Switching power supply circuit, control method thereof, power supply chip and related system

Abstract

The application relates to the technical field of power electronics, and discloses a switching power supply circuit and a control method thereof, a power supply chip and a related system. The switching power supply circuit comprises a self-oscillation circuit, an input end of the self-oscillation circuit receives a power supply voltage, and an output end of the self-oscillation circuit is used for outputting a first driving signal. A boost switching power supply circuit is connected with the output end of the self-oscillation circuit, the boost switching power supply circuit receives the power supply voltage, and the first driving signal is used for driving a switch tube of the boost switching power supply circuit to be turned on or turned off, so that the boost switching power supply circuit outputs a supply voltage, and the lowest power supply voltage required for the switching power supply circuit to work can be reduced. Based on the technical scheme of the application, the applicability of the switching power supply circuit can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a switching power supply circuit, a control method thereof, a power supply chip and a related system. BACKGROUND

[0002] In the prior art, the switching power supply circuit is generally used to provide a higher supply voltage than the power supply voltage, and supply power to a working circuit with a higher demand input voltage based on the supply voltage.

[0003] The defect of the prior art is that the switching power supply circuit needs to receive a driving signal to provide a higher supply voltage than the power supply voltage, and the traditional negative feedback waveform generating circuit has an amplifier and other devices, which results in a still relatively large input voltage required by the negative feedback waveform generating circuit. This makes the power supply voltage at least greater than the input voltage required by the negative feedback waveform generating circuit, greatly limiting the application scenarios of the switching power supply circuit and reducing the applicability of the switching power supply circuit. SUMMARY

[0004] The technical problem solved by the present application is how to reduce the minimum power supply voltage required for the switching power supply circuit to work, so as to improve the applicability of the switching power supply circuit.

[0005] To solve the above technical problem, the first technical solution adopted by the present application is: 1. A switching power supply circuit, comprising: a self-oscillating circuit, the input end of the self-oscillating circuit receiving a power supply voltage, the output end of the self-oscillating circuit being used to output a first driving signal; a boost switching power supply circuit connected with the output end of the self-oscillating circuit, the boost switching power supply circuit receiving the power supply voltage, the first driving signal being used to drive the switching tube of the boost switching power supply circuit to turn on or turn off, so that the boost switching power supply circuit outputs a supply voltage, which can reduce the minimum power supply voltage required for the switching power supply circuit to work.

[0006] To solve the above technical problem, the second technical solution adopted by the present application is: a control method of a switching power supply circuit, applied to the switching power supply circuit; the control method comprises: controlling the switching circuit to make the switching tube receive a first driving signal to turn on or turn off; tracking and determining whether the supply voltage is not less than a preset voltage; if yes, controlling the switching circuit to make the switching tube receive a second driving signal to turn on or turn off.

[0007] To solve the above technical problem, the third technical solution adopted by the present application is: a power supply chip, comprising the switching power supply circuit.

[0008] To solve the above technical problem, the fourth technical solution adopted by the present application is: a battery management system, comprising the power supply chip.

[0009] In order to solve the above technical problems, the fifth technical solution of the present application is a control system, the control system comprising the power supply chip.

[0010] The beneficial effects of the present application are: different from the prior art, the present application adopts a self-oscillation circuit to provide a first driving signal, and uses the first driving signal to drive the switch tube of the boost switching power supply circuit to turn on or turn off, so as to make the boost switching power supply circuit output a higher supply voltage than the power supply voltage, wherein the input voltage required by the self-oscillation circuit is lower than that of the traditional negative feedback waveform generating circuit, therefore, the technical solution of the present application reduces the minimum power supply voltage required for the switching power supply circuit to work, and further improves the applicability of the switching power supply circuit. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows, obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art. Among them:

[0012] Figure 1 is a circuit schematic diagram of the first embodiment of the switching power supply circuit of the present application;

[0013] Figure 2 is a circuit schematic diagram of the second embodiment of the switching power supply circuit of the present application;

[0014] Figure 3 is a circuit schematic diagram of the third embodiment of the switching power supply circuit of the present application;

[0015] Figure 4 is a circuit schematic diagram of the fourth embodiment of the switching power supply circuit of the present application;

[0016] Figure 5 is a circuit schematic diagram of the fifth embodiment of the switching power supply circuit of the present application;

[0017] Figure 6 is a flowchart of an embodiment of the control method of the switching power supply circuit of the present application;

[0018] Figure 7 is a structural schematic diagram of an embodiment of the power supply chip of the present application;

[0019] Figure 8 is a structural schematic diagram of an embodiment of the battery management system of the present application;

[0020] Figure 9 is a structural schematic diagram of an embodiment of the control system of the present application. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0022] The terms "first", "second" in the present application are only used for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed or can optionally include other steps or units inherent to the process, method, product or device.

[0023] Figure 1 is a circuit schematic diagram of a first embodiment of a switching power supply circuit of the present application.

[0024] The present application proposes a switching power supply circuit, as shown in Figure 1 The switching power supply circuit includes a self-oscillation circuit 101 and a boost switching power supply circuit 102.

[0025] The self-oscillation circuit 101 is connected with a power supply to receive a power supply voltage (such as Vin in Figure 1 ), to obtain power supply. After receiving the power supply voltage, the self-oscillation circuit 101 can perform self-oscillation to generate and output a first driving signal.

[0026] The boost switching power supply circuit 102 is connected with a power supply to receive a power supply voltage, to obtain power supply. The boost switching power supply circuit 102 is connected with the output end of the self-oscillation circuit 101, and the boost switching power supply circuit 102 includes a switching tube 1021. The switching tube 1021 can receive the first driving signal output by the self-oscillation circuit 101. The first driving signal functions to turn on or turn off the switching tube 1021, so that the boost switching power supply circuit 102 outputs a power supply voltage (such as Vout in Figure 1 ).

[0027] Traditional negative feedback waveform generation circuits used to generate drive signals to drive the switching transistor 1021 require a relatively large supply voltage to operate (e.g., a 2V supply voltage). However, the self-excited oscillation circuit 101 only requires a relatively small supply voltage to generate the aforementioned first drive signal (e.g., only a 0.8V supply voltage). Therefore, by using the self-excited oscillation circuit 101 to generate and output the first drive signal to drive the switching transistor 1021 of the boost switching power supply circuit 102 to cause the boost switching power supply circuit 102 to output the supply voltage, the minimum supply voltage required by the switching power supply circuit can be reduced, allowing the switching power supply circuit to be used in more application scenarios with only low supply voltages.

[0028] Unlike existing technologies, this application uses a self-excited oscillation circuit 101 to provide a first driving signal, and uses the first driving signal to drive the switching transistor 1021 of the boost-type switching power supply circuit 102 to turn on or off, so that the boost-type switching power supply circuit 102 outputs a supply voltage higher than the power supply voltage. The input voltage required by the self-excited oscillation circuit 101 is lower than that of the traditional negative feedback waveform generation circuit. Therefore, the technical solution of this application reduces the minimum power supply voltage required for the operation of the switching power supply circuit, thereby improving the applicability of the switching power supply circuit.

[0029] Figure 2 This is a circuit diagram of the second embodiment of the switching power supply circuit of this application.

[0030] Optional, such as Figure 2 As shown, the boost-type switching power supply circuit 102 may include: an inductor 1022, a first diode 1023, and a first capacitor 1024.

[0031] One end of inductor 1022 and the anode of first diode 1023 are connected to a power supply to receive the power supply voltage. The first terminal of first capacitor 1024 is connected to the other end of inductor 1022, and the second terminal of first capacitor 1024 is connected to the cathode of first diode 1023. The input terminal of self-excited oscillation circuit 101 is connected to the cathode of first diode 1023 and the second terminal of first capacitor 1024 to receive the voltage at the second terminal of first capacitor 1024.

[0032] As the switch tube 1021 is cycled between the on and off states due to the driving of the first driving signal, the first end voltage of the first capacitor 1024 is constantly switched between the supply voltage and the ground voltage. According to the bootstrap effect of the capacitor, when the voltage at the first end of the first capacitor 1024 is switched from the supply voltage to the ground voltage, the voltage at the second end of the first capacitor 1024 will also drop sharply, and the supply voltage will be charged to the second end of the first capacitor 1024 through the first diode 1023. According to the bootstrap effect of the capacitor, when the voltage at the first end of the first capacitor 1024 is switched from the ground voltage to the supply voltage, although the voltage at the second end of the first capacitor 1024 will rise, due to the reverse blocking of the first diode 1023, the voltage at the second end of the first capacitor 1024 will not drop. Based on this working principle, the voltage at the second end of the first capacitor 1024 will constantly rise.

[0033] The maximum amplitude of the first driving signal output by the self-oscillating circuit 101 has a positive correlation with the voltage received by the self-oscillating circuit 101, so when the voltage at the second end of the first capacitor 1024 increases, the maximum amplitude of the first driving signal will also increase, which can speed up the speed of turning on or off the switch tube, and in turn speed up the speed of increasing the supply voltage.

[0034] Further, as shown in Figure 2 , the switching power supply circuit can further include a second diode 1025 and a second capacitor 1026.

[0035] The anode of the second diode 1025 is connected with the inductor 1022 and the first end of the switch tube 1021, the cathode of the second diode 1025 is connected with the first end of the second capacitor 1026, the second end of the second capacitor 1026 is connected with the second end of the switch tube 1021, and the second end of the switch tube 1021 is grounded. The control end of the switch tube 1021 is connected with the output end of the self-oscillating circuit 101 to receive the first driving signal and turn on or off the connection between the first end of the switch tube 1021 and the second end of the switch tube 1021 under the driving of the first driving signal. The cathode of the second diode 1025 and the first end of the second capacitor 1026 are the output end of the boost switching power supply circuit 102, used to output the supply voltage.

[0036] When the switch tube 1021 is on, the inductor is charged based on the supply voltage, and the current flows to the ground end. When the switch tube 1021 is off, the second capacitor 1026 is charged based on the superimposed voltage of the inductor voltage and the supply voltage to increase the supply voltage. The second diode 1025 plays a role in reverse blocking to prevent the supply voltage from dropping. Based on this working principle, the supply voltage will constantly rise.

[0037] Figure 3 is a circuit schematic diagram of a third embodiment of the switching power supply circuit of the present application.

[0038] Optionally, as shown in Figure 3 The switching power supply circuit further includes a negative feedback waveform generating circuit 103 and a switching circuit 104.

[0039] The power supply end of the negative feedback waveform generating circuit 103 receives a supply voltage, the negative feedback input end of the negative feedback waveform generating circuit 103 receives the supply voltage through at least one resistor, and the output end of the negative feedback waveform generating circuit 103 can output a second driving signal, which can be used to drive the switch tube 1021 to turn on or turn off. The at least one resistor can include a first resistor 1031, a second resistor 1032 and a third resistor 1033 in the negative feedback waveform generating circuit 103.

[0040] The switching circuit 104 is connected with the output end of the self-oscillating circuit 101, the output end of the negative feedback waveform generating circuit 103 and the control end of the switch tube 1021 respectively. The switching circuit 104 can connect the output end of the self-oscillating circuit 101 with the control end of the switch tube 1021, so that the control end of the switch tube 1021 receives the first driving signal, or connect the output end of the negative feedback waveform generating circuit 103 with the control end of the switch tube 1021, so that the control end of the switch tube 1021 receives the second driving signal, so that the boost switching power supply circuit 102 can drive the switch tube to turn on or turn off based on the first driving signal or the second driving signal.

[0041] The negative feedback waveform generating circuit 103 can perform negative feedback adjustment on the second driving signal according to the supply voltage output by the switching power supply circuit due to the existence of negative feedback (the negative feedback input end receives the supply voltage through at least one resistor), so the second driving signal is more stable and reliable than the first driving signal output by the self-oscillating circuit 101 without negative feedback. The user can freely choose to drive the switch tube 1021 with the first driving signal or the second driving signal according to the current working condition, thereby improving the applicability of the switching power supply circuit.

[0042] Figure 4 is a circuit schematic diagram of a fourth embodiment of the switching power supply circuit of the present application.

[0043] Further, as shown in Figure 4 The switching circuit 104 can be a single-pole double-throw switch.

[0044] The single-pole double-throw switch includes a first connection end, a second connection end and a common end, the first connection end is connected to the output end of the self-oscillating circuit, the second connection end is connected to the output end of the negative feedback waveform generating circuit, and the common end is connected to the control end of the switch tube. With the switching of the single-pole double-throw switch, the first connection end can be connected to the common end, or the second connection end can be connected to the common end.

[0045] Specifically, the switching circuit 104 can also be other circuits or devices with the above-mentioned switching connection line function, which are not limited here.

[0046] Figure 5 is a circuit schematic diagram of the fifth embodiment of the switching power supply circuit of the present application.

[0047] Further, as shown in Figure 5 , the negative feedback waveform generating circuit 103 further includes an error amplifier 1034 and a duty cycle analog-digital conversion module 1035.

[0048] The first input end of the error amplifier 1034 receives a reference voltage (such as Vref in Figure 5 ), which is sent by a reference voltage generating circuit, and the second input end of the error amplifier 1034 receives a supply voltage through at least one resistor (such as the first resistor 1031, the second resistor 1032 and the third resistor 1033). The input end of the duty cycle analog-digital conversion module 1035 is connected with the output end of the error amplifier 1034, the output end of the duty cycle analog-digital conversion module 1035 is connected with the switching circuit 104, and the output end of the duty cycle analog-digital conversion module 1035 is used to output a second driving signal.

[0049] Optionally, the self-oscillation circuit 101 can be a self-feedback oscillator or other circuits or devices with a self-oscillation function, which are not limited here.

[0050] It should be noted that the negative feedback waveform generating circuit 103 (error amplifier 1034 and duty cycle analog-digital conversion module 1035) in the above is powered by the higher one of the power supply voltage and the supply voltage.

[0051] Figure 6 is a flowchart of an embodiment of the control method of the switching power supply circuit of the present application.

[0052] The present application also proposes a control method of a switching power supply circuit, which is applied to the switching power supply circuit of any embodiment. Figures 3 to 5

[0053] As shown in Figure 6 , the control method includes:

[0054] Step S1: controlling the switching circuit 104 to make the switching tube 1021 receive the first driving signal to be turned on or turned off.

[0055] Step S2: tracking and determining whether the supply voltage is not less than a preset voltage.

[0056] ​When the result of the step S2 is yes (when the supply voltage is not less than the preset voltage), the step S3 is executed. The step S3: the control switching circuit 104 makes the switch tube 1021 receive the second driving signal to be turned on or turned off.

[0057] As mentioned above, compared with the first driving signal outputted by the self-oscillation circuit 101 without negative feedback, the second driving signal outputted by the negative feedback waveform generating circuit 103 is more stable and reliable, but the negative feedback waveform generating circuit 103 needs a larger voltage to be powered than the self-oscillation circuit 101, if the power supply voltage is small, the negative feedback waveform generating circuit 103 cannot be powered at the beginning based on the power supply voltage to output the second driving signal.

[0058] In the control method adopted in the embodiment, the preset voltage is a voltage enough to power the negative feedback waveform generating circuit 103, and the power supply end of the negative feedback waveform generating circuit receives the supply voltage. When the supply voltage is less than the preset voltage (i.e. when the switching power supply circuit is just started), the self-oscillation circuit 101 (powered by a lower power supply voltage) can be used to output the first driving signal to drive the switch tube 1021. When the supply voltage is not less than the preset voltage (i.e. when the switching power supply circuit runs for a period of time and the supply voltage has been improved to a certain extent), the negative feedback waveform generating circuit 103 (powered by the supply voltage) can be used to output the second driving signal to drive the switch tube 1021. Based on the above working principle, it can be ensured that the self-oscillation circuit 101 can be started with a lower power supply voltage to drive the switch tube 1021, so as to realize the preliminary lifting of the supply voltage. Then, when the supply voltage is not less than the preset voltage, the negative feedback waveform generating circuit 103 is started based on the supply voltage to provide the second driving signal more stable to drive the switch tube 1021, thereby ensuring the long-term stability of the supply voltage.

[0059] Different from the prior art, the control method adopted in the application can drive the switching power supply circuit based on an extremely low power supply voltage to improve the supply voltage, and when the supply voltage is greater than the preset voltage, the second driving signal generated by the negative feedback waveform generating circuit 103 with negative feedback is used to drive the switching power supply circuit to improve the long-term stability of the supply voltage.

[0060] Figure 7 is a structural schematic diagram of an embodiment of the power supply chip of the application.

[0061] The application also proposes a power supply chip, as shown in Figure 7 The power supply chip 70 at least includes a switching power supply circuit 71 for starting the working circuit. The switching power supply circuit 71 is the switching power supply circuit disclosed in the above embodiment, which will not be described here.

[0062] Different from the prior art, the self-oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is used to drive the switch tube 1021 of the boost type switching power supply circuit 102 to be turned on or turned off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than the power supply voltage, wherein the input voltage required by the self-oscillation circuit 101 is lower than that of a traditional negative feedback waveform generating circuit, thus the technical scheme of the application reduces the minimum power supply voltage required for the switching power supply circuit to work, and further improves the applicability of the switching power supply circuit.

[0063] Figure 8 is a structural schematic diagram of an embodiment of the battery management system of the application.

[0064] The application further provides a battery management system, as shown in Figure 8 The battery management system 80 comprises the power supply chip 70. The power supply chip 70 is the power supply chip disclosed in the above embodiment, which will not be described herein again.

[0065] Specifically, the battery management system 80 can be a device battery management system, an automobile battery management system or other types of battery management systems, which will not be limited herein.

[0066] Different from the prior art, the self-oscillation circuit 101 is adopted to provide the first driving signal, and the first driving signal is used to drive the switch tube 1021 of the boost type switching power supply circuit 102 to be turned on or turned off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than the power supply voltage, wherein the input voltage required by the self-oscillation circuit 101 is lower than that of a traditional negative feedback waveform generating circuit, thus the technical scheme of the application reduces the minimum power supply voltage required for the switching power supply circuit to work, and further improves the applicability of the switching power supply circuit.

[0067] Figure 9 is a structural schematic diagram of an embodiment of the control system of the application.

[0068] The application further provides a control system, as shown in Figure 9 The control system 90 comprises the power supply chip 70. The power supply chip 70 is the power supply chip disclosed in the above embodiment, which will not be described herein again.

[0069] Specifically, the control system 90 can be a power control system, a communication control system or other types of control systems, which will not be limited herein.

[0070] Different from the prior art, the application adopts a self-oscillation circuit 101 to provide a first driving signal, and utilizes the first driving signal to drive the switch tube 1021 of the boost type switching power supply circuit 102 to turn on or turn off, so that the boost type switching power supply circuit 102 outputs a supply voltage higher than the power supply voltage, wherein the input voltage required by the self-oscillation circuit 101 is lower than that of a traditional negative feedback waveform generating circuit, thus the technical solution of the application reduces the minimum power supply voltage required for the switching power supply circuit to work, and further improves the applicability of the switching power supply circuit.

[0071] The above is only an embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent flow transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A switching power supply circuit, characterized by comprising: The application relates to a switching power supply circuit. The switching power supply circuit comprises: a self-oscillation circuit, an input end of the self-oscillation circuit receiving a power supply voltage, and an output end of the self-oscillation circuit being used for outputting a first driving signal; a step-up switching power supply circuit, the output end of the self-oscillation circuit being connected with the step-up switching power supply circuit, the step-up switching power supply circuit receiving the power supply voltage, and the first driving signal being used for driving a switch tube of the step-up switching power supply circuit to be turned on or turned off, so that the step-up switching power supply circuit outputs a power supply voltage, and the minimum power supply voltage required for the switching power supply circuit to work can be reduced; wherein the step-up switching power supply circuit comprises: an inductor, one end of the inductor receiving the power supply voltage; a first diode, a positive electrode of the first diode receiving the power supply voltage; a first capacitor, a first end of the first capacitor being connected with the other end of the inductor, and a second end of the first capacitor being connected with a negative electrode of the first diode; the input end of the self-oscillation circuit being connected with the negative electrode of the first diode and the second end of the first capacitor, so as to receive the voltage of the second end of the first capacitor; a negative feedback waveform generating circuit, a power supply end of the negative feedback waveform generating circuit receiving the power supply voltage, a negative feedback input end of the negative feedback waveform generating circuit receiving the power supply voltage through at least one resistor, and an output end of the negative feedback waveform generating circuit being used for outputting a second driving signal, the second driving signal being used for driving the switch tube to be turned on or turned off, and the at least one resistor comprising a first resistor, a second resistor and a third resistor; a switching circuit, the switching circuit connecting the output end of the self-oscillation circuit, the output end of the negative feedback waveform generating circuit and a control end of the switch tube, and the switching circuit being used for switching the signal received by the control end of the switch tube, so that the control end of the switch tube receives the first driving signal or the second driving signal, the switch tube is driven to be turned on or turned off based on the first driving signal or the second driving signal, the minimum power supply voltage required for the switching power supply circuit to work is reduced, and the long-term stability of the power supply voltage is ensured; 2. The switching power supply circuit according to claim 1, characterized by the negative feedback waveform generating circuit further comprises an error amplifier and a duty cycle digital-to-analog conversion module, a first input end of the error amplifier receiving a reference voltage, a second input end of the error amplifier receiving the power supply voltage through the first resistor, the second resistor and the third resistor, an input end of the duty cycle digital-to-analog conversion module being connected with an output end of the error amplifier, an output end of the duty cycle digital-to-analog conversion module being connected with the switching circuit, and the output end of the duty cycle digital-to-analog conversion module being used for outputting the second driving signal. The switching power supply circuit further comprises: a second diode, a positive electrode of the second diode being connected with the other end of the inductor and a first end of the switch tube; a second capacitor, a negative electrode of the second diode being connected to a second end of the switch tube through the second capacitor, and the second end of the switch tube being grounded; 3. The switching power supply circuit according to claim 1, characterized by a control end of the switch tube being connected with the output end of the self-oscillation circuit, so as to receive the first driving signal. The switching circuit comprises: The single-pole double-throw switch comprises a first connection end, a second connection end and a common end, the first connection end is connected to the output end of the self-oscillation circuit, the second connection end is connected to the output end of the negative feedback waveform generating circuit, and the common end is connected to the control end of the switch tube.

4. The switching power supply circuit according to any one of claims 1 to 2, characterized by The self-oscillation circuit is a self-feedback oscillator.

5. A control method of a switching power supply circuit, characterized by, The application is applied to the switching power supply circuit as claimed in claim 1 or 3; the control method comprises: controlling the switching circuit to make the switch tube receive the first driving signal to be turned on or turned off; tracking and judging whether the power supply voltage is not less than a preset voltage; if yes, controlling the switching circuit to make the switch tube receive the second driving signal to be turned on or turned off.

6. A power supply chip, characterized by comprising: The power supply chip comprises the switching power supply circuit as claimed in any one of claims 1 to 4.

7. A battery management system, characterized by, The battery management system comprises the power supply chip as claimed in claim 6.

8. A control system characterized by, The control system comprises the power supply chip as claimed in claim 6.

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