LDO ,开关电源DC-DC的优缺点室外一体化电源机柜,高频开关电源，-48V开关电源

一般LDO电源自身的功耗为（Vin-Vout）*Iout，因此这两者越大，功耗也越大，效率也就越低。

LDO ,开关电源DC-DC的优缺点转载标签： 电源杂谈 低压差线性稳压器，故名思意，为线性的稳压器，仅能使用在降压应用中。也就是输出电压必需小于输入电压。优点：稳定性好，负载响应快。输出纹波小缺点：效率低，输入输出的电压差不能太大。负载不能太大，目前最大的LDO为5A（但要保证5A的输出还有很多的限制条件） DC/DC：直流电压转直流电压。严格来讲，LDO也是DC/DC的一种，但目前DC/DC多指开关电源。具有很多种拓朴结构，如BUCK，BOOST。等。。优点：效率高，输入电压范围较宽。缺点：负载响应比LDO差，输出纹波比LDO大。 LDO是低压降的意思：低压降（LDO）线性稳压器的成本低，噪音低，静态电流小，这些是它的突出优点。它需要的外接元件也很少，通常只需要一两个旁路电容。新的LDO线性稳压器可达到以下指标：输出噪声30μV，PSRR为60dB，静态电流6μA，电压降只有100mV。LDO线性稳压器的性能之所以能够达到这个水平，主要原因在于其中的调整管是用P沟道MOSFET，而普通的线性稳压器是使用PNP晶体管。P沟道MOSFET是电压驱动的，不需要电流，所以大大降低了器件本身消耗的电流；另一方面，采用PNP晶体管的电路中，为了防止PNP晶体管进入饱和状态而降低输出能力，输入和输出之间的电压降不可以太低；而P沟道MOSFET上的电压降大致等于输出电流与导通电阻的乘积。由於MOSFET的导通电阻很小，因而它上面的电压降非常低。 如果输入电压和输出电压很接近，最好是选用LDO稳压器，可达到很高的效率。所以，在把锂离子电池电压转换为3V输出电压的应用中大多选用LDO稳压器。虽说电池的能量最後有百分之十是没有使用，LDO稳压器仍然能够保证电池的工作时间较长，同时噪音较低。 如果输入电压和输出电压不是很接近，就要考虑用开关型的DCDC了，应为从上面的原理可以知道，LDO的输入电流基本上是等于输出电流的，如果压降太大，耗在LDO上能量太大，效率不高。 DC-DC转换器包括升压、降压、升/降压和反相等电路。DC-DC转换器的优点是效率高、可以输出大电流、静态电流小。随著集成度的提高，许多新型DC-DC转换器仅需要几只外接电感器和滤波电容器。但是，这类电源控制器的输出脉动和开关噪音较大、成本相对较高。 总的来说，升压是一定要选DCDC的，降压，是选择DCDC还是LDO，要在成本，效率，噪声和性能上比较。 电源是各种电子设备必不可缺少的组成部分，其性能的优劣直接关系到电子设备的技术指标及能否安全可靠地工作以及它的优点和缺点。 　　电源是各种电子设备必不可缺少的组成部分，其性能的优劣直接关系到电子设备的技术指标及能否安全可靠地工作。目前常用的直流稳压电源分线性电源和开关电源两大类，由于开关电源内部关键元器件工作在高频开关状态，本身消耗的能量很低，开关电源效率可达80％～90％，比普通线性稳压电源提高近一倍，目前已成为稳压电源的主流产品。 　　2 开关稳压电源的结构 　　图(1)画出了开关稳压电源的原理图及等效原理框图，它是由全波整流器，开关管Vi，激励信号，续流二极管VD，储能电感和滤波电容C组成。实际上，开关稳压电源的核心部分是一个直流变压器。这里我们对直流变换器和逆变器作如下解释。逆变器，它是把直流转变为交流的装置。逆变器通常被广泛地应用在采用电平或电池组成的备用电源中。直流变换器，它是把直流转换成交流，然后又把交流转换成直流的装置。这种装置被广泛地应用在开关稳压电源中。采用直流变换器可以把一种直流供电电压变换成极性、数值各不同的多种直流供电电压。 　　3 开关稳压电源的优点和缺点 　　3.1 开关稳压电源的优点 　　功耗小，效率高。在图(1)中的开关稳压电源电路中，晶体管V在激励信号的激励下，它交替地工作在导通截止和截止导通的开关状态，转换速度很快，频率一般为50kHz左右，在一些技术先进的国家，可以做到几百或者近1000kHz。这使得开关晶体管V的功耗很小，电源的效率可以大幅度地提高，其效率可达到80％。 　　体积小，重量轻。从开关稳压电源的原理框图可以清楚地看到这里没有采用笨重的工频变压器。由于调整管V上的耗散功率大幅度降低后，又省去了较大的散热片。由于这两方面原因，所以开关稳压电源的体积小，重量轻。 　　稳压范围宽。从开关稳压电源的输出电压是由激励信号的占空比来调节的，输入信号电压的变化可以通过调频或调宽来进行补偿，这样，在工频电网电压变化较大时，它仍能够保证有较稳定的输出电压。所以开关电源的稳压范围很宽，稳压效果很好。此外，改变占空比的方法有脉宽调制型和频率调制型两种。这样，开关稳压电源不仅具有稳压范围宽的优点，而且实现稳压的方法也较多，设计人员可以根据实际应用的要求，灵活地选用各种类型的开关稳压电源。 　　滤波的效率大为提高，使滤波电容的容量和体积大为减少。开关稳压电源的工作频率目前基本上是工作在50kHz，是线性稳压电源的1000倍，这使整流后的滤波效率几乎也提高了1000倍。就是采用半波整流后加电容滤波，效率也提高了500倍。在相同的纹波输出电压下，采用开关稳压电源时，滤波电容的容量只是线性稳压电源中滤波电容的1／5001／1000。 　　电路形式灵活多样。例如，有自激式和他激式，有调宽型和调频型，有单端式和双端式等等，设计者可以发挥各种类型电路的特长，设计出能满足不同应用场合的开关稳压电源。 　　3.2 开关稳压电源的缺点 　　开关稳压电源的缺点是存在较为严重的开关干扰。开关稳压电源中，功率调整开关晶体管V工作在开关状态，它产生的交流电压和电流通过电路中的其他元器件产生尖峰干扰和谐振干扰，这些干扰如果不采取一定的措施进行抑制、消除和屏蔽，就会严重地影响整机的正常工作。此外由于开关稳压电源振荡器没有工频变压器的隔离，这些干扰就会串入工频电网，使附近的其他电子仪器、设备和家用电器受到严重的干扰。 　　目前，由于国内微电子技术、阻容器件生产技术以及磁性材料技术与一些技术先进国家还有一定的差距，因而造价不能进一步降低，也影响到可靠性的进一步提高。所以在我国的电子仪器以及机电一体化仪器中，开关稳压电源还不能得到十分广泛的普及及使用。特别是对于无工频变压器开关稳压电源中的高压电解电容器、高反压大功率开关管、开关变压器的磁芯材料等器件，在我国还处于研究、开发阶段。在一些技术先进国家，开关稳压电源虽然有了一定的发展，但在实际应用中也还存在一些问题，不能十分令人满意。这暴露出开关稳压电源的又一个缺点，那就是电路结构复杂，故障率高，维修麻烦。对此，如果设计者和制造者不予以充分重视，则它将直接影响到开关稳压电源的推广应用。当今，开关稳压电源推广应用比较困难的主要原因就是它的制作技术难度大、维修麻烦和造价成本较高 　　4 LDO简介 　　LDO是一种微功耗的低压差线性稳压器，它通常具有极低的自有噪声和较高的电源抑制比PSRR(PowerSupplyRejectionRatio)。 　　LDO低压差线性稳压器的结构如图(2)主要包括启动电路、恒流源偏置单元、使能电路、调整元件、基准源、误差放大器、反馈电阻网络和保护电路等。基本工作原理是这样的：系统加电，如果使能脚处于高电平时，电路开始启动，恒流源电路给整个电路提供偏置，基准源电压快速建立，输出随着输入不断上升，当输出即将达到规定值时，由反馈网络得到的输出反馈电压也接近于基准电压值，此时误差放大器将输出反馈电压和基准电压之间的误差小信号进行放大，再经调整管放大到输出，从而形成负反馈，保证了输出电压稳定在规定值上，同理如果输入电压变化或输出电流变化，这个闭环回路将使输出电压保持不变，即：Vout=(R1+R2)／R2 ×Vref 　　实际的低压差线性稳压器还具有如负载短路保护、过压关断、过热关断、反接保护等其它的功能。

The power consumption of the general LDO power supply is (Vin-Vout) *Iout, so the larger the two, the greater the power consumption and the lower the efficiency.

LDO, the merits and demerits of the switching power DC-DC (2008-11-06 22:40:23) reload label: power talk low voltage differential linear regulator, the name idea, for linear regulator, can be used only in the step-down application. That is, the output voltage must be less than the input voltage. Advantages: good stability, fast load response. Low output ripple: low efficiency, voltage difference between input and output can not be too large. The load should not be too large. The largest LDO at present is 5A (but there are still many limitations to ensure the output of 5A) DC/DC: DC voltage to DC voltage. Strictly speaking, LDO is also one of DC/DC, but at present DC/DC r通信电源,室内通信电源机柜,室外通信电源机柜,室外壁挂通信电源机柜,室内壁挂通信电源机柜,嵌入式通信电源系统,整流模块,监控模块,BBU,RRU,逆变器,室外一体化UPS电源,UPS不间断电源,48V50AH锂电池,蓄电池,蓄电池架,蓄电池柜,蓄电池巡检仪,蓄电池连接线, 交流配电单元,直流配电单元,交流配电箱, 局端嵌入式直流远供电源系统, 远端嵌入式直流远供电源系统 ,室外一体化电源机柜,高频开关电源，-48V开关电源 efers to switching power supply. There are many kinds of topological structures, such as BUCK, BOOST. Wait. Advantages: high efficiency and wide input voltage range. Disadvantages: load response is worse than LDO, and output ripple is larger than LDO. LDO is the meaning of low voltage drop: low voltage drop (LDO) linear regulator has the advantages of low cost, low noise and small quiescent current.  It requires very few external components, and usually only needs one or two bypass capacitors. The new LDO linear regulator can achieve the following indicators: output noise is 30 V, PSRR is 60dB, quiescent current is 6 A, voltage drop is only 100mV.  The performance of the LDO linear regulator is able to achieve this level, mainly because the adjustment tube is used in the P channel MOSFET, while the ordinary linear regulator is using the PNP transistor. P channel MOSFET is voltage driven and does not require current, so it greatly reduces the current consumed by the device itself; on the other hand, in a circuit with PNP transistors, the voltage drop between input and output can not be too low in order to prevent PNP transistors from entering the saturation state; and the voltage drop on P channel MOSFET is reduced. It is roughly equal to the product of output current and on resistance. Because the MOSFET on resistance is very small, the voltage drop on it is very low. If the input voltage and output voltage are very close, it is best to use LDO regulator to achieve high efficiency. Therefore, in the application of lithium ion battery voltage to 3V output voltage, LDO regulator is used mostly. Although the last ten percent of the battery energy is not used, the LDO regulator can still ensure that the battery has a longer working time and lower noise. If the input voltage and the output voltage are not very close, we should consider the switch type DCDC. It should be known from the above principle that the input current of LDO is basically equal to the output current. If the pressure drop is too large, the energy is too high and the efficiency is not high on the LDO. The DC-DC converter includes boost, buck, up / down and reverse circuits. The advantages of the DC-DC converter are high efficiency, high output current and small quiescent current. With the improvement of integration, many new DC-DC converters only need several external inductors and filter capacitors. However, the output pulse and switching noise of this type of power controller are large and the cost is relatively high. In general, boosting is the choice of DCDC, and DCDC or LDO should be chosen to compare the cost, efficiency, noise and performance. Power supply is an indispensable component of all kinds of electronic equipment. Its performance is directly related to the technical index of electronic equipment and the safety and reliability of the work as well as its advantages and disadvantages. Power supply is an indispensable component of all kinds of electronic equipment. Its performance is directly related to the technical index of electronic equipment and whether it can work safely and reliably. Currently, the common DC regulated power supply line power supply and switching power supply are two categories. Because the key components in the switching power supply are working in high frequency switching state, the energy consumption is very low, the efficiency of the switching power supply can reach 80% to 90%, which is nearly twice as high as that of the ordinary linear voltage power supply, and has become the mainstream production of the voltage stabilized power supply. Goods. The structure diagram of the 2 switch regulated power supply (1) draws the schematic diagram of the switching regulator and the block diagram of the equivalent principle. It is composed of full wave rectifier, switch tube Vi, excitation signal, continuous current diode VD, energy storage inductor and filter capacitor C. In fact, the core part of switching power supply is a DC transformer. Here we explain the DC converters and inverters as follows. Inverter is a device that converts DC to AC.  Inverters are usually widely used in standby power supply consisting of level or battery.  DC converter is a device that converts DC to AC and then converts AC to DC. This device is widely used in switching power supply. A DC converter can transform a DC supply voltage into various DC supply voltages with different polarity and value. 3 the advantages and disadvantages of switching regulated power supply 3.1. The advantages of switching regulator are low power consumption and high efficiency. In the switch regulated power supply circuit in figure (1), the transistor V operates alternately in the conduction and cut-off switching state under the excitation signal, and the conversion speed is very fast, the frequency is about 50kHz, and in some advanced countries, it can be achieved by a few hundred or nearly 1000kHz. This makes the power consumption of switching transistor V very small, and the efficiency of power supply can be greatly improved, and its efficiency can reach 80%. It is small in size and light in weight. From the schematic diagram of switching power supply, we can clearly see that there is no cumbersome power frequency transformer. As the dissipation power of the adjusting tube V is greatly reduced, large heat sinks are omitted. Because of these two reasons, so