CN115001277A

CN115001277A - Switching power supply circuit

Info

Publication number: CN115001277A
Application number: CN202210850060.7A
Authority: CN
Inventors: 高云云; 孙景涛
Original assignee: Hubei Xinqing Technology Co ltd
Current assignee: Hubei Xinqing Technology Co ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2022-09-02

Abstract

The invention discloses a switch power supply circuit, comprising: a direct current power supply; the sampling module is used for acquiring sampling current and sampling voltage; the PWM controller is connected with the sampling module and used for receiving the sampling current and the sampling voltage and outputting a PWM control signal; the sampling module is also used for reducing the common-mode voltage input to the PWM controller; the power conversion module is connected with the direct-current power supply and the sampling module and is used for converting input direct-current voltage provided by the direct-current power supply into output direct-current voltage; the driving module is connected with the PWM controller and used for outputting a driving signal after receiving the PWM control signal; and the power conversion module is also used for regulating and outputting corresponding output voltage under the control of the driving signal. The invention can realize that the output voltage or the input voltage of the power supply is not limited by the common-mode voltage of the current sampling error amplifier in the PWM controller, and is beneficial to widening the input voltage range and the output voltage range of the switching power supply circuit.

Description

Switching power supply circuit

Technical Field

The invention relates to the technical field of data security, in particular to a switching power supply circuit.

Background

The main circuit of the power supply comprises an input electromagnetic interference filter (EMI), a rectifying and filtering circuit, a power converter, a PWM controller, a MOSFE driving circuit, an output rectifying and filtering circuit, an auxiliary circuit and the like. The PWM controller is divided into a digital controller supplied with 3.3V power and an analog controller supplied with 5V power.

In the prior art, an inductor DCR or a high-end resistor is generally used for current sampling, wherein an inverting input terminal of a current sampling error amplifier is directly connected with a voltage output terminal of a power converter. In the case of a power supply using a digital PWM controller, the common-mode voltage of the input current sampling error amplifier usually does not exceed VCC (3.3V), and the output voltage of the power supply cannot exceed 3.3V × 70% to 2.31V in consideration of the voltage ripple caused by a certain static voltage ripple and load current variation, otherwise, overvoltage damage of the PWM controller may be caused. In the case of a power supply using an analog PWM controller, the common-mode voltage of the input current sampling error amplifier usually does not exceed VCC (5V), and the output voltage of the power supply cannot exceed 5V × 70% to 3.5V in consideration of certain static voltage ripple and voltage ripple caused by load current variation, otherwise overvoltage damage of the PWM controller may be caused.

As can be seen from the above, in the prior art, for a power supply that samples current by using an inductor DCR or a high-side resistor, the output voltage is limited by the common-mode voltage of a current sampling error amplifier in a digital PWM controller or an analog PWM controller, and generally, the common-mode voltage of an input current sampling error amplifier cannot exceed the supply voltage of the PWM controller, so that the output voltage or the input voltage is limited by the common-mode voltage of the current sampling error amplifier.

Disclosure of Invention

An object of the embodiments of the present invention is to provide a switching power supply circuit, which reduces the limitation of the common mode voltage of a current sampling error amplifier on the output voltage or the input voltage.

An embodiment of the present invention provides a switching power supply circuit, including:

a direct current power supply;

the sampling module is used for acquiring sampling current and sampling voltage;

the PWM controller is connected with the sampling module and used for receiving the sampling current and the sampling voltage and outputting a PWM control signal;

the sampling module is also used for reducing the common-mode voltage input to the PWM controller;

the power conversion module is connected with the direct-current power supply and the sampling module and is used for converting input direct-current voltage provided by the direct-current power supply into output direct-current voltage;

the driving module is connected with the PWM controller and used for outputting a driving signal after receiving the PWM control signal;

the power conversion module is also used for regulating and outputting corresponding output voltage under the control of the driving signal.

In some embodiments, the power conversion module comprises: a switch submodule; the sampling module comprises a current sampling submodule, a current sampling RC submodule and a voltage feedback submodule;

the first end of the switch submodule is connected with the direct-current power supply, the second end of the switch submodule is connected with the second end of the driving module, and the third end of the switch submodule is connected with the first end of the driving module;

the third end of the driving module is connected with the first output end of the PWM controller so as to receive a first PWM control signal;

the current sampling sub-module is respectively connected with the fourth end of the switch sub-module, the current sampling RC sub-module and the voltage feedback sub-module;

the current sampling RC sub-module is connected with the sampling input end of the PWM controller;

the voltage feedback submodule is connected with a voltage output end and a feedback input end of the PWM controller, and the voltage output end outputs corresponding output voltage.

the second end of the switch submodule is connected with the first end of the driving module, the third end of the switch submodule is connected with the second end of the driving module, and the fourth end of the switch submodule is connected with the voltage feedback submodule;

the current sampling sub-module is respectively connected with the first end of the switch sub-module, the current sampling RC sub-module and the direct-current power supply, and the current sampling RC sub-module is connected with the direct-current power supply;

In some embodiments, the current sampling RC sub-module comprises: two sets of RC series-parallel units;

the first RC series-parallel unit includes: the circuit comprises a first resistor, a second resistor and a first capacitor;

the first end of the first resistor is connected with the first end of the current sampling submodule, the second end of the first resistor is respectively connected with the first end of the second resistor and the first end of the first capacitor, the second end of the second resistor is connected with the second end of the first capacitor and then grounded, and the first end of the first capacitor is connected with the first sampling input end of the PWM controller;

the second RC series-parallel unit includes: a third resistor, a fourth resistor and a second capacitor;

the first end of the third resistor is connected with the second end of the current sampling submodule, the second end of the third resistor is respectively connected with the first end of the fourth resistor and the first end of the second capacitor, and the second end of the fourth resistor is connected with the second end of the second capacitor and then grounded;

the first resistor and the third resistor have the same resistance value, the second resistor and the fourth resistor have the same resistance value, and the first capacitor and the second capacitor have the same capacitance value.

In some embodiments, the current sampling submodule comprises:

and the inductance sampling unit is respectively connected with the switch submodule, the current sampling RC submodule and the voltage feedback submodule.

In some embodiments, the power conversion module further comprises: a first inductor; the current sampling submodule comprises:

and the resistance sampling unit is respectively connected with the first inductor, the current sampling RC submodule and the voltage feedback submodule, and the first inductor is connected with the switch submodule.

In some of these embodiments, the number of driving modules is two, the PWM controller includes two outputs, and the number of switching sub-modules is two, wherein,

the first end of the first switch submodule is connected with the direct-current power supply, the second end of the first switch submodule is connected with the second end of the first driving module, and the third end of the first switch submodule is connected with the first end of the first driving module;

the third end of the first driving module is connected with the first output end of the PWM controller so as to receive a first PWM control signal;

the second end of the second switch sub-module is connected with the first end of a second drive module, the third end of the second switch sub-module is connected with the second end of the second drive module, and the fourth end of the second switch sub-module is connected with the voltage feedback sub-module;

the third end of the second driving module is connected with the second output end of the PWM controller so as to receive a second PWM control signal;

the fourth end of the first switch sub-module and the first end of the second switch sub-module are respectively connected with two ends of the inductance sampling unit, and the inductance sampling unit is connected with the current sampling RC sub-module.

the first end of the first switch submodule is connected with the resistance sampling unit, the second end of the first switch submodule is connected with the second end of the first driving module, and the third end of the first switch submodule is connected with the first end of the first driving module;

the resistance sampling unit is connected with the current sampling RC sub-module and the direct-current power supply;

the second end of the second switch sub-module is connected with the first end of the second driving module, the third end of the second switch sub-module is connected with the second end of the second driving module, and the fourth end of the second switch sub-module is connected with the voltage feedback sub-module;

and the fourth end of the first switch submodule and the first end of the second switch submodule are respectively connected with two ends of the first inductor.

the second end of the second switch sub-module is connected with the first end of the second driving module, the third end of the second switch sub-module is connected with the second end of the second driving module, the fourth end of the second switch sub-module is connected with the resistance sampling unit, and the resistance sampling unit is connected with the current sampling RC sub-module and the voltage feedback sub-module;

In some embodiments, the switch sub-module comprises: the main control MOS tube and the secondary control MOS tube;

the source level of the main control MOS tube is connected with the drain level of the secondary control MOS tube;

the grid electrode of the main control MOS tube is connected with the second end of the driving module, and the grid electrode of the secondary control MOS tube is connected with the first end of the driving module;

the drain of the main control MOS tube is connected with the direct current power supply or the voltage feedback submodule, and the source of the secondary control MOS tube is grounded;

and the third end of the driving module is connected with the output end of the PWM controller.

The embodiment of the invention provides a switching power supply circuit, which can realize that the output voltage or the input voltage of a power supply is not limited by the common-mode voltage of a current sampling error amplifier in a PWM controller, and is beneficial to widening the input voltage range and the output voltage range of the switching power supply circuit.

Drawings

Fig. 1 is a schematic structural diagram of a switching power supply circuit according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an inductance sampling unit applied to a Buck converter according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a Buck converter to which the resistance sampling unit according to the embodiment of the present invention is applied;

fig. 4 is a schematic structural diagram of an inductor sampling unit applied to a Boost converter according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a resistance sampling unit applied to a Boost converter according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an inductor sampling unit applied to a 4switch Buck-Boost converter according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a resistance sampling unit applied to a 4switch Buck-Boost converter according to an embodiment of the present invention;

fig. 8 is another schematic structural diagram of a resistance sampling unit applied to a 4switch Buck-Boost converter according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be understood that the various steps recited in the method embodiments of the present disclosure may be performed in a different order, and/or performed in parallel. Moreover, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the present disclosure is not limited in this respect.

The term "including" and variations thereof as used herein is intended to be open-ended, i.e., "including but not limited to". The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions for other terms will be given in the following description.

For a circuit, a method conventionally applied is to establish an equation describing the circuit according to a circuit law and a voltage and current relation of an element, the established equation is a linear ordinary differential equation taking time as an independent variable, and then the ordinary differential equation is solved to obtain a solution of a circuit variable in a time domain. The invention transforms the known time domain function into the frequency domain function through Laplace integral transformation, thereby the differential equation of the time domain is converted into the algebraic equation of the frequency domain. Thus, the frequency domain solution function of the algebraic equation is easily solved. And then returning to a time domain through inverse Laplace transform to obtain a solution of an original differential equation meeting the circuit.

As shown in fig. 2-8, the common mode voltage refers to the voltage input to the current sampling error amplifier AMP1 from the non-inverting input terminal to ground or from the inverting input terminal to ground.

As shown in fig. 2 to 8, the differential voltage refers to a difference between the voltage of the non-inverting input terminal to the ground and the voltage of the inverting input terminal to the ground input to the current sampling error amplifier AMP 1.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a switching power supply circuit according to an embodiment of the present invention, where the switching power supply circuit includes:

a DC power supply 40;

the sampling module 30 is used for acquiring sampling current and sampling voltage;

the PWM controller 20 is connected to the sampling module 30, and configured to receive the sampling current and the sampling voltage and output a PWM control signal;

the sampling module 30 is further configured to reduce a common-mode voltage input to the PWM controller;

a power conversion module 10, connected to the dc power supply 40 and the sampling module 30, for converting an input dc voltage provided by the dc power supply into an output dc voltage;

the driving module 50 is connected with the PWM controller 20, and is configured to receive the PWM control signal and output a driving signal;

the power conversion module 10 is further configured to adjust and output a corresponding output voltage under the control of the driving signal.

Specifically, in the switching power supply circuit provided in this embodiment, the PWM controller 20 is connected to the sampling module 30 to sample the current and the voltage in the switching power supply circuit, and then compare the sampled results, and further output the PWM control signal according to the corresponding comparison result. The driving module 50 outputs a corresponding driving signal (including a high level signal or a low level signal) according to the PWM control signal.

Since the sampling module 30 can perform a down-regulation process on the common-mode voltage input to the PWM controller 20, when the same common-mode voltage is input, the power conversion module 10 alternately switches and outputs the corresponding output voltage Vo under the control of the driving signal, so as to convert the input voltage Vin and output the output voltage Vo in the corresponding range. The invention can realize that the output voltage Vo or the input voltage Vin of the switching power supply circuit is not limited by the common-mode voltage in the PWM controller 20, thereby widening the application field.

In one embodiment, referring to fig. 1, 2 and 3, the power conversion module 10 includes: a switch submodule; the sampling module 30 comprises a current sampling submodule, a current sampling RC submodule 12 and a voltage feedback submodule 13;

a first end 1 of the switch submodule is connected with the direct current power supply 40, a second end 2 of the switch submodule is connected with a second end 2 of the driving module 50, and a third end 3 of the switch submodule is connected with the first end 1 of the driving module 50;

the third terminal 3 of the driving module 50 is connected to the first output PWM1 of the PWM controller 20 to receive the first PWM control signal;

the current sampling sub-module is respectively connected with the fourth terminal 4 of the switch sub-module, the current sampling RC sub-module 12 and the voltage feedback sub-module 13;

the current sampling RC sub-module 12 is connected with the sampling input end of the PWM controller 20;

the voltage feedback submodule 13 is connected to a voltage output Vo and a feedback input terminal of the PWM controller 20, and the voltage output Vo outputs a corresponding output voltage.

Specifically, as shown in fig. 2, the current sampling submodule is respectively connected to the first switch submodule 11, the current sampling RC submodule 12, the voltage feedback submodule 13, and the voltage output terminal, so as to output the corresponding output voltage Vo through the voltage output terminal. Alternatively, as shown in fig. 3, the current sampling submodule is connected to the current sampling RC submodule 12, the voltage feedback submodule 13 and the voltage output terminal to output the corresponding output voltage Vo through the voltage output terminal.

The first terminal 1 of the first switch submodule 11 is connected to the dc power supply 40 to receive the input voltage Vin provided by the dc power supply 40, and the current sampling RC submodule 12 is connected to the sampling input terminal of the PWM controller 20 to sample the current at a specific node in the switch power supply circuit and input the sampled current to the sampling input terminal of the PWM controller 20. In addition, the voltage feedback sub-module 13 is connected to the feedback input terminal of the PWM controller 20 so as to sample the voltage at the preset node in the switching power supply circuit and input the sampled voltage to the feedback input terminal of the PWM controller 20.

The PWM controller 20 compares the sampling results and outputs a corresponding PWM control signal according to the comparison result. The second end 2 of the first switch sub-module 11 is connected to the output end of the PWM controller 20 through the driving module 50, so that when the second end 2 of the first switch sub-module 11 receives the PWM control signal sent by the PWM controller 20 through the driving module 50, the current sampling RC sub-module 12 can perform a dimming process on the common-mode voltage input to the PWM controller 20, and therefore, under the condition that the same common-mode voltage is input, the power conversion module 10 alternately switches and outputs the corresponding output voltage Vo under the control of the PWM control signal, so as to convert the input voltage Vin and output the output voltage Vo in the corresponding range. The invention can realize that the output voltage Vo or the input voltage Vin of the switching power supply circuit is not limited by the common-mode voltage in the PWM controller 20, thereby widening the application field.

In one embodiment, referring to fig. 1, 4 and 5, the power conversion module 10 includes: a switch submodule; the sampling module 30 comprises a current sampling submodule, a current sampling RC submodule 12 and a voltage feedback submodule 13;

a second end 2 of the switch submodule is connected with a first end 1 of the driving module 50, a third end 3 of the switch submodule is connected with a second end 2 of the driving module 50, and a fourth end 4 of the switch submodule is connected with the voltage feedback submodule 13;

the current sampling submodule is respectively connected with the first end 1 of the switch submodule, the current sampling RC submodule 12 and the direct current power supply 40, and the current sampling RC submodule 12 is connected with the direct current power supply 40;

the voltage feedback submodule 13 is connected to a voltage output terminal and a feedback input terminal of the PWM controller 20, and the voltage output terminal outputs a corresponding output voltage.

Specifically, as shown in fig. 4, the current sampling submodule is connected to the power input terminal Vin, the first switch submodule 11, and the current sampling RC submodule 12, wherein the dc power source 40 is connected to the current sampling submodule through the power input terminal Vin to provide the input voltage Vin. Alternatively, as shown in fig. 5, the current sampling submodule is connected to the dc power supply 40 and the current sampling RC submodule 12.

The fourth terminal 4 of the first switch submodule 11 is connected to the voltage feedback submodule 13, and the voltage feedback submodule 13 is connected to the voltage output terminal to output the corresponding output voltage Vo. The current sampling RC sub-module 12 is connected to a sampling input of the PWM controller 20 to sample a current at a particular node in the switching power supply circuit and input the sampled current to the sampling input of the PWM controller 20. In addition, the voltage feedback sub-module 13 is connected to the feedback input terminal of the PWM controller 20 so as to sample the voltage at the preset node in the switching power supply circuit and input the sampled voltage to the feedback input terminal of the PWM controller 20.

In one embodiment, referring to fig. 2-8, the current sampling RC sub-module 12 includes: two sets of RC series-parallel units;

the first RC series-parallel unit includes: a first resistor R1, a second resistor R2 and a first capacitor C1;

a first end 1 of the first resistor R1 is connected to a first end 1 of the current sampling submodule, a second end 2 of the first resistor R1 is connected to a first end 1 of the second resistor R2 and a first end 1 of a first capacitor C1, respectively, a second end 2 of the second resistor R2 is connected to a second end 2 of the first capacitor C1 and then grounded, and a first end 1 of the first capacitor C1 is connected to a first sampling input end of the PWM controller 20;

the second RC series-parallel unit includes: a third resistor R3, a fourth resistor R4 and a second capacitor C2;

a first end 1 of the third resistor R3 is connected to a second end 2 of the current sampling submodule, a second end 2 of the third resistor R3 is connected to a first end 1 of the fourth resistor R4 and a first end 1 of the second capacitor C2, respectively, a second end 2 of the fourth resistor R4 is connected to the second end 2 of the second capacitor C2 and then grounded, and a first end 1 of the second capacitor C2 is connected to a second sampling input end of the PWM controller 20;

the first resistor R1 and the third resistor R3 have the same resistance, the second resistor R2 and the fourth resistor R4 have the same resistance, and the first capacitor C1 and the second capacitor C2 have the same capacitance.

Specifically, as shown in fig. 2 to 8, the voltage feedback submodule 13 includes a first voltage dividing resistor Ru and a second voltage dividing resistor Rd. The PWM controller 20 includes a current sampling error amplifier AMP1 and a voltage feedback error amplifier AMP2, wherein the current sampling error amplifier AMP1 includes two sampling input terminals (i.e., the first sampling input terminal and the second sampling input terminal), and the voltage feedback error amplifier AMP2 includes one feedback input terminal and one reference input terminal. Two sampling input ends of the current sampling error amplifier AMP1 are respectively connected with the first capacitor C1 and the second capacitor C2, and are used for respectively inputting the first sampling current collected at the first capacitor C1 and the second sampling current collected at the second capacitor C2 to the two sampling input ends of the current sampling error amplifier AMP 1. A feedback input terminal of the voltage feedback error amplifier AMP2 is connected to a node between the first voltage-dividing resistor Ru and the second voltage-dividing resistor Rd, and is configured to input a sampled voltage collected at the node between the first voltage-dividing resistor Ru and the second voltage-dividing resistor Rd to the feedback input terminal of the voltage feedback error amplifier AMP2, and a reference input terminal of the voltage feedback error amplifier AMP2 is configured to input a reference voltage VRef.

Specifically, the current sampling RC sub-module 12 is connected in parallel with the current sampling sub-module, and the current sampling RC sub-module 12 includes a first RC series-parallel unit connected to the first end 1 of the current sampling sub-module, and a second RC series-parallel unit connected to the second end 2 of the current sampling sub-module.

In one embodiment, the current sampling sub-module comprises:

and the inductance sampling unit 31 is respectively connected with the switch submodule, the current sampling RC submodule 12 and the voltage feedback submodule 13.

Specifically, as shown in fig. 2, the inductance sampling unit 31 includes a sampling inductance L and an equivalent resistance DCR thereof, and if the inductance sampling unit 31 is used for current sampling and the switching power supply circuit is a Buck converter, that is, a Buck converter circuit, a calculation formula of a differential voltage input to the PWM controller 20 is as follows:

if (L) _h /R _DCR )＝((R _q1 ×R _q2 )/(R _q1 +R _q2 ))×C _q Then, the differential voltage input to the PWM controller 20 is as follows:

Vc＝I _L (s)×R _DCR ×(R _q2 /(R _q1 +R _q2 ))

where Vc is the differential voltage I _L (s) is the current flowing through the sampling inductor L, R _DCR Is the resistance value of the equivalent resistor DCR, s is the complex frequency, L _h Is the inductance value, R, of the sampling inductor L _q1 Is the resistance value of the first resistor R1, R _q2 Is the resistance value, C, of said second resistor R2 _q Is the capacitance value of the first capacitor C1.

From fig. 2 and the above equations, it can be seen that the common mode voltage of the error amplifier AMP1 changes to the original R due to the input current sampling, relative to the scenario where the current sampling submodule is not connected in parallel with the current sampling RC submodule 12 _q2 /(R _q1 +R _q2 ) That is, the same common mode voltage is input, the output voltage Vo can be boosted to the original (R) _q1 +R _q2 )/R _q2 . Therefore, the resistance value in the RC series-parallel unit can be set according to requirements, so that the output voltage Vo range of the switching power supply circuit is not limited by common-mode voltage, and the output voltage Vo range of the switching power supply circuit is widened.

In addition, for the scenario that the current sampling sub-module is not connected in parallel with the current sampling RC sub-module 12, since the sampling voltage is proportional to the inductor current, if the resistance of the equivalent resistor DCR in the inductor sampling unit 31 becomes the original (R) _q1 +R _q2 )/R _q2 Thus, the magnitude of the differential voltage Vc input to the PWM controller 20 can be kept constant.

Similarly, as shown in fig. 4, the inductance sampling unit 31 includes a sampling inductance L and an equivalent resistance DCR thereof, and if the inductance sampling unit 31 is used for current sampling and the switching power supply circuit is a Boost converter, that is, a Boost conversion circuit, a calculation formula of a differential voltage input to the PWM controller 20 is as follows:

Vc＝I _L (s)×R _DCR ×(R _q2 /(R _q1 +R _q2 ))

where Vc is the differential voltage, I _L (s) is the current flowing through the sampling inductor L, R _DCR Is the resistance value of the equivalent resistor DCR, s is the complex frequency, L _h Is the inductance value, R, of the sampling inductor L _q1 Is the resistance value of the first resistor R1, R _q2 Is the resistance value, C, of the second resistor R2 _q Is the capacitance value of the first capacitor C1.

From fig. 4 and the above equations, it can be seen that the common mode voltage of the error amplifier AMP1 changes to the original R due to the input current sampling, relative to the scenario where the current sampling submodule is not connected in parallel with the current sampling RC submodule 12 _q2 /(R _q1 +R _q2 ) That is, the same common mode voltage is inputted, and the input voltage Vin can be reduced to the original R _q2 /(R _q1 +R _q2 ). Therefore, the resistance value in the RC series-parallel unit can be set according to requirements, so that the input voltage Vin range of the switching power supply circuit is not limited by common-mode voltage, and the input voltage Vin range of the switching power supply circuit is widened.

In one embodiment, the power conversion module 10 further includes: a first inductance L0; the current sampling submodule comprises:

and the resistance sampling unit 32 is respectively connected with the first inductor L0, the current sampling RC submodule 12 and the voltage feedback submodule 13, and the first inductor L0 is connected with the switch submodule.

Specifically, as shown in fig. 3, the resistance sampling unit 32 includes a sampling resistance Rs and a parasitic inductance ESL thereof, and if the resistance sampling unit 32 is used for current sampling and the switching power supply circuit is a Buck converter, that is, a Buck converter, a calculation formula of the differential voltage input to the PWM controller 20 is as follows:

if (L) _ESL /R _Rs )＝((R _q1 ×R _q2 )/(R _q1 +R _q2 ))×C _q Then, the differential voltage input to the PWM controller 20 is as follows:

Vc＝I _Rs (s)×R _Rs ×(R _q2 /(R _q1 +R _q2 ))

where Vc is the differential voltage, I _Rs (s) is the current flowing through the sampling resistor Rs, R _Rs Is the resistance of the sampling resistor Rs, s is the complex frequency, L _ESL Is the inductance value, R, of the parasitic inductance ESL _q1 Is the resistance value of the first resistor R1, R _q2 Is the resistance value, C, of said second resistor R2 _q Is the capacitance value of the first capacitor C1.

From fig. 3 and the above equations, it can be seen that the common mode voltage of the error amplifier AMP1 changes to the original R due to the input current sampling, relative to the scenario where the current sampling submodule is not connected in parallel with the current sampling RC submodule 12 _q2 /(R _q1 +R _q2 ) That is, the same common mode voltage is input, the output voltage Vo can be boosted to the original (R) _q1 +R _q2 )/R _q2 . Therefore, the resistance value in the RC series-parallel unit can be set according to requirements, so that the output voltage Vo range of the switching power supply circuit is not limited by common-mode voltage, and the output voltage Vo range of the switching power supply circuit is widened.

In addition, for the scenario that the current sampling submodule is not connected in parallel with the current sampling RC submodule 12, since the differential voltage Vc is proportional to the current flowing through the sampling resistor Rs, if the resistance value of the sampling resistor Rs in the resistor sampling unit 32 becomes the original value (R) _q1 +R _q2 )/R _q2 Thus, the magnitude of the differential voltage Vc input to the PWM controller 20 can be kept constant.

Similarly, as shown in fig. 5, the resistance sampling unit 32 includes a sampling resistance Rs and a parasitic inductance ESL thereof, and if the resistance sampling unit 32 is used for current sampling and the switching power supply circuit is a Boost converter, i.e., a Boost conversion circuit, the calculation formula of the differential voltage input to the PWM controller 20 is as follows:

Vc＝I _Rs (s)×R _Rs ×(R _q2 /(R _q1 +R _q2 ))

where Vc is the differential voltage, I _Rs (s) is the current flowing through the sampling resistor Rs, R _Rs Is the resistance of the sampling resistor Rs, s is the complex frequency, L _ESL Is the inductance value, R, of the parasitic inductance ESL _q1 Is the resistance value of the first resistor R1, R _q2 Is the resistance value, C, of the second resistor R2 _q Is the capacitance value of the first capacitor C1.

From fig. 5 and the above equations, it can be seen that the common mode voltage of the error amplifier AMP1 changes to the original R due to the input current sampling, relative to the scenario where the current sampling submodule is not connected in parallel with the current sampling RC submodule 12 _q2 /(R _q1 +R _q2 ) That is, the same common mode voltage is inputted, and the input voltage Vin can be reduced to the original R _q2 /(R _q1 +R _q2 ). Therefore, the resistance value in the RC series-parallel unit can be set according to requirements, so that the input voltage Vin range of the switching power supply circuit is not limited by common-mode voltage, and the input voltage Vin range of the switching power supply circuit is widened.

In addition, the sub-module does not compare with the current sampling sub-moduleIn the scenario that the current sampling RC sub-module 12 is connected in parallel, since the differential voltage Vc is proportional to the current flowing through the sampling resistor, if the resistance value of the sampling resistor Rs in the resistor sampling unit 32 becomes the original value (R) _q1 +R _q2 )/R _q2 Thus, the magnitude of the differential voltage Vc input to the PWM controller 20 may be kept constant.

In one embodiment, as shown in fig. 6, the number of the driving modules 50 is two, the PWM controller 20 includes two output terminals, and the number of the switching sub-modules is two, wherein,

a first end 1 of a first switch submodule 11 is connected with the direct current power supply 40, a second end 2 of the first switch submodule 11 is connected with a second end 2 of a first driving module 51, and a third end 3 of the first switch submodule 11 is connected with the first end 1 of the first driving module 51;

the third terminal 3 of the first driving module 51 is connected to the first output terminal PWM1 of the PWM controller 20 to receive the first PWM control signal;

a second end 2 of the second switch sub-module 14 is connected to a first end 1 of a second driving module 52, a third end 3 of the second switch sub-module 14 is connected to a second end 2 of the second driving module 52, and a fourth end 4 of the second switch sub-module 14 is connected to the voltage feedback sub-module 13;

the third terminal 3 of the second driving module 52 is connected to the second output PWM2 of the PWM controller 20 to receive the second PWM control signal;

the fourth end 4 of the first switch submodule 11 and the first end 1 of the second switch submodule 14 are respectively connected with two ends of the inductance sampling unit 31, and the inductance sampling unit 31 is connected with the current sampling RC submodule 12.

Specifically, as shown in fig. 6, for a structural schematic diagram applied to current sampling by using an inductor DCR, that is, the inductor sampling unit 31 of the present invention, in the Buck-Boost converter, that is, the Buck-Boost conversion circuit of 4 switches (that is, four MOS transistors perform switching), in fig. 6, according to the high level change of the first PWM control signal and the second PWM control signal, the 4 MOS transistors (including two main control MOS transistors and two secondary control MOS transistors) in fig. 6 are controlled to be sequentially and alternately turned on, so that the present invention converts the input voltage Vin of the switching power supply module by using the Buck-Boost converter to obtain the corresponding output voltage Vo.

In one embodiment, as shown in fig. 7, the number of the driving modules 50 is two, the PWM controller 20 includes two output terminals, and the number of the switching sub-modules is two, wherein,

a first end 1 of the first switch submodule 11 is connected to the resistance sampling unit 32, a second end 2 of the first switch submodule 11 is connected to a second end 2 of the first driving module 51, and a third end 3 of the first switch submodule 11 is connected to the first end 1 of the first driving module 51;

the resistance sampling unit 32 is connected with the current sampling RC sub-module 12 and the direct current power supply 40;

the fourth terminal 4 of the first switch submodule 11 and the first terminal 1 of the second switch submodule 14 are respectively connected to two ends of the first inductor L0.

Specifically, as shown in fig. 7, for a structural schematic diagram applied to current sampling by the resistance sampling unit 32, in a Buck-Boost converter, i.e., a Buck-Boost conversion circuit, of the 4-switch (i.e., four MOS transistors perform switching) in fig. 7, according to high-power level changes of the first PWM control signal and the second PWM control signal, the 4 MOS transistors (including two main control MOS transistors and two secondary control MOS transistors) in fig. 7 are controlled to be sequentially and alternately turned on, so that the input voltage Vin of the switching power supply module is converted by the Buck-Boost converter to obtain a corresponding output voltage Vo.

In one embodiment, as shown in fig. 8, the number of the driving modules 50 is two, the PWM controller 20 includes two output terminals, and the number of the switching sub-modules is two, wherein,

a second end 2 of the second switch sub-module 14 is connected to a first end 1 of a second driving module 52, a third end 3 of the second switch sub-module 14 is connected to a second end 2 of the second driving module 52, a fourth end 4 of the second switch sub-module 14 is connected to the resistance sampling unit 32, and the resistance sampling unit 32 is connected to the current sampling RC sub-module 12 and the voltage feedback sub-module 13;

the fourth end 4 of the first switch submodule 11 and the first end 1 of the second switch submodule 14 are respectively connected to two ends of the first inductor L0.

Specifically, as shown in fig. 8, for a structural schematic diagram applied to current sampling by the resistance sampling unit 32, in a Buck-Boost converter, i.e., a Buck-Boost conversion circuit, of the 4switch (i.e., four MOS transistors perform switching), in fig. 8, according to high-power level changes of the first PWM control signal and the second PWM control signal, the 4 MOS transistors (including two main control MOS transistors and two secondary control MOS transistors) in fig. 8 are controlled to be sequentially and alternately turned on, so that the input voltage Vin of the switching power supply module is converted by the Buck-Boost converter to obtain a corresponding output voltage Vo.

In one embodiment, the switch sub-module comprises: the main control MOS tube and the secondary control MOS tube;

the gate of the main control MOS transistor is connected with the second end 2 of the driving module 50, and the gate of the secondary control MOS transistor is connected with the first end 1 of the driving module 50;

the drain of the main control MOS tube is connected with the direct current power supply 40 or the voltage feedback submodule 13, and the source of the secondary control MOS tube is grounded;

the third terminal 3 of the driving module 50 is connected to the output terminal of the PWM controller 20.

Specifically, as shown in fig. 2 to 8, the master MOS includes a first master MOS Q1 and a second master MOS Q4, and the sub-control MOS includes a first sub-control MOS Q2 and a second sub-control MOS Q3. The main control MOS tube and the secondary control MOS tube can be N-channel MOS tubes, and the main control MOS tube and the secondary control MOS tube can be quickly switched on and off through the driving module 50, so that the switching loss is reduced, and the conversion efficiency is improved.

Preferably, the power conversion module 10 further includes an input capacitor Cin and an output capacitor Co, the input capacitor Cin is connected to the dc power supply 40 and then grounded, and the output capacitor Co is connected to the voltage output terminal and then grounded.

Specifically, the input capacitor Cin is connected to the dc power supply 40, so that noise and ac components of the dc power supply 40 are filtered by the input capacitor Cin, and the input voltage Vin input to the input terminal of the power conversion module 10 is more stable and smooth. The output capacitor Co is connected to the output terminal of the power conversion module 10, so as to filter the output voltage Vo obtained by voltage conversion by the power conversion module 10, thereby obtaining a more stable dc voltage.

The current sampling RC sub-module 12 and the current sampling sub-module (including the inductance sampling unit 31 or the resistance sampling unit 32) work at the same time to support current sampling of the whole switching power supply circuit, and the voltage feedback sub-module 13 independently performs voltage sampling feedback on the whole switching power supply circuit. The inductive sampling unit 31 (or the resistive sampling unit 32) may be a part of the sampling module to perform current sampling, or may be a part of the power conversion module 10 to store energy and release energy. The first inductor in the power conversion module 10 is used to store energy and release energy.

The invention can realize that the output voltage or the input voltage of the power supply is not limited by the common-mode voltage of the current sampling error amplifier AMP1 in the PWM controller 20, and is beneficial to widening the input voltage range and the output voltage range of the switching power supply circuit. In addition, the invention can be used for not only Buck converters, but also Boost converters, 4switch Buck-Boost converters and other converters which sample current by using an inductor DCR or a high-end resistor.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The circuits provided by the embodiments of the present application are described in detail above, and specific examples are applied herein to explain the principles and implementations of the present application, and the description of the embodiments is only used to help understand the technical solutions and their core ideas of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A switching power supply circuit, comprising:

a direct current power supply;

2. The switching power supply circuit according to claim 1, wherein the power conversion module comprises: a switch submodule; the sampling module comprises a current sampling submodule, a current sampling RC submodule and a voltage feedback submodule;

3. The switching power supply circuit according to claim 1, wherein the power conversion module comprises: a switch submodule; the sampling module comprises a current sampling submodule, a current sampling RC submodule and a voltage feedback submodule;

4. The switching power supply circuit according to claim 2 or 3, wherein the current sampling RC sub-module comprises: two sets of RC series-parallel units;

the first end of the third resistor is connected with the second end of the current sampling submodule, the second end of the third resistor is respectively connected with the first end of the fourth resistor and the first end of the second capacitor, the second end of the fourth resistor is connected with the second end of the second capacitor and then grounded, and the first end of the second capacitor is connected with the second sampling input end of the PWM controller;

5. The switching power supply circuit according to claim 4, wherein the current sampling sub-module comprises:

6. The switching power supply circuit according to claim 4, wherein the power conversion module further comprises: a first inductor; the current sampling submodule comprises:

7. The switching power supply circuit according to claim 5, wherein the number of the driving modules is two, the PWM controller includes two output terminals, and the number of the switching sub-modules is two, wherein,

and the fourth end of the first switch submodule and the first end of the second switch submodule are respectively connected with two ends of the inductance sampling unit, and the inductance sampling unit is connected with the current sampling RC submodule.

8. The switching power supply circuit according to claim 6, wherein the number of the driving modules is two, the PWM controller includes two output terminals, and the number of the switching sub-modules is two, wherein,

9. The switching power supply circuit according to claim 6, wherein the number of the driving modules is two, the PWM controller includes two output terminals, and the number of the switching sub-modules is two, wherein,

10. The switching power supply circuit according to claim 2, wherein the switching submodule includes: the main control MOS tube and the secondary control MOS tube;