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CN1567721A - PWM buffer circuit for regulating frequency and operating cycle of PWM signal - Google Patents

PWM buffer circuit for regulating frequency and operating cycle of PWM signal Download PDF

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CN1567721A
CN1567721A CN 03137360 CN03137360A CN1567721A CN 1567721 A CN1567721 A CN 1567721A CN 03137360 CN03137360 CN 03137360 CN 03137360 A CN03137360 A CN 03137360A CN 1567721 A CN1567721 A CN 1567721A
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cycle
working
pwm
signal
circuit
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CN 03137360
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CN1290260C (en )
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邱俊隆
黄文喜
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台达电子工业股份有限公司
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Abstract

The invention is a PWM buffer circuit, containing a working cycle converting circuit and a fixed frequency PWM signal generating circuit, where the converting circuit receives a first PWM signal and then generates a working cycle voltage reference based on a first working cycle of the first PWM signal, the working cycle voltage reference is a one-to-one mapping function of the first working cycle, and the generating circuit receives the voltage reference and then outputs a second PWM signal with a fixed frequency. A second working cycle of the second PWM signal is determined based on the working cycle voltage reference. Besides, the second working cycle is a one-to-one function of the working cycle voltage reference.

Description

调整PWM信号的频率与工作循环的PWM缓冲电路 Frequency and duty cycle of the PWM signal PWM to adjust the buffer circuit

技术领域 FIELD

本发明是关于一种应用于脉宽调制(Pulse Width Modulation,PWM)信号的缓冲电路,尤其关于一种用以调整PWM信号的频率与工作循环(Duty Cycle)的PWM缓冲电路。 The present invention relates to a buffer circuit applied to the pulse width modulation (Pulse Width Modulation, PWM) signals, particularly to a PWM signal for adjusting the frequency and the duty cycle (Duty Cycle) a PWM buffer circuit.

背景技术 Background technique

近年来,散热风扇马达的速度的控制方式主要是利用脉宽调制(Pulse Width Modulation,PWM)信号加以达成。 In recent years, the speed control of the motor cooling fan is to be reached mainly (Pulse Width Modulation, PWM) pulse width modulation signal. 图1显示使用现有`PWM控制方法的风扇马达的速度控制电路的电路区块图。 Figure 1 shows the speed of the fan motor using a conventional `PWM control method control circuit block diagram of the circuit. 参照图1,PWM信号产生单元10输出一PWM信号S1至驱动电路11。 Referring to FIG. 1, PWM signal generating unit 10 outputs a PWM signal S1 to the drive circuit 11. 基于PWM信号S1,驱动电路11输出一驱动信号A至风扇马达12,以此控制风扇马达12的速度。 Based on the PWM signals S1, driving circuit 11 outputs a drive signal A to the fan motor 12, thereby controlling the speed of the fan motor 12. 具体而言,PWM信号S1的一信号特征为所谓的「工作循环」,也即PWM信号S1的脉冲宽度与周期的比率。 Specifically, a signal wherein the PWM signal S1 is a so-called "duty cycle", i.e. the ratio of pulse width to the period of the PWM signal S1. 兹假设在图1中PWM信号S1的工作循环由符号D1所表示。 Hereby represented by the symbol D1 is assumed that during the working cycle of the PWM signal S1 in FIG. 在前述现有`的PWM控制方法中,当PWM信号S1的工作循环D1为相对大时,从驱动电路11所输出的驱动信号A可使风扇马达12以相对高的速度运转;而当PWM信号S1的工作循环D1为相对小时,从驱动电路11所输出的驱动信号A可使风扇马达12以相对低的速度运转。 In the conventional PWM control method ', when the duty cycle of the PWM signal S1 D1 is relatively large, the drive signal A output from the drive circuit 11 allows the fan motor 12 is operated at a relatively high speed; and when the PWM signal S1 duty cycle D1 is relatively small, the drive signal a output from the drive circuit 11 allows the fan motor 12 is operated at a relatively low speed.

现有`的PWM控制方法具有至少两项缺点。 `Conventional PWM control method has at least two disadvantages. 第一项缺点是所利用的PWM信号S1的频率必须为相对高,例如高于10kHz。 The first disadvantage is the frequency of the PWM signal S1 is utilized must be relatively high, for example greater than 10kHz. 当PWM信号S1的频率低于10kHz时,风扇马达12的操作会受到由开关噪声(Switching Noise)所造成的不良影响。 When the frequency of the PWM signal S1 is lower than 10kHz, the operation of the fan motor 12 will be adversely affected by the switching noise (Switching Noise) caused. 第二项缺点是所利用的PWM信号S1的工作循环D1必须限制在30%至85%的范围间,以确保驱动电路11与风扇马达12可由PWM信号S1适当地控制。 The second drawback is that the PWM signal S1 D1 utilized duty cycle must be limited to a range between 30-85% in order to ensure proper control driving circuit 11 and the fan motor 12 by PWM signal S1.

发明内容 SUMMARY

有鉴于前述问题,本发明的一目的在于提供一种PWM缓冲电路,设置在风扇马达的速度的控制电路中,用以扩大身为控制信号的PWM信号的可应用的频率的范围。 In view of the foregoing problems, an object of the present invention is to provide a PWM buffer circuit provided in the control circuit of the speed of the fan motor to expand the range of the frequency control signal as a PWM signal may be applied.

本发明的一目的在于提供一种PWM缓冲电路,设置在风扇马达的速度的控制电路中,用以扩大身为控制信号的PWM信号的可应用的工作循环的范围。 An object of the present invention is to provide a PWM buffer circuit provided in the control circuit of the speed of the fan motor, as a control signal to expand the scope of the duty cycle of the PWM signal may be applied.

依据本发明的一方面,提供一种PWM缓冲电路,包含一工作循环转换电路与一固定频率PWM信号产生电路。 According to an aspect of the present invention, there is provided a PWM buffer circuit comprises a converter circuit and the duty cycle of a fixed frequency PWM signal generating circuit. 工作循环转换电路是用以接收一第一PWM信号,然后基于该第一PWM信号的一第一工作循环而产生一工作循环参考电压。 Duty cycle is a duty cycle converter circuit for receiving a first reference voltage PWM signal, and then based on a first duty cycle of the first PWM signal is generated. 工作循环参考电压为第一工作循环的一对一映像函数。 Duty cycle reference voltage is one mapping function of the first duty cycle. 固定频率PWM信号产生电路是用以接收工作循环参考电压,然后输出具有一固定频率的一第二PWM信号。 Fixed frequency PWM signal generating circuit is configured to receive the duty cycle of the reference voltage and outputs a second PWM signal having a fixed frequency. 第二PWM信号的一第二工作循环是基于工作循环参考电压而决定,并且第二工作循环为工作循环参考电压的一对一映像函数。 A second duty cycle of the second PWM signal is the duty cycle based on one mapping function determines the reference voltage, and the second duty cycle is a duty cycle of the reference voltage.

依据本发明的另一方面,提供一种风扇马达的速度控制电路,包含一PWM信号产生单元、一PWM缓冲电路、一驱动电路、以及一风扇马达。 According to another aspect, there is provided a fan motor speed control circuit according to the present invention, comprises a PWM signal generating unit, a PWM buffer circuit, a driver circuit, and a fan motor. PWM信号产生单元是用以产生具有一第一工作循环的一第一PWM信号。 PWM signal generating unit is configured to generate a first PWM signal having a first duty cycle. PWM缓冲电路是连接到PWM信号产生单元,用以将第一PWM信号转换成具有一固定频率与一第二工作循环的一第二PWM信号。 PWM buffer circuit is connected to the PWM signal generating unit to the first PWM signal into a second PWM signal having a fixed frequency and a second operating cycle. 驱动电路是连接到PWM缓冲电路,用以基于第二PWM信号而输出一驱动信号。 PWM driver circuit is connected to a buffer circuit for outputting a driving signal based on the second PWM signal. 风扇马达是连接到驱动电路,其速度由驱动信号所控制。 Fan motor is connected to a drive circuit, which is controlled by the driving speed signal.

在本发明的一较佳实施例中,可使第一PWM信号的频率大于30Hz且第一工作循环位于5%至95%的范围之内。 In a preferred embodiment of the present invention, it allows the frequency of the first PWM signal is greater than 30Hz and the duty cycle is within a first range of 5% to 95% of. 因此,依据本发明的PWM缓冲电路可设置在风扇马达的速度的控制电路中,用以扩大控制信号的PWM信号的可应用的频率的范围,并且扩大控制信号的PWM信号的可应用的工作循环的范围。 Thus the duty cycle can be applied, based on PWM buffer circuit according to the present invention may be provided in the fan motor speed control circuit, the application range of the PWM signal to expand the frequency control signal, and enlarges the PWM signal of the control signal range.

附图说明 BRIEF DESCRIPTION

图1显示使用现有`PWM控制方法的风扇马达的速度控制电路的电路区块图。 Figure 1 shows the speed of the fan motor using a conventional `PWM control method control circuit block diagram of the circuit.

图2显示设置有依据本发明的PWM缓冲电路的风扇马达的速度控制电路的电路区块图。 Figure 2 shows a block diagram of a circuit provided with a speed of the fan motor according to a PWM circuit of the present invention, the buffer control circuit.

图3显示依据本发明的PWM缓冲电路的详细电路区块图。 3 shows a detailed circuit block diagram of the PWM buffer circuit according to the present invention.

图4(a)显示工作循环参考电压V1为PWM信号S1的工作循环D1的一对一映像函数。 FIG. 4 (a) show the working cycle of the reference voltage V1 duty cycle of the PWM signal S1 D1 to-one mapping function.

图4(b)显示PWM信号S2的工作循环D2为工作循环参考电压V1的一对一映像函数。 FIG. 4 (b) show the duty cycle of the PWM signal S2 is a one to one mapping function D2 duty cycle of the reference voltage V1.

图5显示依据本发明的PWM缓冲电路的具体电路组态的一例子。 5 shows an example of a specific circuit PWM buffer circuit according to the present invention is configured.

具体实施方式 detailed description

下文中的说明与附图将使本发明的前述与其它目的、特征、与优点更明显。 The foregoing will hereinafter be described with the accompanying drawings of the present invention and other objects, features, and advantages of the more obvious. 兹将参照图示详细说明依据本发明的较佳实施例。 Hereby will be illustrated with reference to detailed description of the preferred embodiments according to the present invention.

图2显示设置有依据本发明的PWM缓冲电路20的风扇马达的速度控制电路的电路区块图。 Figure 2 shows a block diagram of a circuit provided with a circuit according to the speed of the fan motor PWM circuit of the present invention, the buffer controller 20. 参照图2,本发明不同于图1所示的现有技术之处在于本发明设置一PWM缓冲电路20在PWM信号产生单元10与驱动电路11间,使得从PWM信号产生单元10所输出的PWM信号S1经由PWM缓冲电路20转换成PWM信号S2之后才输入至驱动电路11。 Referring to FIG 2, the prior art of the present invention is different from those shown in FIG. 1 in that the present invention is provided with a buffer circuit 20 PWM PWM signal generating unit 10 and the driving circuit 11, so that the PWM from the PWM signal generating unit 10 output only after the input to the drive circuit 11 to a PWM signal S1 into signal S2, the buffer circuit 20 via the PWM. 随后,基于PWM信号S2,驱动电路11输出一驱动信号B至风扇马达12。 Then, based on the PWM signal S2, the drive circuit 11 outputs a drive signal B to the fan motor 12.

具体地说,PWM缓冲电路20使具有工作循环D1与频率F1的PWM信号S1转换成具有工作循环D2与频率F2的PWM信号S2。 Specifically, the buffer circuit 20 PWM of the PWM signal S1 having a duty cycle D1 and converted into a frequency F1 and the frequency of the PWM duty cycle D2 of the signal S2 F2. 在本发明中,PWM信号S2的工作循环D2与频率F2是设计成位于可在不造成开关噪声的情况下确保风扇马达的速度受到适当的控制的数值范围内。 In the present invention, the duty cycle D2 and F2 of the frequency of the PWM signal S2 is designed to be positioned to ensure that the speed of the fan motor by the appropriate control value range without causing the switching noise. 因而,借着此种组态,即使PWM信号S1的工作循环D1与频率F1并非位于可使风扇马达执行适当操作的应用范围内,由于驱动电路11是接收经过PWM缓冲电路20转换的PWM信号S2,故仍可在不造成开关噪声的情况下确保风扇马达12的速度受到适当的控制。 Thus, by this configuration, even if the duty cycle of the PWM signal S1 and the frequency F1 D1 is not located within the application range of the fan motor can perform proper operation, since the driving circuit 11 is PWM signal S2 received through the buffer circuit 20 converts the PWM , it can ensure the speed of a fan motor 12 are properly controlled without causing switching noise. 换言之,依据本发明的PWM缓冲电路20设置在风扇马达的速度控制电路中,达成扩大控制信号的PWM信号的可应用的频率的范围,并且扩大控制信号的PWM信号的可应用的工作循环的范围。 In other words, based on 20 sets the PWM buffer circuit according to the present invention the speed of the fan motor control circuit, to achieve the applicable range of frequencies enlargement control signal, PWM signal, and expand the scope of the duty cycle may be applied PWM signal of the control signal .

在图1所示的现有技术的PWM控制方法中,PWM信号S1的频率必须高于10kHz且工作循环D1必须限制在30%至85%的范围之内。 In the prior art method of PWM control shown in FIG. 1, the frequency of the PWM signal S1 must be greater than 10kHz and a duty cycle D1 must be limited in range of 30% to 85% of. 在本发明的一实施例中,PWM缓冲电路20可使具有频率大于30Hz且工作循环在5%至95%范围之间的PWM信号S1转换成具有频率F2大于10kHz的PWM信号S2。 In an embodiment of the present invention, the buffer circuit 20 may have the PWM frequency is greater than 30Hz and the duty cycle of the PWM signal S1 between the range of 5% to 95% is converted into a PWM signal S2 having frequency F2 is greater than 10kHz. 因此,借着依据本发明的PWM缓冲电路20,PWM信号S1的可应用的频率的范围扩大成大于30Hz且可应用的工作循环的范围扩大成5%至95%范围之间。 Thus, by the scope of the present invention based on the PWM buffer circuit 20, the frequency range of the PWM signal S1 may be applied to expand to be larger than the duty cycle of 30Hz and may be applied to expand the range of 5-95%.

图3显示依据本发明的PWM缓冲电路20的详细电路区块图。 3 shows a detailed circuit block diagram of PWM buffer circuit 20 according to the present invention. 参照图3,PWM缓冲电路20包括一工作循环转换电路21与一固定频率PWM信号产生电路22。 Referring to FIG. 3, PWM buffer circuit 20 includes a converting circuit 21 and the duty cycle of a fixed frequency PWM signal generating circuit 22. 具体地说,工作循环转换电路21接收PWM信号S1,然后基于PWM信号S1的工作循环D1而产生一工作循环参考电压V1。 Specifically, the duty cycle of the conversion circuit 21 receives the PWM signal S1, and then based on the duty cycle of the PWM signal S1 to generate a duty cycle D1 and a reference voltage V1. 换言之,工作循环参考电压V1为PWM信号S1的工作循环D1的一对一映像函数(one-to-one mapping function),如图4(a)所示。 In other words, the duty cycle of the reference voltage V1 of the duty cycle of the PWM signal S1 and D1-one mapping function (one-to-one mapping function), FIG. 4 (a) shown in FIG. 固定频率PWM信号产生电路22接收工作循环参考电压V1,然后基于工作循环参考电压V1而决定PWM信号S2的工作循环D2。 Fixed frequency signal generating circuit 22 receives the PWM duty cycle of the reference voltage V1, then the duty cycle based on the reference voltage V1 is determined duty cycle of the PWM signal S2 D2. 换言之,PWM信号S2的工作循环D2为工作循环参考电压V1的一对一映像函数,如图4(b)所示。 In other words, the duty cycle of the PWM signal S2 a duty cycle D2 of the reference voltages V1-one mapping function of FIG. 4 (b) shown in FIG. 综上所述,为了将工作循环D1转换成工作循环D2,PWM缓冲电路20在第一阶段时先利用工作循环转换电路21将工作循环D1转换成工作循环参考电压V1,随后在第二阶段时利用固定频率PWM信号产生电路22将工作循环参考电压V1转换成工作循环D2。 In summary, in order to convert the duty cycle of the duty cycle D1 to D2, PWM circuit 20 in the first buffer stage using a first duty cycle converter circuit 21 converts the duty cycle to the duty cycle of the reference voltage D1 V1, then in the second stage when using fixed frequency PWM signal generating circuit 22 converts the reference voltage V1 to the duty cycle of the duty cycle D2.

此外,不论工作循环参考电压V1的大小,固定频率PWM信号产生电路22仅产生具有一固定频率的PWM信号S2。 Further, regardless of the size of the duty cycle of the reference voltage V1, a fixed frequency PWM signal generating circuit 22 generates a PWM signal S2 has only a fixed frequency. 因此可将固定频率PWM信号产生电路22设计成输出具有频率F2的PWM信号S2,其中频率F2是足够大以避免开关噪声的产生。 Thus a fixed frequency PWM signal generating circuit 22 may be designed to output a PWM signal S2 having a frequency F2, where F2 is a frequency sufficient to avoid switching noise.

在本发明的一实施例中,固定频率PWM信号产生电路22得由一微芯片控制单元(Microchip Control Unit)加以实施,其中该微芯片控制单元是经由软件程序的设定而执行前述依据本发明的功能。 In an embodiment of the present invention, a fixed frequency PWM signal generating circuit 22 have to be implemented by a microchip control unit (Microchip Control Unit), wherein the control unit is a microchip according to the present invention is performed via a set of software programs function. 在本发明的另一实施例中,固定频率PWM信号产生电路22包括有一频率控制器23与一PWM信号产生器24,如图3所示。 In another embodiment of the present invention, a fixed frequency PWM signal generating circuit 22 comprises a frequency controller 23 and a PWM signal generator 24, as shown in FIG. 具体地说,频率控制器23提供一频率控制信号FC,用以决定PWM信号产生器24所产生的PWM信号S2的频率。 Specifically, the frequency controller 23 provides a control signal to the FC frequency, for determining the frequency of the PWM signal S2, a PWM signal generated by the generator 24. 基于从工作循环转换电路21而来的工作循环参考电压V1以及从频率控制器23而来的频率控制信号FC,PWM信号产生器24产生具有工作循环D2与频率F2的PWM信号S2。 Duty cycle based on the operating cycle from the conversion circuit 21 from the reference voltage V1 and the frequency control signal FC from the controller 23, the PWM signal generator 24 generates a PWM signal having a duty cycle D2 and S2 frequency F2.

图5显示依据本发明的PWM缓冲电路20的具体电路组态的一例子。 5 shows an example of a specific circuit according to the present invention, the PWM buffer circuit 20 is configured. 参照图5,工作循环转换电路21包括一晶体管Q1、复数个电阻R1至R5、一个二极管Dd1、一电容C1、以及一操作放大器OA1。 Referring to FIG. 5, the duty cycle converter circuit 21 comprises a transistor Q1, a plurality of resistors R1 to R5, a diode Dd1, a capacitor C1, and an operational amplifier OA1. 频率控制器23包括复数个电阻R6至R8、一电容C2、以及一操作放大器OA2。 The controller 23 comprises a frequency R6 to R8, a capacitor C2, and an operational amplifier OA2 plurality of resistors. PWM信号产生器24包括一操作放大器OA3以及一电阻R9。 The PWM signal generator 24 includes an operational amplifier OA3 and a resistor R9.

具体地说,晶体管Q1之栅极用以接收PWM信号S1、其漏极经由电阻R1而连接至一电压源VDD、且其源极接地。 Specifically, the gate of the transistor Q1 for receiving the PWM signals S1, its drain is connected via a resistor R1 to a voltage source VDD, and its source is grounded. 二极管Dd1的P极电连接到晶体管Q1的漏极,且其N极电连接到操作放大器OA1的非反相(Non-inverting)输入端。 P diode Dd1 is electrically connected to the drain of the transistor Q1, and the N pole is electrically connected to the non-inverting (Non-inverting) input terminal of the operation amplifier OA1. 电阻R2与电容C1都电连接到二极管Dd1的N极与地面间。 Resistor R2 and the capacitor C1 are electrically connected to the diode Dd1 between the N pole and the ground. 电阻R3电连接到操作放大器OA1的反相(Inverting)输入端与地面间。 Resistor R3 is electrically connected to the inverting operational amplifier OA1 between (Inverting) input terminal and ground. 电阻R4电连接到操作放大器OA1的输出端与地面间。 Resistor R4 is electrically connected to the output terminal of operational amplifier OA1 and the ground between. 操作放大器OA1的输出端经由电阻R5而输出工作循环参考电压V1至操作放大器OA3的非反相输入端。 The output terminal of the operation amplifier OA1 via the resistor R5 to output the duty cycle of the reference voltages V1 to the non-inverting input terminal of the operation of the amplifier OA3.

电阻R6电连接到操作放大器OA2的非反相输入端与地面间。 Resistor R6 is electrically connected to the non-inverting input terminal and the ground of the operational amplifier OA2. 电阻R7电连接到操作放大器OA2的非反相输入端与输出端间。 Electrically connected between the resistor R7 to the non-inverting input terminal and the output terminal of the operational amplifier OA2. 电容C2电连接到操作放大器OA2的反相输入端与地面间。 Between capacitor C2 is electrically connected to the inverting input of operational amplifier OA2 and the ground. 电阻R8电连接到操作放大器OA2的反相输入端与输出端间。 Between resistor R8 is electrically connected to the operational amplifier OA2 inverting input terminal and the output terminal. 通过此组态,操作放大器OA2的输出端经由电阻R8而输出频率控制信号FC至操作放大器OA3的反相输入端。 By this configuration, the output terminal of operational amplifier OA2 via resistor R8 and outputs the frequency control signal FC to the inverting input of the operational amplifier OA3. 在图5所示的例子中,频率控制信号FC为具有频率f的三角波连续信号,其中:f=12R8C2ln(1+2R6R7).]]>响应于在操作放大器OA3的非反相输入端所接收的工作循环参考电压V1以及在操作放大器OA3的反相输入端所接收的频率控制信号FC,操作放大器OA3的输出端经由电阻R9输出PWM信号S2。 In the example shown in FIG. 5, the frequency control signal FC is a signal having a continuous triangular wave frequency f, where: f = 12R8C2ln (1 + 2R6R7)]]> received in response to the non-inverting input of the operational amplifier OA3. the output of the duty cycle of the reference frequency and the voltage V1 at the inverting input of operational amplifier OA3 to the received control signal FC, OA3 operational amplifier via a resistor R9 PWM output signal S2. 具体地说,操作放大器OA3作用如同一电压比较器,使得当工作循环参考电压V1大于频率控制信号FC的电压电平时,操作放大器OA3输出PWM信号S2的高电平状态,而当工作循环参考电压V1小于频率控制信号FC的电压电平时,操作放大器OA3输出PWM信号S2的低电平状态。 Specifically, the operational amplifier OA3 acts as a voltage comparator, such that when voltage V1 is greater than the duty cycle of the reference voltage level, operational amplifier OA3 high state of the PWM signal S2 output frequency control signal FC, and when the duty cycle of the reference voltage V1 is less than the voltage of the frequency control signal FC level, the operation amplifier OA3 low state PWM output signal S2. 借着此种方式,PWM信号产生器24将工作循环参考电压V1转换成工作循环D2。 By this way, PWM signal generator 24 converts the duty cycle of the duty cycle of the reference voltages V1 to D2. 此外,PWM信号产生器24所产生的PWM信号S2的频率F2等于频率控制信号FC的频率f。 Further, the PWM signal S2, the PWM signal generator 24 generates a frequency F2 equal to frequency control signal FC of the frequency f.

虽然本发明业已通过较佳实施例作为例示加以说明,应了解者为:本发明不限于此被揭露的实施例。 The present invention is not limited to the embodiment disclosed herein is: While the illustrated embodiment of the present invention as will be described, it is understood by those of preferred embodiments have been. 相反地,本发明意欲涵盖对于熟悉此项技术的人士而言是明显的各种修改与相似配置。 Rather, the invention is intended to cover for those skilled in the art that various modifications will be apparent to a similar configuration. 因此,申请专利权利要求的范围应根据最广的诠释,以包容所有此类修改与相似配置。 Accordingly, the scope of patent claims should be based on the broadest interpretation so as to encompass all such modifications and similar configurations.

Claims (12)

1.一种脉宽调制缓冲电路,其特征在于:所述电路包含:一工作循环转换电路,用以接收一第一脉宽调制信号,然后基于该第一脉宽调制信号的一第一工作循环而产生一工作循环参考电压,其中该工作循环参考电压为该第一工作循环的一对一映像函数,以及一固定频率脉宽调制信号产生电路,连接到工作循环转换电路,该用以接收该工作循环参考电压,然后输出具有一固定频率的一第二脉宽调制信号,其中该第二脉宽调制信号的一第二工作循环是基于该工作循环参考电压而决定,并且该第二工作循环为该工作循环参考电压的一对一映像函数。 A pulse width modulation buffer circuit, characterized in that: said circuit comprises: a duty cycle conversion circuit for receiving a first pulse width modulated signal, and a first operation of the pulse width modulated signal based on a first generating a duty cycle cycle reference voltage, wherein the duty cycle of the mapping function of the first reference voltage one working cycle, and a fixed frequency pulse width modulation signal generating circuit, connected to the duty cycle for the converter circuit, for receiving the the duty cycle of the reference voltage, and outputting a second PWM signal having a fixed frequency, wherein the second duty cycle of a second PWM signal based on the determined duty cycle of the reference voltage, and the second work duty cycle for one cycle of the reference voltage mapping function.
2.如权利要求1所述的脉宽调制缓冲电路,其特征在于:该工作循环转换电路包括:一晶体管,其栅极用以接收该第一脉宽调制信号且其源极接地;一第一电阻,连接到该晶体管的漏极与一电压源VDD间;一个二极管,其P极电连接到该晶体管的该漏极;一第二电阻,连接到该二极管的N极与地面间;一第一电容,连接到该二极管的N极与地面间;一第一操作放大器,其非反相输入端连接到该二极管的N极;一第三电阻,连接到该第一操作放大器的反相输入端与地面间;一电四电阻,连接到该第一操作放大器的反相输入端与该第一操作放大器的输出端间;以及一第五电阻,连接到该第一操作放大器的该输出端与该固定频率脉宽调制信号产生电路间。 2. The buffer circuit of the pulse width modulation as claimed in claim 1, wherein: the duty cycle converter circuit comprising: a transistor having a gate receiving the first pulse width modulated signal and its source grounded; a second a resistor connected between the drain of the transistor to a voltage source and the VDD; a diode which is electrically connected to the P drain of the transistor; a second resistor connected between the N-pole of the diode and the ground; a a first capacitor connected between the N pole and the ground of the diode; a first operational amplifier, its non-inverting input terminal connected to the N pole of the diode; a third resistor, the first operational amplifier is connected to the inverting between the output of a four-resistor is electrically connected to the first operational amplifier and the inverting input terminal of the first operational amplifier;; and the ground and between the input terminal of a fifth resistor connected to the output of the first operational amplifier end of the fixed frequency of the PWM signal generating circuit between.
3.如权利要求1所述的脉宽调制缓冲电路,其特征在于:该固定频率脉宽调制信号产生电路是由一微芯片控制单元经由软件程序的设定而加以实施。 A pulse width modulation buffer circuit according to claim 1, wherein: the fixed frequency pulse width modulation signal generating circuit is composed of a microchip control unit implemented by the software program set.
4.如权利要求1所述的脉宽调制缓冲电路,其特征在于:该固定频率脉宽调制信号产生电路包括:一频率控制器,提供一频率控制信号,用以决定该第二脉宽调制信号的该固定频率,以及一脉宽调制信号产生器,连接到该工作循环转换电路与该频率控制器,响应于该工作循环参考电压与该频率控制信号而产生该第二脉宽调制信号。 4. The buffer circuit of the pulse width modulation as claimed in claim 1, wherein: the fixed frequency pulse width modulation signal generating circuit comprises: a frequency controller, the second pulse width modulated to provide a frequency control signal, for determining the fixed frequency signal, and a pulse width modulation signal generator, connected to the frequency controller, in response to the duty cycle of the reference voltage and the frequency control signal generated by the second duty cycle of the PWM signal converting circuit.
5.如权利要求4所述的脉宽调制缓冲电路,其特征在于:该频率控制器包括:一第二操作放大器,具有一非反相输入端、一反相输入端、与一输出端;一第六电阻,连接到该第二操作放大器的该非反相输入端与地面间;一第七电阻,连接到该第二操作放大器的该非反相输入端与该输出端间;一第二电容,连接到该第二操作放大器的该反相输入端与地面间;以及一第八电阻,连接到该第二操作放大器的该非反相输入端与该输出端间。 5. The pulse width modulation buffer circuit according to claim 4, wherein: the frequency controller comprises: a second operational amplifier having a non-inverting input, an inverting input terminal, and an output terminal; between a seventh resistor, the second operational amplifier connected to the non-inverting input terminal and the output terminal;; between a sixth resistor, the second operational amplifier connected to the non-inverting input terminal and a first ground m-capacitor connected to the second operational amplifier inverting input terminal and the ground; and an eighth resistor, the second operational amplifier connected to the non-inverting input terminal and the output terminal between.
6.如权利要求4所述的脉宽调制缓冲电路,其特征在于:该脉宽调制信号产生器包括:一第三操作放大器,其非反相输入端连接到该工作循环转换电路以接收该工作循环参考电压,且其反相输入端连接到该频率控制器以接收该频率控制信号,以及一第九电阻,其一端连接到该第三操作放大器的输出端使得该第二脉宽调制信号经由该第九电阻的另一端而输出。 6. The pulse width modulation buffer circuit according to claim 4, wherein: the PWM signal generator includes: a third operational amplifier, its non-inverting input connected to the duty cycle of the converter circuit to receive duty cycle reference voltage, and its inverting input connected to the frequency controller for receiving the frequency control signal, and a ninth resistor having one end connected to the third output terminal of the operational amplifier such that the second pulse width modulated signal output via the other end of the ninth resistor.
7.如权利要求4所述的脉宽调制缓冲电路,其特征在于:该频率控制信号是一个三角波连续信号。 7. The pulse width modulation buffer circuit according to claim 4, wherein: the frequency control signal is a continuous triangular wave signal.
8.如权利要求1所述的脉宽调制缓冲电路,其特征在于:该第一脉宽调制信号的频率是大于30Hz且该第一工作循环是位于5%至95%的范围间。 8. The buffer circuit of the pulse width modulation of claim 1, wherein: the first pulse width modulated signal is greater than the frequency of 30Hz and the duty cycle is first positioned between 5-95% range.
9.如权利要求1所述的脉宽调制缓冲电路,其特征在于:该第二脉宽调制信号的该固定频率是大于10kHz。 9. The pulse-width modulation buffer circuit according to claim 1, wherein: the second pulse width modulated signal to the fixed frequency greater than 10kHz.
10.一种风扇马达的速度控制电路,其特征在于:所述电路包含:一脉宽调制信号产生单元,用以产生一第一脉宽调制信号,该第一脉宽调制信号具有一第一工作循环;一脉宽调制缓冲电路,连接到该脉宽调制信号产生单元,用以将该第一脉宽调制信号转换成一第二脉宽调制信号,该第二脉宽调制信号具有一固定频率与一第二工作循环;以及一驱动电路,连接到该脉宽调制缓冲电路,用以基于该第二脉宽调制信号而输出一驱动信号至一风扇马达,以此控制该风扇马达的速度。 10. A fan motor speed control circuit, characterized in that: said circuit comprises: a pulse width modulation signal generation unit for generating a first pulse width modulated signal, the first signal having a first pulse width modulated duty cycle; a pulse width modulation buffer circuit connected to the PWM signal generating unit for the second pulse width modulated signal into a pulse width modulated signal into a first, a second pulse width modulated signal having a fixed frequency and a second duty cycle; and a driving circuit, a buffer connected to the PWM circuit for pulse width modulation signal based on the second output a driving signal to a fan motor, thereby controlling the speed of the fan motor.
11.如权利要求10所述的风扇马达的速度控制电路,其特征在于:该脉宽调制缓冲电路包括:一工作循环转换电路,用以接收该第一脉宽调制信号,然后基于该第一脉宽调制信号的该第一工作循环而产生一工作循环参考电压,其中该工作循环参考电压为该第一工作循环的一对一映像函数,以及一固定频率脉宽调制信号产生电路,连接到工作循环转换电路,用以接收该工作循环参考电压,然后输出该第二脉宽调制信号,其中该第二脉宽调制信号的该第二工作循环是基于该工作循环参考电压而决定,并且该第二工作循环为该工作循环参考电压的一对一映像函数。 11. The speed of the fan motor as claimed in claim 10, the control circuit, wherein: the PWM buffer circuit comprising: converting a duty cycle circuit for receiving the first pulse width modulation signal based on the first and the first duty cycle pulse width modulated signal to generate a reference voltage duty cycle, wherein the duty cycle of the mapping function of the first reference voltage one working cycle, and a fixed frequency for the PWM signal generating circuit, connected to duty cycle converter circuit for receiving the duty cycle of the reference voltage, and then outputs the second PWM signal, wherein the second duty cycle of the second PWM signal based on the duty cycle of the reference voltage is determined, and the second duty cycle for duty cycle-one mapping function reference voltage.
12.如权利要求10所述的风扇马达的速度控制电路,其特征在于:该固定频率脉宽调制信号产生电路包括:一频率控制器,提供一频率控制信号,用以决定该第二脉宽调制信号的该固定频率,以及一脉宽调制信号产生器,连接到该工作循环转换电路与该频率控制器,响应该工作循环参考电压与该频率控制信号而产生该第二脉宽调制信号。 12. The speed of the fan motor as claimed in claim 10, the control circuit, characterized in that: the fixed frequency pulse width modulation signal generating circuit comprises: a frequency controller, there is provided a frequency control signal, the second pulse for determining the fixed-frequency modulation signal, and a pulse width modulation signal generator, connected to the frequency controller, in response to the duty cycle of the reference voltage and the frequency control signal generated by the second duty cycle of the PWM signal converting circuit.
CN 03137360 2003-06-19 2003-06-19 PWM buffer circuit for regulating frequency and duty ratio of PWM signal CN1290260C (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100512003C (en) 2005-11-02 2009-07-08 中国科学院沈阳自动化研究所 Pulse generation device with variable frequencies and duty ratio
CN100582985C (en) 2006-12-19 2010-01-20 台达电子工业股份有限公司 Method and device for regulating signal measuring sensitiveness
WO2013138990A1 (en) * 2012-03-20 2013-09-26 Texas Instruments Incorporated Pwm duty cycle synthesizer and method with adjustable corner frequency
CN102084592B (en) 2008-04-18 2014-04-23 努吉拉有限公司 Improved pulse width modulation
CN103944381A (en) * 2014-03-27 2014-07-23 重庆四联光电科技有限公司 Voltage output circuit based on PWM control

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100512003C (en) 2005-11-02 2009-07-08 中国科学院沈阳自动化研究所 Pulse generation device with variable frequencies and duty ratio
CN100582985C (en) 2006-12-19 2010-01-20 台达电子工业股份有限公司 Method and device for regulating signal measuring sensitiveness
CN102084592B (en) 2008-04-18 2014-04-23 努吉拉有限公司 Improved pulse width modulation
WO2013138990A1 (en) * 2012-03-20 2013-09-26 Texas Instruments Incorporated Pwm duty cycle synthesizer and method with adjustable corner frequency
US8836396B2 (en) 2012-03-20 2014-09-16 Texas Instruments Incorporated PWM duty cycle synthesizer and method with adjustable corner frequency
CN104254974B (en) * 2012-03-20 2017-05-17 德克萨斯仪器股份有限公司 Pwm duty cycle it is having a variable synthesizer and a method of the corner frequency
CN103944381A (en) * 2014-03-27 2014-07-23 重庆四联光电科技有限公司 Voltage output circuit based on PWM control

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