技术领域technical field
本实用新型涉及开关电源及半导体技术领域，特别涉及一种对开关电源 (SMPS)的充电电缆产生的电压降进行补偿的电缆电压补偿电路。The utility model relates to the field of switching power supply and semiconductor technology, in particular to a cable voltage compensation circuit for compensating the voltage drop generated by a charging cable of a switching power supply (SMPS).
背景技术Background technique
开关电源技术主要是通过功率变换器来实现电能的变换，不需要使用工频变压器，具有体积小、重量轻的优点，被广泛应用于LED照明、通讯设备、消费类电子等领域。Switching power supply technology mainly realizes the transformation of electric energy through power converters, and does not need to use power frequency transformers. It has the advantages of small size and light weight, and is widely used in LED lighting, communication equipment, consumer electronics and other fields.
开关电源通常向输出提供恒定电流(CC模式)或者恒定电压(CV模式)，恒定电流或者恒定电压输出都是通过检测负载状态实现的。负载状态检测一般有两种方法：副边控制(SSR)和原边控制(PSR)。Switching power supplies usually provide constant current (CC mode) or constant voltage (CV mode) to the output, and the constant current or constant voltage output is realized by detecting the load status. There are generally two methods for load status detection: secondary side control (SSR) and primary side control (PSR).
副边控制通常通过光耦反馈负载状态，可以直接反映负载的状态。副边控制是抗干扰能力、工作稳定性和传输效率等方面有很大的优势，但是副边控制需要增加额外的器件，成本高，体积大。The secondary side control usually feeds back the load status through the optocoupler, which can directly reflect the status of the load. The secondary side control has great advantages in anti-interference ability, working stability and transmission efficiency, but the secondary side control needs to add additional devices, which is costly and bulky.
原边控制通过变压器的辅助线圈反馈负载状态，不需要光耦元件、环路补偿及稳压器件，简化了芯片外围反馈回路的设计，达到了节省系统成本和空间的目的。The primary side control feeds back the load status through the auxiliary coil of the transformer, and does not require optocoupler components, loop compensation and voltage regulator devices, which simplifies the design of the external feedback loop of the chip and achieves the purpose of saving system cost and space.
图1是一种采用原边控制的开关电源100。开关电源100的电路板终端输出电压为Vcap，开关电源100的电缆终端输出电压为Vload，开关电源100的电路板终端与电缆终端通过输出电缆cable耦接。开关电源100通过调整DRIVE的脉冲宽度或者脉冲频率，保持电路板终端输出电压Vcap的恒定。输出电缆cable 的导通阻抗不随负载变化而变换，输出电缆cable两端的压降会随负载变化而变化，导致电缆终端输出电压随负载变化而变化。FIG. 1 is a switching power supply 100 using primary side control. The output voltage of the circuit board terminal of the switching power supply 100 is Vcap, the output voltage of the cable terminal of the switching power supply 100 is Vload , and the circuit board terminal and the cable terminal of the switching power supply 100 are coupled through the output cable cable. The switching power supply 100 keeps the circuit board terminal output voltage Vcap constant by adjusting the pulse width or pulse frequency of DRIVE. The on-resistance of the output cable does not change with the change of the load, and the voltage drop at both ends of the output cable changes with the change of the load, causing the output voltage of the cable terminal to change with the change of the load.
传统的输出电缆压降补偿方法通过检测原边峰值电流，并对原边峰值电流进行处理，实现负载变化检测，保证电缆终端输出电压恒定。但是在连续控制模式下，原边峰值电流与负载变化没有必然关联，因此传统的输出电缆压降补偿方法仅适用于断续控制模式(DCM)中，无法保证在连续控制模式(CCM)下提供精确的输出电缆压降补偿。The traditional output cable voltage drop compensation method detects the peak current of the primary side and processes the peak current of the primary side to realize load change detection and ensure a constant output voltage of the cable terminal. However, in the continuous control mode, the peak current of the primary side is not necessarily related to the load change, so the traditional output cable voltage drop compensation method is only applicable to the discontinuous control mode (DCM), and cannot guarantee to provide Accurate output cable voltage drop compensation.
实用新型内容Utility model content
实用新型目的：为了解决现有技术存在的问题，保证在断续控制模式和连续控制模式下实现开关电源电缆终端输出电压的精确控制，本实用新型提供一种开关电源输出电缆压降补偿电路。Purpose of the utility model: In order to solve the problems existing in the prior art and ensure accurate control of the output voltage of the switching power supply cable terminal under intermittent control mode and continuous control mode, the utility model provides a switching power supply output cable voltage drop compensation circuit.
技术方案：一种开关电源输出电缆压降补偿电路，包括电源管理芯片和变压器，变压器的辅助绕组通过检测电阻Ra和检测电阻Rb接至电源管理芯片的反馈脚，所述电源管理芯片用于检测变压器原边峰值电流实现负载变化检测，包括原边电流中值采样电路、低通滤波电路和补偿电流转换电路，所述原边电流中值采样电路为变压器原边电流的采样保持电路，低通滤波电路通过反馈脚电压对原边电流中值信号进行占空比调制处理输出补偿电压，补偿电压输出至补偿电流转换电路，所述补偿电流转换电路用于将补偿电压转换为补偿电流输出至反馈脚进行补偿。Technical solution: a switching power supply output cable voltage drop compensation circuit, including a power management chip and a transformer, the auxiliary winding of the transformer is connected to the feedback pin of the power management chip through the detection resistor Ra and the detection resistor Rb, and the power management chip is used for detecting Transformer primary side peak current realizes load change detection, including primary side current median value sampling circuit, low-pass filter circuit and compensation current conversion circuit, said primary side current median value sampling circuit is the sampling and holding circuit of transformer primary side current, low pass The filter circuit performs duty ratio modulation on the primary side current median signal through the feedback pin voltage to output a compensation voltage, and the compensation voltage is output to the compensation current conversion circuit, and the compensation current conversion circuit is used to convert the compensation voltage into a compensation current output to the feedback feet to compensate.
进一步的，所述低通滤波电路包括运算放大器I401、比较器I402、反相器I403、第一开关S402、第二开关S403、滤波电阻R401、滤波电容C402，运算放大器I401的同向输入端耦接至原边电流中值采样电路的输出端，反向输入端接输出端，输出端经第一开关接RC低通滤波器；比较器I402的同相输入端耦接至反馈脚，比较器I402的反相输入端耦接基准电压，比较器I402的输出端控制第一开关S402，比较器I402的输出端通过反相器I403控制第二开关S403，第二开关S403一段接地，另一端接RC低通滤波器，RC低通滤波器输出接补偿电流转换电路。Further, the low-pass filter circuit includes an operational amplifier I401 , a comparator I402 , an inverter I403 , a first switch S402 , a second switch S403 , a filter resistor R401 , a filter capacitor C402 , the operational amplifier The same-inverting input terminal of I401 is coupled to the output terminal of the primary side current median value sampling circuit, the inverting input terminal is connected to the output terminal, and the output terminal is connected to the RC low-pass filter through the first switch; the non-inverting input terminal of the comparator I402 Coupled to the feedback pin, the inverting input terminal of the comparator I402 is coupled to the reference voltage, the output terminal of the comparator I402 controls the first switch S402 , the output terminal of the comparator I402 controls the second switch S 402 through the inverter I403 Switch S403 , one end of the second switch S403 is grounded, the other end is connected to an RC low-pass filter, and the output of the RC low-pass filter is connected to a compensation current conversion circuit.
进一步的，所述补偿电流转换电路包括运算放大器I404、电阻R402、三极管 M401、电流比例变换电路，运算放大器I404的同向输入端耦接低通滤波电路的输出，运算放大器I404的输出端接三极管M401基极，三极管M401发射极经电阻R402接地，运算放大器I404的反向输入端接三极管M401发射极，三极管M401集电极接由三极管M402与三极管M403组成的电流比例变换电路。Further, the compensation current conversion circuit includes an operational amplifier I404 , a resistor R402 , a triode M401 , and a current proportional conversion circuit. The same input terminal of the operational amplifier I404 is coupled to the output of the low-pass filter circuit. The output terminal of the operational amplifier is connected to the base of the transistor M401 , the emitter of the transistor M401 is grounded through the resistor R402 , the reverse input terminal of the operational amplifier I404 is connected to the emitter of the transistor M401 , and the collector of the transistor M401 is connected to the transistor M402 and the transistor M403 composed of current proportional conversion circuit.
进一步的，所述原边中值采样电路包括采样开关S401和采样电容C401，采样开关S401与采样电容串联C401，采样电容C401另一端接地，采样电容C401上的电压为原边电流中值信号。Further, the primary-side median sampling circuit includes a sampling switch S401 and a sampling capacitor C401 , the sampling switch S401 is connected in series with the sampling capacitor C401 , the other end of the sampling capacitor C401 is grounded, and the voltage on the sampling capacitor C401 is the original Edge current median signal.
进一步的，所述原边电流中值采样电路、低通滤波电路和补偿电流转换电路集成在电源管理芯片内。Further, the median value sampling circuit of the primary side current, the low-pass filter circuit and the compensation current conversion circuit are integrated in the power management chip.
有益效果：本实用新型提供的一种开关电源输出电缆压降补偿电路，可以在断续模式和连续模式下实现对开关电源电缆终端输出电压的精确控制，使电缆终端输出电压不随负载变化而变化；该电路系统稳定、成本低、体积小、重量轻。Beneficial effects: the output cable voltage drop compensation circuit of the switching power supply provided by the utility model can realize precise control of the output voltage of the switching power supply cable terminal in the discontinuous mode and the continuous mode, so that the output voltage of the cable terminal does not change with the change of the load ; The circuit system is stable, low in cost, small in size and light in weight.
附图说明Description of drawings
图1为一种采用原边控制的开关电源；Figure 1 is a switching power supply using primary side control;
图2为图1断续控制模式下的原边电流、副边电流及反馈电压的波形图；FIG. 2 is a waveform diagram of the primary current, the secondary current and the feedback voltage in the discontinuous control mode of FIG. 1;
图3为图1连续控制模式下的原边电流、副边电流及反馈电压的波形图；FIG. 3 is a waveform diagram of the primary current, the secondary current and the feedback voltage in the continuous control mode of FIG. 1;
图4为本实用新型的开关电源输出电缆压降补偿电路示意图；4 is a schematic diagram of a switching power supply output cable voltage drop compensation circuit of the present invention;
图5为图4中的原边电流中值采样电路的原理图；Fig. 5 is the schematic diagram of the primary current median sampling circuit in Fig. 4;
图6为图4中的低通滤波电路的原理图；Fig. 6 is a schematic diagram of the low-pass filter circuit in Fig. 4;
图7为图4中的补偿电流转换电路的原理图。FIG. 7 is a schematic diagram of the compensation current conversion circuit in FIG. 4 .
具体实施方式detailed description
下面结合附图和具体实施例对本实用新型作进一步说明。Below in conjunction with accompanying drawing and specific embodiment the utility model is further described.
图1是一种采用原边控制的开关电源100，包括电源管理芯片101和变压器 102，变压器102的辅助绕组103通过检测电阻Ra和检测电阻Rb接至电源管理芯片101的反馈脚104FB端口，所述电源管理芯片101用于检测变压器原边105 峰值电流实现负载变化检测。开关电源100的电路板终端输出电压为Vcap，开关电源100的电缆终端输出电压为Vload，开关电源100的电路板终端与电缆终端通过输出电缆cable耦接。开关电源100通过调整电源管理芯片101的DRIVE 引脚输出的脉冲宽度或者脉冲频率，保持电路板终端输出电压Vcap的恒定。Fig. 1 is a switching power supply 100 using primary side control, including a power management chip 101 and a transformer 102, the auxiliary winding 103 of the transformer 102 is connected to the feedback pin 104FB port of the power management chip 101 through a detection resistor Ra and a detection resistor Rb, so The power management chip 101 described above is used to detect the peak current of the transformer primary side 105 to realize load change detection. The output voltage of the circuit board terminal of the switching power supply 100 is Vcap , the output voltage of the cable terminal of the switching power supply 100 is Vload , and the circuit board terminal and the cable terminal of the switching power supply 100 are coupled through the output cable cable. The switching power supply 100 keeps the circuit board terminal output voltage Vcap constant by adjusting the pulse width or pulse frequency output by the DRIVE pin of the power management chip 101 .
开关电源100采用反激式隔离架构，通过变压器(包含初级绕组NP、次级绕组NS、辅助绕组NA)来隔离初级侧和次级侧。The switching power supply 100 adopts a flyback isolation architecture, and isolates the primary side and the secondary side through a transformer (including a primary winding NP , a secondary winding NS , and an auxiliary winding NA ).
其中，NA是辅助绕组匝数，NS是副边绕组匝数，Vaux是辅助绕组上的压降， Vsec是次级绕组上的压降。Among them, NA is the number of turns of the auxiliary winding,NS is the number of turns of the secondary winding, Vaux is the voltage drop on the auxiliary winding, and Vsec is the voltage drop on the secondary winding.
又有there are
其中，VFB为反馈脚104处即FB端口的压降。Wherein, VFB is the voltage drop at the feedback pin 104 , that is, the FB port.
又有there are
Vsec＝VD+IO*Rcable+Vload (3)Vsec ＝VD +IO *Rcable +Vload (3)
其中，VD是二极管D6的正向导通压降，IO是负载电流，Rcable是输出电缆等效电阻。Among them, VD is the forward conduction voltage drop of diodeD6 , IO is the load current, and Rcable is the equivalent resistance of the output cable.
可得Available
电源管理芯片101是通过控制VFB与内部基准VREF相等来实现输出电压 Vload的调整，可以认为稳定条件下，VFB＝VREF，即VFB是固定值。式(4)中Ra、 Rb、NA、NS是不随负载电流变化的固定值，因此VD+IO*Rcable+Vload也是固定值，设为固定值K。可得The power management chip 101 adjusts the output voltage Vload by controlling VFB to be equal to the internal reference VREF . It can be considered that under stable conditions, VFB =VREF , that is, VFB is a fixed value. In formula (4), Ra , Rb , NA , andNS are fixed values that do not change with the load current, so VD +IO *Rcable +Vload is also a fixed value, which is set to a fixed value K. Available
Vload＝K-VD-IO*Rcable (5)Vload ＝KVD -IO *Rcable (5)
其中VD是二极管D6的正向导通压降，不随负载电流变化。Among them, VD is the forward conduction voltage drop of diodeD6 , which does not change with the load current.
从式(5)中可以看出，输出电缆cable的导通阻抗不随负载变化而变换，线缆cable的电压降IO*Rcable会随负载电流增加而增加，进而影响输出电压的负载调整率。为了保证输出电压的负载调整率，需要对输出电缆上的压降进行补偿。It can be seen from formula (5) that the on-resistance of the output cable does not change with the change of the load, and the voltage drop IO * Rcable of the cable will increase with the increase of the load current, thereby affecting the load regulation of the output voltage . In order to ensure the load regulation of the output voltage, it is necessary to compensate the voltage drop on the output cable.
图1中的原边电流IP通过检测电阻RCS获得，原边电流IP流经RCS形成电压降VCS，即原边电流IP＝VCS/RCS。The primary current IP in Figure 1 is obtained through the detection resistor RCS , and the primary current IP flows through RCS to form a voltage drop VCS , that is, the primary current IP =VCS /RCS .
在以下描述中，原边电流打开的时间被定名为Ton，副边电流打开的时间被定名为Tdemag，原边电流和副边电流同时关断的时间被定名为Toff，开关周期被定名为T，同时有T＝Ton+Tdemag+Toff。In the following description, the time when the primary current is turned on is named Ton , the time when the secondary current is turned on is named Tdemag , the time when both the primary and secondary currents are turned off is named Toff , and the switching cycle is It is named as T, and at the same time T=Ton +Tdemag +Toff .
断续控制模式一般是指变压器磁能释放完毕或者激磁电流下降到零，延时一段后原边开关再打开。断续控制模式下的原边谷值电流为零，原边电流从零开始上升，原边电流波形为锯齿波。断续控制模式在延时段内原边电流和副边电流同时关断。The discontinuous control mode generally means that the transformer magnetic energy is released or the excitation current drops to zero, and the primary side switch is turned on again after a delay. In the discontinuous control mode, the valley current of the primary side is zero, the current of the primary side rises from zero, and the waveform of the current of the primary side is a sawtooth wave. In the discontinuous control mode, the primary current and the secondary current are simultaneously turned off during the delay period.
如图2所示为断续控制模式下的原边电流、副边电流及反馈电压的波形图。图2中IP,peak是断续控制模式下原边峰值电流，IP,mid是断续控制模式下1/2Ton时的原边电流，IS,peak是断续控制模式下副边峰值电流。Figure 2 shows the waveforms of primary current, secondary current and feedback voltage in discontinuous control mode. In Figure 2, IP,peak is the peak current of the primary side in discontinuous control mode, IP,mid is the primary current at 1/2Ton in discontinuous control mode, IS,peak is the secondary side in discontinuous control mode peak current.
根据图2，断续控制模式下的输出均值电流IOD为：According to Figure 2, the average output current IOD in discontinuous control mode is:
连续控制模式一般是指变压器磁能尚未释放完毕或者激磁电流未下降到零时原边开关再次打开。连控制模式下的原边谷值电流不为零，原边电流从未下降到零的激磁电流开始上升，原边电流为侧梯形波。连续控制模式在开关周期内不存在原边电流和副边电流同时关断的时刻。The continuous control mode generally means that the primary side switch is turned on again when the magnetic energy of the transformer has not been released or the excitation current has not dropped to zero. In the continuous control mode, the valley current of the primary side is not zero, the excitation current of the primary side current never drops to zero, and the excitation current starts to rise, and the primary side current is a side trapezoidal wave. In the continuous control mode, there is no moment when the primary current and the secondary current are turned off at the same time during the switching cycle.
如图3所示为连续控制模式下的原边电流、副边电流及反馈电压的波形图，可以看出图3中Toff＝0。图3中IP,T是连续控制模式下原边峰值电流，IP,B是连续控制模式下原边谷值电流，IP,mid是连续控制模式下1/2Ton时的原边电流，IS,T是连续控制模式下副边峰值电流，IS,B是连续控制模式下副边谷值电流。FIG. 3 is a waveform diagram of the primary current, the secondary current and the feedback voltage in the continuous control mode. It can be seen that Toff =0 in FIG. 3 . In Figure 3, IP, T is the peak current of the primary side in the continuous control mode, IP, B is the valley current of the primary side in the continuous control mode, IP, mid is the primary current at 1/2Ton in the continuous control mode , IS,T is the peak current of the secondary side in continuous control mode, IS,B is the valley current of the secondary side in continuous control mode.
根据图3，连续控制模式下的输出均值电流IOC为：According to Figure 3, the average output current IOC in continuous control mode is:
从方程(6)和方程(7)可以看出，断续控制模式和连续控制模式下的输出均值电流均与原边电流中值有关，可以得到：From Equation (6) and Equation (7), it can be seen that the average output current in both the discontinuous control mode and the continuous control mode is related to the median value of the primary current, and it can be obtained:
从方程(8)可以看出，无论断续控制模式还是连续控制模式，只要得到原边电流中值IP,mid、去磁时间占空比Tdemag/T、变压器原边线圈与副边线圈匝比 NP/NS，就可以得到输出电流IO。进而可以根据输出均值电流不同来调整输出电压，实现输出电缆压降补偿的目的。It can be seen from equation (8) that regardless of the discontinuous control mode or the continuous control mode, as long as the median value of the primary current IP,mid , the demagnetization time duty ratio Tdemag /T, the transformer primary coil and secondary coil Turn ratio NP /NS , the output current IO can be obtained. Furthermore, the output voltage can be adjusted according to the difference of the output average current, so as to realize the purpose of output cable voltage drop compensation.
图4是本实施例开关电源输出电缆压降补偿电路，输出电缆压降补偿电路包括原边电流中值采样电路201、低通滤波电路202、补偿电流转换电路203。原边电流中值采样电路201的输入为原边电流，对原边电流中值进行采样保持，并输出至低通滤波电路202。低通滤波电路202通过检测电压VFB对原边电流中值进行占空比调制处理，并对所得结果进行低通滤波，保证系统稳定性；低通滤波结果与输出均值电流呈线性比例关系，并输出至补偿电流转换电路203。补偿电流转换线路203通过V-I变换及适当的比例变换将补偿电压转换为补偿电流，并将该线缆压降补偿电流输出至电源管理芯片101的反馈脚FB端口；线缆压降补偿电流流经电阻Ra和Rb形成压降，改变电压VFB，实现线缆压降补偿的目的；通过调节的Ra和Rb值，可以调节线缆压降补偿。FIG. 4 is the output cable voltage drop compensation circuit of the switching power supply in this embodiment. The output cable voltage drop compensation circuit includes a primary current median value sampling circuit 201 , a low-pass filter circuit 202 , and a compensation current conversion circuit 203 . The input of the primary current median value sampling circuit 201 is the primary current, samples and holds the primary current median value, and outputs it to the low-pass filter circuit 202 . The low-pass filter circuit 202 performs duty cycle modulation processing on the median value of the primary current by detecting the voltage VFB , and performs low-pass filtering on the obtained result to ensure system stability; the low-pass filtering result is linearly proportional to the output average current, And output to the compensation current conversion circuit 203. The compensation current conversion circuit 203 converts the compensation voltage into a compensation current through VI conversion and appropriate ratio conversion, and outputs the cable voltage drop compensation current to the feedback pin FB port of the power management chip 101; the cable voltage drop compensation current flows through The resistors Ra and Rb form a voltage drop to change the voltage VFB to achieve the purpose of cable voltage drop compensation; the cable voltage drop compensation can be adjusted by adjusting the values of Ra and Rb .
图5是图4中的原边电流中值采样电路一实施例。原边电流中值采样电路包括采样开关S401及采样电容C401。采样开关S401在1/2Ton时刻导通，将原边电流中值输出至采样电容C401，采样电容C401将原边电流中值保持到下一个1/2Ton时刻到来。采样电容C401上保存的电压值为该开关周期原边电流的中值VCS,mid。FIG. 5 is an embodiment of the primary side current median value sampling circuit in FIG. 4 . The primary side current median value sampling circuit includes a sampling switch S401 and a sampling capacitor C401 . The sampling switch S401 is turned on at 1/2Ton time, and outputs the median value of the primary current to the sampling capacitor C401 , and the sampling capacitor C401 keeps the median value of the primary current until the next 1/2Ton time. The voltage value stored on the sampling capacitor C401 is the median value VCS,mid of the primary current in the switching cycle.
图6是图4中的低通滤波电路一实施例。低通滤波电路包括运算放大器I401，比较器I402，反相器I403，开关S402、S403，滤波电阻R401，滤波电容C402。运算放大器I401的同相输入端耦接至原边电流中值采样电路的输出端，即运算放大器 I401的构成的缓冲电路的输入电压为VCS,mid，因此运算放大器I401的反相输入端及输出端电压为VCS,mid。比较器I402的输出端控制开关S402，比较器I402的输出端通过反相器I403控制开关S403。比较器I402的同相输入端连接至VFB，比较器 I402的反相输入端连接至基准电压Vzcd。当VFB电压值大于Vzcd电压值时，对应图2及图3中的Tdemag时间段，此时控制开关S402打开，滤波电阻R401及滤波电容C402组成的低通滤波单元的输入为VCS,mid。当VFB电压值小于Vzcd电压值时，对应图2中Ton和Toff时间段及图3中的Ton时间段，此时控制开关S403打开，滤波电阻R401及滤波电容C402组成的低通滤波单元的输入为0。滤波电阻R401及滤波电容C402组成的低通滤波单元的输出电压为VCS,mid*Tdemag/T。FIG. 6 is an embodiment of the low-pass filter circuit in FIG. 4 . The low-pass filter circuit includes an operational amplifier I401 , a comparator I402 , an inverter I403 , switches S402 and S403 , a filter resistor R401 , and a filter capacitor C402 . The non-inverting input terminal of the operational amplifier I401 is coupled to the output terminal of the primary side current median value sampling circuit, that is, the input voltage of the buffer circuit formed by the operational amplifier I401 is VCS,mid , so the inverting input terminal of the operational amplifier I401 And the output terminal voltage is VCS,mid . The output terminal of the comparator I402 controls the switch S402 , and the output terminal of the comparator I402 controls the switch S403 through the inverter I 403. The non-inverting input of the comparator I402 is connected to VFB , and the inverting input of the comparator I402 is connected to the reference voltage Vzcd . When the VFB voltage value is greater than the Vzcd voltage value, corresponding to the Tdemag time period in Figure 2 and Figure 3, at this time the control switch S402 is turned on, and the input of the low-pass filter unit composed of the filter resistor R401 and the filter capacitor C402 is VCS, mid . When the VFB voltage value is less than the Vzcd voltage value, corresponding to the Ton and Toff time periods in Figure 2 and the Ton time period in Figure 3, at this time the control switch S403 is turned on, and the filter resistor R401 and filter capacitor C402 The input of the composed low-pass filter unit is 0. The output voltage of the low-pass filter unit composed of filter resistor R401 and filter capacitor C402 is VCS,mid *Tdemag /T.
图7是图4中的补偿电流转换电路的一实施例。补偿电流转换电路包括运算放大器I404，电阻R402，三极管M401～M403。运算放大器I404，电阻R402，M401组成电压转电流电路。电压转电流电路的输入连接至低通滤波电路的输出，即电压转电流电路的输入为电压VCS,mid*Tdemag/T。经过电压转电流电路变换，电压转电流电路的输出为电流VCS,mid*Tdemag/T/R402。三极管M402和M403组成电流比例变换电路204，电流比例变换比为k。即最终输出到芯片FB端的补偿电流值为 k*VCS,mid*Tdemag/T/R402。FIG. 7 is an embodiment of the compensation current conversion circuit in FIG. 4 . The compensation current conversion circuit includes an operational amplifier I404 , a resistor R402 , and transistors M401 -M403 . The operational amplifier I404 , the resistors R402 and M401 form a voltage-to-current circuit. The input of the voltage-to-current circuit is connected to the output of the low-pass filter circuit, that is, the input of the voltage-to-current circuit is the voltage VCS,mid *Tdemag /T. After conversion by the voltage-to-current circuit, the output of the voltage-to-current circuit is the current VCS,mid *Tdemag /T/R402 . Transistors M402 and M403 form a current proportional conversion circuit 204, and the current proportional conversion ratio is k. That is, the value of the compensation current finally output to the FB terminal of the chip is k*VCS,mid *Tdemag /T/R402 .
根据式(8)，补偿电流k*VCS,mid*Tdemag/T/R402与输出均值电流IO存在比例关系，通过设定合适的电流变换比k，可以实现补偿电流随输出均值电流IO变化而变化，进而实现线损补偿的目的。According to formula (8), there is a proportional relationship between the compensation current k*VCS, mid *Tdemag /T/R402 and the output average current IO. By setting an appropriate current conversion ratio k, the compensation current can be realized to follow the output average current IO changes and changes, thereby achieving the purpose of line loss compensation.
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720148442.XUCN206698119U (en) | 2017-02-20 | 2017-02-20 | A kind of Switching Power Supply output cable voltage-drop compensation circuit |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720148442.XUCN206698119U (en) | 2017-02-20 | 2017-02-20 | A kind of Switching Power Supply output cable voltage-drop compensation circuit |
| Publication Number | Publication Date |
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| CN206698119Utrue CN206698119U (en) | 2017-12-01 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720148442.XUActiveCN206698119U (en) | 2017-02-20 | 2017-02-20 | A kind of Switching Power Supply output cable voltage-drop compensation circuit |
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| CN (1) | CN206698119U (en) |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667285A (en)* | 2018-04-20 | 2018-10-16 | 深圳市芯飞凌半导体有限公司 | Adjust the control circuit and Switching Power Supply of switching frequency and load current relationship |
| CN108988711A (en)* | 2018-07-20 | 2018-12-11 | 吉林大学 | A kind of motor control method of the electronic bridge plug delivery tool in oil field |
| CN110350760A (en)* | 2019-06-01 | 2019-10-18 | 上海沪工焊接集团股份有限公司 | A kind of sample hold method of the input peak point current of inverter |
| CN110943612A (en)* | 2018-09-25 | 2020-03-31 | 深圳市华芯邦科技有限公司 | Load current detection circuit and method for switching power supply converter |
| CN115296511A (en)* | 2022-10-08 | 2022-11-04 | 青岛鼎信通讯股份有限公司 | An output voltage sampling method and circuit suitable for power field |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667285A (en)* | 2018-04-20 | 2018-10-16 | 深圳市芯飞凌半导体有限公司 | Adjust the control circuit and Switching Power Supply of switching frequency and load current relationship |
| CN108667285B (en)* | 2018-04-20 | 2024-05-28 | 上海芯飞半导体技术有限公司 | Control circuit for adjusting relation between switching frequency and load current and switching power supply |
| CN108988711A (en)* | 2018-07-20 | 2018-12-11 | 吉林大学 | A kind of motor control method of the electronic bridge plug delivery tool in oil field |
| CN110943612A (en)* | 2018-09-25 | 2020-03-31 | 深圳市华芯邦科技有限公司 | Load current detection circuit and method for switching power supply converter |
| CN110350760A (en)* | 2019-06-01 | 2019-10-18 | 上海沪工焊接集团股份有限公司 | A kind of sample hold method of the input peak point current of inverter |
| CN115296511A (en)* | 2022-10-08 | 2022-11-04 | 青岛鼎信通讯股份有限公司 | An output voltage sampling method and circuit suitable for power field |
| CN115296511B (en)* | 2022-10-08 | 2023-01-13 | 青岛鼎信通讯股份有限公司 | An output voltage sampling method and circuit applicable to the electric power field |
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