KR20210008456A - multi-level Class D amplifier of low voltage-stress - Google Patents

Abstract

The present invention generally relates to a technology for improving reverse recovery characteristics of a switching transistor in a digital amplifier and reducing the voltage stress applied to a switching transistor. Specifically, the present invention relates to a multi-level digital amplifier having low voltage-stress, in which a circuit of a digital amplifier is configured in a multi-level method, thereby lowering the voltage stress applied to the switching transistor during a switching operation by a PWM carrier signal, and reducing the switching loss that occurs during switching, such that the reverse recovery characteristics can be improved through a freewheeling diode. According to the present invention, it is possible to apply a digital amplifier to a high voltage application field by lowering the voltage stress of the switching transistor; and a Si-FET component device having a body diode with slow reverse recovery characteristics can be applied to a digital amplifier, thereby lowering product price and securing product design flexibility. In addition, since the voltage stress of the switching transistor is low, it is possible to reduce a switching loss occurring during switching, thereby being advantageous in terms of efficiency and heat generation.

Description

Multi-level Class D amplifier of low voltage-stress

The present invention generally relates to a technique for improving reverse recovery characteristics of a switching transistor in a digital amplifier (Class D amplifier) and lowering a voltage stress applied to the switching transistor.

In particular, the present invention reduces the voltage stress applied to the switching transistor during the switching operation process by the PWM carrier signal by configuring the circuit of the digital amplifier in a multilevel method, thereby reducing the switching loss generated during switching and freewheeling. It relates to a low voltage stress multilevel digital amplifier that improves reverse recovery characteristics through a diode.

In general, analog amplifiers directly amplify analog signals with power transistors, so there are many advantages in terms of sound quality. However, analog amplifiers at the level to be matched with high-quality speakers generate a lot of heat from the power transistor, so a large heat sink must be mounted to dissipate the heat, resulting in an increase in size, weight, and price. There is this.

In response to these shortcomings of analog amplifiers, a digital amplifier, also called a Class D amplifier, has been proposed. The digital amplifier synthesizes the analog input signal with a high-frequency carrier signal and modulates it using a PWM (Pulse Width Modulation) method, and then operates a switching transistor with this synthesized PWM signal to amplify the signal and convert the amplified PWM signal into an LC low-pass filter. By passing the (Low Pass Filter), as a result, a small-signal analog input signal is amplified into a large-signal analog signal with a large amplitude.

[Fig. 1] is a schematic configuration diagram of a general digital amplifier, [Fig. 2] is a waveform graph when there is no input signal in such a digital amplifier, and [Fig. 3] is a waveform graph when there is an input signal in a digital amplifier. to be. The waveform graphs of [Fig. 2] and [Fig. 3] are conceptually shown to explain the operation method of the digital amplifier, and in reality, the output capacitance of the switching transistors 11 and 12 or the LC low-pass filters 13 and 14 There is quite a difference from this by the characteristics of.

Referring to FIG. 1, the amplifier control unit 15 receives an input signal (audio signal) of a low frequency (eg, 20 Hz to 20 kHz) and a carrier signal of a high frequency (eg, 200 kHz to 550 kHz). These input signals and carrier signals are small signals (eg 3.3 V). At this time, the carrier signal is also called a sampling signal, and a triangle wave, a sawtooth wave, or the like may be used. The amplifier control unit 15 generates a high frequency (for example, 200 kHz to 550 kHz) synthesized PWM signal by synthesizing the input signal and the carrier signal and performing PWM modulation. In this process, the signal amplitude of the input signal is reflected in the duty ratio of the synthesized PWM signal.

The upper switching transistor 11 and the lower switching transistor 12 are switched in opposite directions according to the synthesized PWM signal. In general, MOSFET power transistors are used as these switching transistors 11 and 12. Through the switching control of these transistors (11, 12), a PWM signal amplified to a high voltage (±HV) (for example, ±70 V) is obtained, and the amplified PWM signal is passed through the LC low-pass filters (13, 14). Get the output signal. This output signal is transmitted to the speaker to drive the speaker unit.

An internal mechanism in which the digital amplifier 10 operates will be described with additional reference to FIGS. 2 and 3.

First, referring to [Fig. 1] and [Fig. 2], when there is no input signal, the amplifier control unit 15 outputs a carrier signal having a duty ratio of 50% as a synthesized PWM signal, and accordingly, the upper and lower switching transistors (11, 12) are alternately turned on and off for the same time period corresponding to the duty ratio of 50%. At this time, while the upper switching transistor 11 is in the ON state, current is supplied from the +HV power supply to the low-pass filters 13 and 14, and while the lower switching transistor 12 is in the ON state, the low pass The current is drained from the filters 13 and 14 to the -HV power supply. Since the duty ratio of the synthesized PWM signal is 50%, there is no energy accumulated in the low-pass filter capacitor Cf 14.

On the other hand, referring to Figs. 1 and 3, for example, when there is a rising input signal, the amplifier control unit 15 outputs a synthesized PWM signal in which the duty ratio is increased. Accordingly, the upper switching transistor The time ratio in which (11) is in the ON state gradually increases, while the time ratio in which the lower switching transistor 12 is in the ON state gradually decreases. Accordingly, more energy is gradually accumulated in the low-pass filter capacitor Cf 14 each time the duty cycle elapses, and thus the output signal follows the input signal and gradually increases.

The digital amplifier 10 operates by this mechanism, and the upper and lower switching transistors 11 and 12 constituting the digital amplifier 10 only come and go in a cut-off region and a saturation region, Since it does not operate in the linear) domain, the loss is definitely smaller than that of an analog amplifier.

However, the digital amplifier 10 is unsuitable for high voltage applications despite the above advantages due to the problems described later.

[Fig. 4] is a diagram showing a typical equivalent circuit configuration and current signal of a digital amplifier (Class D amplifier). [Fig. 4] is a simplified representation of the circuit configuration of [Fig. 1] so that electric circuit analysis can be intuitively performed. Referring to FIG. 4, in the digital amplifier, two switching transistors 11 and 12 are switched on and off in opposite directions by the voltage Vin of the synthesized PWM signal. In Fig. 4, the voltage stress applied to the switching transistors 11 and 12 is twice the value of Vin.

In a digital amplifier, it is common to use a MOSFET power transistor as the switching transistors 11 and 12, and the body diode of the switching transistors 11 and 12 must have a fast reverse recovery characteristic. According to the manufacturing method of the field effect transistor (FET), when a transistor is made, diode characteristics are inherent even if it is not intended, and this is called a body diode. In FIG. 4, diodes D1 and D2 connected from a source to a drain direction of the switching transistors 11 and 12 are body diodes of the switching transistors 11 and 12.

When a reverse voltage is applied to the diode device, the current is not cut off immediately, but is cut off after a certain time has elapsed due to physical properties. This elapsed time is called a reverse recovery time (Trr). Conventional diodes do not guarantee a fast reverse recovery time (Trr), and if a short reverse recovery time is required, a specially designed device should be used. In the digital amplifier, switching transistors 11 and 12 with built-in body diodes D1 and D2 having high-speed reverse recovery characteristics must be used, otherwise permanent burnout occurs in the circuit of the digital amplifier. Referring to (b) of FIG. 4, the body diode D2 of the lower switching transistor 12 is still open due to the slow reverse recovery characteristic at the time tA when the upper switching transistor 11 is turned on. The current flows in and the parts are damaged.

By the way, the field effect transistor made of Si material in which the body diode D2 having a high-speed reverse recovery characteristic is embedded has a breakdown voltage of approximately 200V or less. For this reason, most digital amplifiers are used only in applications where the driving voltage is 200V or less, and digital amplifiers cannot be used in high voltage applications, for example, applications where the driving voltage is about 400V. Of course, by changing the material of the transistor, for example, a transistor made of SiC (SiC-FET) or a transistor made of GaN (GaN-FET) has high breakdown voltage and excellent reverse recovery characteristics of a body diode. However, these are very expensive.

In addition, the digital amplifier kept heat generation low by using the switching transistor as a switching element rather than as an amplifying element. Since the switching loss is slightly lost only in the on-off transition period (transient period), even if the switching transistor is switched at a high frequency, for example, several hundred kHz, there is no problem. However, when the driving voltage increases, the switching loss increases in proportion to the increase, so that the heat generation of the digital amplifier increases. As a result, an additional heat dissipation means is required, and the advantage of the digital amplifier is lost.

Accordingly, there is a need for a technique capable of solving the problems of the prior art as described above by improving the circuit configuration of the digital amplifier.

An object of the present invention is to provide a technique for improving the reverse recovery characteristic of a switching transistor and lowering a voltage stress applied to the switching transistor in a digital amplifier (Class D amplifier) in general.

In particular, an object of the present invention is to reduce the voltage stress applied to the switching transistor during the switching operation by the PWM carrier signal by configuring the circuit of the digital amplifier in a multi-level method, thereby reducing the switching loss generated during switching. To provide a low voltage stress multilevel digital amplifier that improves reverse recovery characteristics through freewheeling diodes.

In order to achieve the above object, the multilevel digital amplifier of low voltage stress according to the present invention is sequentially connected in series, the upper first switching transistor 111 and the upper second switching transistor 112 connecting both ends of the digital amplifier driving power source. ) And a lower first switching transistor 121 and a lower second switching transistor 122; An inner loop capacitor 150 connecting the contact points of the upper first and second switching transistors 111 and 112 and the contact points of the lower first and second switching transistors 121 and 122; First and second inner loop diodes 161 and 162 respectively connected in forward and reverse directions to both ends of the inner loop capacitor 150 from the common potential of the digital amplifier driving power supply; And a low-pass filter inductor 130 and a low-pass filter capacitor 140 connected to the contact points of the upper second switching transistor 112 and the lower first switching transistor 121 to form a low-pass filter.

In addition, the multilevel digital amplifier of low voltage stress according to the present invention includes: a first freewheeling diode 171 for reversely connecting the final ends of the upper first and second switching transistors 111 and 112 connected in series; A second freewheeling diode 172 for reversely connecting the final ends of the lower first and second switching transistors 121 and 122 connected in series above may be further included.

At this time, the first inner loop diode 161 is connected in a forward direction from the common potential of the digital amplifier driving power to the contact points of the upper first and second switching transistors 111 and 112, and the second inner loop diode 162 is digital It is preferable that it is configured to reversely connect to the contact points of the lower first and second switching transistors 121 and 122 from the common potential of the amplifier driving power supply.

In addition, the upper first and second switching transistors 111 and 112 and the lower first and second switching transistors 121 and 122 are field effect transistors (Si-FETs) made of Si material having a body diode having a slow reverse recovery characteristic. It can be composed of.

According to the present invention, not only can the digital amplifier be applied to high voltage applications by lowering the voltage stress of the switching transistor, but also the Si-FET component element having a body diode with slow reverse recovery characteristics can be applied to the digital amplifier, thereby lowering the product price. It has the advantage of securing flexibility in product design. In addition, since the voltage stress of the switching transistor is low, switching loss generated during switching can be reduced, thereby having advantageous advantages in terms of efficiency and heat generation.

[Figure 1] is a schematic configuration diagram of a general digital amplifier.
[Fig. 2] is a waveform graph when there is no input signal in a digital amplifier.
[Fig. 3] is a waveform graph when there is an input signal in a digital amplifier.
[Fig. 4] is a diagram showing an equivalent circuit configuration and a current signal of a digital amplifier according to the prior art.
[Fig. 5] is a diagram showing a circuit configuration of a multilevel digital amplifier according to the present invention.
6 is a diagram showing an internal signal loop corresponding to PWM level switching of a driving power supply in a multilevel digital amplifier of the present invention.
[Fig. 7] is a diagram showing the concept of reducing the switching loss of a digital amplifier in the present invention.
8 is a diagram conceptually showing the role of a freewheeling diode in the multilevel digital amplifier of the present invention.
9 is a diagram showing a conduction path of an operating current configured by a freewheeling diode in a reverse recovery process in a multilevel digital amplifier of the present invention.
[Fig. 10] is a diagram showing a general method of externally connecting a diode to a switching transistor in the prior art.
[Fig. 11] is an operation waveform showing the role of the freewheeling diode in the multilevel digital amplifier according to the present invention.
12 is a diagram showing an operation waveform through a simulation of a multi-level digital amplifier according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

[Fig. 5] is a diagram showing a circuit configuration of a multilevel digital amplifier 100 according to the present invention, and [Fig. 6] is a diagram showing an internal signal loop corresponding to PWM level switching of a driving power supply in the present invention.

The circuit configuration of [Fig. 5] is made to have the following advantages over the prior art in implementing a digital amplifier. First, by reducing the voltage stress applied to the switching transistor, the digital amplifier can be used in high voltage applications, and the switching loss of the switching transistor is also reduced, thereby reducing heat generation of the digital amplifier. In addition, by specially connecting a separate freewheeling diode with excellent reverse recovery characteristics to the switching transistor, it is possible to construct a digital amplifier using a field effect transistor (Si-FET) made of Si material, which generally has a body diode with slow reverse recovery characteristics. To be able to.

First, referring to [Fig. 5], four switching transistors 111, 112, 121, and 122 are connected in series to connect both ends of the digital amplifier driving power supply. Among them, the upper switching transistor based on the output terminal connected to the LC low-pass filter (130, 140) is called the upper first switching transistor 111 and the upper second switching transistor 112, and the lower switching transistor Is referred to as a lower first switching transistor 121 and a lower second switching transistor 122.

In addition, an inner loop capacitor Ccl 150 connects a contact point where the upper first and second switching transistors 111 and 112 meet and a contact point where the lower first and second switching transistors 121 and 122 meet.

Further, the first and second inner loop diodes Dcl1 and Dcl2 161 and 162 are connected in forward and reverse directions to both ends of the inner loop capacitor Ccl 150 from the common potential of the digital amplifier driving power supply, respectively. As shown in FIG. 5, the first inner loop diode Dcl1 161 is forwardly connected to the contact points of the upper first and second switching transistors 111 and 112 from a common potential of the digital amplifier driving power source, and The loop diode Dcl2 162 is reversely connected to the contact points of the lower first and second switching transistors 121 and 122 from the common potential of the digital amplifier driving power supply.

In this case, a contact point where the source terminal of the upper second switching transistor 112 and the drain terminal of the lower first switching transistor 121 meet constitutes the output terminals of the switching transistor circuits 111 to 122.

Like the prior art, a low-pass filter inductor (Lf; 130) constituting a low-pass filter (LPF) to remove the switching frequency component and pass only the frequency component of the analog input signal at the output terminal of the switching transistor circuits 111 to 122, and The low pass filter capacitor Cf 140 is connected.

Further, first and second freewheeling diodes 171 and 172 are provided from this output terminal to the final ends of the upper switching transistors 111 and 112 and the lower switching transistors 121 and 122. That is, the first freewheeling diode 171 connects the upper first and second switching transistors 111 and 112 connected in series in reverse direction to each other. Likewise, the second freewheeling diode 172 reversely connects the final ends of the lower first and second switching transistors 121 and 122 connected in series.

These first and second freewheeling diodes 171 and 172 neutralize the body diodes D11 to D22 built in the switching transistors 111 to 122, as described later with reference to [Fig. 8] and [Fig. 9]. It was installed to do. That is, the body diodes D11 to D22 do not function due to these freewheeling diodes 171 and 172. Accordingly, the switching transistors 111 to 122 do not have to have a fast reverse recovery characteristic, and even if a device composed of, for example, a field effect transistor (Si-FET) made of Si material having a body diode having a slow reverse recovery characteristic is adopted. It's okay.

6 shows the inner loop of the digital amplifier circuit according to the present invention corresponding to the PWM level switching of the driving power supply. [Fig. 6] (a) and (b) show the charging paths of the inner loop capacitor Cc1 according to the operation of the switching transistor. For each case, the internal loop capacitor Cc1 indicated by a thick line in [Fig. 6] A loop is formed. In the present invention, high voltage applications of 100V or higher are the main concern, so the voltage drop in the turn-on state Vds of the switching transistors 111 and 122 having a value within 1.0V and the forward voltage of the inner loop diodes Dcl1, Dcl2; 161, 162 The descent Vf is ignored for convenience.

If you follow the inner loop indicated by the thick line in (a) and (b) of Fig. 6, it can be seen that in both cases, the voltage Vcl at both ends of the inner loop capacitor Ccl becomes the same as the driving voltage Vin. That is, among the four switching transistors 111 to 122 connected in series, the driving voltage Vin is always applied to the two switching transistors 112 and 121 located inside, and if so, the same analysis as previously described with reference to FIG. 4 The voltage stress applied to the internal switching transistors 112 and 121 through the process becomes Vin.

As described above, in the present invention, a series of switching transistors 111 to 122 connected in series are configured to share the driving voltage. Such a characteristic is referred to herein as'multilevel'.

While the voltage stress applied to the switching transistor in the prior art was Vin, in the present invention, the voltage stress was reduced by half. Therefore, the circuit configuration of the present invention can be applied to a high voltage application field having twice the driving voltage by using the same switching transistor component compared to the prior art.

In addition, according to the present invention, it is possible to obtain an advantage of lowering the switching loss of a digital amplifier, and [Fig. 7] conceptually shows this. [Fig. 7] (a) and (b) show the switching loss occurring in one of the switching transistors 11 and 12 in the prior art of [Fig. 4], and (c) and (d) of [Fig. 7] In the present invention of [Fig. 5], it shows the switching loss occurring in one of the switching transistors 111 to 122. As the voltage stress is reduced by half, it can be expected that the switching loss of one switching transistor is intuitively reduced to (1/4).In the present invention, since the number of switching transistors is doubled, the switching loss of the digital amplifier is ( 1/2) can be expected.

Even if this is calculated mathematically, the same result can be obtained. The switching loss occurring in the digital amplifier 10 of the prior art of [Fig. 4] can be expressed by [Equation 1], and the switching loss occurring in the digital amplifier 100 of the present invention of [Fig. 5] is [math It can be represented by Equation 2]. At this time, Cds represents the capacitance of the output capacitor inherent in the switching transistor. Comparing [Equation 1] and [Equation 2], it can be seen that the switching loss is reduced to (1/2) according to the present invention.

[Fig. 8] is a diagram conceptually showing the role of the freewheeling diode in the multilevel digital amplifier 100 of the present invention, and [Fig. 9] is a freewheeling in the reverse recovery process in the multilevel digital amplifier 100 of the present invention It is a diagram showing the conduction path of the operating current constituted by the diodes Dfw1, Dfw2; 171, 172.

Referring to the circuit diagram of [Fig. 5], in the present invention, a freewheeling diode is used to reversely connect the final ends of the upper switching transistors 111 and 112 and the lower switching transistors 121 and 122, each of which two transistors are connected in series. (freewheeling diode) (Dfw1, Dfw2; 171, 172) is preferably installed. These freewheeling diodes 171 and 172 are installed to disable the body diodes D11 to D22 built in the switching transistors 111 to 122.

Referring to FIG. 8, in the dead time period in which the reverse recovery current should flow, the reverse recovery current should flow through any one of these diodes D11, D12, and Dfw1. The path to the body diodes (D11, D12) is two times the positive voltage drop (Vf), that is, a voltage drop of 2Vf, because two diodes are connected in series, whereas the path to the freewheeling diode (Dfw1; 171) The voltage drop is only Vf. Accordingly, the reverse recovery current flows through the path of the freewheeling diode Dfw1 171 with a relatively low voltage drop and does not flow toward the body diodes D11 and D12 of the switching transistor.

[Fig. 9] is a diagram showing a signal loop of freewheeling diodes Dfw1 and Dfw2 171 and 172 in a reverse recovery process in the multilevel digital amplifier 100 of the present invention. In the reverse recovery process, no current flows through the body diodes D11 to D22, and current flows through the freewheeling diodes Dfw1, Dfw2; 171, 172.

As a result, as shown in FIG. 5, if the diode components 171 and 172 having excellent reverse recovery characteristics are connected to the outside, the switching transistors 111 to 122 do not have to have a fast reverse recovery characteristic. Therefore, although the reverse recovery characteristics of the body diodes present in the switching transistors 111 to 122 are bad, it is safe to adopt a device composed of a component having high breakdown voltage and low cost, for example, a field effect transistor (Si-FET) made of Si.

Meanwhile, even in the prior art, when the body diode characteristics of the switching transistor are unsatisfactory, there is an approach to solve by connecting a separate diode to the outside. 10 is a diagram showing a general approach of externally connecting a diode to a switching transistor in the prior art.

Referring to FIG. 10, in the prior art, when the body diode Da of the switching transistor is unsatisfactory, the blocking diode Db is connected to the drain terminal of the switching transistor in the reverse direction to block the function of the body diode Da. , And then an external diode (Dext) was connected to the outside.

In the prior art, there is not only the inconvenience of connecting the blocking diode (Db), but also the positive voltage drop caused by the blocking diode (Db) is added when the driving power is applied in the forward direction, and there is a conduction loss due to this. There is this. On the other hand, in the present invention, the path of the reverse recovery current is set to the external freewheeling diode by the forward voltage drop inherent in the switching transistor stacked in multilevels to share the voltage stress, so unlike the prior art, the blocking diode (Db) is used. There is no need to connect so that no such problem occurs.

[Fig. 11] is an operation waveform showing the role of a freewheeling diode in the multilevel digital amplifier 100 according to the present invention. Referring to FIG. 11, the current flow for reverse recovery is not through the body diodes D11 to D22 inside the switching transistors Q11 to Q22, but the freewheeling diodes Dfw1 and Dfw2 connected externally. It is shown that it is achieved through.

12 is a diagram showing an operation waveform through a simulation of the multilevel digital amplifier 100 according to the present invention.

For simulation conditions, the driving voltage Vin is ±70V, the output voltage Vout is 60V, and the total power capacity is designed to be 360W. Since the driving voltage Vin is ±70V, a voltage of 140V, which is effectively peak-to-peak (Vpp), is applied. From the simulation results of FIG. 12, it can be seen that the voltage stress applied to the switching transistors 111 and 122 is only (1/2) of the prior art, about 70V. According to the prior art of FIG. 4, a voltage twice as high as Vin, that is, 140V, which is a peak-to-peak voltage (Vpp), would have been applied to the switching transistor as a voltage stress. In addition, from the simulation results of [Fig. 12], it can be confirmed that a current flows through the freewheeling diode in the dead time period.

On the other hand, the present invention can be implemented in the form of a computer-readable code on a nonvolatile computer-readable recording medium. Various types of storage devices exist as such non-volatile recording media, such as hard disks, SSDs, CD-ROMs, NAS, magnetic tapes, web disks, and cloud disks, and codes are distributed and stored in multiple storage devices connected through a network. It can be implemented and executed. In addition, the present invention may be implemented in the form of a computer program stored in a medium in order to execute a specific procedure in combination with hardware.

100: digital amplifier
111, 112: upper switching transistor (Q11, Q12)
121, 122: lower switching transistor (Q21, Q22)
130: low pass filter inductor (Lf)
140: low pass filter capacitor (Cf)
150: inner loop capacitor (Ccl)
161, 162: inner loop diode (Dcl1, Dcl2)
171, 172: Freewheeling diode (Dfw1, Dfw2)

Claims (4)

An upper first switching transistor 111, an upper second switching transistor 112, a lower first switching transistor 121 and a lower second switching transistor 122 connected in series to connect both ends of the digital amplifier driving power supply;
An inner loop capacitor 150 connecting the contact points of the upper first and second switching transistors 111 and 112 and the contact points of the lower first and second switching transistors 121 and 122;
First and second inner loop diodes (161, 162) connected in forward and reverse directions to both ends of the inner loop capacitor 150 from a common potential of the digital amplifier driving power supply, respectively;
A low pass filter inductor 130 and a low pass filter capacitor 140 connected to the contact points of the upper second switching transistor 112 and the lower first switching transistor 121 to constitute a low pass filter;
Low voltage stress multi-level digital amplifier comprising a.
The method according to claim 1,
A first freewheeling diode 171 for reversely connecting the final ends of the upper first and second switching transistors 111 and 112 connected in series;
A second freewheeling diode 172 for reversely connecting the final ends of the lower first and second switching transistors 121 and 122 connected in series;
Multi-level digital amplifier of low voltage stress, characterized in that the configuration further comprises a.
The method according to claim 1,
The first inner loop diode 161 is forward-connected to the contact points of the upper first and second switching transistors 111 and 112 from a common potential of the digital amplifier driving power source,
The second inner loop diode 162 is configured to be connected in a reverse direction to the contact points of the lower first and second switching transistors 121 and 122 from a common potential of the digital amplifier driving power supply. Level digital amplifier.
The method according to claim 2,
The upper first and second switching transistors 111 and 112 and the lower first and second switching transistors 121 and 122 are field effect transistors (Si-FETs) made of Si material having a body diode having a slow reverse recovery characteristic. Low voltage stress multi-level digital amplifier, characterized in that consisting of.

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