A DCDC power supply ripple reduction method and device

Abstract

The present application relates to a kind of DCDC power supply ripple reduction method, this method is based on the circuit structure for reducing the DCDC power supply ripple, method includes: when the circuit structure for reducing the DCDC power supply ripple charges, according to the input voltage of voltage source, the first output voltage of circuit model and the inductance value of inductance, the first influence parameter of first load current when charging is determined;When the circuit structure for reducing the DCDC power supply ripple discharges, according to the second output voltage of circuit model and the inductance value of inductance, the second influence parameter of second load current when discharging is determined;According to first influence parameter and second influence parameter, target influence parameter is determined;Adjust target influence parameter, to reduce the DCDC power supply ripple.Therefore, by adjusting duty ratio and the inductance value of inductance to reduce the DCDC power supply ripple, with stability and extremely high efficiency.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a method and apparatus for reducing DC-DC power supply ripple. Background Technology

[0002] All power supplies generally contain some ripple. Ripple is a phenomenon caused by voltage fluctuations in a DC power supply. Since a DC power supply is typically formed by rectifying and regulating an AC power source, it inevitably contains some AC component in the DC stable quantity. This AC component superimposed on the DC stable quantity is called ripple. The composition of ripple is quite complex. Its form is generally a harmonic wave similar to a sine wave with a frequency higher than the power frequency, or a pulse wave with a very narrow width.

[0003] A good power supply will have very little ripple, generally within a certain range. Larger ripple can have significant negative impacts, such as: 1. Generating harmonics in electrical appliances, which can cause considerable damage; 2. Reducing power supply efficiency; 3. Causeing surge voltages or currents, potentially burning out electrical appliances; 4. Interfering with the logic of digital circuits, affecting their normal operation; 5. Providing noise interference, causing image and audio equipment to malfunction.

[0004] Currently, reducing ripple typically involves increasing the frequency of the DC-DC converter. However, DC-DC converters are essentially based on Pulse Width Modulation (PWM), which adjusts the duty cycle of the high and low voltage levels below the specified frequency. Increasing the frequency increases the duty cycle accordingly, but the ripple issue remains unresolved. Therefore, finding a way to reduce DC-DC power supply ripple without increasing the frequency is a problem that needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a circuit structure and method for reducing DC-DC power supply ripple, thereby solving the problem that increasing the frequency of DC-DC converters does not improve ripple in existing technologies.

[0006] The first aspect of the present invention provides a circuit structure for reducing DC-DC power supply ripple, comprising: a voltage source, an inductor, a BUCK capacitor, and a load;

[0007] The BUCK capacitor is connected in parallel with the load, and the inductor is connected in series with both the BUCK capacitor and the load.

[0008] When the voltage source and the inductor are connected in series, the circuit structure for reducing DC-DC power supply ripple is charged.

[0009] When the voltage source and the inductor are disconnected, the circuit structure used to reduce DC-DC power supply ripple discharges.

[0010] In one possible implementation, the input voltage of the voltage source comes from the vehicle battery;

[0011] The load is an on-board electrical component.

[0012] A second aspect of the present invention provides a method for reducing DC-DC power supply ripple, based on any of the circuit structures for reducing DC-DC power supply ripple described in the first aspect, the method comprising:

[0013] When the circuit structure for reducing DC-DC power supply ripple is charging, a first influence parameter of the first load current during charging is determined based on the input voltage of the voltage source, the first output voltage of the circuit model, and the inductance value of the inductor.

[0014] When the circuit structure for reducing DC-DC power supply ripple discharges, a second influence parameter of the second load current during discharge is determined based on the second output voltage of the circuit model and the inductance value of the inductor.

[0015] Based on the first influence parameter and the second influence parameter, determine the target influence parameter;

[0016] Adjust the target impact parameters to reduce DC-DC power supply ripple.

[0017] In one possible implementation, the first influencing parameter for determining the first load current during charging specifically includes:

[0018] The first load current during the charging of the DC-DC model is determined based on the input voltage of the voltage source, the first output voltage across the load, and the inductance value of the inductor.

[0019] Based on the first load current, a first influencing parameter affecting the first load current is determined; the first influencing parameter includes the duty cycle of the voltage source relative to its input voltage and the inductance value of the inductor.

[0020] In one possible implementation, the second influencing parameter for determining the second load current during discharge specifically includes:

[0021] Based on the second output voltage of the circuit model and the inductance value of the inductor, determine the second load current when the DC-DC model discharges;

[0022] Based on the second load current, a second influencing parameter affecting the second load current is determined; the second influencing parameter includes the inductance value of the inductor.

[0023] In one possible implementation, determining the target influence parameter based on the first influence parameter and the second influence parameter specifically includes:

[0024] The target influence parameter is obtained by taking the union of the first influence parameter and the second influence parameter; the target influence parameter includes the duty cycle of the voltage source relative to its input voltage and the inductance value of the inductor.

[0025] In one possible implementation, adjusting the target influencing parameter to reduce DC-DC power supply ripple specifically includes:

[0026] Reduce the duty cycle of the voltage source relative to its input voltage; and / or,

[0027] Increase the inductance value of the inductor.

[0028] In one possible implementation, the method further includes:

[0029] Reduce the equivalent series resistance of the BUCK capacitor to reduce DC-DC power supply ripple.

[0030] By applying the circuit structure and method for reducing DC-DC power supply ripple provided by this invention, the DC-DC power supply ripple can be reduced by adjusting the duty cycle and the inductance value of the inductor. This method is stable and highly efficient. Furthermore, the ESR of the BUCK capacitor can be taken into account, thus taking into account the BUCK capacitor when reducing DC-DC power supply ripple. This further optimizes the method of reducing DC-DC power supply ripple by adjusting the duty cycle and the inductance value of the inductor. Attached Figure Description

[0031] Figure 1 A schematic diagram of a circuit structure for reducing DC-DC power supply ripple provided in an embodiment of the present invention;

[0032] Figure 2 This is one of the schematic diagrams of the DC-DC power supply ripple reduction method provided in the embodiments of the present invention;

[0033] Figure 3 This is the second schematic diagram of the DC-DC power supply ripple reduction method provided in the embodiment of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] This invention provides a circuit structure and a method for reducing DC-DC power supply ripple, thereby reducing the ripple voltage V. RIPP The purpose.

[0036] Figure 1 The circuit structure diagram for reducing DC-DC power supply ripple provided in the embodiments of the present invention is as follows: Figure 1 As shown, the circuit structure for reducing DC-DC power supply ripple includes: a voltage source, an inductor, a BUCK capacitor, and a load; the BUCK capacitor and the load are connected in parallel, and the inductor is connected in series with both the BUCK capacitor and the load.

[0037] When a voltage source and an inductor are connected in series, the circuit structure used to reduce DC-DC power supply ripple is charged.

[0038] When the voltage source and inductor are disconnected, the circuit structure used to reduce DC-DC power supply ripple discharges.

[0039] Figure 1 The circuit structure shown is used to convert the input voltage Vin of the voltage source into the voltage V required for the load to operate. However, due to the ripple voltage V of the DC-DC power supply... RIPP The actual voltage across the load, Vout = V ± V, is due to the presence of the load. RIPP To ensure the normal operation of the load, it is necessary to minimize the ripple voltage V. RIPP .

[0040] In one possible design, the input voltage of the voltage source comes from the output of the Vin vehicle battery, such as a nominal 12V vehicle battery; the load is an on-board electrical device, such as an on-board controller with a rated voltage of 5V. Figure 1 The circuit structure shown converts the output voltage Vin from the vehicle battery into the voltage V required by the vehicle's electrical components, while ensuring the actual generated ripple voltage V. RIPP The ripple voltage should not exceed the range that the on-board electrical components can tolerate during normal operation.

[0041] Figure 2 This is a schematic flowchart of a DC-DC power supply ripple reduction method provided in an embodiment of the present invention. The following is in conjunction with… Figure 1 and Figure 2 Taking an application in an automotive environment as an example, this invention introduces a method for reducing DC-DC power supply ripple, which includes the following steps:

[0042] Step 210: When the circuit structure used to reduce DC-DC power supply ripple is charging, determine the first influence parameter of the first load current i1 during charging based on the input voltage Vin of the voltage source, the first output voltage Vout of the circuit model, and the inductance value L of the inductor.

[0043] Specifically, determining the first influencing parameter of the first load current during charging includes: determining the first load current i1 during DCDC model charging based on the input voltage Vin of the voltage source, the first output voltage Vout across the load, and the inductance value L of the inductor; determining the first influencing parameter affecting the first load current based on the first load current i1; the first influencing parameter includes the duty cycle PWM of the voltage source Vg relative to its input voltage Vin and the inductance value L of the inductor.

[0044] See Figure 1 If switch 1 is connected, it indicates that the circuit structure used to reduce DC-DC power supply ripple is charging, and V L =Vg - Vout, and Vout = V ± V RIPP At this point, we can obtain the formula:

[0045] di1 / dt1=(Vg-Vout) / L (1)

[0046] In formula (1), V L The voltage across inductor L is in volts (V), and L is the inductance value in henries (H). When current flows through the coil, it generates a magnetic field in the space around the coil, causing magnetic lines of force to pass through it. If the current changes, the magnetic flux changes, inducing an electromotive force (EMF) in the coil. di1 / dt1 is the differential of the first load current i1 with respect to time, representing the slope of the change in the first load current. Vg is the voltage value of the voltage source, which is also the output voltage Vin of the vehicle battery (the input voltage of the voltage source) during the time the MOSFET is turned on. This voltage is related to the duty cycle PWM, i.e., Vg = Vin * PWM. The larger the duty cycle PWM, the larger the voltage Vg. Since the duty cycle is a maximum of 100%, Vg will not exceed the output voltage Vin of the vehicle battery.

[0047] At this time, di1 / dt1 in formula (1) represents the slope of the change of the first load current i1. It can be seen from formula (1) and the following discussion that the first influencing parameter affecting the first load current during charging is the duty cycle PWM and the inductance value L of the inductor.

[0048] Step 220: When the circuit structure used to reduce DC-DC power supply ripple discharges, determine the second influence parameter of the second load current i2 during discharge based on the second output voltage Vout of the circuit model and the inductance value L of the inductor.

[0049] Specifically, determining the second influencing parameter of the second load current i2 during discharge includes: determining the second load current i2 during discharge of the DCDC model based on the second output voltage Vout of the circuit model and the inductance value L of the inductor; determining the second influencing parameter affecting the second load current based on the second load current i2; the second influencing parameter includes the inductance value L of the inductor.

[0050] See also Figure 1 When switch 2 is connected, it indicates that the circuit structure used to reduce DC-DC power supply ripple is discharging. During discharge, V L = -Vout, where Vout represents the actual output voltage value used to reduce DC-DC power supply ripple. This leads to the formula:

[0051] di2 / dt2=-Vout / L (2)

[0052] In formula (2), di2 / dt2 represents the slope of the change of the second load current i2. It can be seen from formula (2) that the second influencing parameter affecting the second load current i2 during discharge is the inductance value L of the inductor.

[0053] Step 230: Determine the target influence parameter based on the first influence parameter and the second influence parameter;

[0054] Specifically, determining the target influence parameter based on the first influence parameter and the second influence parameter includes: taking the union of the first influence parameter and the second influence parameter to obtain the target influence parameter; the target influence parameter includes the duty cycle PWM of the voltage source Vg to its input voltage Vin and the inductance value L of the inductor.

[0055] Continue to combine Figure 1 The first influencing parameter includes the duty cycle PWM of the voltage source Vg relative to its input voltage Vin and the inductance value L of the inductor. The second influencing parameter includes the inductance value L of the inductor. Therefore, the target influencing parameters are the duty cycle PWM of the voltage source Vg relative to its input voltage Vin and the inductance value L of the inductor.

[0056] Step 240: Adjust the target influencing parameters to reduce DC-DC power supply ripple.

[0057] Specifically, adjusting the target influencing parameters includes: reducing the duty cycle PWM of the voltage source Vg relative to its input voltage Vin; and / or increasing the inductance value L of the inductor.

[0058] The formula for ripple is: V RIPP= i * ESR; where ESR is the equivalent series resistance (ESR) provided by the BUCK capacitor. The change in ripple is the change in Vout, and the changing current is provided by L, thus obtaining V. RIPP = (di / dt)*ESR.

[0059] When the circuit structure used to reduce DC-DC power supply ripple is charged:

[0060] i is the first load current i1, V RIPP = (di1 / dt)*ESR, at this time V RIPP The magnitude can be adjusted by the first influencing parameter (i.e., the duty cycle of the voltage source Vg to its input voltage Vin, PWM, and the inductance value L of the inductor).

[0061] When the circuit structure used to reduce DC-DC power supply ripple discharges:

[0062] i is the second load current i2, V RIPP = (di² / dt)*ESR, where V RIPP The value of L can be adjusted by the second influencing parameter (i.e., the inductance value L of the inductor).

[0063] Combining the two situations above, the DC-DC power supply ripple can be reduced by adjusting the duty cycle (PWM) of the voltage source (Vg) relative to its input voltage (Vin) and the inductance value (L) of the inductor.

[0064] In one of the alternative implementation schemes, such as Figure 3 As shown, since the ripple is also related to the capacitance value of the BUCK capacitor, the DC-DC power supply ripple reduction method provided in this embodiment of the invention may further include step 250: reducing the equivalent series resistance (ESR) of the BUCK capacitor to reduce the DC-DC power supply ripple.

[0065] Specifically, reduce the duty cycle of the voltage source Vg relative to the input voltage Vin (PWM); and / or increase the inductance value L of the inductor; and / or reduce the equivalent series resistance (ESR) of the BUCK capacitor to reduce DC-DC power supply ripple.

[0066] Since the inductance value L cannot be increased indefinitely, and current carrying capacity must be considered, the inductance value L is related to the inductor's volume (related to the number of coils), and current carrying capacity is related to the wire diameter. Increasing the inductance value increases the volume, which will cause area issues for the PCB. Therefore, it is necessary to adjust both the inductance value L and the equivalent series resistance ESR to adjust the ripple.

[0067] By applying the circuit structure and method for reducing DC-DC power supply ripple provided by this invention, the DC-DC power supply ripple can be reduced by adjusting the duty cycle and the inductance value of the inductor. This method is stable and highly efficient. Furthermore, the ESR of the BUCK capacitor can be taken into account, thus taking into account the BUCK capacitor when reducing DC-DC power supply ripple. This further optimizes the method of reducing DC-DC power supply ripple by adjusting the duty cycle and the inductance value of the inductor.

[0068] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A circuit structure for reducing ripple of a DCDC power supply, characterized by, include: Voltage source, inductor, BUCK capacitor, and load; The BUCK capacitor is connected in parallel with the load, and the inductor is connected in series with both the BUCK capacitor and the load. When the voltage source and the inductor are connected in series, the circuit structure for reducing DC-DC power supply ripple is charged. When the voltage source and the inductor are disconnected, the circuit structure used to reduce DC-DC power supply ripple discharges. When the circuit structure for reducing DC-DC power supply ripple is charging, a first influence parameter of the first load current during charging is determined based on the input voltage of the voltage source, the first output voltage of the circuit structure, and the inductance value of the inductor; the first influence parameter includes the duty cycle of the voltage source relative to its input voltage and the inductance value of the inductor. When the circuit structure for reducing DC-DC power supply ripple discharges, a second influence parameter of the second load current during discharge is determined based on the second output voltage of the circuit structure and the inductance value of the inductor; the second influence parameter includes the inductance value of the inductor. The target influence parameter is determined based on the union of the first influence parameter and the second influence parameter; the target influence parameter includes the duty cycle of the voltage source relative to its input voltage and the inductance value of the inductor; Adjust the target impact parameters to reduce DC-DC power supply ripple.

2. The circuit structure according to claim 1, characterized in that, The input voltage of the voltage source comes from the vehicle battery; The load is an on-board electrical component.

3. A DCDC power supply ripple reduction method, characterized by, Based on the circuit structure for reducing DC-DC power supply ripple according to any one of claims 1-2, the DC-DC power supply ripple reduction method includes: When the circuit structure for reducing DC-DC power supply ripple is charging, a first influence parameter of the first load current during charging is determined based on the input voltage of the voltage source, the first output voltage of the circuit structure, and the inductance value of the inductor. When the circuit structure for reducing DC-DC power supply ripple discharges, a second influence parameter of the second load current during discharge is determined based on the second output voltage of the circuit structure and the inductance value of the inductor. Based on the first influence parameter and the second influence parameter, determine the target influence parameter; Adjust the target impact parameters to reduce DC-DC power supply ripple.

4. The method of claim 3, wherein, The first influencing parameter for determining the first load current during charging specifically includes: The first load current during the charging of the DC-DC model is determined based on the input voltage of the voltage source, the first output voltage across the load, and the inductance value of the inductor. Based on the first load current, determine the first influencing parameter that affects the first load current.

5. The method of claim 3, wherein, The second influencing parameter for determining the second load current during discharge specifically includes: Based on the second output voltage of the circuit structure and the inductance value of the inductor, determine the second load current when the DC-DC model discharges; Based on the second load current, determine the second influencing parameter that affects the second load current.

6. The method according to claim 3, characterized in that, The adjustment of the target influencing parameters to reduce DC-DC power supply ripple specifically includes: Reduce the duty cycle of the voltage source relative to its input voltage; and / or, Increase the inductance value of the inductor.

7. The method according to claim 6, characterized in that, The method further includes: Reduce the equivalent series resistance of the BUCK capacitor to reduce DC-DC power supply ripple.

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