CN113965052B - Switching power supply circuits, switching power supplies and electronic equipment - Google Patents

Abstract

The application relates to the field of switching power supplies, and provides a switching power supply circuit, a switching power supply and electronic equipment, so as to solve the problem that a power supply cannot exit a low-power-consumption mode in a traditional scheme. The circuit comprises a control module, a power level circuit, an inductance unit, a low-power-consumption opening and closing detection module, an output capacitor, a sampling switch tube, a sampling holding capacitor and a dummy load module; one end of the power level circuit and the inductance unit is connected to the first end of the control module, the other end is connected to one end of the dummy load module, one end of the output capacitor, the first end of the sampling switch tube and the first input end of the low-power-consumption closing detection module, the second end is connected to the second input end of the low-power-consumption closing detection module and one end of the sampling hold capacitor, the output end of the low-power-consumption closing detection module is connected to the second end of the control module and the control end of the sampling switch tube, the output end of the low-power-consumption opening detection module is connected to the control end of the sampling switch tube, and the input end is connected to the third end of the control module.

Description

Switching power supply circuits, switching power supplies and electronic equipment

Technical field

The present invention relates to the technical field of low power consumption processing of switching power supplies, and in particular to a switching power supply circuit, switching power supply and electronic equipment.

Background technique

At present, the standby power consumption of switching power supplies is required to be lower and lower. A common practice for low-power switching power supplies is to enter a low-power consumption mode when the load is detected to be extremely low. In the traditional solution, the sampling and holding capacitor C1 is connected to the back end of the switching power supply and a MOS tube is used. When the load is detected to be less than a certain set value, the switching power supply enters the low power consumption mode, the sampling MOS tube is turned off, and the sampling and holding capacitor C1 is connected. The voltage Cvref is the output voltage Vout on the output capacitor Cout when the sampling MOS tube is initially turned off. That is to say, when initially entering the low-power mode, Cvref is equal to Vout. When the output voltage Vout is lower than the reference voltage generated by Cvref, the low-power mode is exited.

The inventor found that in the above scheme, the output capacitor Cout probably does not have a load, and the sampling and holding capacitor C1 cannot be too large due to cost constraints and other reasons. This results in a weak leakage of the process itself that cannot be ignored. When the output capacitor Cout When there is no load, and the weak leakage of the sample and hold capacitor process itself cannot be ignored, it will cause Cvref to decrease faster than the output voltage Vout, making the output voltage Vout higher than the reference voltage generated by Cvref, ultimately resulting in the inability to exit low power. Consumption mode, low practicality.

Contents of the invention

The purpose of the present invention is to provide a switching power supply circuit, switching power supply and electronic equipment to solve the technical problem in the traditional solution that causes the power supply to be unable to exit the low power consumption mode and has low practicality.

A switching power supply circuit, which includes a control module, a power stage circuit and an inductance unit, a low-power turn-on detection module, a low-power turn-off detection module, an output capacitor, a sampling switch tube, a sampling and holding capacitor and a false load module ;

Wherein, the first end of the control module is connected to one end of the power stage circuit, the other end of the power stage circuit is connected to one end of the inductance unit, and the other end of the inductance unit is connected to the virtual One end of the load module, one end of the output capacitor, the first end of the sampling switch tube and the first input end of the low power shutdown detection module, the second end of the sampling switch tube is connected to the low The second input end of the power consumption shutdown detection module and one end of the sampling and holding capacitor, the output end of the low power consumption shutdown detection module is connected to the second end of the control module and the control end of the sampling switch tube

The output end of the low-power turn-on detection module is connected to the control end of the sampling switch, the input end of the low-power turn-on detection module is connected to the third end of the control module, the output capacitor and the The other ends of the sampling and holding capacitors are connected to the ground.

In one embodiment, the dummy load module includes a current source, one end of the current source serves as one end of the dummy load module, and the other end of the current source is connected to the ground end.

In one embodiment, the value of the current source is related to the output voltage of the switching power supply.

In one embodiment, the dummy load module includes a resistor unit, one end of the resistor unit is one end of the dummy load module, and the other end of the resistor unit is connected to the ground end.

In one embodiment, the resistance of the resistor unit is related to the output voltage of the switching power supply.

In one embodiment, the low-power startup detection module includes a first comparator, the input terminal of the first comparator serves as the input terminal of the low-power startup detection module, and the output of the first comparator The terminal serves as the output terminal of the low-power turn-on detection module.

In one embodiment, the low-power shutdown detection module includes a second comparator, the first input terminal of the second comparator serves as the first input terminal of the low-power shutdown detection module, and the second The second input terminal of the comparator serves as the second input terminal of the low-power shutdown detection module, and the output terminal of the second comparator serves as the output terminal of the low-power shutdown detection module.

In one embodiment, the sampling switch transistor is a PMOS field effect transistor.

A switching power supply, which includes a switching power supply circuit as described in any one of the preceding items.

An electronic device includes the switching power supply according to any one of the foregoing items, or the switching power supply circuit according to any one of the foregoing items.

After the switching power supply enters low-power consumption mode, the output capacitor Cout may or may not have a load. When the output capacitor Cout has a load, the voltage Vout will slowly decrease due to the existence of the load. When the low-power shutdown detection module detects that Vout is less than the reference voltage generated by Cvref, it exits the low-power mode, and the sampling switch Q turns on again, connecting the sampling and holding capacitor C1 and the output capacitor Cout. When the load of the output capacitor Cout is 0, that is, when the output capacitor Cout has no load, due to the existence of the dummy load module 105, the output voltage Vout can be effectively guaranteed, and the decrease speed will be faster than that without the dummy load module 105. It can be seen that , by adding a dummy load module, the output voltage Vout can be made to drop faster than Cvref, effectively preventing the voltage Cvref from dropping faster, allowing the switching power supply to successfully exit the low-power mode, improving practicality performance and reliability.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings in the following description are only illustrative of the present invention. For some embodiments, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a switching power supply circuit provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram of a dummy load module provided by an embodiment of the present invention;

Figure 3 is another structural schematic diagram of a dummy load module provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

In order to illustrate the technical solution of the present invention, specific examples will be described below.

As shown in Figure 1, the embodiment of the present application provides a switching power supply circuit for use in a switching power supply. The switching power supply circuit includes a control module 101, a power stage circuit and an inductance unit 102, a low-power turn-on detection module 103, and a low-power turn-on detection module 103. The power consumption shutdown detection module 104 includes the output capacitor Cout, the sampling switch Q, the sampling and holding capacitor C1 and the dummy load module 105.

The first end of the control module 101 is connected to one end of the power stage circuit, the other end of the power stage circuit is connected to one end of the inductor unit, and the other end of the inductor unit is connected to one end of the dummy load module 105 and one end of the output capacitor Cout. , the first end of the sampling switch P and the first input end of the low-power shutdown detection module 104. In Figure 1, to simplify the description, the power stage circuit and the inductance unit are represented by a box, that is, the third part of the control module 101 One end is connected to the power stage circuit and one end of the inductance unit 102, and the other end of the power stage circuit and the inductance unit 102 is connected to one end of the dummy load module 105, one end of the output capacitor Cout, the first end of the sampling switch Q and the low power The first input terminal of the power consumption shutdown detection module 104, the second terminal of the sampling switch Q is connected to the second input terminal of the low power consumption shutdown detection module 104 and one end of the sampling and holding capacitor C1, and the output of the low power consumption shutdown detection module 104 The terminal (LPM_out) is connected to the second terminal of the control module 101 and the control terminal of the sampling switch Q;

The first end (LPM_in) of the low-power turn-on detection module 103 is connected to the control end of the sampling switch P, the second end of the low-power turn-on detection module 103 is connected to the third end of the control module 101, and the output capacitor Cout and sampling The other end of the holding capacitor C1 is connected to the ground.

In this embodiment, the low power consumption start-up detection module 103 is used to detect the load information of the switching power supply in real time. When it is detected that the load information is less than a certain set value, the control module controls the switching power supply to enter a low power consumption mode. Entering the low power consumption mode includes but is not limited to performing the following operations: closing the low power consumption shutdown detection module 104, and/ Or all power-consuming modules except the dummy load module 105. When entering the low power consumption mode, when the sampling switch Q is turned off, the voltage Cvref on the sampling and holding capacitor C1 is the Vout when the sampling switch Q is initially turned off. In other words, when initially entering low-power mode, Cvref is equal to Vout.

After the switching power supply enters low-power consumption mode, the output capacitor Cout may or may not have a load. When the output capacitor Cout has a load, the voltage Vout will slowly decrease due to the existence of the load. When the low-power shutdown detection module 104 detects that Vout is less than the reference voltage generated by Cvref, it exits the low-power mode, and the sampling switch Q turns on again, connecting the sampling and holding capacitor C1 and the output capacitor Cout. When the load of the output capacitor Cout is 0, that is, when the output capacitor Cout has no load, the presence of the dummy load module 105 can effectively ensure that the output voltage Vout decreases faster than without the dummy load module 105 .

It should be noted that due to the existence of the dummy load module 105, in order to avoid increasing the power consumption in the low power consumption mode, the dummy load module 105 cannot be too large. Therefore, in order to further prevent the output voltage VOUT from falling very slowly to ensure that the output The voltage Vout drops much faster than Cvref. This embodiment needs to reasonably consider the weak leakage of the sampling and holding capacitor C1 process itself and the value of the sampling and holding capacitor C1.

For example, generally speaking, the output capacitor Cout can have a value of about 10uF, and the dummy load module 105 can have a value of about 10nA. For the sample and hold capacitor C1, the weak leakage of the process itself can usually be estimated to be about 10fA. To sum up, when the value of the sampling and holding capacitor C1 is 10pf, the falling speed of the output voltage Vout will be the same as Cvref. In order to ensure that the falling speed of the output voltage Vout is always much greater than Cvref, for example, the value of the sampling and holding capacitor C1 It can be greater than 100pF, or the dummy load module can be increased to about 20nA. There is no specific limit.

It can be seen that in this embodiment, by adding the dummy load module 105, the falling speed of the output voltage Vout can be greater than the falling speed of Cvref, effectively preventing the voltage Cvref from falling faster, so that the switching power supply can successfully exit the low power consumption mode. mode, the practicability and reliability are improved, and the values of the sampling and holding capacitor C1 and the dummy load module can also be reasonably configured to take into account both cost and power consumption.

In one embodiment, as shown in Figure 2, the dummy load module 105 includes a current source I1. Specifically, the dummy load module 105 is implemented by a current source I1, wherein one end of the current source I1 serves as one end of the dummy load module 105. , the other end of the current source I1 is connected to the ground.

In one embodiment, as analyzed above, in order to ensure that the falling speed of the output voltage Vout is always much greater than Cvref, the value of the current source is related to the output voltage of the switching power supply. Taking the above example as an example, the value range of the current source can be It is 10nA~20nA, so that the decreasing speed of the output voltage Vout is always much greater than Cvref.

It should be noted that in some embodiments, the current source I1 can be a current source generated by using a current mirror, and the current mirror can be generated from other modules of the switching power supply circuit. For example, when low power consumption turns off the detection module When 104 includes a current mirror, the current source I1 can be generated from the current mirror in the low-power shutdown detection module 104, and is not specifically limited.

In one embodiment, as shown in Figure 3, the dummy load module includes a resistor unit R. Specifically, the dummy load module uses a resistor unit R, where one end of the resistor unit R is one end of the dummy load module 105, and the resistor unit R1 The other end is connected to ground.

In one embodiment, as analyzed above, in order to ensure that the falling speed of the output voltage Vout is always much greater than Cvref, the resistance of the resistor unit R is related to the output voltage of the switching power supply. The resistance of the resistor unit R can be adjusted according to the voltage of Vout. Size, taking the above example as an example, in order to make the power consumption of the resistor unit R be more than 10nA, for example, if Vout is 1V, the resistor unit R can be 100M ohms, and it is determined that its power consumption is more than 10nA.

In one embodiment, the low-power startup detection module 103 includes a first comparator. Specifically, the low-power startup detection module 103 is a first comparator, and the first terminal of the first comparator serves as the low-power startup detection module. The first terminal of the module 103 and the second terminal of the first comparator serve as the second terminal of the low-power turn-on detection module 103. The first terminal of the first comparator is connected to the control terminal of the sampling switch Q, and the second comparator The second end is connected to the control module 101.

In one embodiment, the low-power shutdown detection module 104 includes a second comparator. Specifically, the low-power shutdown detection module 104 is a second comparator, and the first input terminal of the second comparator serves as the low-power shutdown detection module. The first input terminal of the module 104 and the second input terminal of the second comparator serve as the second input terminal of the low-power shutdown detection module 104 , and the output terminal of the second comparator serves as the output terminal of the low-power shutdown detection module 104 .

Wherein, the first input terminal of the second comparator is used to receive the output voltage Vout, the second input terminal receives the voltage Cvref, and the first comparator is used to compare the output Vout with the reference voltage generated by Cvref. For example, Cvref The generated reference low voltage is tens of millivolts smaller than Cvref, which is generally about 20mV. The LPM_out signal is output to the control module 101 or the sampling switch Q through the output terminal, and the sampling switch Q is turned on or off according to the LPM_out signal.

It can be understood that in this embodiment, the low-power shutdown detection module 104 is a second comparator, and the power consumption of the comparator is about 40 nA, and the dummy load module 105 in the embodiment of the present application is a current source I1 or a resistor unit R. , the power consumption will not be too large, it is enough to meet the requirement that the output voltage Vout’s falling speed is always much greater than Cvref, and it can achieve lower static power consumption requirements during normal operation of DCDC.

It should be noted that in the above embodiments, the low power consumption on detection module 103 and the low power consumption off detection module 104 are implemented by comparators. In other embodiments, other alternative comparison circuits can also be used. Specifically, this There are no restrictions on application.

In one embodiment, the sampling switch Q can be a PMOS field effect transistor. The D pole of the PMOS field effect transistor serves as the first terminal of the sampling switch, the S pole serves as the second terminal of the sampling switch, and the G pole serves as the sampling switch. of the control end. It should be noted that the sampling switch transistor Q can also be implemented by other alternative switch transistors, such as a junction field effect transistor, etc., which is not limited in this application.

In one embodiment, a switching power supply is provided. The switching power supply includes a switching power supply circuit as in any of the preceding embodiments. The switching power supply circuit can be applied to various types of switching power supplies. For example, The switching power supply includes DC-DC switching power supply or other types of switching power supply, and is not specifically limited.

In one embodiment, an electronic device is provided. The electronic device may be a wearable device, such as a bracelet, a helmet, or other electronic device with low power consumption requirements. The details are not limited. The electronic device includes such as The aforementioned switching power supply, or the electronic device includes the switching power supply circuit mentioned in any of the aforementioned embodiments.

In this embodiment, since electronic devices such as wearable devices adopt the switching power supply circuit used in the embodiment of the present application, the working performance of their power supplies can be effectively maintained, confirming that the electronic devices can normally enter the low power consumption mode and can also operate normally. Exiting the low power consumption mode makes the electronic equipment using the switching power supply circuit have strong reliability and practicality.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the foregoing embodiments. Modifications are made to the recorded technical solutions, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention, and should all be included in the present invention. within the scope of protection.

Claims (10)

1. A switching power supply circuit, characterized in that the switching power supply circuit includes a control module, a power stage circuit and an inductance unit, a low-power turn-on detection module, a low-power turn-off detection module, an output capacitor, a sampling switch tube, a sampling switch Holding capacitor and dummy load modules; Wherein, the first end of the control module is connected to one end of the power stage circuit, the other end of the power stage circuit is connected to one end of the inductance unit, and the other end of the inductance unit is connected to the dummy load One end of the module, one end of the output capacitor, the first end of the sampling switch tube and the first input end of the low-power shutdown detection module, the second end of the sampling switch tube is connected to the low-power The second input end of the power consumption shutdown detection module and one end of the sampling and holding capacitor, the output end of the low power consumption shutdown detection module is connected to the second end of the control module and the control end of the sampling switch tube; The output end of the low-power turn-on detection module is connected to the control end of the sampling switch, the input end of the low-power turn-on detection module is connected to the third end of the control module, the output capacitor and the The other ends of the sampling and holding capacitors are connected to the ground; Through the dummy load module, the falling speed of the output voltage Vout of the output capacitor is greater than the falling speed of the voltage Cvref of the sampling and holding capacitor. 2. The switching power supply circuit of claim 1, wherein the dummy load module includes a current source, one end of the current source serves as one end of the dummy load module, and the other end of the current source is connected to The end of the land. 3. The switching power supply circuit of claim 2, wherein the value of the current source is related to the output voltage of the switching power supply circuit. 4. The switching power supply circuit of claim 1, wherein the dummy load module includes a resistor unit, one end of the resistor unit is one end of the dummy load module, and the other end of the resistor unit is connected to The end of the land. 5. The switching power supply circuit of claim 4, wherein the resistance of the resistor unit is related to the output voltage of the switching power supply circuit. 6. The switching power supply circuit according to any one of claims 1 to 5, wherein the low-power turn-on detection module includes a first comparator, and the input terminal of the first comparator serves as the low-power The input terminal of the low-power consumption startup detection module is used as the output terminal of the low-power consumption startup detection module. 7. The switching power supply circuit according to any one of claims 1 to 5, wherein the low-power shutdown detection module includes a second comparator, and the first input terminal of the second comparator serves as the The first input terminal of the low-power shutdown detection module, the second input terminal of the second comparator serves as the second input terminal of the low-power shutdown detection module, and the output terminal of the second comparator serves as the Low power consumption turns off the output of the detection module. 8. The switching power supply circuit according to any one of claims 1 to 5, characterized in that the sampling switch tube adopts a PMOS field effect tube. 9. A switching power supply, characterized in that the switching power supply includes the switching power supply circuit according to any one of claims 1-8. 10. An electronic device, characterized by comprising the switching power supply as claimed in claim 9, or the switching power supply circuit as claimed in any one of claims 1-8.