CN101621250B - Device and method for detecting output current of voltage regulator - Google Patents

Abstract

The voltage regulator includes one upper bridge component, one lower bridge component and one inductor coupled together to one switching node and with the other ends coupled to one input end, one earthing potential and one output end separately; the voltage regulator further comprises a controller for controlling the operation of at least one of the upper bridge and the lower bridge components to generate an output voltage at the output terminal; the output current detection device comprises an upper bridge current sensing circuit, a lower bridge current sensing circuit and a set resistor, and is characterized in that: the upper bridge current sensing circuit senses the current of the upper bridge component to generate a first current; the lower bridge current sensing circuit senses the current of the lower bridge component to generate a second current; a summing circuit for summing the first and second currents to produce a summed current; the setting resistor detects the change of the sum current, and the voltage change on the setting resistor is provided for the controller to perform feedback control.

Description

Device and method for detecting output current of voltage regulator

technical field

The invention relates to a voltage regulator, in particular, an output current detection device and method applied to the voltage regulator of a charger.

Background technique

It is known that when a voltage regulator is used to provide a regulated current, such as a charger, the common output current detection method is to connect a detection resistor in series with the inductance of the voltage regulator, please refer to Figure 1, Figure 1 is a known voltage converter schematic diagram. As shown in the figure, the output current Io of the voltage regulator flows through the sense resistor Rsense, such as US Patent No. 6369561, LTC4001 or SMB135, the voltage change on the sense resistor Rsense is related to the output current Io, and the distance between the output current Io The proportional relationship of 1:1 is fixed, and the voltage change on the sense resistor Rsense is differentially input to the controller 12 through the error amplifier 10 for feedback control, so as to control the driver 14 to switch the power transistor.

Since the known detection method is to set the detection resistor Rsense on the charging path of the voltage regulator, in order to reduce the output power loss of the detection resistor Rsense, the detection resistor Rsense must be a precision resistor with low resistance, but the low resistance can detect The voltage change is small, and it is sensitive to noise, and is easily disturbed by noise.

Therefore, the known output current detection device of the voltage regulator has the above-mentioned inconveniences and problems.

Contents of the invention

The object of the present invention is to provide an output current detection device of a voltage regulator.

Another object of the present invention is to provide a method for detecting output current of a voltage regulator.

Another object of the present invention is to provide a voltage regulator with output current detection function.

For realizing the above object, technical solution of the present invention is:

An output current detection device of a voltage regulator, the voltage regulator includes an upper bridge component, a lower bridge component and an inductor, the upper bridge component, the lower bridge component and the inductor are jointly coupled to a switching node, And the other ends of the upper bridge component, the lower bridge component and the inductance are respectively coupled to an input terminal, a ground potential and an output terminal; the voltage regulator also includes a controller, and the controller controls at least The action of one of the upper bridge and the lower bridge assembly is to generate an output voltage at the output terminal; the output current detection device includes an upper bridge current sensing circuit, a lower bridge current sensing circuit, and a summing circuit and a set resistor, where,

The upper bridge current sensing circuit senses the current of the upper bridge component to generate a first current;

The lower bridge current sensing circuit senses the current of the lower bridge component to generate a second current;

the summing circuit sums the first and second currents to generate a summed current;

The setting resistor detects the change of the total current, and the voltage change on the setting resistor is provided to the controller for feedback control.

The output current detection device of the voltage regulator of the present invention can also be further realized by adopting the following technical measures.

In the aforementioned output current detection device, the upper-bridge current sensing circuit and the lower-bridge current sensing circuit are part of an over-current protection mechanism or a zero-current protection mechanism of the voltage regulator.

In the aforementioned output current detection device, one end of the setting resistor is connected to the summing circuit, and the other end is grounded.

In the aforementioned output current detection device, both the upper and lower bridge components are transistors.

In the aforementioned output current detection device, the upper bridge component is a transistor, and the lower bridge component is a diode.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the output terminal and the switching node.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the output terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the input terminal and the switching node.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the output terminal and the switching node, the An inductance is coupled between the ground potential and the switching node.

A method for detecting output current of a voltage regulator, wherein the voltage regulator includes an upper bridge component, a lower bridge component and an inductor, and the upper bridge component, the lower bridge component and the inductor are jointly coupled to a switching node, And the other ends of the upper bridge component, the lower bridge component and the inductance are respectively coupled to an input terminal, a ground potential and an output terminal; the voltage regulator also includes a controller, and the controller controls at least The action of one of the upper bridge and the lower bridge components to generate an output voltage at the output terminal, characterized in that the output current detection method includes the following steps:

The first step: sensing the current of the upper bridge component to generate a first current;

The second step: sensing the current of the lower bridge component to generate a second current;

The third step: summing up the first and second currents to generate a total current;

The fourth step: providing the total current to a setting resistor;

Fifth step: providing the voltage change on the set resistor to the controller for feedback control.

The output current detection method of the voltage regulator of the present invention can also be further realized by adopting the following technical measures.

In the aforementioned output current detection method, both the upper and lower bridge components are transistors.

In the aforementioned output current detection method, the upper bridge component is a transistor, and the lower bridge component is a diode.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the output terminal and the switching node.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the output terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the input terminal and the switching node.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the output terminal and the switching node, the An inductance is coupled between the ground potential and the switching node.

A voltage regulator comprising an upper bridge assembly, a lower bridge assembly, an inductor, a controller, an upper bridge current sensing circuit, a lower bridge current sensing circuit, a summing circuit and a setting resistor, wherein,

The upper bridge component, the lower bridge component and the inductor are jointly coupled to a switching node, and the other ends of the upper bridge component, the lower bridge component and the inductor are respectively connected to an input terminal, a ground potential and an output terminal coupling;

The controller controls the operation of at least one of the upper bridge component and the lower bridge component to generate an output voltage at the output terminal;

The upper bridge current sensing circuit senses the current of the upper bridge component to generate a first current;

The lower bridge current sensing circuit senses the current of the lower bridge component to generate a second current;

the summing circuit sums the first and second currents to generate a summed current;

The setting resistor detects the change of the total current, and the voltage change on the setting resistor is provided to the controller for feedback control.

The voltage regulator of the present invention can also be further realized by adopting the following technical measures.

In the aforementioned voltage regulator, the upper-side current sensing circuit and the lower-side current sensing circuit are part of an over-current protection mechanism or a zero-current protection mechanism of the voltage regulator.

In the aforementioned voltage regulator, one end of the setting resistor is connected to the summing circuit, and the other end is grounded.

In the aforementioned voltage regulator, both the upper and lower bridge components are transistors.

In the aforementioned voltage regulator, the upper bridge component is a transistor, and the lower bridge component is a diode.

The foregoing voltage regulator, wherein the upper bridge component is coupled between the input terminal and the switching node, the lower bridge component is coupled between the ground potential and the switching node, and the inductor coupled between the output terminal and the switching node.

In the foregoing voltage regulator, wherein the upper bridge component is coupled between the output terminal and the switching node, the lower bridge component is coupled between the ground potential and the switching node, and the inductor coupled between the input terminal and the switching node.

In the aforementioned voltage regulator, wherein the upper bridge component is coupled between the input terminal and the switching node, the lower bridge component is coupled between the output terminal and the switching node, and the inductor coupled between the ground potential and the switching node.

An output current detection device of a voltage regulator, the voltage regulator includes an upper bridge component, a lower bridge component, and an inductor, and the upper bridge component, the lower bridge component and the inductor are jointly coupled to A switching node, and the other ends of the upper bridge component, the lower bridge component and the inductor are respectively coupled to an input terminal, a ground potential and an output terminal, and the voltage regulator also includes a control device, the controller controls the switching of the upper bridge and the lower bridge components to generate an output voltage at the output terminal; the output current detection device includes a sensing circuit, an emulation circuit and a setting resistor, in,

The sensing circuit senses the current of the upper bridge component to generate a sensing current;

The simulation circuit simulates and generates a total current according to the sensing current;

The setting resistor detects the change of the total current, and the voltage change on the setting resistor is provided to the controller for feedback control.

The output current detection device of the voltage regulator of the present invention can also be further realized by adopting the following technical measures.

In the aforementioned output current detection device, the upper-bridge current sensing circuit and the lower-bridge current sensing circuit are part of an over-current protection mechanism or a zero-current protection mechanism of the voltage regulator.

In the aforementioned output current detection device, one end of the setting resistor is connected to the simulation circuit, and the other end is grounded.

In the aforementioned output current detection device, both the upper and lower bridge components are transistors.

In the aforementioned output current detection device, the upper bridge component is a transistor, and the lower bridge component is a diode.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the output terminal and the switching node.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the output terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the input terminal and the switching node.

In the aforementioned output current detection device, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the output terminal and the switching node, the An inductance is coupled between the ground potential and the switching node.

A method for detecting output current of a voltage regulator. The voltage regulator includes an upper bridge component, a lower bridge component, and an inductor. The upper bridge component, the lower bridge component, and the inductor are jointly coupled to the A switching node, and the other ends of the upper bridge component, the lower bridge component and the inductor are respectively coupled to an input terminal, a ground potential and an output terminal, and the voltage regulator also includes a control device, the switching of the upper bridge component and the lower bridge component is controlled to generate an output voltage at the output terminal, and it is characterized in that the output current detection method includes the following steps:

The first step: sensing the current of the upper bridge component to generate a sensing current;

Step 2: Simulating and generating a total current according to the sensing current;

The third step: providing the total current to a setting resistor;

Fourth step: providing the voltage change on the set resistor to the controller for feedback control.

The output current detection method of the voltage regulator of the present invention can also be further realized by adopting the following technical measures.

In the aforementioned output current detection method, both the upper and lower bridge components are transistors.

In the aforementioned output current detection method, the upper bridge component is a transistor, and the lower bridge component is a diode.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the output terminal and the switching node.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the output terminal and the switching node, and the lower bridge component is coupled between the ground potential and the switching node, the An inductance is coupled between the input terminal and the switching node.

In the aforementioned output current detection method, wherein the upper bridge component is coupled between the input terminal and the switching node, and the lower bridge component is coupled between the output terminal and the switching node, the An inductance is coupled between the ground potential and the switching node.

A voltage regulator comprising an upper bridge component, a lower bridge component, an inductor, a controller, a sensing circuit, an emulation circuit and a setting resistor, wherein,

The upper bridge component, the lower bridge component and the inductor are jointly coupled to a switch node, and the other ends of the upper bridge component, the lower bridge component and the inductor are respectively connected to an input terminal, a ground potential and an output terminal coupling;

The controller controls switching of the upper bridge component and the lower bridge component to generate an output voltage at the output terminal;

The sensing circuit senses the current of the upper bridge component to generate a sensing current;

The simulation circuit simulates and generates a total current according to the sensing current;

The setting resistor detects the change of the total current, and the voltage change on the setting resistor is provided to the controller for feedback control.

The voltage regulator of the present invention can also be further realized by adopting the following technical measures.

The aforementioned voltage regulator, wherein the sensing circuit is part of an over-current protection mechanism or a zero-current detection mechanism of the voltage regulator.

In the aforementioned voltage regulator, one end of the setting resistor is connected to the simulation circuit, and the other end is grounded.

In the aforementioned voltage regulator, both the upper and lower bridge components are transistors.

In the aforementioned voltage regulator, the upper bridge component is a transistor, and the lower bridge component is a diode.

The foregoing voltage regulator, wherein the upper bridge component is coupled between the input terminal and the switching node, the lower bridge component is coupled between the ground potential and the switching node, and the inductor coupled between the output terminal and the switching node.

In the foregoing voltage regulator, wherein the upper bridge component is coupled between the output terminal and the switching node, the lower bridge component is coupled between the ground potential and the switching node, and the inductor coupled between the input terminal and the switching node.

In the aforementioned voltage regulator, wherein the upper bridge component is coupled between the input terminal and the switching node, the lower bridge component is coupled between the output terminal and the switching node, and the inductor coupled between the ground potential and the switching node.

After adopting the above technical solution, the output current detection device of the voltage regulator of the present invention has the following advantages:

1. Avoid the use of precision resistors to reduce production costs.

2. Not easily disturbed by noise.

Description of drawings

Figure 1 is a schematic diagram of a known voltage converter;

Fig. 2 is the schematic diagram of the first embodiment of the present invention;

Fig. 3 is a schematic diagram of the summing circuit of Fig. 2;

Fig. 4 is the schematic diagram of the second embodiment of the present invention;

Fig. 5 is the schematic diagram of the third embodiment of the present invention;

FIG. 6 is a schematic diagram of a variation of the embodiment in FIG. 5 .

Detailed ways

The present invention will be further described below in conjunction with embodiment and accompanying drawing.

Please refer to FIG. 2 now. FIG. 2 is a schematic diagram of the first embodiment of the present invention. As shown in the figure, the upper bridge transistor 26 is connected between the input voltage Vi and the switching node SW, the lower bridge transistor 28 is connected between the switching node SW and the ground potential GND, and the inductor is connected to the switching node SW. The bridge transistor 26 and the lower bridge transistor 28 are switched under the control of the driver 30 to generate an output current Io flowing through the inductor and generate an output voltage Vo at the output terminal. The upper bridge detection circuit 20 senses the current of the upper bridge transistor 26 and generates a current I1 accordingly, and the lower bridge detection circuit 22 senses the current of the lower bridge transistor 28 to generate a current I2, and the current I1 and the current I2 pass through the summing circuit 24 After summing up, it is provided to the setting resistor Rset. In this embodiment, the proportional relationship between the current I1 and I2 and the output current Io is no longer fixed at 1:1, and the ratio of the upper and lower bridge currents can also be adjusted, for example, the proportional relationship between the upper and lower bridge currents is adjusted by K1 and K2 , the current flowing through the setting resistor Rset after summing up is represented by Io/K3, and K1 and K2 can be adjusted according to actual needs to achieve the purpose of eliminating offset or delay. The comparator 34 detects the voltage change on the node A, compares it with the reference voltage Vref, and provides it to the controller 32 for feedback control. Since the setting resistor Rset is not on the charging path of the voltage regulator, the resistance value of the setting resistor Rset can be increased to make the voltage change of node A more obvious, so the use of precision resistors can be avoided, the cost can be reduced, and it is less likely to be disturbed by noise .

When the voltage regulator is applied to the charger, it will have an over current protection (OCP) mechanism, or a zero current detection mechanism, which monitors the current on the power transistor to provide protection when the output current is too high or too low. The invention utilizes these basic detection mechanisms as the upper-bridge detection circuit 20 and the lower-bridge detection circuit 22 to monitor the change of the output current Io for feedback control.

Please refer to FIG. 3 again. FIG. 3 is a schematic diagram of the summing circuit in FIG. 2 . As shown in the figure, the current I1 (Psense output) waveform slope generated by the upper bridge detection circuit 20 is Vi/L, and the current I2 (Nsense output) waveform slope generated by the lower bridge detection circuit 22 is (Vo-Vi) /L is summed up by the summing circuit 24 into a current Io/K shown at the bottom of FIG. 3 , flows through the setting resistor Rset and generates a voltage at node A.

Please refer to FIG. 4 now. FIG. 4 is a schematic diagram of the second embodiment of the present invention, which is to set the current detection device of the present invention in an asynchronous step-down voltage converter. In this embodiment, the current on the diode D is not detected, only the current on the upper bridge transistor 40 is sensed by the sensing circuit 42, and then the current waveform as shown in Figure 3 is simulated by the current simulation circuit 44 and provided to the setting resistor Rset , monitoring the voltage change on the setting resistor Rset for feedback control (not shown in the figure). In other embodiments, the current flowing through the diode D can also be directly detected without simulation, and then summed with the current of the upper bridge transistor to provide the setting resistor Rset.

Please refer to FIG. 5 , which is a schematic diagram of a third embodiment of the present invention. As shown in the figure, the sensing device 56 detects the current of the upper bridge transistor 54 of the boost voltage converter to generate a current I1, and the sensing device 58 detects the current of the lower bridge transistor 52 of the boost voltage converter to generate The current I2, the current I1 and the current I2 are summed into the sensing current Is by the summing circuit 60, and a voltage is generated on the node B for the comparator 66 to compare with the reference voltage Vref, so as to provide the controller 64 for feedback control, Make the driver 62 generate driving signals to the upper bridge and lower bridge transistors 54 and 52 . In this embodiment, the currents I1 and I2 can also be adjusted in proportion to K4 and K5.

Finally, please refer to FIG. 6 . FIG. 6 is a schematic diagram of the variation of the embodiment in FIG. 5 . As shown in the figure, the reciprocal of K5 is designed to be 0, in other words, only the current change of the upper bridge transistor 54 is sensed, so as to generate the sensing current Is to the setting resistor Rset to monitor the change of the output voltage Vo.

In other embodiments, the output current detection device of the present invention can also be applied to other types of voltage converters, such as buck-boost type, reverse voltage type, and so on.

The above embodiments are only for illustrating the present invention, rather than limiting the present invention. Those skilled in the relevant technical field can also make various transformations or changes without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the category of the present invention and should be defined by each claim.

Description of component symbols

10 Error Amplifier

12 controllers

14 drives

20 Upper bridge detection circuit

22 Lower bridge detection circuit

24 summing circuit

26 high bridge transistor

28 lower bridge transistor

30 drives

32 controllers

34 Comparators

40 high bridge transistors

42 sensing circuit

44 Current simulation circuit

50 boost voltage converter

52 lower bridge transistor

54 high bridge transistor

56 sensing circuit

Claims (22)

1. the detecting device for output current of a voltage regulator, described voltage regulator comprises axle assemble on, axle assemble once, one inductance, described upper axle assemble, described lower axle assemble and described inductance three's a end jointly is coupled to one and switches node, described voltage regulator also comprises a controller, and described controller is controlled the switching of described upper bridge and described lower axle assemble to produce output voltage at an output; Described detecting device for output current comprises a sensing circuit, and an artificial circuit and is set resistance, it is characterized in that:

The electric current of the described upper axle assemble of described sensing circuit senses is to produce a current sensor;

Described artificial circuit produces a summed current according to described current sensor simulation;

The variation of the described summed current of described setting resistance detection, and the ohmically change in voltage of described setting offers described controller and does and feedback control.

2. detecting device for output current as claimed in claim 1 is characterized in that, described sensing circuit is the over current protection protection mechanism of described voltage regulator or the part of zero current protection mechanism.

3. detecting device for output current as claimed in claim 1 is characterized in that, an end of described setting resistance connects described artificial circuit, other end ground connection.

4. detecting device for output current as claimed in claim 1 is characterized in that, described upper and lower axle assemble is all transistor.

5. detecting device for output current as claimed in claim 1 is characterized in that, described upper axle assemble is transistor, and lower axle assemble is diode.

6. detecting device for output current as claimed in claim 1, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between described output and the described switching node.

7. detecting device for output current as claimed in claim 1, it is characterized in that, described upper axle assemble is coupled between described output and the described switching node, described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between an input and the described switching node.

8. detecting device for output current as claimed in claim 1, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, described lower axle assemble is coupled between described output and the described switching node, and described inductance is coupled between an earthing potential and the described switching node.

9. the method for detecting output current of a voltage regulator, described voltage regulator comprises axle assemble on, axle assemble once, one inductance, described upper axle assemble, described lower axle assemble and described inductance three's a end jointly is coupled to one and switches node, described voltage regulator also comprises a controller, and described controller is controlled the switching of described upper axle assemble and described lower axle assemble to produce output voltage at an output, it is characterized in that described method for detecting output current comprises the following steps:

First step: the electric current of the described upper axle assemble of sensing is to produce a current sensor;

Second step: produce a sum total electric current according to described current sensor simulation;

Third step: described sum total electric current is offered one set resistance;

The 4th step: the ohmically change in voltage of described setting is offered described controller do back coupling control.

10. method for detecting output current as claimed in claim 9 is characterized in that, described upper and lower axle assemble is all transistor.

11. method for detecting output current as claimed in claim 9 is characterized in that, described upper axle assemble is transistor, and lower axle assemble is diode.

12. method for detecting output current as claimed in claim 9, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between described output and the described switching node.

13. method for detecting output current as claimed in claim 9, it is characterized in that, described upper axle assemble is coupled between described output and the described switching node, described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between an input and the described switching node.

14. method for detecting output current as claimed in claim 9, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, described lower axle assemble is coupled between described output and the described switching node, and described inductance is coupled between an earthing potential and the described switching node.

15. a voltage regulator comprises axle assemble on, axle assemble once, and an inductance, a controller, a sensing circuit, an artificial circuit and is set resistance, it is characterized in that:

Described upper axle assemble, described lower axle assemble and described inductance three's a end jointly is coupled to one and switches node;

Described controller is controlled the switching of described upper axle assemble and described lower axle assemble to produce output voltage at an output;

The electric current of the described upper axle assemble of described sensing circuit senses is to produce a current sensor;

Described artificial circuit produces a summed current according to described current sensor simulation;

The variation of the described summed current of described setting resistance detection, and the ohmically change in voltage of described setting offers described controller and does and feedback control.

16. voltage regulator as claimed in claim 15 is characterized in that, described sensing circuit is the over current protection protection mechanism of described voltage regulator or the part of zero current detection mechanism.

17. voltage regulator as claimed in claim 15 is characterized in that, an end of described setting resistance connects described artificial circuit, other end ground connection.

18. voltage regulator as claimed in claim 15 is characterized in that, described upper and lower axle assemble is all transistor.

19. voltage regulator as claimed in claim 15 is characterized in that, described upper axle assemble is transistor, and lower axle assemble is diode.

20. voltage regulator as claimed in claim 15, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, and described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between described output and the described switching node.

21. voltage regulator as claimed in claim 15, it is characterized in that, described upper axle assemble is coupled between described output and the described switching node, and described lower axle assemble is coupled between an earthing potential and the described switching node, and described inductance is coupled between an input and the described switching node.

22. voltage regulator as claimed in claim 15, it is characterized in that, described upper axle assemble is coupled between an input and the described switching node, and described lower axle assemble is coupled between described output and the described switching node, and described inductance is coupled between an earthing potential and the described switching node.

Images