the second connecting end is connected with the ground wire, and the feedback output end is connected with the feedback input end of the differential pressure amplification unit; the sampling unit is used for sampling the output voltage and outputting the sampled output voltage to the differential pressure amplifying unit;
the first feedback unit is connected between the feedback output end of the mirror image amplification unit and the input end of the mirror image amplification unit and is used for correcting errors caused by second power supply voltage fluctuation;
and the input end of the second feedback unit is connected with the first feedback output end of the mirror image conversion unit, the output end of the second feedback unit is connected with the input end of the mirror image amplification unit, and the second feedback unit is used for improving the stability of the output voltage.
According to the utility model discloses high stability low dropout linear regulator has following technological effect at least: the voltage difference amplifying unit can compare and amplify the reference voltage and the voltage signal fed back by the sampling unit; the current output by the differential pressure amplification unit can be mirrored and amplified through the mirror image amplification unit, so that the mirror image conversion unit can be controlled to work; the first power supply voltage and the second power supply voltage can be virtually short through the mirror image conversion unit, so that when the second power supply voltage changes, feedback can be carried out through the first feedback unit, errors generated by the second power supply voltage can be further corrected, and the power supply rejection ratio is increased. The output voltage can be directly fed back to the differential pressure amplifying unit through the sampling unit, and the purpose of adjusting the output voltage is further achieved. The feedback signal of the mirror image conversion unit is output to the input end of the mirror image amplification unit through the second feedback unit, so that the number of feedback intermediate links is reduced, and a basis for quick feedback is provided.
According to some embodiments of the invention, the pressure difference amplification unit comprises: the source electrode of the first N-channel MOS tube is connected with the ground wire, and the grid electrode of the first N-channel MOS tube is connected with the drain electrode; the source electrode of the second N-channel MOS tube is connected with the ground wire, the grid electrode of the second N-channel MOS tube is connected with the grid electrode of the first N-channel MOS tube, and the drain electrode of the second N-channel MOS tube is used as the output end of the differential pressure amplification unit; the drain electrode of the first P-channel MOS tube is connected with the drain electrode of the first N-channel MOS tube, and the grid electrode of the first P-channel MOS tube is connected with the feedback output end of the sampling unit; the drain electrode of the second P-channel MOS tube is connected with the drain electrode of the second N-channel MOS tube, the grid electrode of the second P-channel MOS tube is used as a reference voltage end of the differential pressure amplification unit, and the source electrode of the second P-channel MOS tube is connected with the source electrode of the first P-channel MOS tube; and one end of the first current source is connected with the source electrode of the second P-channel MOS tube, and the other end of the first current source is used for connecting the first power supply voltage.
According to some embodiments of the invention, the mirror image amplification unit comprises: a grid electrode of the third N-channel MOS tube is respectively connected with the output end of the differential pressure amplifying unit and the output end of the second feedback unit, and a source electrode of the third N-channel MOS tube is connected with the ground wire; a grid electrode of the fourth N-channel MOS tube is connected with a drain electrode of the third N-channel MOS tube, and the first feedback unit is connected between the drain electrode and the grid electrode of the third N-channel MOS tube; a fifth N-channel MOS tube, wherein the source electrode of the fifth N-channel MOS tube is connected with the ground wire, the drain electrode of the fifth N-channel MOS tube is connected with the source electrode of the fourth N-channel MOS tube, and the grid electrode of the fifth N-channel MOS tube is connected with the second feedback output end of the mirror image conversion unit; a drain electrode of the third P-channel MOS transistor is connected with a drain electrode of the fourth N-channel MOS transistor, a gate electrode of the third P-channel MOS transistor is connected with a drain electrode of the third P-channel MOS transistor, and a source electrode of the third P-channel MOS transistor is used for connecting the first power supply voltage; a grid electrode of the fourth P-channel MOS tube is connected with the grid electrode of the third P-channel MOS tube, and a source electrode of the fourth P-channel MOS tube is connected with the source electrode of the third P-channel MOS tube; a grid electrode of the sixth N-channel MOS tube is respectively connected with a drain electrode and the input end of the mirror image amplification unit, the drain electrode of the sixth N-channel MOS tube is connected with the drain electrode of the fourth P-channel MOS tube, and a source electrode of the sixth N-channel MOS tube is connected with the first connection end of the sampling unit; and one end of the second current source is connected with the drain electrode of the third N-channel MOS tube, and the other end of the second current source is used for connecting the first power supply voltage.
According to some embodiments of the present invention, the mirror image conversion unit comprises: a gate of the seventh N-channel MOS transistor is connected to the output terminal of the mirror amplification unit, a source of the seventh N-channel MOS transistor is connected to the first connection terminal of the sampling unit, and a drain of the seventh N-channel MOS transistor is used for connecting the second supply voltage; a gate of the eighth N-channel MOS transistor is connected to the gate of the seventh N-channel MOS transistor, a drain of the eighth N-channel MOS transistor is connected to the drain of the seventh N-channel MOS transistor, a first feedback resistor is connected between a source of the eighth N-channel MOS transistor and the first connection end of the sampling unit, and the source of the eighth N-channel MOS transistor is also connected to the input end of the second feedback unit; the negative input end of the operational amplifier unit is connected with the drain electrode of the eighth N-channel MOS tube; a fifth P-channel MOS transistor, a gate of which is connected to the output terminal of the operational amplifier unit, a drain of which is connected to the positive input terminal of the operational amplifier unit, and a source of which is used for connecting the first supply voltage; a ninth N-channel MOS transistor, a gate of which is connected to the gate of the eighth N-channel MOS transistor, a drain of which is connected to the drain of the fifth P-channel MOS transistor, and a source of which is connected to the first connection end of the sampling unit; a gate of the sixth P-channel MOS transistor is connected to a gate of the fifth P-channel MOS transistor, and a source of the sixth P-channel MOS transistor is used for connecting the first power supply voltage; a tenth N-channel MOS tube, the drain of which is connected with the drain of the sixth P-channel MOS tube, the gate of which is connected with the source, and the source of which is connected with the ground wire; the grid electrode of the eleventh N-channel MOS tube is connected with the grid electrode of the tenth N-channel MOS tube, the source electrode of the eleventh N-channel MOS tube is connected with the ground wire, and the drain electrode of the eleventh N-channel MOS tube is connected with the feedback input end of the mirror image amplification unit; and one end of the third current source is connected with the drain electrode of the eleventh N-channel MOS tube, and the other end of the third current source is used for connecting the first power supply voltage.
According to some embodiments of the invention, the third current source is a variable current source.
According to some embodiments of the present invention, the sampling unit comprises a first sampling resistor and a second sampling resistor sequentially connected between the output end of the image conversion unit and the ground line; and the common connecting end of the first sampling resistor and the second sampling resistor is connected with the feedback input end of the differential pressure amplifying unit.
According to some embodiments of the invention, the first sampling resistor and/or the second sampling resistor is/are an adjustable resistor.
According to some embodiments of the invention, the first feedback unit comprises: a gate of the seventh P-channel MOS transistor is connected to the feedback output end of the mirror amplification unit, and a drain of the seventh P-channel MOS transistor is connected to the input end of the mirror amplification unit; and one end of the fourth current source is connected with the source electrode of the seventh P-channel MOS tube, and the other end of the fourth current source is used for connecting a first power supply voltage.
According to some embodiments of the present invention, the second feedback unit includes a first feedback capacitor connected between the input of the mirror image amplification unit and the first feedback output of the mirror image conversion unit.
According to the utility model discloses a some embodiments, above-mentioned high stability low dropout linear regulator still includes the mirror image acquisition circuit, the mirror image acquisition circuit is used for gathering through the mirror image circuit structure the output current of mirror image conversion unit.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic diagram of a high stability low dropout linear regulator according to an embodiment of the present invention;
FIG. 2 is a typical circuit diagram of a conventional low dropout linear regulator;
fig. 3 is a schematic diagram of a third current source of an embodiment of the present invention using a variable current source;
fig. 4 is a simulation diagram of gain and phase margin under different loads (low current load) of the high stability low dropout linear regulator according to the embodiment of the present invention;
fig. 5 is a simulation diagram of gain and phase margin (heavy current load) of the high-stability low-dropout linear regulator according to the embodiment of the present invention under different loads.
Reference numerals:
a differential pressure amplifying unit 100,
A mirror image amplifying unit 200,
A mirror image conversion unit 300,
A sampling unit 400,
A first feedback unit 500,
A second feedback unit 600,
The image acquisition circuit 700.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.
In the description of the present invention, if there are first, second, third, fourth, etc. described, it is only for the purpose of distinguishing technical features, and it is not understood that relative importance is indicated or implied or that the number of indicated technical features is implicitly indicated or that the precedence of the indicated technical features is implicitly indicated.
In the description of the present invention, unless there is an explicit limitation, the words such as setting and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the above words in the present invention by combining the specific contents of the technical solution.
A high-stability low dropout linear regulator according to an embodiment of the present invention is described below with reference to fig. 1 to 5.
According to the utility model discloses high stability low dropout linear regulator, including pressure differential amplification unit 100, mirror image amplification unit 200, mirror image conversion unit 300, the first feedback unit 500 of sampling unit 400, second feedback unit 600.
The voltage difference amplifying unit 100 is provided with a grounding end for connecting a ground wire, a power supply voltage end for connecting a first power supply voltage VDD1, a reference voltage end, a feedback input end and an output end; the voltage difference amplifying unit 100 is configured to amplify a voltage difference between a reference voltage terminal and a feedback input terminal; the reference voltage end is used for connecting a reference voltage Vref, and the feedback input end is used for connecting a feedback signal Vb transmitted by the feedback output end of the sampling unit 400;
the mirror image amplification unit 200 has an input end connected to the output end of the voltage difference amplification unit 100, a ground end connected to the ground line, a power supply voltage end connected to the first power supply voltage VDD1, an output end, a feedback input end, and a feedback output end; the mirror amplification unit 200 is configured to mirror-amplify a current at an input end thereof;
the mirror image conversion unit 300 has an input terminal connected to the output terminal of the mirror image amplification unit 200, a first power supply voltage terminal connected to the first power supply voltage VDD1, a second power supply voltage terminal for connecting to the second power supply voltage VDD2, a ground terminal connected to ground, an output terminal for providing an output voltage, a first feedback output terminal, and a second feedback output terminal connected to the feedback input terminal of the mirror image amplification unit 200; the image conversion unit 300 is used for virtually shorting the second supply voltage VDD2 and the first supply voltage VDD1 and mirroring the current at the input terminals thereof;
the sampling unit 400 has a first connection end, a second connection end, and a feedback output end, wherein the first connection end is connected with the output end of the mirror image conversion unit 300, the second connection end is connected with the ground wire, and the feedback output end is connected with the feedback input end of the differential pressure amplification unit 100; the sampling unit 400 is used for sampling the output voltage and outputting the sampled output voltage to the differential pressure amplifying unit 100;
a first feedback unit 500, connected between the feedback output terminal of the mirror amplification unit 200 and the input terminal of the mirror amplification unit 200, for correcting an error caused by the fluctuation of the second supply voltage VDD 2;
an input end of the second feedback unit 600 is connected to the first feedback output end of the mirror image conversion unit 300, an output end of the second feedback unit 600 is connected to an input end of the mirror image amplification unit 200, and the second feedback unit 600 is configured to improve stability of the output voltage.
Before introducing the embodiment of the present invention, a simple introduction is first performed on a conventional low dropout regulator.
Fig. 2 shows a typical circuit of a conventional low dropout regulator, in fig. 2, P101, P102, P103, and M102 are P-channel MOS transistors, N101, N102, M101, and M _ device are N-channel MOS transistors, and the rule in the figure is: the lower side of the N-channel MOS tube in the figure is a source electrode, the upper side of the N-channel MOS tube is a drain electrode, and the lower side of the P-channel MOS tube in the figure is a drain electrode, and the upper side of the P-channel MOS tube is a source electrode. Fig. 1 may refer to the rules of fig. 2. Regardless of small signals and load variations, ideally:
Vout1＝Vref1*(R101+R102)/R102
where Vout1 is the output voltage of the low dropout regulator, R101 and R102 are divider resistors, and Vref1 is the reference input voltage.
Because the load current is subjected to uncertain change, the value of the output voltage Vout1 cannot be guaranteed to be an ideal value all the time, so that the conventional low dropout linear regulator adopts a negative feedback circuit, and the current is negatively fed back to the gate of the MOS transistor N101 through the MOS transistors M101, M102 and P101 in the negative feedback circuit. After negative feedback is formed, when the load current suddenly increases, the feedback current also increases, the gate voltage of the MOS transistor N101 increases, and further, when the gate voltage of the MOS transistor N101 is mirrored to N102, the Vgs of the MOS transistor M _ device also increases, the driving force also increases along with the increase of the current load, so that the Vout1 is maintained to be unchanged; and vice versa.
However, the feedback speed of the circuit structure is relatively slow, and the feedback process can be finally completed only by carrying out multiple current mirror images through the MOS transistors M101, M102, P101, N101, and N102. A more serious problem is that if the supply voltage VDD102 changes, Vout1 will not be corrected sufficiently because the feedback loop only acts in the voltage domain of VDD101, and the output stability is poor.
In addition, consumer electronics applied to low dropout linear regulators at present are digital-analog hybrid electronic systems, and the systems generally need to strictly control the output voltage and current of the LDO. In order to monitor the output of the LDO, a current mirror branch is usually added beside the MOS transistor M _ device for current detection, but the mirror branch for current detection itself is equivalent to adding a load to the low dropout linear regulator, and eventually the detected current value deviates from the net consumption value.
The high-stability low-dropout linear regulator according to an embodiment of the present invention will be described with reference to fig. 1 and 3.
The differential amplifying unit 100 and the mirror amplifying unit 200 are operated in a voltage domain of the first power supply voltage VDD 1.
The reference voltage terminal of the voltage difference amplifying unit 100 is used for being connected with a reference voltage Vref, the feedback input terminal is used for being connected with a feedback signal Vb transmitted by the feedback output terminal of the sampling unit 400, and the voltage difference amplifying unit 100 can amplify the voltage difference between the feedback signal and the reference voltage Vref.
The input end of the mirror amplification unit 200 is connected to the output end of the differential pressure amplification unit 100, and the current signal at the output end of the differential pressure amplification unit 100 can be output after being mirrored and amplified. The first feedback unit 500 is connected between the input terminal and the feedback output terminal of the mirror amplification unit 200. After the feedback input end of the mirror image amplification unit 200 is connected to the second feedback output end of the mirror image conversion unit 300, the feedback current signal output by the second feedback output end of the mirror image conversion unit 300 can be sent to the feedback input end of the mirror image amplification unit 200, so that the first feedback unit 500 is controlled by the mirror image amplification unit 200, and finally the input signal of the mirror image amplification unit 200 is adjusted by the first feedback unit 500.
Mirror image conversion unit 300's first power supply voltage end is connected with first power supply voltage VDD1, and second power supply voltage end is connected with second power supply voltage VDD2, and mirror image conversion unit 300 will through the mode of virtual weak point the utility model discloses a high stability low dropout linear regulator's feedback current has been converted into the voltage domain of first power supply voltage VDD1 from second power supply voltage VDD 2's voltage domain, and then can the effectual error that corrects second power supply voltage VDD2 and produce to the power supply rejection ratio has been increased. Meanwhile, the mirror image conversion unit 300 may mirror-input the feedback current from the input terminal of the mirror image conversion unit 300 to the feedback input terminal of the mirror image amplification unit 200 through a mirror image circuit structure to form a feedback loop.
The second feedback unit 600 is connected between the input terminal of the mirror amplification unit 200 and the first feedback output terminal of the mirror conversion unit 300, and a fast feedback loop is constructed, so that when the output of the mirror conversion unit 300 fluctuates, the output is directly fed back to the input terminal of the mirror amplification unit 200. The defect of the first feedback unit 500 adjustment mechanism is remedied, so that the utility model discloses the high stability low dropout linear regulator's of embodiment reaction rate and stability are better.
According to the high-stability low-dropout linear regulator of the embodiment of the present invention, the voltage difference amplifying unit 100 can compare and amplify the reference voltage and the voltage signal fed back by the sampling unit 400; the current output by the voltage difference amplification unit 100 can be mirrored and amplified by the mirror amplification unit 200, and the mirror conversion unit 300 can be controlled to work; the mirror image conversion unit 300 can make the first power supply voltage VDD1 and the second power supply voltage VDD2 virtually short, so that when the second power supply voltage VDD2 changes, the feedback can be performed through the first feedback unit 500, and further, the error generated by the second power supply voltage VDD2 can be corrected, and the power supply rejection ratio is increased. The output voltage can be directly fed back to the differential pressure amplifying unit 100 through the sampling unit 400, thereby achieving the purpose of adjusting the output voltage. The feedback signal of the mirror image conversion unit 300 is output to the input end of the mirror image amplification unit 200 through the second feedback unit 600, so that the number of feedback intermediate links is reduced, and a basis for fast feedback is provided.
In some embodiments of the present invention, referring to fig. 1, the pressure difference amplification unit 100 includes: the current source circuit comprises a first N-channel MOS transistor N1, a second N-channel MOS transistor N2, a first P-channel MOS transistor P1, a second P-channel MOS transistor P2 and a first current source I1. A first N-channel MOS transistor N1 having a source connected to ground and a gate connected to a drain; a second N-channel MOS transistor N2, having a source connected to ground, a gate connected to the gate of the first N-channel MOS transistor N1, and a drain serving as an output terminal of the differential pressure amplification unit 100; a first P-channel MOS transistor P1, the drain of which is connected to the drain of the first N-channel MOS transistor N1, and the gate of which is connected to the feedback output terminal of the sampling unit 400; a second P-channel MOS transistor P2, having a drain connected to the drain of the second N-channel MOS transistor N2, a gate serving as a reference voltage terminal of the differential pressure amplification unit 100, and a source connected to the source of the first P-channel MOS transistor P1; and a first current source I1, having one end connected to the source of the second P-channel MOS transistor P2 and the other end connected to the first power supply voltage VDD 1.
The voltage difference amplification unit 100 adopts a common-source mirror image amplification circuit, the gate of the second P-channel MOS transistor P2 is connected to the reference voltage Vref, and after the gate of the first P-channel MOS transistor P1 is connected to the feedback signal output by the sampling unit 400, mirror image amplification can be achieved, so that the input signal of the mirror image amplification unit 200 can be changed. The differential pressure amplification unit 100 may also employ an operational amplifier as a circuit of a core component.
In some embodiments of the present invention, referring to fig. 1, the mirror image amplification unit 200 includes: a third N-channel MOS transistor N3, a fourth N-channel MOS transistor N4, a fifth N-channel MOS transistor N5, a sixth N-channel MOS transistor N6, a third P-channel MOS transistor P3, a fourth P-channel MOS transistor P4, and a second current source I2. A third N-channel MOS transistor N3, a gate of which is connected to the output terminal of the differential pressure amplification unit 100 and the output terminal of the second feedback unit 600, respectively, and a source of which is connected to the ground; a fourth N-channel MOS transistor N4, a gate of which is connected to the drain of the third N-channel MOS transistor N3, and a first feedback unit 500 is connected between the drain and the gate of the third N-channel MOS transistor N3; a fifth N-channel MOS transistor N5, having a source connected to the ground, a drain connected to the source of the fourth N-channel MOS transistor N4, and a gate connected to the second feedback output terminal of the mirror image conversion unit 300; a third P-channel MOS transistor P3, having a drain connected to the drain of the fourth N-channel MOS transistor N4, a gate connected to the drain, and a source for connecting to the first supply voltage VDD 1; a fourth P-channel MOS transistor P4, whose gate is connected to the gate of the third P-channel MOS transistor P3, and whose source is connected to the source of the third P-channel MOS transistor P3; a sixth N-channel MOS transistor N6, a gate of which is connected to the drain of the sixth N-channel MOS transistor N6 and the input terminal of the mirror amplifying unit 200, respectively, a drain of which is connected to the drain of the fourth P-channel MOS transistor P4, and a source of which is connected to the first connection terminal of the sampling unit 400; and a second current source I2, having one end connected to the drain of the third N-channel MOS transistor N3 and the other end connected to the first supply voltage VDD 1.
When the gate electrical signal of the third N-channel MOS transistor N3 changes, the output of the sixth N-channel MOS transistor N6 is changed, i.e., the ndrive voltage in fig. 1 is changed.
Referring to fig. 1, the mirror conversion unit 300 includes: a seventh N-channel MOS transistor N7, an eighth N-channel MOS transistor N8, a ninth N-channel MOS transistor N9, a tenth N-channel MOS transistor N10, an eleventh N-channel MOS transistor N11, a fifth P-channel MOS transistor P5, a sixth P-channel MOS transistor P6, an operational amplifier unit U1, and a third current source I3. A seventh N-channel MOS transistor N7, having a gate connected to the output terminal of the mirror amplifying unit 200, a source connected to the first connection terminal of the sampling unit 400, and a drain connected to the second supply voltage VDD 2; the gate of the eighth N-channel MOS transistor N8 is connected to the gate of the seventh N-channel MOS transistor N7, the drain of the eighth N-channel MOS transistor N8 is connected to the drain of the seventh N-channel MOS transistor N7, a first feedback resistor is connected between the source of the eighth N-channel MOS transistor N8 and the first connection end of the sampling unit 400, and the source of the eighth N-channel MOS transistor N8 is also connected to the input end of the second feedback unit 600; the negative input end of the operational amplifier unit U1 is connected with the drain electrode of the eighth N-channel MOS tube N8; a fifth P-channel MOS transistor P5, having a gate connected to the output terminal of the operational amplifier unit U1, a drain connected to the positive input terminal of the operational amplifier unit U1, and a source connected to the first supply voltage VDD 1; a ninth N-channel MOS transistor N9, having a gate connected to the gate of the eighth N-channel MOS transistor N8, a drain connected to the drain of the fifth P-channel MOS transistor P5, and a source connected to the first connection end of the sampling unit 400; a sixth P-channel MOS transistor P6, having a gate connected to the gate of the fifth P-channel MOS transistor P5, and a source for connecting to the first supply voltage VDD 1; a tenth N-channel MOS transistor N10, having a drain connected to the drain of the sixth P-channel MOS transistor P6, a gate connected to the source, and a source connected to the ground; an eleventh N-channel MOS transistor N11, having a gate connected to the gate of the tenth N-channel MOS transistor N10, a source connected to the ground, and a drain connected to the feedback input terminal of the mirror amplification unit 200; and a third current source I3, having one end connected to the drain of the eleventh N-channel MOS transistor N11 and the other end connected to the first supply voltage VDD 1.
The positive input end and the negative input end of the operational amplifier unit U1 are in a virtual short state, so that the second supply voltage VDD2 can be virtually short to the drain of the ninth N-channel MOS transistor N9, the gate of the ninth N-channel MOS transistor N9 is controlled by the ndrive voltage, and thus the current of the seventh N-channel MOS transistor N7 can be proportionally mirrored to a mirror current branch composed of the fifth P-channel MOS transistor P5 and the ninth N-channel MOS transistor P9, and the magnitude of the mirror current branch is proportional to the width-to-length ratio of the fifth P-channel MOS transistor P5 and the ninth N-channel MOS transistor N9. And the source of the fifth P-channel MOS transistor P5 is connected to the first supply voltage VDD1, so that the conversion of the voltage domain of the second supply voltage VDD2 to the voltage domain of the first supply voltage VDD1 is completed. Finally, the feedback current reaches the gate of the fifth N-channel MOS transistor N5 through the fifth P-channel MOS transistor P5, the sixth P-channel MOS transistor P6, the tenth N-channel MOS transistor N10 and the eleventh N-channel MOS transistor N11, and finally the purpose of controlling the first feedback unit 500 is achieved by controlling the gate voltage of the fifth N-channel MOS transistor N5.
The circuit structure formed by the mirror amplification unit 200, the mirror conversion unit 300 and the first feedback unit 500 realizes the conversion of current feedback from the voltage domain of the second supply voltage VDD2 to the voltage domain of the first supply voltage VDD1, and when the voltage domain of the second supply voltage VDD2 changes, the current feedback circuit structure formed by the first feedback unit 500 and the first feedback unit 500 can effectively correct the error generated in the voltage domain of the second supply voltage VDD2 and increase the power supply rejection ratio.
In some embodiments of the present invention, the third current source I3 is a variable current source. Referring to fig. 3, the application range of the current load can be increased by using the variable current source, so that the applicability of the high-stability low-dropout linear regulator according to the embodiment of the present invention is increased. The utility model discloses an in some embodiments, variable current source adopts the parallelly connected structure of a plurality of current sources, and the number that comes the control current source to connect in parallel through control or break off alright in order to realize the control to current source output capacity.
In some embodiments of the present invention, the sampling unit 400 includes a first sampling resistor R1 and a second sampling resistor R2 sequentially connected between the output end of the mirror image conversion unit 300 and the ground line; the common connection end of the first sampling resistor R1 and the second sampling resistor R2 is connected to the feedback input end of the differential pressure amplifying unit 100. The sampling unit 400 adopts a voltage division sampling method, and a desired voltage value can be obtained by adjusting the ratio of the resistances of the first sampling resistor R1 and the second sampling resistor R2.
In some embodiments of the present invention, the first sampling resistor R1 and/or the second sampling resistor R2 is an adjustable resistor. The utility model discloses high stability low dropout linear regulator's output voltage under ideal state's expression does:
Vout＝Vref*(R1+R2)/R2
vout is the output voltage and Vref is the reference voltage. The reference voltage is usually not changed after being given, and the resistance values of the first sampling resistor R1 and/or the second sampling resistor R2 are adjusted, so that the ratio of the resistance values of the first sampling resistor R1 and the second sampling resistor R2 can be adjusted, and the purpose of adjusting the output is achieved.
In some embodiments of the present invention, referring to fig. 1, the first feedback unit 500 includes: a seventh P-channel MOS transistor P7, having a gate connected to the feedback output terminal of the mirror amplification unit 200 and a drain connected to the input terminal of the mirror amplification unit 200; and one end of the fourth current source I4 is connected to the source of the seventh P-channel MOS transistor P7, and the other end is used for connecting the first power supply voltage VDD 1. The working state of the first feedback unit 500 is controlled by the fifth N-channel MOS transistor N5, and the control line of the fifth N-channel MOS transistor N5 controls the gate voltage of the third N-channel MOS transistor N3.
In some embodiments of the present invention, referring to fig. 1, the second feedback unit 600 includes a first feedback capacitor C1 connected between the input terminal of the mirror amplification unit 200 and the first feedback output terminal of the mirror conversion unit 300. Second feedback unit 600 has not only introduced high-speed feedback mechanism, and the feedback load that can be quick changes the error of bringing, is increasing first feedback electric capacity C1 back simultaneously, makes the phase place redundancy wideer between primary and the secondary, has increased the utility model discloses a high stability low dropout linear regulator.
In some embodiments of the present invention, the high-stability low-dropout linear regulator further includes a mirror image acquisition circuit 700, and the mirror image acquisition circuit 700 is used for acquiring the output current of the mirror image conversion unit 300 through the mirror image circuit structure. Referring to fig. 1, since the operational amplifier unit U1 isolates the first supply voltage VDD1 from the second supply voltage VDD2, the mirror current branch can be increased infinitely in theory without affecting the stability of the second supply voltage VDD2 as in the conventional low dropout linear regulator, so that the magnitude of the current load can be measured accurately.
In some embodiments of the present invention, referring to fig. 1, the mirror image acquisition circuit 700 includes: the gate of the eighth P-channel MOS transistor P8 is connected to the gate of the sixth P-channel MOS transistor P6, and the source of the eighth P-channel MOS transistor P8 is used for connecting the first supply voltage VDD 1; one end of the output sampling resistor is connected with the drain electrode of the eighth P-channel MOS tube P8, and the other end of the output sampling resistor is connected with the ground wire; the drain of the eighth P-channel MOS transistor P8 may be sampled with a mirror current. The sampled voltage Vadc is a mirror voltage converted from the mirror current through the output sampling resistor Radc, and the value of the mirror voltage Vadc can be measured and monitored by an off-chip controller.
Finally, the practical simulation effect of the high-stability low-dropout linear regulator according to some embodiments of the present invention will be described with reference to fig. 4 and 5.
Fig. 4 shows the phase margin for increasing the capacitive load from 1uF to 1pF in the case of a low current load, and fig. 5 shows the phase margin for increasing the capacitive load from 1uF to 1pF in the case of a high current load. It can be seen from fig. 4 and 5 that the feedback loop is quite stable in most application cases, and the phase margin is greater than 60 degrees in most cases, which has excellent stability. Even under the worst case, increase the situation of 1uF capacitive load under the heavy current load condition promptly, the utility model discloses a high stability low dropout linear regulator still has the phase margin about 45 degrees.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to the above embodiments, and those skilled in the art can understand that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (10)
1. A high stability low dropout linear regulator, comprising:
the voltage difference amplifying unit (100) is provided with a grounding end used for being connected with a ground wire, a power supply voltage end used for being connected with a first power supply voltage, a reference voltage end, a feedback input end and an output end; the voltage difference amplifying unit (100) is used for amplifying the voltage difference between the reference voltage end and the feedback input end;
a mirror amplification unit (200) having an input terminal connected to an output terminal of the differential voltage amplification unit (100), a ground terminal connected to the ground line, a supply voltage terminal connected to the first supply voltage, an output terminal, a feedback input terminal, and a feedback output terminal; the mirror amplification unit (200) is used for mirror amplifying the current at the input end of the mirror amplification unit;
the image conversion unit (300) is provided with an input end connected with the output end of the image amplification unit (200), a first power supply voltage end connected with the first power supply voltage, a second power supply voltage end used for connecting a second power supply voltage, a grounding end connected with a ground wire, an output end used for providing output voltage, a first feedback output end and a second feedback output end connected with the feedback input end of the image amplification unit (200); the mirror conversion unit (300) is used for virtually shortening the second supply voltage and the first supply voltage and mirroring the current at the input end of the mirror conversion unit;
the sampling unit (400) is provided with a first connecting end, a second connecting end and a feedback output end, wherein the first connecting end is connected with the output end of the mirror image conversion unit (300), the second connecting end is connected with the ground wire, and the feedback output end is connected with the feedback input end of the differential pressure amplification unit (100); the sampling unit (400) is used for sampling the output voltage and outputting the sampled output voltage to the differential pressure amplifying unit (100);
the first feedback unit (500) is connected between the feedback output end of the mirror image amplification unit (200) and the input end of the mirror image amplification unit (200) and is used for correcting errors caused by the second power supply voltage fluctuation;
and the input end of the second feedback unit (600) is connected with the first feedback output end of the mirror image conversion unit (300), the output end of the second feedback unit is connected with the input end of the mirror image amplification unit (200), and the second feedback unit (600) is used for improving the stability of the output voltage.
2. The high stability low dropout regulator according to claim 1, wherein said dropout amplification unit (100) comprises:
the source electrode of the first N-channel MOS tube is connected with the ground wire, and the grid electrode of the first N-channel MOS tube is connected with the drain electrode;
the source electrode of the second N-channel MOS tube is connected with the ground wire, the grid electrode of the second N-channel MOS tube is connected with the grid electrode of the first N-channel MOS tube, and the drain electrode of the second N-channel MOS tube is used as the output end of the differential pressure amplification unit (100);
the drain electrode of the first P-channel MOS tube is connected with the drain electrode of the first N-channel MOS tube, and the grid electrode of the first P-channel MOS tube is connected with the feedback output end of the sampling unit (400);
the drain electrode of the second P-channel MOS tube is connected with the drain electrode of the second N-channel MOS tube, the grid electrode of the second P-channel MOS tube is used as a reference voltage end of the differential pressure amplification unit (100), and the source electrode of the second P-channel MOS tube is connected with the source electrode of the first P-channel MOS tube;
and one end of the first current source is connected with the source electrode of the second P-channel MOS tube, and the other end of the first current source is used for connecting the first power supply voltage.
3. The high stability LDO according to claim 1, wherein said mirror amplification unit (200) comprises:
a grid electrode of the third N-channel MOS tube is respectively connected with the output end of the differential pressure amplification unit (100) and the output end of the second feedback unit (600), and a source electrode of the third N-channel MOS tube is connected with the ground wire;
a grid electrode of the fourth N-channel MOS tube is connected with a drain electrode of the third N-channel MOS tube, and the first feedback unit (500) is connected between the drain electrode and the grid electrode of the third N-channel MOS tube;
a source electrode of the fifth N-channel MOS tube is connected with the ground wire, a drain electrode of the fifth N-channel MOS tube is connected with a source electrode of the fourth N-channel MOS tube, and a grid electrode of the fifth N-channel MOS tube is connected with a second feedback output end of the mirror image conversion unit (300);
a drain electrode of the third P-channel MOS transistor is connected with a drain electrode of the fourth N-channel MOS transistor, a gate electrode of the third P-channel MOS transistor is connected with a drain electrode of the third P-channel MOS transistor, and a source electrode of the third P-channel MOS transistor is used for connecting the first power supply voltage;
a grid electrode of the fourth P-channel MOS tube is connected with the grid electrode of the third P-channel MOS tube, and a source electrode of the fourth P-channel MOS tube is connected with the source electrode of the third P-channel MOS tube;
a grid electrode of the sixth N-channel MOS tube is respectively connected with a drain electrode and the input end of the mirror image amplification unit (200), the drain electrode of the sixth N-channel MOS tube is connected with the drain electrode of the fourth P-channel MOS tube, and a source electrode of the sixth N-channel MOS tube is connected with the first connecting end of the sampling unit (400);
and one end of the second current source is connected with the drain electrode of the third N-channel MOS tube, and the other end of the second current source is used for connecting the first power supply voltage.
4. The high stability LDO according to claim 1, wherein said mirror conversion unit (300) comprises:
a gate of the seventh N-channel MOS transistor is connected to the output terminal of the mirror amplification unit (200), a source of the seventh N-channel MOS transistor is connected to the first connection terminal of the sampling unit (400), and a drain of the seventh N-channel MOS transistor is connected to the second supply voltage;
the grid electrode of the eighth N-channel MOS tube is connected with the grid electrode of the seventh N-channel MOS tube, the drain electrode of the eighth N-channel MOS tube is connected with the drain electrode of the seventh N-channel MOS tube, a first feedback resistor is connected between the source electrode of the eighth N-channel MOS tube and the first connecting end of the sampling unit (400), and the source electrode of the eighth N-channel MOS tube is also connected with the input end of the second feedback unit (600);
the negative input end of the operational amplifier unit is connected with the drain electrode of the eighth N-channel MOS tube;
a fifth P-channel MOS transistor, a gate of which is connected to the output terminal of the operational amplifier unit, a drain of which is connected to the positive input terminal of the operational amplifier unit, and a source of which is used for connecting the first supply voltage;
a ninth N-channel MOS tube, the grid of which is connected with the grid of the eighth N-channel MOS tube, the drain of which is connected with the drain of the fifth P-channel MOS tube, and the source of which is connected with the first connecting end of the sampling unit (400);
a gate of the sixth P-channel MOS transistor is connected to a gate of the fifth P-channel MOS transistor, and a source of the sixth P-channel MOS transistor is used for connecting the first power supply voltage;
a tenth N-channel MOS tube, the drain of which is connected with the drain of the sixth P-channel MOS tube, the gate of which is connected with the source, and the source of which is connected with the ground wire;
the grid electrode of the eleventh N-channel MOS tube is connected with the grid electrode of the tenth N-channel MOS tube, the source electrode of the eleventh N-channel MOS tube is connected with the ground wire, and the drain electrode of the eleventh N-channel MOS tube is connected with the feedback input end of the mirror image amplification unit (200);
and one end of the third current source is connected with the drain electrode of the eleventh N-channel MOS tube, and the other end of the third current source is used for connecting the first power supply voltage.
5. The high stability low dropout regulator of claim 4 wherein said third current source is a variable current source.
6. The high-stability low dropout regulator according to claim 1, wherein the sampling unit (400) comprises a first sampling resistor and a second sampling resistor sequentially connected between the output terminal of the mirror image conversion unit (300) and the ground; and the common connection end of the first sampling resistor and the second sampling resistor is connected with the feedback input end of the differential pressure amplifying unit (100).
7. The high stability low dropout regulator according to claim 6, wherein said first sampling resistor and/or said second sampling resistor is an adjustable resistor.
8. The high stability low dropout linear regulator of claim 1 wherein the first feedback unit (500) comprises:
a gate of the seventh P-channel MOS transistor is connected with the feedback output end of the mirror image amplification unit (200), and a drain of the seventh P-channel MOS transistor is connected with the input end of the mirror image amplification unit (200);
and one end of the fourth current source is connected with the source electrode of the seventh P-channel MOS tube, and the other end of the fourth current source is used for connecting a first power supply voltage.
9. The high stability LDO according to claim 1, wherein said second feedback unit (600) comprises a first feedback capacitor connected between an input of said mirror amplifying unit (200) and a first feedback output of said mirror converting unit (300).
10. The high-stability low dropout regulator according to claim 1, further comprising a mirror image acquisition circuit (700), wherein the mirror image acquisition circuit (700) is configured to acquire the output current of the mirror image conversion unit (300) through a mirror image circuit structure.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114967819A (en) * | 2022-08-01 | 2022-08-30 | 苏州悉芯射频微电子有限公司 | Band-gap reference circuit based on SOI technology |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114967819A (en) * | 2022-08-01 | 2022-08-30 | 苏州悉芯射频微电子有限公司 | Band-gap reference circuit based on SOI technology |
| CN114967819B (en) * | 2022-08-01 | 2022-10-25 | 苏州悉芯射频微电子有限公司 | Band-gap reference circuit based on SOI technology |
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