CN114764125A - Testing device for low dropout regulator - Google Patents
Testing device for low dropout regulator Download PDFInfo
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- CN114764125A CN114764125A CN202011615748.4A CN202011615748A CN114764125A CN 114764125 A CN114764125 A CN 114764125A CN 202011615748 A CN202011615748 A CN 202011615748A CN 114764125 A CN114764125 A CN 114764125A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
Abstract
The application discloses low dropout regulator's testing arrangement includes: the variable load module is connected with the voltage output end of the low dropout linear regulator, and the low dropout linear regulator generates output voltage according to the load value of the variable load module and outputs the output voltage at the voltage output end; the signal source is used for providing a pulse signal; the driving module is used for generating a driving signal according to the pulse signal; the adjusting tube is connected between the variable load module and the reference ground and used for adjusting the output current of the load end according to the driving signal; and the signal adjusting module adjusts the conduction speed of the adjusting tube by adjusting the rising edge speed of the pulse signal, so that the change speed of the output current is changed. The testing device solves the problems of ringing and oscillation of output voltage in the load transient response test, and is favorable for improving the stability of the system.
Description
Technical Field
The invention relates to the technical field of linear regulators, in particular to a testing device of a low dropout regulator.
Background
A Low Dropout Regulator (LDO) converts an unstable input voltage into an adjustable dc output voltage for use as a power supply of other systems. Because the linear voltage regulator has the characteristics of simple structure, low static power consumption, low output voltage ripple and the like, the linear voltage regulator is often used for on-chip power management of a mobile consumer electronics chip.
The LDO is used as a complete functional module, some performance indexes must be considered during design, and the LDO can be finally applied to a system and a product only by meeting the design of corresponding indexes, wherein the performance indexes of the LDO mainly comprise: input/output differential pressure, drive load capability, quiescent current, power supply rejection ratio, efficiency, start-up time, load transient response, and the like. In the process of mass production, the actual performance index of the LDO often has a certain deviation from the nominal value, which causes inconsistency between the theoretical value and the actual value, and the inconsistency of the system or the product can be increased, so that the test of the LDO plays an important role in improving the consistency and stability of the whole circuit system.
The traditional load transient response test method of the LDO mainly uses a voltage source instrument to supply power to the LDO and a module thereof, and judges the performance of the LDO by regulating output voltage or load size and gradually changing the working conditions of the LDO. As shown in fig. 1, in the conventional load transient response test method, when the load changes, the rise time of the output current Iout is short, which easily causes ringing and oscillation of the output voltage Vout. In addition, with the improvement of the performance of the LDO, the requirement for the test apparatus for the transient response of the load is higher and higher, and the same product often has different test conditions, and the requirement for the system stability of the test apparatus is higher and higher, so the conventional test apparatus cannot meet the requirement of the existing LDO test.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a testing apparatus for a low dropout regulator, which can adjust the rise time of the output current during the load transient response test, and avoid ringing or oscillation of the output voltage.
According to an embodiment of the present invention, a testing apparatus for a low dropout regulator is provided, where the low dropout regulator includes a voltage input terminal and a voltage output terminal, and the testing apparatus includes: the variable load module is connected with a voltage output end of the low dropout linear regulator, and the low dropout linear regulator generates output voltage according to a load value of the variable load module and outputs the output voltage at the voltage output end; the signal source is used for providing a pulse signal; the driving module is used for generating a driving signal according to the pulse signal; the adjusting tube is connected between the variable load module and a reference ground and used for adjusting the output current of a load end according to the driving signal; and the signal adjusting module adjusts the conduction speed of the adjusting tube by adjusting the rising edge speed of the pulse signal, so that the change speed of the output current is changed.
Optionally, the testing apparatus further includes: the direct current voltage source is connected between the voltage input end of the low dropout linear regulator and a reference ground and is used for supplying power to the low dropout linear regulator; the input capacitor is connected between the voltage input end of the low dropout linear regulator and the reference ground; and the output capacitor is connected between the voltage output end of the low dropout linear regulator and the reference ground.
Optionally, the driving module includes: the first transistor and the second transistor are sequentially connected between the voltage input end of the low dropout linear regulator and the reference ground, the control ends of the first transistor and the second transistor receive the pulse signal, and the intermediate node of the first transistor and the intermediate node of the second transistor outputs the driving signal.
Optionally, the signal conditioning module includes: a variable resistor having a first terminal connected to an output terminal of the signal source and a second terminal connected to control terminals of the first transistor and the second transistor.
Optionally, the signal conditioning module further includes: and the variable capacitor is connected between the control end of the adjusting tube and the reference ground.
Optionally, the variable load module includes: the first end of the first variable load resistor is connected to the voltage output end of the low dropout regulator, and the second end of the first variable load resistor is connected to the first end of the adjusting tube; and a second variable load resistor, wherein a first end of the second variable load resistor is connected to the voltage output end of the low dropout regulator, and a second end of the second variable load resistor is connected to the reference ground.
Optionally, the adjusting tube is selected from an N-type metal oxide semiconductor field effect transistor.
Optionally, the first transistor is selected from an NPN-type bipolar transistor, and the second transistor is selected from a PNP-type bipolar transistor.
The testing device of the low dropout regulator of the embodiment of the invention comprises: the variable load module is connected with the voltage output end of the low dropout linear regulator, and the low dropout linear regulator generates output voltage according to the load value of the variable load module and outputs the output voltage at the voltage output end; the signal source is used for providing a pulse signal; the driving module is used for generating a driving signal according to the pulse signal; the adjusting tube is connected between the variable load module and a reference ground and used for adjusting the output current of a load end according to the driving signal; and the signal adjusting module adjusts the conduction speed of the adjusting tube by adjusting the rising edge speed of the pulse signal, so that the change speed of the output current is changed. The testing device of the embodiment of the invention solves the problems of ringing and oscillation of the output voltage in the load transient response test, and is beneficial to improving the stability of the system. In addition, the testing device provided by the embodiment of the invention can provide different testing conditions and is suitable for testing the low dropout linear regulator with higher performance.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings, in which:
FIG. 1 shows voltage diagrams of output current and output voltage during a load transient response test of a conventional LDO;
FIG. 2 is a circuit diagram of a testing apparatus for a low dropout linear regulator according to an embodiment of the present invention;
FIG. 3 is a voltage diagram of an output current and an output voltage during a load transient response test of a testing apparatus of a conventional LDO;
fig. 4 shows voltage diagrams of output current and output voltage during a load transient response test of the testing apparatus of the low dropout linear regulator according to the embodiment of the invention.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
It should be understood that in the following description, a "circuit" refers to a conductive loop formed by at least one element or sub-circuit through an electrical or electromagnetic connection. When an element or circuit is referred to as being "connected to" another element or element/circuit is referred to as being "connected between" two nodes, it may be directly coupled or connected to the other element or intervening elements may be present, and the connection between the elements may be physical, logical, or a combination thereof. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, it is intended that there are no intervening elements present.
In this application, the MOSFET comprises a first terminal, a second terminal and a control terminal, and in the on-state of the MOSFET a current flows from the first terminal to the second terminal. The first end, the second end and the control end of the P-type MOSFET are respectively a source electrode, a drain electrode and a grid electrode, and the first end, the second end and the control end of the N-type MOSFET are respectively a drain electrode, a source electrode and a grid electrode. The bipolar transistor comprises a first terminal, a second terminal and a control terminal, and in an on-state of the bipolar transistor, a current flows from the first terminal to the second terminal. The first end, the second end and the control end of the PNP type bipolar transistor are respectively an emitter, a collector and a base, and the first end, the second end and the control end of the NPN type bipolar transistor are respectively a collector, an emitter and a base.
The invention is further illustrated with reference to the following figures and examples.
Fig. 2 is a circuit diagram of a testing apparatus of a low dropout linear regulator according to an embodiment of the present invention. As shown in fig. 2, the testing apparatus includes a signal source 110, a driving module 120, a regulating tube Q1 and a variable load module 130. The variable load module 130 is connected to a voltage output terminal of the low dropout regulator 200, and the low dropout regulator 200 generates an output voltage according to a load value of the variable load module 130 and outputs the output voltage at the voltage output terminal. The signal source 110 is configured to provide a pulse signal, the driving module 120 is configured to generate a driving signal according to the pulse signal, and the adjusting tube Q1 is connected between the variable load module 130 and the reference ground and configured to adjust an output current of the load terminal according to the driving signal.
The testing device 100 further comprises a signal adjusting module, and the signal adjusting module adjusts the conduction speed of the adjusting tube Q1 by adjusting the rising edge speed of the pulse signal, so as to change the change speed of the output current at the load end.
Further, the testing apparatus 100 further includes a DC voltage source DC, an input capacitor Cin, and an output capacitor Cout. The DC voltage source DC is connected between the voltage input terminal of the low dropout regulator 200 and the reference ground, and is used for supplying power to the low dropout regulator 200. The input capacitor Cin and the output capacitor Cout are respectively connected between the voltage input terminal of the low dropout regulator 200 and the reference ground and between the voltage output terminal of the low dropout regulator 200 and the reference ground.
Further, the driving module 120 includes transistors P1 and P2. The transistors P1 and P2 are sequentially connected between the voltage input end of the low dropout linear regulator 200 and the reference ground, the control ends of the transistors P1 and P2 receive the pulse signal, and the intermediate nodes of the transistors P1 and P2 output the driving signal.
Further, the signal conditioning module includes a variable resistor Rs and/or a variable capacitor C1, a first terminal of the variable resistor Rs is connected to the output terminal of the signal source 110, a second terminal of the variable resistor Rs is connected to the control terminals of the transistors P1 and P2, and the variable capacitor C1 is connected between the control terminal of the adjusting transistor Q1 and the reference ground.
Further, the variable load module 130 includes: the first end of the first variable load resistor R1 is connected to the voltage output end of the low dropout linear regulator 200, the second end of the first variable load resistor R1 is connected to the first end of the regulating tube Q1, the first end of the second variable load resistor R2 is connected to the voltage output end of the low dropout linear regulator 200, and the second end of the second variable load resistor R2 is connected to the reference ground. The first variable load resistor R1 is a dynamic variable load resistor, and the second variable load resistor R2 is a static variable load resistor, so that any combination of dynamic load and static load can be obtained by adjusting the resistance values of the first variable load resistor R1 and the second variable load resistor R2.
Further, the adjusting tube Q1 is selected from an N-type MOSFET, the transistor P1 is selected from an NPN-type bipolar transistor, the transistor P2 is selected from a PNP-type bipolar transistor, when the pulse signal provided by the signal source 110 is at a logic high level, the transistor P1 is turned on, the transistor P2 is turned off, the adjusting tube Q1 is turned on, and an output current required by the test is provided, at this time, an RC circuit formed by the variable resistor Rs and the variable capacitor C1 can slow down the turn-on speed of the adjusting tube Q1, so that the system is more stable; when the pulse signal provided by the signal source 110 is at a logic low level, the transistor P1 is turned off, the transistor P2 is turned on, and the control terminal of the transistor Q1 discharges to ground through the transistor P2, so that the turn-off speed of the transistor Q1 is increased, and the switching loss is reduced.
In the process of turning on the regulating tube Q1, the rising time of the output current can be changed by changing the resistance value of the variable resistor Rs or the capacitance value of the variable capacitor C1. Since the rising speed of the pulse signal supplied from the signal source 110 is constant, if the capacitance value of the variable capacitor C1 is constant, the smaller the resistance value of the variable resistor Rs is, the shorter the rising time of the pulse signal is, the faster the rising speed of the current at the load side is, and the larger the resistance value of the variable resistor Rs is, the longer the rising time of the pulse signal is, the slower the rising speed of the current at the load side is. Similarly, if the resistance value of the variable resistor Rs is constant, the smaller the capacitance value of the variable capacitor C1 is, the shorter the rise time of the pulse signal is, the faster the rise speed of the current at the load side is, and the larger the capacitance value of the variable capacitor C1 is, the longer the rise time of the pulse signal is, the slower the rise speed of the current at the load side is.
Fig. 3 and 4 respectively show voltage diagrams of output current and output voltage of a testing device of a conventional low dropout linear regulator and a testing device of a low dropout linear regulator according to an embodiment of the invention during a load transient response test. In fig. 3 and 4, the broken line indicates the output voltage Vout, and the solid line indicates the output current Iout. As shown in fig. 4, the rising time of the output current Iout in the load transient response test process can be increased from 200ns to 500ns by increasing the resistance value of the variable resistor Rs, and meanwhile, the output voltage Vout does not have the phenomena of burrs, ringing and the like in the process, so that the test device can solve the problems of ringing and oscillation of the output voltage in the load transient response test, improve the stability of the system, and is suitable for testing the low-dropout linear regulator with higher performance.
In summary, the testing apparatus of the low dropout linear regulator according to the embodiment of the present invention includes: the variable load module is connected with the voltage output end of the low dropout linear regulator, and the low dropout linear regulator generates output voltage according to the load value of the variable load module and outputs the output voltage at the voltage output end; the signal source is used for providing a pulse signal; the driving module is used for generating a driving signal according to the pulse signal; the adjusting tube is connected between the variable load module and a reference ground and used for adjusting the output current of a load end according to the driving signal; and the signal adjusting module adjusts the conduction speed of the adjusting tube by adjusting the rising edge speed of the pulse signal, so that the change speed of the output current is changed. The testing device of the embodiment of the invention solves the problems of ringing and oscillation of the output voltage in the load transient response test, and is beneficial to improving the stability of the system. In addition, the testing device provided by the embodiment of the invention can provide different testing conditions and is suitable for testing the low dropout linear regulator with higher performance.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In accordance with the present invention, as set forth above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The scope of the invention should be determined from the following claims.
Claims (8)
1. A testing arrangement of a low dropout regulator, the low dropout regulator comprising a voltage input and a voltage output, wherein the testing arrangement comprises:
the variable load module is connected with a voltage output end of the low dropout linear regulator, and the low dropout linear regulator generates output voltage according to a load value of the variable load module and outputs the output voltage at the voltage output end;
the signal source is used for providing a pulse signal;
the driving module is used for generating a driving signal according to the pulse signal;
the adjusting tube is connected between the variable load module and a reference ground and used for adjusting the output current of a load end according to the driving signal; and
and the signal adjusting module adjusts the conduction speed of the adjusting tube by adjusting the rising edge speed of the pulse signal, so that the change speed of the output current is changed.
2. The test device of claim 1, further comprising:
the direct-current voltage source is connected between the voltage input end of the low dropout linear regulator and a reference ground and is used for supplying power to the low dropout linear regulator;
the input capacitor is connected between the voltage input end of the low dropout linear regulator and the reference ground; and
and the output capacitor is connected between the voltage output end of the low dropout linear regulator and the reference ground.
3. The test device of claim 2, wherein the drive module comprises:
the first transistor and the second transistor are sequentially connected between the voltage input end of the low dropout linear regulator and the reference ground, the control ends of the first transistor and the second transistor receive the pulse signal, and the intermediate node of the first transistor and the intermediate node of the second transistor outputs the driving signal.
4. The test device of claim 3, wherein the signal conditioning module comprises:
a variable resistor having a first terminal connected to an output terminal of the signal source and a second terminal connected to control terminals of the first transistor and the second transistor.
5. The test device of claim 4, wherein the signal conditioning module further comprises:
and the variable capacitor is connected between the control end of the adjusting tube and the reference ground.
6. The test apparatus of claim 1, wherein the variable load module comprises:
the first end of the first variable load resistor is connected to the voltage output end of the low dropout regulator, and the second end of the first variable load resistor is connected to the first end of the adjusting tube; and
and a first end of the second variable load resistor is connected to the voltage output end of the low dropout linear regulator, and a second end of the second variable load resistor is connected to the reference ground.
7. The test apparatus of claim 1, wherein the tuning tube is selected from an N-type mosfet.
8. A test device according to claim 3, wherein the first transistor is selected from NPN type bipolar transistors and the second transistor is selected from PNP type bipolar transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011615748.4A CN114764125A (en) | 2020-12-31 | 2020-12-31 | Testing device for low dropout regulator |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011615748.4A CN114764125A (en) | 2020-12-31 | 2020-12-31 | Testing device for low dropout regulator |
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| CN114764125A true CN114764125A (en) | 2022-07-19 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116338509A (en) * | 2023-03-20 | 2023-06-27 | 武汉芯必达微电子有限公司 | Test method and test circuit for rapidly-changing power supply signal |
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- 2020-12-31 CN CN202011615748.4A patent/CN114764125A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116338509A (en) * | 2023-03-20 | 2023-06-27 | 武汉芯必达微电子有限公司 | Test method and test circuit for rapidly-changing power supply signal |
| CN116338509B (en) * | 2023-03-20 | 2023-08-29 | 武汉芯必达微电子有限公司 | Test method and test circuit for rapidly-changing power supply signal |
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