Wide-range regulator delivers 12V, 3A output from 16 to 100V source

Synchronous buck regulators offer high efficiency and are popular in applications in which available input voltages are 12V or less. However, as input voltage approaches 100V, wide-range-regulator design becomes more difficult, and the choice of suitable ICs narrows considerably. This Design Idea combines a current-mode PWM IC for flyback-regulator circuits with a 100V gate-driver IC to produce a relatively high-performance synchronous buck regulator that can operate at inputs as high as 100V.

The circuit in Figure 1 uses National Semiconductor‘s LM5020 current-mode PWM, IC1, to drive an LM5104 gate driver, IC2, forming a synchronous controller. The LM5020 contains an internal linear regulator that accepts input as high as 100V and can also deliver an output that can supply drive current to the LM5104. To reduce power dissipation at high input voltages, after initial power application, diode D2, a 1N4148, supplies an 11.5V bootstrap voltage to the remainder of the circuit. Transformer T1, a 100-to-1 current transformer from Pulse Engineering, provides current feedback during MOSFET Q1‘s on-time. Q1 and Q2 are Siliconix Dpak devices, which have low gate-charge requirements and low on-resistances to minimize total switching losses at the circuit‘s 200-kHz operating frequency. All capacitors are of ceramic-dielectric construction to withstand high temperature and to meet packaging-size constraints.

For sustained operation at high input voltage, maximum current, and elevated-temperature conditions, transistor Q1 requires an adequate heat sink or cooling airflow to maintain its junction temperature below the 175°C maximum specification. Q1 has a low junction-to-case thermal resistance, and thus its case temperature must not exceed 160°C. L1, the model DO5010 unshielded ferrite-core inductor from Coilcraft, presents a small pc-board footprint and offers a high saturation-current rating but represents this design‘s dominant loss component. For applications with less critical space requirements, you can improve circuit efficiency by increasing L1‘s inductance and size, thus reducing ripple current and enabling use of a larger core and increased winding-wire gauge. Reducing the output voltage improves efficiency, but, as output voltage drops below the circuit‘s 8V bootstrap voltage, IC1 dissipates additional power and requires caution to avoid exceeding its ratings. Figure 2 shows the circuit‘s measured efficiency versus output current for three input voltages.

One practical application for the circuit met a customer‘s requirement for a dc/dc converter that would operate from a 24V source and deliver 12V output at currents as high as 3A. This routine-sounding specification also requires operation in a physically and electrically harsh environment in which the packaged circuit resides on an engine block that reaches a temperature of 125°C, and ambient-air temperature reaches 100°C. In addition, the power source comprises two series-connected 12V batteries that provide a nominal voltage of 24V, which in practice varies from 18 to 40V and includes inductively induced load-dump voltage spikes that reach 100V.

时间: 2024-11-10 00:58:25

Wide-range regulator delivers 12V, 3A output from 16 to 100V source的相关文章

Maven修改test/rsource的output folder报错Test source folder 'src/test/java'... is not also used for main s

eclipse新建maven项目时候,只出来三个文件夹,然后大都督手动添加了缺失的src/test/resource 的文件夹,最后想修改一下 Output folder的路径为 (原来是     default 啥啥的路径)随即出现了报错 解决方法:大都督通过科学搜索,终于找到问题所在:对比其他文件夹,发现了啥 看到没,那个Contains test source:显示的是NO,而java文件夹显示的是YES所以大都督秀手一挥,果断双击 这个东东,噔噔蹬蹬..... 完好无报错!!!!!———

hdu 5344 MZL's xor

MZL's xor Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 911    Accepted Submission(s): 589 Problem Description MZL loves xor very much.Now he gets an array A.The length of A is n.He wants to k

HDOJ 题目1881 毕业bg(DFS)

毕业bg Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 32768/32768K (Java/Other) Total Submission(s) : 6   Accepted Submission(s) : 3 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description 每年毕业的季节都会有大量毕业生发起狂欢,好朋友们相约吃散伙饭,网络上

HDU 5344(MZL's xor-(ai+aj)的异或和)

MZL's xor Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 800    Accepted Submission(s): 518 Problem Description MZL loves xor very much.Now he gets an array A.The length of A is n.He wants to

OpAmp Voltage Follower/Regulator

By using an emitter-follower or a Darlington pair, a voltage-follower op amp configuration can source higher currents than the op amp otherwise could. With high-voltage regulators, powering the IC through the drive resistor for the pass transistors c

MOSFET shunt regulator substitutes for series regulator

You would normally use a series linear regulator or a dc/dc converter to obtain 3V dc from a higher supply. However, when breadboarding a concept, you may be able to use a shunt regulator, especially if a series regulator of the correct voltage is un

Get buck-boost performance from a boost regulator

The SEPIC (single-ended, primary-inductance-converter) topology is generally a good choice for voltage regulators that must produce an on output voltage that falls in the middle of the input-voltage range, such as a 5V output from a 2.7 to 6V input,

Cascode MOSFET increases boost regulator's input- and output-voltage ranges

Targeting use in portable-system applications that require raising a battery's voltage to a higher level, IC boost regulators often include output transistors that can drive storage inductors. However, most boost regulators' absolute-maximum input-vo

Java – Generate random integers in a range

In this article, we will show you three ways to generate random integers in a range. java.util.Random.nextIntMath.randomjava.util.Random.ints (Java 8)1. java.util.RandomThis Random().nextInt(int bound) generates a random integer from 0 (inclusive) to