0-30V稳压电源（电压电流可控，电流0.002A<-->3A）[转自外国网站]
今天无意中再国外一个网站上看到一个电源方案，觉得不错，但是有些地方还是看不懂，看到 春风兄之前发的电源方案，大家讨论激烈，我也从中学到了不少，所以转过来跟大家分享一下，也希望从讨论中解决一些问题。。。转帖很累啊。。
因为是英文的，我自己看的也是半解，所以那位高手有空可以翻译一下，让更多的人可以参与其中。。
0-30 VDC STABILIZED POWER SUPPLY WITH CURRENT CONTROL 0.002-3 A
原文出自：http://www.electronics-lab.com/projects/power/003/index.html。
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387693.gif
实物图 (原文件名:z1.gif)
General Description
——————————————————————————————————————————————————————————————————————
This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC. The circuit also
incorporates an electronic output current limiter that effectively controls the output current from a few milliamperes (2 mA) to the maximum output of
three amperes that the circuit can deliver. This feature makes this power supply indispensable in the experimenters laboratory as it is possible to limit
the current to the typical maximum that a circuit under test may require, and power it up then, without any fear that it may be damaged if something
goes wrong. There is also a visual indication that the current limiter is in operation so that you can see at a glance that your circuit is exceeding or not
its preset limits.
Technical Specifications - Characteristics
————————————————————————————————————————————————————————————————————————
Technical Specifications
Input Voltage: ................ 24 VAC
Input Current: ................ 3 A (max)
Output Voltage: ............. 0-30 V adjustable
Output Current: ............. 2 mA-3 A adjustable
Output Voltage Ripple: .... 0.01 % maximum
Features
- Reduced dimensions, easy construction, simple operation.
- Output voltage easily adjustable.
- Output current limiting with visual indication.
- Complete protection of the supplied device against over loads and malfunction.
How it Works
________________________________________________________________________________________________________________
To start with, there is a step-down mains transformer with a secondary winding rated at 24 V/3 A, which is connected across the input points of the
circuit at pins 1 & 2. (the quality of the supplies output will be directly proportional to the quality of the transformer). The AC voltage of the
transformers secondary winding is rectified by the bridge formed by the four diodes D1-D4. The DC voltage taken across the output of the bridge is
smoothed by the filter formed by the reservoir capacitor C1 and the resistor R1. The circuit incorporates some unique features which make it quite
different from other power supplies of its class. Instead of using a variable feedback arrangement to control the output voltage, our circuit uses a
constant gain amplifier to provide the reference voltage necessary for its stable operation. The reference voltage is generated at the output of U1.
The circuit operates as follows: The diode D8 is a 5.6 V zener, which here operates at its zero temperature coefficient current. The voltage in the
output of U1 gradually increases till the diode D8 is turned on. When this happens the circuit stabilises and the Zener reference voltage (5.6 V)
appears across the resistor R5. The current which flows through the non inverting input of the op-amp is negligible, therefore the same current flows
through R5 and R6, and as the two resistors have the same value the voltage across the two of them in series will be exactly twice the voltage across
each one. Thus the voltage present at the output of the op-amp (pin 6 of U1) is 11.2 V, twice the zeners reference voltage. The integrated circuit U2
has a constant amplification factor of approximately 3 X, according to the formula A=(R11+R12)/R11, and raises the 11.2 V reference voltage to
approximately 33 V. The trimmer RV1 and the resistor R10 are used for the adjustment of the output voltages limits so that it can be reduced to 0 V,
despite any value tolerances of the other components in the circuit.
Schematic diagramm
____________________________________________________________________________________________________________
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387694.gif
原理图 (原文件名:sch1.gif)
————————————————————————————————————————————————————————————————————————
Another very important feature of the circuit, is the possibility to preset the maximum output current which can be drawn from the p.s.u., effectively
converting it from a constant voltage source to a constant current one. To make this possible the circuit detects the voltage drop across a resistor
(R7) which is connected in series with the load. The IC responsible for this function of the circuit is U3. The inverting input of U3 is biased at 0 V via
R21. At the same time the non inverting input of the same IC can be adjusted to any voltage by means of P2.
Let us assume that for a given output of several volts, P2 is set so that the input of the IC is kept at 1 V. If the load is increased the output voltage
will be kept constant by the voltage amplifier section of the circuit and the presence of R7 in series with the output will have a negligible effect because
of its low value and because of its location outside the feedback loop of the voltage control circuit. While the load is kept constant and the output
voltage is not changed the circuit is stable. If the load is increased so that the voltage drop across R7 is greater than 1 V, IC3 is forced into action and
the circuit is shifted into the constant current mode. The output of U3 is coupled to the non inverting input of U2 by D9. U2 is responsible for the
voltage control and as U3 is coupled to its input the latter can effectively override its function. What happens is that the voltage across R7 is monitored
and is not allowed to increase above the preset value (1 V in our example) by reducing the output voltage of the circuit.
This is in effect a means of maintaining the output current constant and is so accurate that it is possible to preset the current limit to as low as 2 mA.
The capacitor C8 is there to increase the stability of the circuit. Q3 is used to drive the LED whenever the current limiter is activated in order to provide
a visual indication of the limiters operation. In order to make it possible for U2 to control the output voltage down to 0 V, it is necessary to provide a
negative supply rail and this is done by means of the circuit around C2 & C3. The same negative supply is also used for U3. As U1 is working under
fixed conditions it can be run from the unregulated positive supply rail and the earth.
The negative supply rail is produced by a simple voltage pump circuit which is stabilised by means of R3 and D7. In order to avoid uncontrolled
situations at shut-down there is a protection circuit built around Q1. As soon as the negative supply rail collapses Q1 removes all drive to the output
stage. This in effect brings the output voltage to zero as soon as the AC is removed protecting the circuit and the appliances connected to its output.
During normal operation Q1 is kept off by means of R14 but when the negative supply rail collapses the transistor is turned on and brings the output
of U2 low. The IC has internal protection and can not be damaged because of this effective short circuiting of its output. It is a great advantage in
experimental work to be able to kill the output of a power supply without having to wait for the capacitors to discharge and there is also an added
protection because the output of many stabilised power supplies tends to rise instantaneously at switch off with disastrous results.
Construction
————————————————————————————————————————————————————————————————————————————
First of all let us consider a few basics in building electronic circuits on a printed circuit board. The board is made of a thin insulating material clad with
a thin layer of conductive copper that is shaped in such a way as to form the necessary conductors between the various components of the circuit.
The use of a properly designed printed circuit board is very desirable as it speeds construction up considerably and reduces the possibility of making
errors. To protect the board during storage from oxidation and assure it gets to you in perfect condition the copper is tinned during manufacturing and
covered with a special varnish that protects it from getting oxidised and also makes soldering easier.
Soldering the components to the board is the only way to build your circuit and from the way you do it depends greatly your success or failure. This work is not very difficult and if you stick to a few rules you should have no problems. The soldering iron that you use must be light and its power
should not exceed the 25 Watts. The tip should be fine and must be kept clean at all times. For this purpose come very handy specially made sponges
that are kept wet and from time to time you can wipe the hot tip on them to remove all the residues that tend to accumulate on it.
DO NOT file or sandpaper a dirty or worn out tip. If the tip cannot be cleaned, replace it. There are many different types of solder in the market and
you should choose a good quality one that contains the necessary flux in its core, to assure a perfect joint every time.
DO NOT use soldering flux apart from that which is already included in your solder. Too much flux can cause many problems and is one of the main
causes of circuit malfunction. If nevertheless you have to use extra flux, as it is the case when you have to tin copper wires, clean it very thoroughly
after you finish your work.
In order to solder a component correctly you should do the following:
*
Clean the component leads with a small piece of emery paper.
*
Bend them at the correct distance from the components body and insert he component in its place on the board.
*
You may find sometimes a component with heavier gauge leads than usual, that are too thick to enter in the holes of the p.c. board. In this case
use a mini drill to enlarge the holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.
*
Take the hot iron and place its tip on the component lead while holding the end of the solder wire at the point where the lead emerges from the
board. The iron tip must touch the lead slightly above the p.c. board.
*
When the solder starts to melt and flow wait till it covers evenly the area around the hole and the flux boils and gets out from underneath the
solder.
*
The whole operation should not take more than 5 seconds. Remove the iron and allow the solder to cool naturally without blowing on it or
moving the component. If everything was done properly the surface of the joint must have a bright metallic finish and its edges should be smoothly
ended on the component lead and the board track. If the solder looks dull, cracked, or has the shape of a blob then you have made a dry joint and
you should remove the solder (with a pump, or a solder wick) and redo it. Take care not to overheat the tracks as it is very easy to lift them from the
board and break them.
*
When you are soldering a sensitive component it is good practice to hold the lead from the component side of the board with a pair of long-nose
pliers to divert any heat that could possibly damage the component.
*
Make sure that you do not use more solder than it is necessary as you are running the risk of short-circuiting adjacent tracks on the board,
especially if they are very close together.
*
When you finish your work, cut off the excess of the component leads and clean the board thoroughly with a suitable solvent to remove all flux
residues that may still remain on it.
PCB - Connections
————————————————————————————————————————————————————————————————————————————
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387699.gif
(原文件名:pcb12.gif)
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387700.gif
(原文件名:pcb22.gif)
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387701.gif
(原文件名:layout2.gif)
Construction (... continued)
————————————————————————————————————————————————————————————————————————————
As it is recommended start working by identifying the components and separating them in groups. Place first of all the sockets for the ICs and the
pins for the external connections and solder them in their places. Continue with the resistors. Remember to mound R7 at a certain distance from the
printed circuit board as it tends to become quite hot, especially when the circuit is supplying heavy currents, and this could possibly damage the
board. It is also advisable to mount R1 at a certain distance from the surface of the PCB as well. Continue with the capacitors observing the polarity of
the electrolytic and finally solder in place the diodes and the transistors taking care not to overheat them and being at the same time very careful to
align them correctly.
Mount the power transistor on the heatsink. To do this follow the diagram and remember to use the mica insulator between the transistor body and
the heatsink and the special fibber washers to insulate the screws from the heatsink. Remember to place the soldering tag on one of the screws from
the side of the transistor body, this is going to be used as the collector lead of the transistor. Use a little amount of Heat Transfer Compound between
the transistor and the heatsink to ensure the maximum transfer of heat between them, and tighten the screws as far as they will go.
Attach a piece of insulated wire to each lead taking care to make very good joints as the current that flows in this part of the circuit is quite heavy,
especially between the emitter and the collector of the transistor.
It is convenient to know where you are going to place every thing inside the case that is going to accommodate your power supply, in order to
calculate the length of the wires to use between the PCB and the potentiometers, the power transistor and for the input and output connections to the
circuit. (It does not really matter if the wires are longer but it makes a much neater project if the wires are trimmed at exactly the length necessary).
Connect the potentiometers, the LED and the power transistor and attach two pairs of leads for the input and output connections. Make sure that
you follow the circuit diagram very care fully for these connections as there are 15 external connections to the circuit in total and if you make a
mistake it may be very difficult to find it afterwards. It is a good idea to use cables of different colours in order to make trouble shooting easier.
The external connections are:
- 1 & 2 AC input, the secondary of the transformer.
- 3 (+) & 4 (-) DC output.
- 5, 10 & 12 to P1.
- 6, 11 & 13 to P2.
- 7 (E), 8 (B), 9 (E) to the power transistor Q4.
- The LED should also be placed on the front panel of the case where it is always visible but the pins where it is connected at are not numbered.
When all the external connections have been finished make a very careful inspection of the board and clean it to remove soldering flux residues.
Make sure that there are no bridges that may short circuit adjacent tracks and if everything seems to be all right connect the input of the circuit with
the secondary of a suitable mains transformer. Connect a voltmeter across the output of the circuit and the primary of the transformer to the mains.
DO NOT TOUCH ANY PART OF THE CIRCUIT WHILE IT IS UNDER POWER.
The voltmeter should measure a voltage between 0 and 30 VDC depending on the setting of P1, and should follow any changes of this setting to
indicate that the variable voltage control is working properly. Turning P2 counter-clockwise should turn the LED on, indicating that the current limiter is
in operation.
Adjustments
————————————————————————————————————————————————————————————————————————————
If you want the output of your supply to be adjustable between 0 and 30 V you should adjust RV1 to make sure that when P1 is at its minimum
setting the output of the supply is exactly 0 V. As it is not possible to measure very small values with a conventional panel meter it is better to use a
digital meter for this adjustment, and to set it at a very low scale to increase its sensitivity.
Warning
——————————————————————————————————————————————————————————————————————————
While using electrical parts, handle power supply and equipment with great care, following safety standards as described by international specs and
regulations.
CAUTION
This circuit works off the mains and there are 220 VAC present in some of its parts.
Voltages above 50 V are DANGEROUS and could even be LETHAL.
In order to avoid accidents that could be fatal to you or members of your family please observe the following rules:
- DO NOT work if you are tired or in a hurry, double check every thing before connecting your circuit to the mains and be ready
- to disconnect it if something looks wrong.
- DO NOT touch any part of the circuit when it is under power.
- DO NOT leave mains leads exposed. All mains leads should be well insulated.
- DO NOT change the fuses with others of higher rating or replace them with wire or aluminium foil.
- DO NOT work with wet hands.
- If you are wearing a chain, necklace or anything that may be hanging and touch an exposed part of the circuit BE CAREFUL.
- ALWAYS use a proper mains lead with the correct plug and earth your circuit properly.
- If the case of your project is made of metal make sure that it is properly earthen.
- If it is possible use a mains transformer with a 1:1 ratio to isolate your circuit from the mains.
- When you are testing a circuit that works off the mains wear shoes with rubber soles, stand on dry non conductive floor
- and keep one hand in your pocket or behind your back.
- If you take all the above precautions you are reducing the
- risks you are taking to a minimum and this way you are protecting
- yourself and those around you.
- A carefully built and well insulated device does not constitute any danger for its user.
- BEWARE: ELECTRICITY CAN KILL IF YOU ARE NOT CAREFUL.
If it does not work
——————————————————————————————————————————————————————————————————————————
Check your work for possible dry joints, bridges across adjacent tracks or soldering flux residues that usually cause problems.
Check again all the external connections to and from the circuit to see if there is a mistake there.
- See that there are no components missing or inserted in the wrong places.
- Make sure that all the polarised components have been soldered the right way round. - Make sure the supply has the correct voltage and is
connected the right way round to your circuit.
- Check your project for faulty or damaged components.
Parts List
————————————————————————————————————————————————————————————————————————————
R1 = 2,2 KOhm 1W
R2 = 82 Ohm 1/4W
R3 = 220 Ohm 1/4W
R4 = 4,7 KOhm 1/4W
R5, R6, R13, R20, R21 = 10 KOhm 1/4W
R7 = 0,47 Ohm 5W
R8, R11 = 27 KOhm 1/4W
R9, R19 = 2,2 KOhm 1/4W
R10 = 270 KOhm 1/4W
R12, R18 = 56KOhm 1/4W
R14 = 1,5 KOhm 1/4W
R15, R16 = 1 KOhm 1/4W
R17 = 33 Ohm 1/4W
R22 = 3,9 KOhm 1/4W
RV1 = 100K trimmer
P1, P2 = 10KOhmlinear pontesiometer
C1 = 3300 uF/50V electrolytic
C2, C3 = 47uF/50V electrolytic
C4 = 100nF polyester
C5 = 200nF polyester
C6 = 100pF ceramic
C7 = 10uF/50V electrolytic
C8 = 330pF ceramic
C9 = 100pF ceramic
D1, D2, D3, D4 = 1N5402,3,4 diode 2A - RAX GI837U
D5, D6 = 1N4148
D7, D8 = 5,6V Zener
D9, D10 = 1N4148
D11 = 1N4001 diode 1A
Q1 = BC548, NPN transistor or BC547
Q2 = 2N2219 NPN transistor
Q3 = BC557, PNP transistor or BC327
Q4 = 2N3055 NPN power transistor
U1, U2, U3 = TL081, operational amplifier
D12 = LED diode
——————————————————————————————————————————————————————————————————————————————
增加了压流表和外壳后的图片：
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387698.jpg
(原文件名:P1010016.jpg) mark!! 不错 春风，可不可以帮忙解析一下他那个负电压部分的电路啊？？R3,D7,C3…… 【3楼】 jamiedu
春风，可不可以帮忙解析一下他那个负电压部分的电路啊？？R3,D7,C3……
-----------------------------------------------------------------------------------------
这个电路我是这样理解的：
1.交流电正半周时，输入端1为正，输入端2为负，电流走向是输入端1到D1到C1到D4到输入端2，给C1充电
2.交流电负半周时，输入端2为正，输入端1为正，电流走向是输入端2到D2到C1到D3到输入端1，给C1充电
完成桥式整流的一个循环过程。
在交流电负半周时还有一个电流回路：输入端2到R2到C2到D5到D3到输入端1，完成了给C2也充上了和C1
差不多相同的电压
3.交流电的第二个周期的正半周时，重复步骤1的给C1充电过程，在给C1充电同时，还有一路
电流回路，就是：输入端1到D1到C1到C3到D6到C2到R2到输入端2，就是C2向C3放电的过程
使C3充电产生负电压，经R3限流D7稳压提供运放负电源的供电。 学习了 串联稳压，效率极低。不符合环保要求。 MARK 谢谢春风。 好孩子，mark 这个电路我试过的，在12V以下工作时，1A的时候开关管发热就特别严重，后来在前面加了一级可控硅电路才改善 好东西啊，正是我想要的
不知楼上的是怎么改善的呢？ 有没有后续的参考图 风兄,什么时候出高级版的电源?
高级版面对的客户群更高端,应该和2.2版没冲突. 春风兄分析的精彩，学习了。 【10楼】 praxis
可以把可控硅电路发上来吗？我也做了这个电路，5V功率管热的很厉害。一直没有找到合适的解决方法。 前面加个开关电源进行跟随。 Cool 最近做这个，也搜到了这个电路图，上传中文繁体字版。
http://cache.amobbs.com/bbs_upload782111/files_39/ourdev_641037GOQ53J.jpg
(原文件名:原理图.jpg)
点击此处下载 ourdev_641038UT2KYI.pdf(文件大小:155K) (原文件名:0-30V-VV-VC-PSU.pdf) mark 看看 这个电路里面的稳压管是出于恒流状态的，应该稳定性不错！ mark mark...... mark 标记 好东西要学习的 mark mark mark 学习 mark 学习了~~~ 有空做一做 mark mark markmarkmark~~~~ g00d mark 学习下 这个要码住。 mark 看不懂 mark 引用图片【楼主位】jamiedu A&C
-----------------------------------------------------------------------
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387699.gif
(原文件名:pcb12.gif)
引用图片【楼主位】jamiedu A&C
-----------------------------------------------------------------------
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387699.gif
(原文件名:pcb12.gif)
引用图片【楼主位】jamiedu A&C
-----------------------------------------------------------------------
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387700.gif
(原文件名:pcb22.gif)
引用图片【楼主位】jamiedu A&C
-----------------------------------------------------------------------
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387701.gif
(原文件名:layout2.gif)
引用图片【楼主位】jamiedu A&C
-----------------------------------------------------------------------
http://cache.amobbs.com/bbs_upload782111/files_10/ourdev_387698.jpg
(原文件名:P1010016.jpg) mark! 不怎么懂 不懂，mark一下 果断mark！ 各种不懂，回去画一下 貌似水平太差了，還看不懂 mark mark 非常不错，MARK GOOD 我一定的好好看看！ Mark一记~~~ 马克
！！ 负压产生电路不错，mark。 这个得mark mark 电源 mark mark 谢谢 电源看起来简单做起来烦啊 mark！！ 记号 学习！ 看不懂我的功力不行的 希望通过后续的学习能有些进步吧 先mark吧 http://cache.amobbs.com/bbs_upload782111/files_49/ourdev_706486IBWW79.jpg
N-MOSFET应用 (原文件名:2007928151110379.jpg)
参考一下。 嗯，谢谢！ 不错不错不错 再次mark！！！！ 看不懂，记下，下次再看，最近也想做个电源，但启动电压要很低，0.5V吧。 路过，学习一下 运放上正负电压不相等？负电压好象用D7稳在了－5.6V左右。 mark！{:biggrin:}{:biggrin:} cool
页:
[1]