DC / DC voltage converter, audio product and anti-audio control method

Abstract

The present invention relates to a DC / DC voltage converter, an audio product and an anti-audio control method, wherein the DC / DC voltage converter includes a power stage, a driving module for outputting a pulse control signal to the power stage, and an anti-audio control module for detecting whether the frequency of the pulse signal falls within the audio band in each cycle, and when it falls within the audio band, the driving module controls the pulse energy output by the power stage to be reduced by generating a pulse energy control signal, wherein the pulse energy control signal includes a current peak control signal and / or a switching time control signal. In the implementation of the technical solution of the present invention, the anti-audio control module controls the pulse energy output by the power stage by generating a pulse energy control signal, thereby increasing the pulse frequency, and further making the system frequency away from the audio band, thus having an anti-audio function.

Description

Technical Field

[0001] The present invention relates to the field of power supplies, and in particular to a DC / DC voltage converter, an audio product and an anti-audio control method. Background Art

[0002] With the development of the Internet of Things ecosystem, audio products based on IOT (Internet of Things) technology are increasingly favored by the market, which puts higher requirements on the power performance of the DC / DC converters that power them. Among them, anti-audio function is one of its key performance indicators.

[0003] Most DC / DC converters in existing audio products are PFM (Pulse frequency modulation) modulated DC / DC converters. Since this modulation method is variable frequency operation, the operating frequency of the DC / DC converter changes with the load current. When the load current decreases, the operating frequency also decreases, so the operating frequency will inevitably enter the audio band range (20Hz ~ 20kHz), which will affect the audio performance of the load module. Therefore, the DC / DC converter of this architecture needs to have an anti-audio function when used in audio products. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a DC / DC voltage converter, an audio product and an anti-audio control method in view of the defect in the prior art that the audio performance of the load module will be affected when the load current decreases.

[0005] The technical solution adopted by the present invention to solve the technical problem is: construct a DC / DC voltage converter, including a power stage and a driving module for outputting a pulse control signal to the power stage, and the DC / DC voltage converter also includes:

[0006] The anti-audio control module is used to detect whether the frequency of the pulse signal falls within the audio band in each cycle, and when it falls within the audio band, the driving module controls the pulse energy output of the power stage to reduce by generating a pulse energy control signal, wherein the pulse energy control signal includes an inductor current peak control signal and / or a switching time control signal.

[0007] Preferably, it also includes:

[0008] The sampling control module is used to sample the inductor current and control the driving module according to the sampled current and the pulse energy control signal.

[0009] Preferably, the anti-audio control module comprises:

[0010] A pulse frequency detection module, used to detect whether the frequency of the pulse signal falls within the audio band in each cycle, and generate a trigger signal when it falls within the audio band;

[0011] an inductor current peak control module, configured to determine whether the current inductor current peak reaches a preset current peak value upon receiving the trigger signal, and if the current peak value does not reach the preset current peak value, reduce the inductor current peak value by outputting an inductor current peak control signal;

[0012] The switching time adjustment module is used to adjust the switching time by outputting a switching time control signal when the current inductor current peak value does not reach the current peak preset value; when the current inductor current peak value reaches the current peak preset value, determine whether the current switching time reaches the switching time preset value.

[0013] Preferably, the switching time adjustment module is further configured to reduce the switching time by outputting a switching time control signal when the current switching time does not reach the preset switching time value;

[0014] Or, when the current switching time reaches the preset switching time value, the switching time is increased by outputting a switching time control signal.

[0015] Preferably, the inductor current peak control module includes a first add-subtract counter and a first inverter, the trigger signal is input to a clock end of the first add-subtract counter, a high level is input to an input end of the first inverter and a second data input end of the first add-subtract counter respectively, the first data input end of the first add-subtract counter is connected to an output end of the first inverter, the first data output end of the first add-subtract counter outputs the inductor current peak control signal, and the second data output end of the first add-subtract counter outputs the current peak preset value.

[0016] Preferably, the switching time adjustment module includes a second up-and-down counter, a third up-and-down counter, a first AND gate, a second AND gate, a second inverter and a two-to-one selector, wherein the first data input terminal and the second data input terminal of the second up-and-down counter are respectively input with the inductor current zero-crossing detection signal, the clock terminal of the second up-and-down counter is input with the pulse control signal of the second power tube of the power stage, and the data output terminal of the second up-and-down counter is connected to the first input terminal of the two-to-one selector; the first input terminal of the first AND gate is input with the current peak preset value, the second input terminal of the first AND gate is input with the switching time preset value, and the input terminal of the second inverter is input with the current peak preset value. The first input terminal of the second AND gate inputs the preset switching time value, the first input terminal of the second AND gate inputs the preset current peak value, the second input terminal of the second AND gate is connected to the output terminal of the second inverter, the first data input terminal of the third up-and-down counter is connected to the output terminal of the first AND gate, the second data input terminal of the third up-and-down counter is connected to the output terminal of the second AND gate, the clock terminal of the third up-and-down counter inputs the trigger signal, the first output terminal of the third up-and-down counter is connected to the second input terminal of the two-to-one selector, the control terminal of the two-to-one selector inputs the preset current peak value, and the output terminal of the two-to-one selector outputs the switching time control signal.

[0017] Preferably, the sampling control module comprises: a sampling unit, a comparator, a switch, and a sampling resistor with adjustable resistance, wherein the input end of the sampling unit is connected to the first end of the first power tube of the power stage, the output end of the sampling unit is connected to the sampling resistor through the switch, the inverting input end of the comparator is connected to the output end of the sampling unit, the non-inverting input end of the comparator inputs a sampling reference voltage, and the state of the switch and the resistance value of the sampling resistor are determined by the inductor current peak control signal.

[0018] Preferably, the sampling control module also includes an energy storage capacitor, a discharge resistor and a current source, the energy storage capacitor, the discharge resistor and the current source are respectively connected between the inverting input terminal of the comparator and the ground, and at least one of the capacitance value of the energy storage capacitor, the resistance value of the discharge resistor and the output current value of the current source is determined by the switching time control signal.

[0019] The present invention also constructs an audio product, characterized by comprising the DC / DC voltage converter mentioned above.

[0020] The present invention also constructs an anti-audio control method, which is applied to the DC / DC voltage converter mentioned above, and is characterized by comprising:

[0021] In each cycle, detecting whether the frequency of the pulse signal falls within the audio band;

[0022] If it falls within the audio band, the pulse energy output by the driving module to control the power stage is reduced by generating a pulse energy control signal, wherein the pulse energy control signal includes an inductor current control signal and / or a switching time control signal.

[0023] Preferably, it also includes:

[0024] The inductor current is sampled, and the driving module is controlled according to the sampled current and the pulse energy control signal.

[0025] Preferably, if it falls within the audio band, a pulse energy control signal is generated to enable the driving module to control the pulse energy outputted by the power stage to be reduced, specifically including:

[0026] If it falls within the audio band, a trigger signal is generated;

[0027] When receiving the trigger signal, determining whether the current inductor current peak value reaches a current peak preset value;

[0028] If the current peak value preset value is not reached, the inductor current peak value is reduced by outputting an inductor current peak value control signal, and the switching time is adjusted by outputting a switching time control signal according to a zero-crossing detection result of the inductor current;

[0029] If the current peak value reaches the preset value, it is determined whether the current switching time reaches the preset switching time value. If the current switching time does not reach the preset switching time value, the switching time is reduced by outputting a switching time control signal.

[0030] Preferably, after the pulse energy control signal is generated to enable the driving module to control the reduction of the pulse energy output by the power stage, the method further comprises:

[0031] If the switching time preset value is reached, the switching time is increased by outputting a switching time control signal.

[0032] In implementing the technical solution of the present invention, an anti-audio control module is added to the DC / DC voltage converter. Moreover, when the load gradually decreases so that the frequency of the pulse signal falls into the audio band range, the anti-audio control module starts to work, and it reduces the pulse energy output by the driving module controlling the power stage by outputting a pulse energy control signal, thereby increasing the pulse frequency, and further making the system frequency away from the audio band, so that it has an anti-audio function. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 is a circuit diagram of a first embodiment of a DC / DC voltage converter of the present invention;

[0035] Figure 2 1 is a logic structure diagram of the first embodiment of the anti-audio control module in the DC / DC voltage converter of the present invention;

[0036] Figure 3 The present invention Figure 2 The logical structure diagram of the first embodiment of the inductor current peak control module;

[0037] Figure 4 The present invention Figure 2 The logical structure diagram of the first embodiment of the switching time adjustment module;

[0038] Figure 5 1 is a circuit diagram of a first embodiment of a sampling control module in a DC / DC voltage converter of the present invention;

[0039] Figure 6 is a flow chart of Embodiment 1 of the anti-audio control method of the present invention;

[0040] Figure 7 yes Figure 6 Step S20 is a flow chart of Embodiment 1;

[0041] Figure 8 It is a waveform diagram of key signals of the DC / DC voltage converter of the present invention. DETAILED DESCRIPTION

[0042] The specific implementation of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] The specific embodiments / examples recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention, are explanatory and exemplary, and should not be construed as limiting the embodiments of the present invention and the scope of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims and the specification of the present application, and these technical solutions include the use of any obvious replacement and modification of the embodiments recorded herein, which are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other, and the order of steps in the following embodiments is only for example and can be adjusted in the absence of conflict.

[0044] In view of the fact that existing PFM modulated DC / DC converters easily enter the audio band in the light load range, thereby affecting the audio performance of the power supply system, the present application provides a DC / DC voltage converter that can achieve audio resistance in the full load range.

[0045] Figure 1 2 is a circuit diagram of a first embodiment of a DC / DC voltage converter of the present invention. The DC / DC voltage converter of this embodiment includes: a power stage, a driving module 2110 and an anti-audio control module 2108. In addition, it also includes a sampling control module 2111, a comparator 2109, a comparator 2106, and an output capacitor C 2104.

[0046] Moreover, in this embodiment, the power stage includes a first power tube 2101, a second power tube 2102, and an inductor L 2103, and the first power tube 2101 is a PMOS tube, the second power tube 2102 is an NMOS tube, and the first power tube 2101 and the second power tube 2102 are connected in series, that is, the source of the first power tube 2101 is connected to the power supply voltage, the drain of the first power tube 2101 is connected to the drain of the second power tube 2102, and the source of the second power tube 2102 is grounded. The first end of the inductor 2103 is connected to the connection point of the first power tube 2101 and the second power tube 2102, and the second end of the inductor 2103 is connected to the load R1 2105. One end of the output capacitor 2104 is connected to the second end of the inductor 2103, and the other end is grounded. It should be understood that in other embodiments, the connection relationship between the first power tube 2101, the second power tube 2102, and the inductor L 2103 can be other forms.

[0047] The driving module 2110 is used to output corresponding pulse control signals (PCON, NCON) to the first power tube 2101 and the second power tube 2102, respectively, so as to control the on and off of the first power tube 2101 and the second power tube 2102. The inverting input terminal of the comparator 2106 is connected to the drain of the second power tube 2102, the non-inverting input terminal of the comparator 2106 inputs the zero-crossing detection reference voltage (Vref_Zero), and the output terminal of the comparator 2106 is connected to the first input terminal of the anti-audio control module 2108. The non-inverting input terminal of the comparator 2109 inputs the output reference voltage (Vref), the non-inverting input terminal of the comparator 2109 inputs the output voltage, and the output terminal of the comparator 2109 is connected to an input terminal of the driving module 2110.

[0048] In addition, the anti-audio control module 2108 is used to detect whether the frequency of the pulse signal falls within the audio band in each cycle. Specifically, the frequency of the pulse signal can be determined by detecting the pulse control signal (PCON) of the first power tube 2101, and the frequency of the pulse signal can also be determined by detecting the pulse control signal (NCON) of the second power tube 2102. When it is determined that the frequency of the pulse signal falls within the audio band (20Hz to 20kHz), the pulse energy control signal is generated to reduce the pulse energy output by the driving module to control the power stage, wherein the pulse energy control signal includes the inductor current peak control signal (Ipk_CTL) and / or the switch time control signal (Tsw_CTL).

[0049] The sampling control module 2111 is used to sample the inductor current and control the driving module 2110 according to the sampled current and the pulse energy control signal. It should be understood that the sampling control module 2111 can be separately set according to its logical function, or integrated with other modules.

[0050] In this embodiment, an anti-audio control module 2108 is added to the DC / DC voltage converter, and when the load gradually decreases so that the pulse frequency enters the audio band, the anti-audio control module 2108 starts to work, and the pulse energy control signal output by the anti-audio control module 2108 can reduce the pulse energy output by the power stage controlled by the driving module, thereby increasing the frequency of the pulse signal, and further making the system frequency away from the audio band.

[0051] In addition, since the PFM mode has the characteristics of high conversion efficiency under light load, it is also necessary to have high conversion efficiency performance while realizing the anti-audio function. Figure 2The anti-audio control module 2108 in the DC / DC voltage converter of the present invention includes: a pulse frequency detection module 21081, an inductor current peak control module 21082 and a switch time adjustment module 21083, wherein the pulse frequency detection module 21081 is used to detect whether the frequency of the pulse signal falls within the audio band in each cycle, and generate a trigger signal when it falls within the audio band; the inductor current peak control module 21082 is used to determine whether the current inductor current peak reaches a preset current peak value when receiving the trigger signal, and if it does not reach the preset current peak value, reduce the inductor current peak by outputting an inductor current peak control signal (Ipk_CTL); the switch time adjustment module 21083 is used to adjust the switch time by outputting a switch time control signal (Tsw_CTL) according to a zero crossing detection result (ZCDT) of the inductor current when the current inductor current peak does not reach the preset current peak value; when the current inductor current peak reaches the preset current peak value, determine whether the current switch time reaches the preset switch time value.

[0052] Furthermore, the switching time adjustment module 21083 is also used to reduce the switching time by outputting a switching time control signal (Tsw_CTL) when the current switching time does not reach the preset switching time value; or, when the current switching time reaches the preset switching time value, increase the switching time by outputting a switching time control signal (Tsw_CTL).

[0053] In this embodiment, combined Figure 2 and Figure 3When the load current gradually decreases, the pulse frequency detection module 21081 is always detecting whether the system operating frequency falls into the audio band range (20Hz-20kHz). If it is detected that the frequency of the pulse signal falls into the audio band range, a trigger signal Fsw_dt is generated, which is sent to the driving module 2110, the inductor current peak control module 21082 and the switch time adjustment module 21083 respectively, so that: the driving module 2110 turns on the first power tube 2101 and turns off the second power tube 2102 to generate a pulse energy packet to provide to the output load; the inductor current peak control module 21082 is controlled to generate an inductor current peak control signal (Ipk_CTL); the switch time generation module 21083 is adjusted to generate a switch time control signal (Tsw_CTL). In this embodiment, the inductor current peak is adjusted first when it falls into the audio band range, and the switch time is adjusted only when the inductor current peak reaches the current peak preset value, and when the switch time reaches the switch time preset value, the switch time is increased and continues. Since in a PFM modulated DC / DC voltage converter, the efficiency of the DC / DC voltage converter is almost constant within a certain load range, and at this time the peak value of the inductor current is linearly positively correlated with the load current, that is, within a certain load range, the conversion efficiency can be maintained high by controlling the peak value of the inductor current to follow the load current decrease; when the load of the DC / DC voltage converter is extremely light or unloaded, the energy will accumulate at the output end due to the periodic triggering of the anti-audio control module, which will lead to the phenomenon of high output voltage. Therefore, when the switching time reaches the preset value of the switching time, this embodiment appropriately discharges the energy accumulated at the output end by increasing the time of the freewheeling tube (that is, increasing the switching time), thereby avoiding the situation where the output end floats high and is uncontrollable. From the above process, it can be seen that this embodiment can not only realize the anti-audio function, but also realize high conversion efficiency, and at the same time, it also avoids the phenomenon of high output voltage.

[0054] Figure 3 The present invention Figure 2The logic structure diagram of the first embodiment of the inductor current peak control module is shown in FIG. 1 . The inductor current peak control module of the embodiment includes a first up-and-down counter A4 and a first inverter A8. The clock end (CLK) of the first up-and-down counter A4 inputs a trigger signal (Fsw_dt). The input end of the first inverter A8 and the second data input end (DN) of the first up-and-down counter A4 respectively input a high level. The first data input end (UP) of the first up-and-down counter A4 is connected to the output end of the first inverter A8. The first data output end (Q1) of the first up-and-down counter A4 outputs an inductor current peak control signal (Ipk_CTL). The second data output end (Q2) of the first up-and-down counter A4 outputs a current peak preset value (Ipk_min). It should be noted here that when the trigger condition (whether the frequency of the pulse signal falls within the audio band) is met in each cycle, the inductor current peak value is controlled by the inductor current peak control signal to continuously reduce the inductor current peak value until the inductor current peak value reaches the current peak preset value. Therefore, the current peak preset value is actually a smaller value, and therefore, it can be expressed as Ipk_min.

[0055] In this embodiment, when the anti-audio function is not turned on, the enable terminal (EN_ANTIAUDIO) of the first up-and-down counter A4 is at a low level. At this time, the output data of the first up-and-down counter A4 is a constant set value Ipk_CTL[N:0], indicating that the peak value of the inductor current is a fixed value; when the anti-audio function is turned on, the enable terminal (EN_ANTIAUDIO) of the first up-and-down counter is at a high level. Thereafter, the output data Ipk_CTL[N:0] of the first up-and-down counter A4 is updated at the rising edge of the clock Fsw_dt and gradually decreases, that is, the peak value of the inductor current decreases after each trigger signal Fsw_dt until the peak value of the inductor current reaches the current peak preset value, and the characteristic signal Ipk_min is sent out.

[0056] Figure 4 The present invention Figure 2The logic structure diagram of the first embodiment of the switching time adjustment module in FIG. 1 , the switching time adjustment module of this embodiment includes: a second up-and-down counter A1, a third up-and-down counter A2, a first AND gate A5, a second AND gate A6, a second inverter A7 and a two-to-one selector A3. The first data input terminal (UP) of the second up-and-down counter A1 inputs the first inductor current zero-crossing detection signal (UP), the second data input terminal (DN) of the up-and-down counter A1 inputs the second inductor current zero-crossing detection signal (DN), the clock terminal (CLK) of the second up-and-down counter A1 inputs the pulse control signal (NCCON) of the second power tube, and the data output terminal (Q1) of the second up-and-down counter A1 is connected to the first input terminal of the two-to-one selector A3; the first input terminal of the first AND gate A5 inputs the current peak preset value (Ipk_min), and the second input terminal of the first AND gate A5 inputs the switching time preset value (Tsw_min). It should be noted that, when the trigger condition is met in each cycle (the current inductor current peak value reaches the current peak preset value), the switching time is controlled to continuously decrease by the switching time control signal until the switching time reaches the switching time preset value, so the switching time preset value is actually a smaller value, and therefore, it can be expressed as Tsw_min. The input end of the second inverter A7 inputs the switching time preset value (Tsw_min), the first input end of the second AND gate A6 inputs the current peak preset value (Ipk_min), the second input end of the second AND gate A6 is connected to the output end of the second inverter A7, the first data input end (UP) of the third up-and-down counter A2 is connected to the output end of the first AND gate A5, the second data input end (DN) of the third up-and-down counter A2 is connected to the output end of the second AND gate A6, the clock end (CLK) of the third up-and-down counter A2 inputs the trigger signal (Fsw_dt), the first output end (Q1) of the third up-and-down counter A2 is connected to the second input end of the two-to-one selector A3, the control end of the two-to-one selector inputs the current peak preset value (Ipk_min), and the output end of the two-to-one selector A3 outputs the switching time control signal (Tsw_CTL).

[0057] In this embodiment, the main function of the switch time control module is to generate the time of each pulse energy packet, including the sum of the conduction time of the first power tube 2101 and the conduction time of the second power tube 2102. When the peak value of the inductor current does not reach the current peak preset value, that is, Ipk_min=0, the switch time control signal (Tsw_CTL[N:0]) is adaptively adjusted according to the zero-crossing condition of the inductor current, that is, the two-to-one selector A3 makes the data of the second up-down counter A1 as the switch time control signal; when the peak value of the inductor current reaches the current peak preset value (that is, Ipk_min=1), the two-to-one selector A3 makes the data of the third up-down counter A2 as the switch time control signal TSW_CTL[N:0]. The data is updated at each rising edge of the anti-audio trigger signal Fsw_dt. Before the switch time preset value is reached, the third up-down counter A2 reduces the data each time the trigger signal Fsw_dt is triggered, thereby reducing the switch time. After the preset value of the switching time is reached, the third up-down counter A2 increases the data each time the signal Fsw_dt is triggered, thereby increasing the switching time.

[0058] Figure 5 21 is a circuit diagram of a sampling control module embodiment 1 in a DC / DC voltage converter of the present invention. The sampling control module 2111 includes: a sampling unit 21113, a comparator 21119, a switch 21117, a sampling resistor Rsens 21118 with adjustable resistance, a discharge resistor Rtsw 21116, and an energy storage capacitor Ctsw with adjustable capacitance. 21115 and a current source Itsw21114 with adjustable current value, wherein the input end of the sampling unit 21113 is connected to the source of the first power tube 2101, the output end of the sampling unit 21113 is connected to the sampling resistor 21118 through the switch 21117, the energy storage capacitor 21115, the discharge resistor 21116 and the current source 21114 are respectively connected between the inverting input end of the comparator 21119 and the ground, the inverting input end of the comparator 21119 is connected to the output end of the sampling unit 21113, the sampling reference voltage (Vref_cs) is input to the non-inverting input end of the comparator 21119, and the output end of the comparator 21119 is connected to the driving module. Moreover, the state of the switch 21117 and the resistance value of the sampling resistor 21118 are determined by the inductor current peak control signal, and at least one of the capacitance value of the energy storage capacitor 21115, the resistance value of the discharge resistor 21116, and the output current value of the current source 21114 is determined by the switch time control signal.

[0059] In this embodiment, the inductor current is converted into a sampling voltage Vcs by the sampling unit 21113 and the sampling resistor 21118, and the peak value of the inductor current is controlled by the comparator 21119. The control principle can be expressed by the formula: Isens*Rsens=Ipk*α*Rsens=Vcs=Vref_cs, where Isens is the sampling current of the sampling unit 21113, Ipk is the peak value of the inductor current, α is the current sampling rate, Rsens is the sampling resistor value, Vcs is the sampling voltage converted from the sampling current, and Vref_cs is the sampling reference voltage. It can be seen from the above formula that the peak value of the inductor current can be controlled by α, Rsens, and Vref_cs. In addition, the switching time can be controlled by combining the current source 21114, the discharge resistor 21116, and the energy storage capacitor 21115. Therefore, the sampling control module can adjust the inductor current peak value and the switching time according to the sent inductor current peak value control signal Ipk_CTL and the switching time control signal Tsw_CTL.

[0060] The present invention also constructs an audio product, which includes the DC / DC voltage converter described above.

[0061] Figure 6 1 is a flow chart of Embodiment 1 of the anti-audio control method of the present invention. The anti-audio control method of this embodiment includes:

[0062] Step S10. In each cycle, detect whether the frequency of the pulse signal falls within the audio band. If so, execute step S20;

[0063] Step S20: reducing the pulse energy outputted by the driving module to control the power stage by generating a pulse energy control signal, wherein the pulse energy control signal includes an inductor current peak control signal and / or a switching time control signal.

[0064] Furthermore, it also includes:

[0065] The inductor current is sampled, and the driving module is controlled according to the sampled current and the pulse energy control signal.

[0066] Furthermore, combined with Figure 7 , step S20 comprises:

[0067] Step S201. If it falls within the audio band, a trigger signal is generated;

[0068] Step S202. When the trigger signal is received, determine whether the current inductor current peak value reaches the current peak preset value, if so, execute step S204; if not, execute step S203;

[0069] Step S203: reducing the inductor current peak value by outputting an inductor current peak value control signal, and adjusting the switching time by outputting a switching time control signal;

[0070] Step S204: Determine whether the current switch time reaches the preset switch time value. If not, execute step S205; if yes, execute step S206;

[0071] Step S205. Reducing the switching time by outputting a switching time control signal;

[0072] Step S206: Increase the switching time by outputting a switching time control signal.

[0073] This embodiment realizes the control of pulse energy by adjusting the inductor current peak value and the switching time respectively. Specifically, first, detect whether the pulse signal frequency of the system falls within the audio band range. If not, keep the original inductor current peak value and continue to detect the frequency of the pulse signal; if so, automatically reduce the inductor current peak value until it is reduced to the current peak preset value (Ipk=Ipk_min), then keep the inductor current peak value as the current peak preset value and reduce the switching time. If the inductor current peak value does not reach the current peak preset value, continue to reduce the inductor current peak value. When the switching time does not reach the switching time preset value, continue to reduce the switching time. When the switching time preset value (Tsw=Tsw_min) is reached, further trigger to start increasing the switching time, and continue until the frequency of the pulse signal of the system is no longer within the audio band range.

[0074] Figure 8It is a waveform diagram of the key signal of the DC / DC voltage converter of the present invention. When the pulse frequency detection module detects that the frequency between two pulse signals falls within the audio band range, a trigger signal Fsw_dt is generated, and a pulse energy packet is started, and the inductor current peak value Ipk is reduced at the same time; when the next trigger signal Fsw_dt is generated, the inductor current peak value Ipk continues to decrease until it is reduced to the current peak preset value Ipk_min; after the inductor current peak value Ipk is reduced to the current peak preset value Ipk_min, when the next trigger signal Fsw_dt arrives, a pulse energy packet is generated at the same time and the switching time Tsw is reduced. At this time, the inductor current freewheeling loop will be shut down in advance. When the switching time Tsw gradually decreases, the inductor current freewheeling loop will be shut down more and more in advance and present a body diode. Tube freewheeling situation; when the switching time Tsw gradually decreases to the preset value of the switching time, when the trigger signal Fsw_dt arrives, the switching time is increased while the pulse energy packet is turned on. Basically, only the first power tube is turned on in each pulse energy packet, and the second power tube is disconnected, showing a body diode freewheeling situation, until the zero-crossing detection module sends a zero-crossing signal (ZCDT), the second power tube is turned on and lasts for Toff time. At this time, the switching time consists of two parts, one part is the first power tube turn-on (PCON) time Tp, and the other part is the second power tube turn-on (NCON) time Toff; when the next trigger signal Fsw_dt arrives, the switching time Tsw is increased while the pulse energy packet is turned on. In terms of the waveform, the Tp time remains unchanged, and the Toff time is increased until the overall anti-audio requirement is met.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A DC / DC voltage converter, comprising a power stage and a driving module for outputting a pulse control signal to the power stage, characterized in that: The DC / DC voltage converter further comprises: an anti-audio control module, configured to detect whether the frequency of the pulse signal falls within the audio band in each cycle, and when it falls within the audio band, to reduce the pulse energy output by the power stage controlled by the driving module by generating a pulse energy control signal, wherein the pulse energy control signal includes an inductor current peak control signal and / or a switching time control signal; A sampling control module, used for sampling the inductor current and controlling the driving module according to the sampled current and the pulse energy control signal; Wherein, the anti-audio control module includes: A pulse frequency detection module, used to detect whether the frequency of the pulse signal falls within the audio band in each cycle, and generate a trigger signal when it falls within the audio band; an inductor current peak control module, configured to determine whether the current inductor current peak reaches a preset current peak value upon receiving the trigger signal, and if the current peak value does not reach the preset current peak value, reduce the inductor current peak value by outputting an inductor current peak control signal; A switching time adjustment module is used to adjust the switching time by outputting a switching time control signal when the current inductor current peak value does not reach the current peak preset value; and is also used to: When the current inductor current peak value reaches the current peak preset value and the current switching time does not reach the switching time preset value, reducing the switching time by outputting a switching time control signal; Or, when the current inductor current peak value reaches the current peak preset value and when the current switching time reaches the switching time preset value, the switching time is increased by outputting a switching time control signal.

2. The DC / DC voltage converter according to claim 1, characterized in that: The inductor current peak control module includes a first add-subtract counter and a first inverter. The trigger signal is input to a clock end of the first add-subtract counter, a high level is input to an input end of the first inverter and a second data input end of the first add-subtract counter respectively, a first data input end of the first add-subtract counter is connected to an output end of the first inverter, a first data output end of the first add-subtract counter outputs the inductor current peak control signal, and a second data output end of the first add-subtract counter outputs the current peak preset value.

3. The DC / DC voltage converter according to claim 1, characterized in that: The switch time adjustment module includes a second add-subtract counter, a third add-subtract counter, a first AND gate, a second AND gate, a second inverter and a two-to-one selector, wherein the first data input terminal and the second data input terminal of the second add-subtract counter are respectively input with the inductor current zero-crossing detection signal, the clock terminal of the second add-subtract counter is input with the pulse control signal of the second power tube of the power stage, and the data output terminal of the second add-subtract counter is connected to the first input terminal of the two-to-one selector; the first input terminal of the first AND gate is input with the current peak preset value, the second input terminal of the first AND gate is input with the switch time preset value, and the input terminal of the second inverter is input with the preset value of the current peak value. The switching time preset value is inputted into the first input terminal of the second AND gate, the current peak preset value is inputted into the second input terminal of the second AND gate, the output terminal of the second inverter is connected to the first data input terminal of the third up-and-down counter, the second data input terminal of the third up-and-down counter is connected to the output terminal of the second AND gate, the clock terminal of the third up-and-down counter inputs the trigger signal, the first output terminal of the third up-and-down counter is connected to the second input terminal of the two-to-one selector, the control terminal of the two-to-one selector inputs the current peak preset value, and the output terminal of the two-to-one selector outputs the switching time control signal.

4. The DC / DC voltage converter according to claim 1, characterized in that: The sampling control module includes: a sampling unit, a comparator, a switch, and a sampling resistor with adjustable resistance, wherein the input end of the sampling unit is connected to the first end of the first power tube of the power stage, the output end of the sampling unit is connected to the sampling resistor through the switch, the inverting input end of the comparator is connected to the output end of the sampling unit, the non-inverting input end of the comparator inputs a sampling reference voltage, and the state of the switch and the resistance value of the sampling resistor are determined by the inductor current peak control signal.

5. The DC / DC voltage converter according to claim 4, characterized in that: The sampling control module also includes an energy storage capacitor, a discharge resistor and a current source. The energy storage capacitor, the discharge resistor and the current source are respectively connected between the inverting input terminal of the comparator and the ground, and at least one of the capacitance value of the energy storage capacitor, the resistance value of the discharge resistor and the output current value of the current source is determined by the switching time control signal.

6. An audio product, characterized in that: A DC / DC voltage converter comprising any one of claims 1 to 5.

7. An anti-audio control method, applied to the DC / DC voltage converter according to any one of claims 1 to 5, characterized in that: include: In each cycle, detecting whether the frequency of the pulse signal falls within the audio band; If it falls within the audio band, the pulse energy output by the driving module to control the power stage is reduced by generating a pulse energy control signal, wherein the pulse energy control signal includes an inductor current control signal and / or a switching time control signal.

8. The anti-audio control method according to claim 7, characterized in that: Also includes: The inductor current is sampled, and the driving module is controlled according to the sampled current and the pulse energy control signal.

9. The anti-audio control method according to claim 7, characterized in that: If it falls within the audio band, a pulse energy control signal is generated to enable the driving module to control the pulse energy outputted by the power stage to be reduced, specifically including: If it falls within the audio band, a trigger signal is generated; When receiving the trigger signal, determining whether the current inductor current peak value reaches a current peak preset value; If the current peak value preset value is not reached, the inductor current peak value is reduced by outputting an inductor current peak value control signal, and the switching time is adjusted by outputting a switching time control signal; If the current peak value reaches the preset value, it is determined whether the current switching time reaches the preset switching time value. If the current switching time does not reach the preset switching time value, the switching time is reduced by outputting a switching time control signal.

10. The anti-audio control method according to claim 9, characterized in that: After the pulse energy control signal is generated to enable the driving module to control the pulse energy outputted by the power stage to be reduced, the method further includes: If the switching time preset value is reached, the switching time is increased by outputting a switching time control signal.

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