Amplification device and method of operating amplification device

Abstract

A magnification device and a method of operating the magnification device are provided. The amplification apparatus includes: a pulse generation circuit configured to generate a pulse signal from an input signal and a triangular wave signal; a driver circuit configured to output an output signal corresponding to the pulse signal based on a first pair of operating voltages among the plurality of operating voltages; and a triangular wave generation circuit configured to generate a triangular wave signal and adjust a level of the triangular wave signal in proportion to the second pair of operating voltages when the first pair of operating voltages is changed to the second pair of operating voltages.

Description

[0001] This application claims the priority of Korean Patent Application No. 10-2023-0197631, filed with the Korean Intellectual Property Office on December 29, 2023, and Korean Patent Application No. 10-2024-0035472, filed with the Korean Intellectual Property Office on March 13, 2024, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0002] Embodiments of the present disclosure described herein relate to an amplification device and a method of operating the amplification device. Background Art

[0003] Mobile devices (such as smartphones) generally require a long battery life, which can be achieved by reducing static power consumption or increasing power efficiency. However, when a switching amplifier (such as a class-D amplifier) is used to achieve high power efficiency, the static current can become a problem. One method for alleviating this situation is to reduce the static current by using a multi-level operating voltage, however this may degrade the linearity of the amplifier. Summary of the Invention

[0004] Embodiments of the present disclosure provide an amplification device and a method of operating the amplification device that can improve linearity.

[0005] According to an embodiment of the present disclosure, an amplification device includes: a pulse generation circuit configured to generate a pulse signal from an input signal and a triangular wave signal; a driver circuit configured to output an output signal corresponding to the pulse signal based on a first pair of operating voltages among a plurality of operating voltages; and a triangular wave generation circuit configured to generate a triangular wave signal and, when the first pair of operating voltages is changed to a second pair of operating voltages, adjust the level of the triangular wave signal in proportion to the second pair of operating voltages.

[0006] According to an embodiment of the present disclosure, an amplification device includes: a pair of amplification circuits configured to generate a differential pulse signal from a differential input signal, a common-mode signal, and a differential triangular wave signal and output a differential output signal corresponding to the differential pulse signal based on a first pair of operating voltages; and a triangular wave generation circuit configured to generate a differential triangular wave signal and, when the first pair of operating voltages is switched to a second pair of operating voltages, adjust the level of the differential triangular wave signal in proportion to the second pair of operating voltages.

[0007] According to an embodiment of the present disclosure, a method of operating an amplification device includes: generating a pulse signal from an input signal and a triangular wave signal; outputting an output signal corresponding to the pulse signal based on a first pair of operating voltages; switching the first pair of operating voltages to a second pair of operating voltages; and when the first pair of operating voltages is switched to the second pair of operating voltages, adjusting the level of the triangular wave signal in proportion to the second pair of operating voltages. Description of the Drawings

[0008] The above and other features of the present disclosure will become apparent by describing embodiments of the present disclosure in detail with reference to the drawings.

[0009] Figure 1 Shows a magnification device according to some embodiments.

[0010] Figure 2 Shows a pulse generation circuit according to some embodiments.

[0011] Figure 3 Shows a driver circuit according to some embodiments.

[0012] Figure 4 is according to some embodiments Figure 3 circuit diagram of the switching network circuit of.

[0013] Figure 5 Shows a triangular wave generation circuit according to some embodiments.

[0014] Figure 6 Shows a magnification device according to some embodiments.

[0015] Figure 7 and Figure 8 Shows the operation waveform of a magnification device according to some embodiments.

[0016] Figure 9 is a circuit diagram of a reference voltage generation circuit according to some embodiments.

[0017] Figure 10 is a circuit diagram of a reference triangular wave generation circuit according to some embodiments.

[0018] Figure 11 is a circuit diagram of an adjustment circuit according to some embodiments.

[0019] Figure 12 Shows the waveform of a triangular wave signal output by a triangular wave generation circuit according to some embodiments.

[0020] Figure 13 is a flowchart showing a method of operating a magnification device according to some embodiments.

[0021] Figure 14 Shows an audio device according to some embodiments. Detailed Description of the Embodiments

[0022] Hereinafter, embodiments of the present disclosure will be described in detail, providing clarity and distinctness sufficient for those skilled in the art to implement the present disclosure.

[0023] Figure 1An amplification device according to some embodiments is shown.

[0024] Referring Figure 1 , an amplification device 100 according to some embodiments may include a pulse generation circuit 110, a driver circuit 120, and a triangular wave generation circuit 130.

[0025] The pulse generation circuit 110 may be configured to generate a pulse signal PS from an input signal IN and a triangular wave signal TRI generated by the triangular wave generation circuit 130. For example, when the amplification device 100 is applied to an audio system, the input signal IN may be a signal converted from an audio signal as a digital signal to an analog signal. The triangular wave signal TRI is generated by the triangular wave generation circuit 130 and may be a non-sinusoidal wave having a triangular shape. In other words, the triangular wave signal TRI may have a non-sinusoidal triangular waveform. The triangular wave signal TRI may be referred to as a triangular waveform signal. The triangular wave signal TRI may be a reference signal with respect to the input signal IN.

[0026] According to some embodiments, the level of the triangular wave signal TRI may be adjusted while maintaining the same distribution of the common-mode voltage. In this case, the pulse generation circuit 110 will generate the pulse signal PS based on the triangular wave signal TRI having the adjusted level.

[0027] According to some embodiments, the pulse generation circuit 110 may compare the input signal IN with the triangular wave signal TRI, and thus, generate a pulse signal PS having a duty cycle proportional to the instantaneous value of the input signal IN. Specifically, the pulse generation circuit 110 may generate the pulse signal PS for the input signal IN based on pulse width modulation (PWM).

[0028] The driver circuit 120 may be configured to output an output signal OUT corresponding to the pulse signal PS. The output signal OUT may be represented as a binary signal having a pulse width proportional to the input signal IN.

[0029] According to some embodiments, the driver circuit 120 may operate based on a plurality of operating voltages and a ground voltage. The plurality of operating voltages may have different voltage levels, forming a multi-level configuration. The plurality of operating voltages may include voltages VDD1 to VDDn. The plurality of operating voltages may be supplied to the driver circuit 120 through different power supply lines.

[0030] According to some embodiments, the ground voltage and "n" operating voltages VDD1 to VDDn may be supplied to the driver circuit 120, where "n" is a natural number greater than 0 that may be configured in various ways according to the requirements and implementation examples of the amplification device 100.

[0031] The driver circuit 120 may output an output signal OUT based on a pair of operating voltages selected from among a plurality of operating voltages. In this case, the output signal OUT may be output in the form of pulses of a high-level voltage and a low-level voltage according to the levels of the pair of operating voltages. In other words, the output signal OUT may be generated as a pulse that alternates between a high-level voltage and a low-level voltage based on the levels of the pair of operating voltages.

[0032] According to some embodiments, a pair of operating voltages may be switched based on an input signal IN. Specifically, the driver circuit 120 may adjust a first pair of operating voltages to a second pair of operating voltages in response to a change in the level of the input signal IN. For example, when the input signal IN is at a low level, the driver circuit 120 may operate in a low-power mode using a low-level operating voltage. Alternatively, when the input signal IN is at a high level, the driver circuit 120 may operate in a high-power mode using a high-level operating voltage.

[0033] When a pair of operating voltages is switched according to a part of the above embodiments, the duty cycle of the output signal OUT should also change. However, in a typical amplifying device 100 having a limited bandwidth, if the triangular wave signal TRI used as a reference signal does not change, the duty cycle remains constant. Although the duty cycle remains the same, the level of the output signal OUT changes as the pair of operating voltages is switched, which may cause deterioration of the linearity of the output signal OUT. To solve this problem, it may be necessary to appropriately adjust the duty cycle of the output signal OUT to maintain linearity.

[0034] The triangular wave generation circuit 130 may be configured to generate a triangular wave signal TRI. For example, the triangular wave generation circuit 130 may be implemented with an oscillator. According to some embodiments, the triangular wave generation circuit 130 may output a clock signal for driving the amplifying device 100 together with the triangular wave signal TRI.

[0035] According to some embodiments, the triangular wave generation circuit 130 may generate a triangular wave signal TRI having a level that changes based on the switching of a pair of operating voltages. For example, when the first pair of operating voltages is switched to the second pair of operating voltages, the triangular wave generation circuit 130 may adjust the level (or amplitude) of the triangular wave signal TRI in proportion to the second pair of switched operating voltages. In this context, "adjusting in proportion to the switched second pair of operating voltages" means that when the level of the output signal OUT changes due to the switching of the operating voltages, the level of the triangular wave signal TRI is adjusted to modify the duty cycle according to the changed level of the output signal OUT. Specifically, the triangular wave generation circuit 130 may adjust the level of the triangular wave signal TRI such that the duty cycle of the output signal OUT is adjusted according to the changed level of the output signal OUT based on the switching of the operating voltages. In other words, the triangular wave generation circuit 130 adjusts the level of the triangular wave signal TRI to ensure that the duty cycle of the output signal OUT is appropriately modified in response to the change in the output signal OUT caused by the switching of the operating voltages.

[0036] For example, when the level of the output signal OUT increases after the switching of the operating voltages, the triangular wave generation circuit 130 may generate a triangular wave signal TRI having a higher level. Optionally, when the level of the output signal OUT decreases after the switching of the operating voltages, the triangular wave generation circuit 130 may generate a triangular wave signal TRI having a lower level.

[0037] According to some embodiments, the triangular wave generation circuit 130 may generate a triangular wave signal TRI having the same common-mode voltage. Specifically, even though the level of the triangular wave signal TRI changes due to dynamic voltage switching, all triangular wave signals TRI may have the same common-mode voltage.

[0038] When operating with a multi-level voltage, the amplification device 100 according to the above embodiments may adjust the level of the triangular wave signal TRI in response to the switched operating voltage. By adjusting the level of the triangular wave signal TRI such that the output signal OUT has an appropriate duty cycle corresponding to the change in the level of the triangular wave signal TRI, degradation in the linearity of the amplification device 100 may be alleviated.

[0039] Figure 2 A pulse generation circuit according to some embodiments is shown.

[0040] Referring to Figure 2 , the pulse generation circuit 110 according to some embodiments may include a feedback loop 111, a loop filter 112, and a comparator 113.

[0041] The feedback loop 111 is connected to the input terminal of the loop filter 112 and the output terminal that outputs the output signal OUT. The feedback loop 111 is configured to provide a feedback signal FED to the input terminal of the loop filter 112. The feedback signal FED may correspond to the output signal OUT provided to the loop filter 112 through the feedback loop 111.

[0042] The input terminal of the loop filter 112 is provided with an input signal IN and a feedback signal FED. The signal at the input terminal of the loop filter 112 may represent the difference between the input signal IN and the feedback signal FED. The loop filter 112 may be configured to output an error signal ERR based on the filtered input signal IN and the feedback signal FED. By performing this filtering operation, the loop filter 112 helps to minimize the distortion in the output signal OUT of the amplifying device 100. According to some embodiments, the loop filter 112 may be implemented as a high-order filter for improving the filtering performance. According to some embodiments, the loop filter 112 may include one or more integrators.

[0043] The error signal ERR output by the loop filter 112 may be a sine wave. In some embodiments, the frequency of the triangular wave signal TRI may be set to be sufficiently higher than the frequency of the error signal ERR.

[0044] The comparator 113 may generate a pulse signal PS by comparing the error signal ERR with the triangular wave signal TRI. The triangular wave signal TRI may be provided by Figure 1 the triangular wave generation circuit 130 and may have an adjusted level according to the switching of the operating voltage. The comparator 113 may generate the pulse signal PS based on the comparison between the levels of the error signal ERR and the triangular wave signal TRI, and the pulse signal PS is a binary waveform. Therefore, the pulse signal PS is output with a duty cycle that "reflects the amplitude of the error signal ERR".

[0045] When the multi-level operating voltage is switched, the pulse generation circuit 110 according to the above embodiments may generate the pulse signal PS based on the triangular wave signal TRI with an adjusted level.

[0046] Figure 3 Shows a driver circuit according to some embodiments.

[0047] Refer to Figure 3 According to some embodiments, the driver circuit 120 may include a gate driver 121 and a switching network circuit 122.

[0048] The gate driver 121 may be configured to be based on Figure 2The pulse signal PS generated by the comparator is used to apply a plurality of control signals CON for controlling the switching network circuit 122 to the switching network circuit 122. Each of the plurality of control signals CON can be used to select and control a plurality of transistors included in the switching network circuit 122. The gate driver 121 can generate a plurality of control signals CON for driving the switching network circuit 122 according to the duty cycle of the pulse signal PS.

[0049] The switching network circuit 122 can be configured to output an output signal OUT through a pull-up or pull-down operation corresponding to a pair of operating voltages among a plurality of operating voltages. According to some embodiments, a pair of operating voltages can be switched by the plurality of control signals CON.

[0050] Figure 4 is according to some embodiments Figure 3 The circuit diagram of the switching network circuit.

[0051] Refer to Figure 4 , according to some embodiments, the switching network circuit 122 can include a plurality of pull-up transistors PU1 to PUn and pull-down transistors PD. In addition to those shown, a plurality of pull-down transistors PD can also be included.

[0052] The plurality of pull-up transistors PU1 to PUn can be implemented by P-type metal-oxide-semiconductor field-effect transistors (PMOSFETs). In this case, the plurality of pull-up transistors PU1 to PUn can include a source connected to a plurality of operating voltages, a gate receiving a part of the plurality of control signals CON, and a drain connected to an output terminal, and the output signal OUT is output through the output terminal. Different multi-level operating voltages can be applied to the source of each pull-up transistor. When "n" operating voltages are applied, "n" pull-up transistors can also be configured.

[0053] The pull-down transistor PD can be implemented by an N-type metal-oxide-semiconductor field-effect transistor (NMOSFET). In this case, the pull-down transistor PD can include a drain connected to the output terminal, a gate receiving one control signal CONa from the plurality of control signals CON, and a source connected to the ground.

[0054] The plurality of pull-up transistors PU1 to PUn can perform a pull-up operation on the output voltage at the output terminal based on a plurality of operating voltages, and can perform a pull-down operation on the output voltage to the ground voltage. A pair of transistors can be selected from the plurality of pull-up transistors PU1 to PUn and the pull-down transistor PD through a plurality of control signals, and the selected pair of transistors can perform a pull-up operation and a pull-down operation according to the duty cycle.

[0055] Finally, since a pair of transistors that operate according to a pair of operating voltages are selected by a plurality of control signals, the plurality of control signals are configured to select a first pair of operating voltages or a second pair of operating voltages different from the first pair of operating voltages from among the plurality of operating voltages according to the level of the input signal IN.

[0056] Figure 5 FIG. shows a triangular wave generation circuit according to some embodiments.

[0057] Refer to Figure 5 , the triangular wave generation circuit 130 according to some embodiments may include a reference voltage generation circuit 131, a reference triangular wave generation circuit 132, an adjustment circuit 133, and a selection logic 134.

[0058] The reference voltage generation circuit 131 may be configured to generate a reference voltage VREF for generating a reference triangular wave. For example, the reference voltage generation circuit 131 may generate the reference voltage VREF from one of the operating voltages (e.g., the battery voltage of the amplifier device) or may buffer the generated reference voltage VREF.

[0059] The reference triangular wave generation circuit 132 may be configured to generate a reference triangular wave signal TRI_REF from the reference voltage VREF. The reference triangular wave signal TRI_REF may be a signal for a specific pair of operating voltages. For example, the reference triangular wave generation circuit 132 may be configured to have a structure in which the reference voltage VREF oscillates according to an amplifier and a capacitor. The reference triangular wave signal TRI_REF may have a specific level or amplitude. In this case, the reference triangular wave signal TRI_REF may oscillate based on a common mode voltage.

[0060] The adjustment circuit 133 may be configured to generate one or more adjusted triangular wave signals TRI_ADJ having a level different from the generated reference triangular wave signal TRI_REF. The one or more adjusted triangular wave signals TRI_ADJ may have a level or amplitude different from the reference triangular wave signal TRI_REF. The adjustment circuit 133 may be implemented according to various structures and methods to generate a triangular wave signal TRI that shares the same common mode voltage as the reference triangular wave signal TRI_REF but has a level different from the level of the reference triangular wave signal TRI_REF. As an example, the adjustment circuit 133 may utilize a voltage distribution structure having a variable resistor to generate one or more adjusted triangular wave signals TRI_ADJ having a level different from the level of the reference triangular wave signal TRI_REF.

[0061] The selection logic 134 can be configured to select the triangular wave signal S_TRI from among the reference triangular wave signal TRI_REF and one or more adjusted triangular wave signals TRI_ADJ when the first pair of operating voltages is changed to the second pair of operating voltages. Considering the switched pair of operating voltages, the selection logic 134 can select the triangular wave signal S_TRI having a level that ensures that the output signal OUT has a duty cycle corresponding to the new voltage level. According to some embodiments, the selection logic 134 can be implemented to detect a pair of switched operating voltages in the driver circuit 120.

[0062] The triangular wave generation circuit 130 according to the above embodiment is merely an example. It is understood that various other triangular wave generation circuits 130 that generate triangular wave signals TRI having the same common-mode voltage but different amplitude levels using different structures or methods are included in the embodiments of the present disclosure.

[0063] Considering the level of a pair of switched operating voltages, the triangular wave generation circuit 130 according to the above embodiment can generate a triangular wave signal TRI having a level that maintains the linearity of the output signal OUT.

[0064] Figure 6 An amplification device according to some embodiments is shown.

[0065] Referring to Figure 6 , an amplification device 200 according to some embodiments can include a pair of amplification circuits 210 and 220 and a triangular wave generation circuit 230.

[0066] The pair of amplification circuits 210 and 220 can be configured to generate differential pulse signals PS1 and differential pulse signals PS2 from the differential input signal IN1 and the differential input signal IN2, the common-mode signal CM, and the differential triangular wave signals TRI1 and differential triangular wave signals TRI2. The pair of amplification circuits 210 and 220 can also be configured to output differential output signals OUT1 and differential output signals OUT2 corresponding to the differential pulse signals PS1 and differential pulse signals PS2, respectively, based on a first pair of operating voltages among a plurality of operating voltages including voltage VDD1 to VDDn and ground voltage. According to some embodiments, the pair of amplification circuits 210 and 220 can adjust the first pair of operating voltages to a second pair of operating voltages based on a change in the levels of the differential input signal IN1 and the differential input signal IN2.

[0067] The pair of amplification circuits 210 and 220 can include a first amplification circuit 210 and a second amplification circuit 220 connected to the load ZL. According to some embodiments, each of the amplification circuits 210 and 220 can be based on Figures 1 to 5configured according to the embodiments. Specifically, the first amplifier circuit 210 may be configured to be the same as the second amplifier circuit 220. However, when the signal associated with the first amplifier circuit 210 corresponds to one of the pair of differential signals, the signal associated with the second amplifier circuit 220 may correspond to the other differential signal. Specifically, the signal associated with the first amplifier circuit 210 and the signal associated with the second amplifier circuit 220 may have different phases.

[0068] According to some embodiments, the pair of amplifier circuits 210 and 220 may include a pair of loop filters 211 and 221, a pair of comparators 212 and 222, a pair of feedback loops 213 and 223, and a pair of driver circuits 214 and 224. The first loop filter 211 and the second loop filter 221, the first comparator 212 and the second comparator 222, and the first feedback loop 213 and the second feedback loop 223 may be configured according to the above Figure 2 embodiments.

[0069] The pair of loop filters 211 and 221 may be configured to output differential error signals ERR1 and ERR2 based on filtering of the differential input signals IN1 and IN2, the common-mode signal CM, and signals fed back from the differential output signals OUT1 and OUT2. Each of the pair of loop filters 211 and 221 receives a signal corresponding to the difference between an input signal and a feedback signal and the common-mode signal CM. Then, the differential error signals ERR1 and ERR2 are output as signals that vary the common-mode voltage corresponding to the common-mode signal CM.

[0070] The pair of comparators 212 and 222 may generate differential pulse signals PS1 and PS2 by comparing the differential error signals ERR1 and ERR2 with the differential triangular wave signals TRI1 and TRI2, respectively. As an example, the first comparator may output a first pulse signal by comparing a first error signal with a first triangular wave signal.

[0071] The pair of feedback loops 213 and 223 are respectively connected to the input terminals of the pair of loop filters 211 and 221 and the output terminals that output the differential output signal OUT1 and the differential output signal OUT2. The pair of feedback loops 213 and 223 can be configured to provide feedback signals to the input terminals of the pair of loop filters 211 and 221. As an example, the first feedback loop 213 can be connected to the input terminal of the first loop filter 211 and the first output node NO1, and the first output signal OUT1 is output through the first output node NO1. As another example, the second feedback loop 223 can be connected to the input terminal of the second loop filter 221 and the second output node NO2, and the second output signal OUT2 is output through the second output node NO2.

[0072] The pair of driver circuits 214 and 224 can be configured to output the differential output signal OUT1 and the differential output signal OUT2 based on the differential pulse signal PS1 and the differential pulse signal PS2 through a pull-up or pull-down operation corresponding to the first pair of operating voltages. As an example, the first driver circuit 214 can output the first output signal OUT1 through a pull-up or pull-down operation based on the differential pulse signal PS1. The first output signal OUT1 can have a polarity opposite to that of the differential input signal IN1.

[0073] The triangular wave generation circuit 230 can be configured to generate a differential triangular wave signal TRI1 and a differential triangular wave signal TRI2. According to some embodiments, the triangular wave generation circuit 230 can be configured according to Figure 5 the embodiments. Specifically, the triangular wave generation circuit 230 can include a reference voltage generation circuit, a reference triangular wave generation circuit, an adjustment circuit, and a selection logic. The reference voltage generation circuit is configured to generate a reference voltage. The reference triangular wave generation circuit is configured to generate a differential reference triangular wave signal from the reference voltage. The adjustment circuit is configured to generate a plurality of differential adjusted triangular wave signals having different levels from the differential reference triangular wave signal. The selection logic is configured to select a differential triangular wave signal from among the differential reference triangular wave signal and the plurality of differential adjusted triangular wave signals when the first pair of operating voltages is changed to the second pair of operating voltages.

[0074] The generated differential triangular wave signal TRI1 is provided to the first amplifier circuit 210, and the differential triangular wave signal TRI2 is provided to the second amplifier circuit 220. The differential triangular wave signal TRI1 and the differential triangular wave signal TRI2 can have the same common-mode voltage, amplitude level, and frequency. The amplitude level can vary according to the switching of a pair of operating voltages.

[0075] According to some embodiments, when the first pair of operating voltages is changed to the second pair of operating voltages, the triangular wave generation circuit 230 may adjust the levels of the differential triangular wave signal TRI1 and the differential triangular wave signal TRI2 in proportion to the second pair of operating voltages. For example, the triangular wave generation circuit 230 may adjust the level of the differential triangular wave signal TRI1 such that the duty cycle of the first output signal OUT1, which is now at the changed level, is adjusted in response to the new operating voltage.

[0076] Thus, in the amplifier device 200 described in the above embodiments, even if the levels of the differential output signal OUT1 and the differential output signal OUT2 change due to the changed operating voltage, the duty cycles of the differential output signal OUT1 and the differential output signal OUT2 are adjusted by adjusting the level of the triangular wave signal. This adjustment helps prevent deterioration of the linearity of the differential output signal OUT1 and the differential output signal OUT2.

[0077] Figure 7 and Figure 8 show the operation waveforms of the amplifier device according to some embodiments. As an example, Figure 7 shows the operation waveform when the triangular wave is not adjusted according to the level, and Figure 8 shows the operation waveform when the triangular wave is adjusted according to the level.

[0078] Referring to Figure 7 and Figure 8 , the waveforms of the triangular wave signal Vtri, the differential error signal Verr+, the differential error signal Verr-, the differential output signal Vo+, the differential output signal Vo-, and the effective output signal Vdiff are shown. The effective output signal Vdiff is an output signal corresponding to the difference between the differential output signal Vo+ and the differential output signal Vo-, and is the signal actually output to the load ZL. In addition, it is assumed that the frequency of the triangular wave signal Vtri is sufficiently large compared to the frequencies of the differential error signal Verr+ and the differential error signal Verr-, and thus the differential error signal Verr+ and the differential error signal Verr- are shown as direct current (DC) components. Specifically, the corresponding operation waveforms are to be understood for a very small time segment.

[0079] The amplification device according to the above embodiment can output a differential output signal Vo+ by comparing the level of the triangular wave signal Vtri with the level of the differential error signal Verr+. In addition, the amplification device can output a differential output signal Vo- by comparing the level of the same triangular wave signal Vtri with the level of the differential error signal Verr-. Therefore, the differential output signal Vo+ represents a logic high in a section where the level of the differential error signal Verr+ is higher than the level of the triangular wave signal Vtri (e.g., from t1 to t4), and represents a logic low in a section where the level of the differential error signal Verr+ is lower than the level of the triangular wave signal Vtri (e.g., from t4 to t5). In addition, the differential output signal Vo- represents a logic high in a section where the level of the differential error signal Verr- is higher than the level of the triangular wave signal Vtri (e.g., from t2 to t3), and represents a logic low in a section where the level of the differential error signal Verr- is lower than the level of the triangular wave signal Vtri (e.g., from t1 to t2).

[0080] When the levels of a pair of operating voltages are switched based on a specific time "tx", the levels of the differential output signal Vo+ and the differential output signal Vo- will also change. For example, when the level of the high-voltage side of a pair of operating voltages increases, the levels of the differential output signal Vo+ and the high-voltage side (i.e., Vo+) of the differential output signal Vo- will also increase from h1 to h2.

[0081] However, when the duty cycle needs to be maintained within a limited bandwidth (i.e., when using the same triangular wave signal without adjusting the level of the triangular wave signal), the area of each pulse in the effective output signal Vdiff will change suddenly. This occurs because only the output level changes while the duty cycles of the differential output signal Vo+ and the differential output signal Vo- remain constant. Therefore, the linearity of the amplification device may deteriorate due to the sudden change in the effective output signal Vdiff.

[0082] In contrast, as shown in Figure 8 , when the levels of a pair of operating voltages are switched based on a specific time "tx", the level of the triangular wave signal also changes. In some embodiments, the amplification device can adjust the level of the triangular wave signal Vtri1 at the highest (or lowest) point (e.g., the maximum point or the minimum point) of the level of the triangular wave signal Vtri1 before the change occurs. Since the triangular wave signal Vtri2 after the change has the adjusted level, the pulse widths of the differential output signal Vo+ and the differential output signal Vo- after the specific time "tx" change accordingly. Due to this change in the pulse width, the pulse width of the effective output signal Vdiff also changes from w1 to w2. As an example, Figure 8There is shown a situation where the levels of the differential output signal Vo+ and the differential output signal Vo- increase (i.e., the level of the operating voltage increases), resulting in a decrease in the pulse widths of the differential output signal Vo+ and the differential output signal Vo- and the effective output signal Vdiff. Specifically, the duty cycle of the output signal decreases. Due to this change in the duty cycle, the area of each pulse of the effective output signal Vdiff remains the same before a specific time "tx" and after the specific time "tx".

[0083] Finally, although the levels of the pair of operating voltages are switched, the duty cycle is appropriately adjusted (i.e., the duty cycle is adjusted to ensure that the area of each pulse of the effective output signal Vdiff remains the same before and after the switching). Thus, the area of each pulse of the effective output signal Vdiff remains consistent, thereby solving potential degradation in the linearity of the output signal.

[0084] Figure 9 is a circuit diagram of a reference voltage generation circuit 300 according to some embodiments.

[0085] Referring to Figure 9 and according to some embodiments, the reference voltage generation circuit 300 (or Figure 5 the reference voltage generation circuit 131 or the reference voltage generation circuit included in Figure 6 the triangular wave generation circuit 230 of

[0086] The first-stage circuit 310 is configured to generate a reference voltage VREF from the operating voltage VBAT. For example, the first-stage circuit 310 may include a plurality of resistors, a plurality of capacitors, and a plurality of buffers.

[0087] The operating voltage VBAT is divided by the voltage division of the first resistor R1 and the second resistor R2 connected to the first node N1 and is applied to the first node N1. Then, this voltage division is applied to a plurality of buffers through the third resistor R3 connected between the first node N1 and the second node N2. In this configuration, the third resistor R3 can provide a high impedance to the first buffer BF1 and the second buffer BF2. The voltage at the first node N1 can be 1 / N times the operating voltage VBAT, where "N" is a real number greater than "0".

[0088] The first capacitor C1 is connected to the second node N2, and the second node N2 corresponds to the input terminals of the first buffer BF1 and the second buffer BF2. In addition, the second capacitor C2 is connected to the output terminal of the first buffer BF1. The reference voltage VREF is output through the first buffer BF1 and the second buffer BF2. One end of each of the second resistor R2, the first capacitor C1, and the second capacitor C2 is connected to the ground.

[0089] The first - stage circuit 310 is connected to the second - stage circuit 320 through the output terminal of the second buffer BF2 and the ground node. The second - stage circuit 320 is connected to the first - stage circuit 310 through the fourth resistor R4 and the fifth resistor R5. The fourth resistor R4 is connected to the input terminal of the third buffer BF3 through the third node N3, and the fifth resistor R5 is connected to the input terminal of the third buffer BF3 through the fourth node N4. The third buffer BF3 can buffer the reference voltage VREF based on the common - mode voltage VCM and can output the differential reference voltage VREFN and the differential reference voltage VREFP. The first differential reference voltage VREFN is output to the fifth node N5 through the sixth resistor R6 connected to the third node N3, and the second differential reference voltage VREFP is output to the sixth node N6 through the seventh resistor R7 connected to the fourth node N4. The output differential reference voltages VREFN and VREFP can be used to generate a triangular - wave signal.

[0090] According to some embodiments, the sixth resistor R6 is M times the resistance value of the fourth resistor R4, where "M" is a real number greater than "0", and the seventh resistor R7 can be M times the resistance value of the fifth resistor R5. In this case, the first differential reference voltage VREFN can be expressed as and the second differential reference voltage VREFP can be expressed as .

[0091] Figure 10 is a circuit diagram of a reference triangular - wave generation circuit according to some embodiments.

[0092] Referring to Figure 10 According to some embodiments, the reference triangular - wave generation circuit 400 (or Figure 5 the reference triangular - wave generation circuit 132 of Figure 6 or the reference triangular - wave generation circuit included in the triangular - wave generation circuit 230 of

[0093] A plurality of switches SW1 to SW4 can be closed or opened under the control of the logic circuit 430. The first switch SW1 and the second switch SW2 can be operated together, and the third switch SW3 and the fourth switch SW4 can be operated together. When the first switch SW1 and the second switch SW2 are closed, the third switch SW3 and the fourth switch SW4 are opened, the sixth node N6 and the seventh node N7 are connected to each other, and the fifth node N5 and the eighth node N8 are connected to each other. In contrast, when the first switch SW1 and the second switch SW2 are opened, the third switch SW3 and the fourth switch SW4 are closed, the sixth node N6 and the eighth node N8 are connected to each other, and the fifth node N5 and the seventh node N7 are connected to each other. The slope direction of the signal output from the oscillation circuit 410 is based on the operation of the plurality of switches SW1 to SW4, thereby generating a triangular wave signal.

[0094] The oscillation circuit 410 can be implemented by an integrator. The first variable resistor VR1 connected to the seventh node N7 is connected to the ninth node N9 corresponding to the input terminal of the amplifier 411, and the second variable resistor VR2 connected to the eighth node N8 is connected to the tenth node N10. For example, the first variable resistor VR1 and the second variable resistor VR2 can have the same variable resistance "R".

[0095] In addition, a common mode voltage VCM is applied to the amplifier 411. In the integrator structure of the oscillation circuit 410, the third capacitor C3 connected to the ninth node N9 is connected to the eleventh node N11 corresponding to the output terminal of the amplifier 411, and the fourth capacitor C4 connected to the tenth node N10 is connected to the twelfth node N12 corresponding to the other output terminal of the amplifier 411. For example, the third capacitor C3 and the fourth capacitor C4 can have the same capacitance "C".

[0096] Through the oscillation of the oscillation circuit 410, a differential reference triangular wave signal TRI1,N and a differential reference triangular wave signal TRI1,P are output to the eleventh node N11 and the twelfth node N12. In this case, the levels of the differential reference triangular wave signal TRI1,N and the differential reference triangular wave signal TRI1,P can be changed according to the change of the resistance of the first variable resistor VR1 and the second variable resistor VR2. In addition, the differential reference triangular wave signal TRI1,N and the differential reference triangular wave signal TRI1,P can oscillate based on the common mode voltage VCM.

[0097] A plurality of comparators 421 to 424 are connected to the output terminals (i.e., the eleventh node N11 and the twelfth node N12) of the oscillation circuit 410, and a logic circuit 430 is connected to the output terminals of the plurality of comparators 421 to 424. The first comparator 421 and the second comparator 422 are commonly provided with a first differential reference voltage VREFN, and the third comparator 423 and the fourth comparator 424 are commonly provided with a second differential reference voltage VREFP. The first comparator 421 compares the voltage at the eleventh node N11 with the first differential reference voltage VREFN and provides the comparison result to the logic circuit 430. The second comparator 422 compares the voltage at the twelfth node N12 with the first differential reference voltage VREFN and provides the comparison result to the logic circuit 430. The third comparator 423 compares the voltage at the twelfth node N12 with the second differential reference voltage VREFP and provides the comparison result to the logic circuit 430. The fourth comparator 424 compares the voltage at the eleventh node N11 with the second differential reference voltage VREFP and provides the comparison result to the logic circuit 430. The logic circuit 430 can use the comparison results to determine the switching timing of the plurality of switches SW1 to SW4.

[0098] The logic circuit 430 can determine the switching timing (including which switch to close (or open)) of the plurality of switches SW1 to SW4 based on the comparison results received from the plurality of comparators 421 to 424. According to some embodiments, the logic circuit 430 can output a clock signal corresponding to the triangular wave signal and a clipping signal for detecting clipping.

[0099] Figure 11 is a circuit diagram of an adjustment circuit according to some embodiments.

[0100] Referring to Figure 11 , the adjustment circuit 500 according to some embodiments (or Figure 5 the adjustment circuit 133 or the adjustment circuit included in Figure 6 the triangular wave generation circuit 230) can generate a plurality of differentially adjusted triangular wave signals TRI2,N and TRI2,P with different levels from the differential reference triangular wave signal TRI1,N and the differential reference triangular wave signal TRI1,P.

[0101] For example, the adjustment circuit 500 may include a plurality of resistors R8 and R9 and a variable resistor VR3. A differential reference triangular wave signal TRI1,N and a differential reference triangular wave signal TRI1,P are provided by the plurality of resistors R8 and R9. The plurality of resistors R8 and R9 are connected to the variable resistor VR3 through a thirteenth node N13 and a fourteenth node N14. A plurality of differentially adjusted triangular wave signals TRI2,N and TRI2,P may be output from the thirteenth node N13 and the fourteenth node N14 by voltage division. The plurality of differentially adjusted triangular wave signals TRI2,N and TRI2,P may have levels different from the levels of the differential reference triangular wave signal TRI1,N and the differential reference triangular wave signal TRI1,P.

[0102] According to some embodiments, a plurality of adjustment circuits 500 may be provided, allowing differentially adjusted triangular wave signals having different levels to be output from each adjustment circuit.

[0103] According to the above embodiments, the triangular wave signal generation circuit may generate triangular wave signals having varying levels while maintaining the same common-mode voltage VCM. This is achieved by the reference voltage generation circuit 300, the reference triangular wave generation circuit 400, and the adjustment circuit 500. The generated triangular wave signals ensure that the output signal maintains an appropriate duty cycle during the operation voltage switching.

[0104] Figure 12 The waveform of the triangular wave signal output by the triangular wave generation circuit according to some embodiments is shown.

[0105] Referring to Figure 12 , as shown, the triangular wave signal may be represented as a waveform oscillating between a first differential reference voltage VREFN and a second differential reference voltage VREFP based on the common-mode voltage VCM. For example, referring to Figure 9 the coefficients "M" and "N" and the operating voltage VBAT described in the reference voltage generation circuit of . Here, GPWM may be the signal gain, and the signal gain is N / M.

[0106] Furthermore, referring to Figure 10 the resistance values "R" of the first variable resistor VR1 and the second variable resistor VR2 and the capacitance values "C" of the third capacitor C3 and the fourth capacitor C4 in the reference triangular wave generation circuit 400 of

[0107] Finally, through a triangular wave generation circuit according to some embodiments, a triangular wave signal can be designed to have a gain determined by parameters in the circuit and a switching frequency determined by resistors and capacitors in the circuit. This allows for ensuring stable gain and switching frequency. In addition, regardless of the amplitude of the triangular wave signal, the triangular wave signal can be designed to have the same common-mode voltage VCM.

[0108] Figure 13 is a flowchart showing a method of operating an amplification device according to some embodiments.

[0109] Referring Figure 13 , according to some embodiments, in operation S110, the amplification device can generate a pulse signal from an input signal and a triangular wave signal. For example, in operation S110, a pulse signal can be generated by comparing the input signal with the triangular wave signal. The pulse period of the pulse signal can be proportional to the instantaneous value of the input signal.

[0110] In operation S120, the amplification device can output an output signal corresponding to the pulse signal based on a first pair of operating voltages among a plurality of operating voltages. The plurality of operating voltages can include different multi-level voltages, and the different multi-level voltages include a ground voltage. The amplitudes of the low level and the high level of the output signal having binary pulses can be determined according to the first pair of operating voltages. In other words, the amplitudes of the low level and the high level of the output signal having binary pulses can be determined by the first pair of operating voltages.

[0111] In operation S130, the amplification device can switch the first pair of operating voltages to a second pair of operating voltages. The operation S130 involving the execution of the switching can be performed according to a change in the level of the input signal. The second pair of operating voltages after the switching can be different from the first pair of operating voltages, or can be common with respect to one operating voltage. In other words, the second pair of operating voltages after the switching can be different from the first pair of operating voltages, or one of the operating voltages can remain common between the two pairs.

[0112] In operation S140, the amplification device can adjust the level of the triangular wave signal in proportion to the second pair of operating voltages based on the condition that the first pair of operating voltages is changed to the second pair of operating voltages. Both the triangular wave signal after the level adjustment and the triangular wave signal before the level adjustment can have the same common-mode voltage. Specifically, only the amplitude of the triangular wave signal can be adjusted based on the same common-mode voltage.

[0113] According to the operation method described in the above embodiments, the level of the triangular wave signal can be changed as the multi-level operating voltage of the amplification device is switched. The adjusted level of the triangular wave signal ensures that the output signal has an appropriate duty cycle, thereby preventing deterioration of linearity.

[0114] Figure 14An audio device according to some embodiments is shown.

[0115] Referring Figure 14 , an audio device 600 according to some embodiments may include a processor 610, an interface (IF) 620, an amplifier 630, and an audio output device 640.

[0116] The processor 610 may perform various processes on digital audio signals. For example, the processor 610 may perform sample rate conversion, filter application, interpolation processing, amplification or attenuation of frequency bands, noise processing, channel change, mixing, extraction of specific signals, etc. on digital audio signals.

[0117] The interface 620 may include an analog-to-digital converter (ADC) and / or a digital-to-analog converter (DAC). The interface 620 may convert a digital audio signal into an analog audio signal, or may convert an analog audio signal into a digital audio signal.

[0118] The amplifier 630 may receive an analog audio signal as an input signal IN from the interface 620, may amplify the input signal IN, and may output an output signal. The amplifier 630 may be implemented to include an amplification device according to the above embodiments (e.g., Figures 1 to 13 ), or may be configured to perform the function of an amplification device. According to some embodiments, the amplifier 630 may operate according to a plurality of operating voltages having multiple levels (including voltages VDD1 to VDDn and a ground voltage). When the levels of a pair of operating voltages are switched, the amplifier 630 may generate a pulse signal PS by comparing a triangular wave signal TRI having a changed level with the input signal IN via a comparator CMP. The amplifier 630 may output an output signal OUT1 and an output signal OUT2 based on the pulse signal PS through a pull-up operation or a pull-down operation.

[0119] The audio output device 640 may be implemented as a speaker that outputs sound according to the output signal OUT1 and the output signal OUT2 output from the amplifier 630. Optionally, the audio output device 640 may include a receiver that receives sound. Optionally, the audio output device 640 may include a plurality of speakers, and may output sound through a plurality of different channels.

[0120] The audio device 600 according to the above embodiments may operate based on an operating voltage having multiple levels, thereby reducing standby current. In addition, when the operating voltage changes during multi-level operation, the audio device 600 may improve the degradation in the linearity of the output signal by adjusting the level of the triangular wave signal TRI according to the changed level.

[0121] According to an embodiment of the present disclosure, an amplification device capable of improving linearity and a method of operating the amplification device are provided.

[0122] The above description details specific embodiments of the present disclosure. Simple design changes or modifications that can be easily implemented may also fall within the scope of the present disclosure. In addition, techniques that can be easily modified or adapted using the above embodiments are included in the present disclosure. Although the present disclosure has been described with reference to these embodiments, it will be apparent to those of ordinary skill in the art that various changes and modifications can be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

Claims

1. An amplification device, comprising: a pulse generating circuit configured to generate a pulse signal from an input signal and a triangular wave signal; a driver circuit configured to output an output signal corresponding to the pulse signal based on a first pair of operating voltages among a plurality of operating voltages; as well as The triangle wave generating circuit is configured to generate a triangle wave signal and adjust a level of the triangle wave signal in proportion to the second pair of operating voltages when the first pair of operating voltages is changed to the second pair of operating voltages.

2. The amplifying device according to claim 1, wherein: The pulse generation circuit includes: a loop filter configured to output an error signal by filtering an input signal and a signal fed back from an output signal; and The comparator is configured to generate a pulse signal by comparing the error signal with the triangle wave signal.

3. The amplifying device according to claim 1, wherein: The driver circuit includes: a switching network circuit configured to output an output signal through a pull-up or pull-down operation corresponding to a first pair of operating voltages; and The gate driver is configured to apply a plurality of control signals to the switching network circuit based on the pulse signal to control the switching network circuit.

4. The amplifying device according to claim 3, wherein: The switching network circuit includes: a plurality of pull-up transistors including sources connected to the plurality of operating voltages, gates for receiving a portion of the plurality of control signals, and drains connected to output terminals through which output signals are output; and The pull-down transistor includes a drain connected to the output terminal, a gate for receiving a portion of the plurality of control signals, and a source connected to ground.

5. The amplifying device according to claim 3, wherein: The plurality of control signals are used to select a first pair of operating voltages or a second pair of operating voltages from among the plurality of operating voltages based on a level of an input signal.

6. The amplifying device according to claim 1, wherein: The triangle wave generating circuit is configured to generate a triangle wave signal having the same common mode voltage.

7. The amplifying device according to claim 1, wherein: The triangle wave generating circuit includes: A reference voltage generating circuit configured to generate a reference voltage; A reference triangle wave generating circuit configured to generate a reference triangle wave signal from a reference voltage; a conditioning circuit configured to generate one or more conditioned triangle wave signals having different levels from the reference triangle wave signal; and The selection logic is configured to select the triangle wave signal from among the reference triangle wave signal and the one or more adjusted triangle wave signals when the first pair of operating voltages is changed to the second pair of operating voltages.

8. The amplifying device according to claim 2, wherein: The pulse generating circuit also includes: The feedback loop is connected to the output terminal and the input terminal of the loop filter and is configured to provide the fed-back signal to the input terminal of the loop filter, and the output signal is outputted through the output terminal.

9. The amplifying device according to claim 1, wherein: The driver circuit adjusts the first pair of operating voltages to a second pair of operating voltages in response to a change in the level of the input signal.

10. The amplifying device according to claim 1, wherein: The triangle wave generation circuit is configured as: The level of the triangular wave signal is adjusted at the maximum or minimum point of the level of the triangular wave signal.

11. An amplifying device, comprising: a pair of amplification circuits configured to generate a differential pulse signal from a differential input signal, a common mode signal, and a differential triangle wave signal, and to output a differential output signal corresponding to the differential pulse signal based on a first pair of operating voltages; as well as The triangle wave generating circuit is configured to generate a differential triangle wave signal and adjust the level of the differential triangle wave signal in proportion to the second pair of operating voltages when the first pair of operating voltages is switched to the second pair of operating voltages.

12. The amplifying device according to claim 11, wherein: The pair of amplification circuits comprises: a pair of loop filters configured to output a differential error signal by filtering a differential input signal, a common mode signal, and a signal fed back from a differential output signal; a pair of comparators configured to generate a differential pulse signal by comparing the differential error signal with the differential triangle wave signal; and A pair of feedback loops are connected to the input terminals of the pair of loop filters and output terminals outputting differential output signals, and are configured to provide the fed-back signals to the input terminals of the pair of loop filters.

13. The amplifying device according to claim 11, wherein: The triangle wave generating circuit is configured to generate differential triangle wave signals having the same common mode voltage.

14. The amplifying device according to claim 11, wherein: The pair of amplification circuits comprises: A pair of driver circuits are configured to output differential output signals through pull-up or pull-down operations corresponding to a first pair of operating voltages based on the differential pulse signals.

15. The amplifying device according to claim 11, wherein: The triangle wave generating circuit includes: A reference voltage generating circuit configured to generate a reference voltage; a reference triangle wave generating circuit configured to generate a differential reference triangle wave signal from a reference voltage; a conditioning circuit configured to generate a plurality of differential conditioned triangle wave signals having different levels from the differential reference triangle wave signal; and The selection logic is configured to select the differential triangle wave signal from among the differential reference triangle wave signal and the plurality of differential adjusted triangle wave signals when the first pair of operating voltages is switched to the second pair of operating voltages.

16. The amplifying device according to claim 11, wherein: The pair of amplification circuits adjust the first pair of operating voltages to a second pair of operating voltages in response to changes in the levels of the differential input signals.

17. The amplifying device according to claim 11, wherein: The triangle wave generation circuit is configured as: The level of the differential triangle wave signal is adjusted at a maximum or minimum point of the level of the differential triangle wave signal.

18. A method of operating an amplification device, the method comprising: generating a pulse signal from an input signal and a triangular wave signal; outputting an output signal corresponding to the pulse signal based on the first pair of operating voltages; switching the first pair of operating voltages to the second pair of operating voltages; as well as When the first pair of operating voltages is switched to the second pair of operating voltages, the level of the triangular wave signal is adjusted in proportion to the second pair of operating voltages.

19. The method of claim 18, wherein: The triangle wave signals have the same common-mode voltage.

20. The method of claim 18, wherein: The step of switching the first pair of operating voltages to the second pair of operating voltages is performed in response to a change in the level of the input signal.

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