Inferno #05 30 апреля 2004

Железо

Iron - Once again, the protection circuits KR1818VG93.

Once again, the protection of KR1818VG93

       Once again, the protection of KR1818VG93.

  KSA-7G


   Recently in our town died three floppy drive controller 
podryad.Pervy - through an electromagnetic pulse, and the rest 
themselves. Probably were already podpalennye. Personally, I do 
not burn, though long ago, when I picked her, not then, my PC 
at STEVE, the controller died. Like, from DAVE

I heard that there is a fire-proof mikruhi, and seems to have 
such DAVE. Even at the Pentagon schemes 128 + written about the 
connection of output power 12 In the main terminal, in case the 
power supply through one of nih.Eto was done to the controller 
was applied immediately and 5, and 12V. Then I learned that the 
disappearance of 12B in the presence of +5 V mikruhu burns. Sad 
but true! 

   Then he heard about some protection, but
did not know what. And since I did not have
documentation, I especially did not think about it, bought a 
spare mikruhi, propayal and obkonderil complex, and no problems 
bylo.Ya decided that the electronic key to the +5 V on VGshku,

which turns off the power during the failure
+12 V, is comparable in complexity and the fact reliability is 
normally collected by comp. Ie easier propayat or well to 
collect a block nutrition and self Speccy, than the city 
makeweights. As a result, reliability depends on the quality of 
used parts, and the risk of burning the controller part is 
proportional to their number. 



         From the stories my Speccy.


   Prisvisnuty PSU (partnerovsky) does not always correctly 
included, but it worked, whistling horosho.Pozdnee 
dosvistelsya, I found a bad place and propayannoe zatknul it 
... But once he ceased to be included, and I decided to buy a 
good PC-shny block supply. At 230 W power. And since they are 
sometimes explode (overvoltage does not stand varistor), bought 
a surge protector Pilot-GL, no regrets, as he removed

picture noise from the fan PSU.

   Thinking about the possible failure stress on the network 
decided to put makeup literally seconds to ten (the batteries 
were old, but the food a while, I thought, pull). Collected 
charging scheme, but there was a problem ... You should have 
two voltages. I thought at the time of disabling the main 
support logic - as if the drive does not prescribe, we can 
survive even when a voltage is applied to seti.Takim, I decided 
to feed the 5V battery companies, and 12 do not feed. But the 
disk controller must nurture and because it is short, I decided

use the capacity of 4700 uF. Of course,
to eat only the controller, and Conder
not discharged to the drive, put the diode.
To reduce the losses - germanium, such as D9,
anode at 12, the cathode to the controller and
Conder plus (minus to minus Conder companies, of course).

   And an electronic switch with the relay to 12V, which is fed 
from another Conder large capacity. The idea is that when power 
failure an electronic switch was to connect the batteries to +5 
V companies, with the controller and relays fed

by Conder. By reducing the supply (if
network and not included) relays logged in batteries - PC 
switched off. This has happened before sinking power 
controller, and therefore he could not burn. 

   All would be nothing, but I have broken off with 
akkumulyatorami.Oni not not want to work, see, were already 
worn out - once I them given as unnecessary. In the end, I 
soldered scheme and threw batteries, but Conder

recharge the controller and a diode ostavil.Ne were needed and 
not interfere with the scheme. 

   Then I bought bespereboynik POWERCOM. AND
time: started disruptions in the network, it is not just
I vyruchil.Ni never fully discharged - the maximum switched off 
for 15 minutes. 



            The passion to protect.


   When there were three unexpected combustion KR1818VG93, I 
thought it would be good somehow protect mikruhu. One friend 
said that it is done by two diodes, but I do not represented as 
possible, then he said that during the failure of the +12 V 
remain 5, and mikruha, though not working with this

reduced, but not burnt. Then all became
clear. This again feature the chip. After
There mikruhi not tolerate even a small decline, but there are 
those who do not allow some logical options

control signals (general insanity!) - some old PZUshki.



    Few of the most mikruhe KR1818VG93.


   According to data from some books
Speccy, this chip, as an analogue of a
imported or manufactured by the n-MOS technology. 
T.e.ispolzuyutsya transistors of one Type: field, n-channel 
MOS. This is the one hand, is easier to do, but the scheme 
within mikruhi more cumbersome. 

   I suggest that to improve the reliability and performance 
using an additional supply voltage: +12 V. Main - +5 V. 
Additional uses for the same bias control voltage and current 
switching keys. In some cases, it is unlocked in the other 
(with inversion) zapirayuschee.Otsutstvie it may disrupt the 
logic mikruhi and cause a large pass-through current through 
its unbiased cascades. As a result, logic is overheating, and 
an unrecoverable thermal breakdown. 

   It seems to be (long ago it was ... I do not remember), y
faulty mikruhi increased temperatura.Normalny chip - just warm 
and dead - Tolerates hot. (Ed.: it depends.) If

remember that power is not gobbling VGshkoy
more than 0.5W, and the surface area is much
more than an equally powerful resistor
It will be really warm (not long to resistor kosneshsya) in 
good sostoyanii.Otsenka complicated by the fact that in a 
closed body temperature is much higher. But not

be afraid, for adequate nutrition, even
in the heat, the temperature is far from critical.

   For technical data, mikruha consumes less than 20mA of 
supply voltage +12 V. It can be assumed (quite logically)

that at lower voltage consumption
to +12 V current is also reduced, again, I will not argue, do 
not meryal.Zamechu that the decrease core logic supply may lead 
to increase current consumption due to violations of key modes, 
and possible self-excitation of individual kaskadov.No it 
refers to a complex scheme for single mikruhi unlikely. In any 
case, while reducing power within acceptable limits, and even 
slightly over the limit, there is a direct correlation - the 
current also decreases, while reducing the unacceptably strong 
- can dramatically increase. Favorable condition is the scheme 
without Conder in the food chain, it can fail for any reason. 

   Usually in the literature on the application of the
a series of chips indicate nominal
capacitor and the number of chips for which you want to put 
Conder. Usually 1 Conder on 10 chips. Under these and load 
(output) conditions bessboynaya guaranteed work schemes of any 
complexity for any voltage in the permissible range (eg, TTL 
4.75Ў5.25). 

   If the voltage of +12 V will fall, but will not disappear 
entirely, the work KR1818VG93 violated - I can not imagine that 
it would create. But a small offset voltage will not allow a 
complete violation of modes and unlocking / electronic locking 
klyuchey.Tok consumption will grow to a certain limit, 
depending on the remaining voltage on the leg 40. Mikruha will 
bask and sboit.Pri further reduce the voltage of +12 V 
unregulated tokopotreblenie will increase and lead to 
overheating. Conclusion: do not allow the complete 
disappearance of the auxiliary voltage. Due to the nature 
mikruhi it allows you to dispel the increased power

and does not overheat, if the stress on the leg
40 had not fallen below 4V.



              End of story.


   By opening your computer, I remembered the old English 
(supposedly) saying: "do not break - Do not touch "(or 
similar), confirmed by a couple of years ago: put the scheme 
384X304, and the system passed out for a week due to 
imperceptible crumb of solder, it is unknown how did the 
ill-fated place. 

   Well, since I decided to ... Withdrew flopogryz and
fee (AY, Kempston Joy., Z80, amp.) unsolder
barrel Conder (4700/16), which hung over
kontrollerom.Odin diode already have - from the previous 
experiments, it remains to solder a diode from +5 V to the 
controller, and high-frequency, tradition, Conder 0.1mkF. 
Instinctively, I take tester and check the soldered diode - it 
is closed! Maybe I'll put a jumper somewhere ... But what for? 
Something I do not remember ... Unsolder diode checked - he's 
trying! Why would it? Certainly not to 20mA, which eats the 
controller! Maybe a marriage? However, remembering all the 
features I have connected circuitry, I understood why it 
happened. 

   As is known, the rate of increase of supply voltage at the 
pulse blocks more than the transformer. The latter rectified 
voltage drops to the required, output, and because of the low 
(100Hz) frequency power using large containers that are not 
immediately charged, and, consequently, gradually increases the 
output voltage bloka.Poskolku frequency conversion of pulsed 
power supply is high, on their way out are Conder small 
capacity, and power supply very quickly established after 
inclusion. Of course, Conder's nutrition VGshki (I 4700mkF) 
requires a large current for fast charge, as its capacity is 
more than kodensatorov in switching power power, he is charged 
under the same conditions medlenney.A given more power power 
supply, ready to give more current to charge point germanium 
diode such current could not resist, here are his and struck - 
overheated, melted and locked inside ... 

   I soldered a diode according to two new schemes
protection, Conder 0.1mkF, and could turn off
electrolyte (for me and so good food)
but more interesting to solve the problem than to abandon it.

   The problem is that when you turn flows
high current charge and must be abated. Of course, ideally put 
in series with Conder choke (inductor),

but its value must be very large,
and hence, inconvenient size. Can
put a resistor, but such that the loss
on it at a food VGshki from Conder were
minimal. So I did ...

   Soldered in series with Conder rezyuk
10 Om.Mgnovenny charge current when you turn on will not exceed 
1A, and will fall. Overloading will last no longer than a 
second, and germanium diodes (and transistors) allow great 
multiplicity of overload for a short period of time. With 
regard to the capacitor 0.1mkF, which is directly soldered to 
the diode without resistor, its charge time (due to low 
capacity) is much lower than rise voltage pulse, even the 
block. For several months I have hundreds of time includes the 
system, but diodes are not struck, so that the scheme is quite 
reliable. 



                  Scheme # 1.

    +12

     | Diodes - almost all (thin)

     |

  ---+--- DalekOoo not the full list:

    | /

    | / KD521, KD522, KD503, KD510, D220

    | / KD105, D106, KD509, KD102, KD103

  ---+--- D223, D226, D7, D310, D311, D312

     | (All with any letter index)

     |

     *------> The 40 th leg KR1818VG93

     | /

     | Absolutely not be ISPO
  ---+--- Lzovat power and vysokovolt
    / | Nye diodes. Best germanium
   / | Curves (Ge) diodes. Namely:

  / |

  ---+--- D9B, D9G, D9D, D9E, D9I, D9K, D9M

     |

     | On the other letter is not used!

   +5 V


   The very minimum that is probably used by other companies 
and ORIONah 80-90 godov.Verhny diode - basic and nourishes 
mikruhu in normal mode (the presence of +12 V) and the lower 
operating in emergency mode (no +12). T.e.diody like change 
places for eating disorders. 



           The implementation of the scheme # 1.


   Comfortable doing it on the back side
board. But the track (+12 V power connector from
to pin 40) may be from the other side. Look for the track and 
cut ee.Obychno everything can be checked visually. But not rely 
on A-EIGHTH, in doubt - check the tester. VGshka usually in the 
sockets, remove it, cut the track, can enable 5V power supply 
and check on the derivation of 21 and 0V at pin 40.


   At Pentagonah output diodes enough
solder them to the back of the card
directly from the XP3 connector pins B20,
B21 to D90 stem 40, a diode from the 5V attached to a 
neighboring mikruhe D52 (LL1) leg 14. On other systems may have 
to extend the findings of the diodes. Better wire MGTF. 

   Isolate conclusions can cambric suitable diameter, duct tape 
or duct tape. You can use the spray (TSAPONLAK) - it dries 
quickly and seals of (times 3 apply). But the main thing - it's 
soldered, good, accurate, she will keep diodes.


   Attention! If your card is just lying around in a plastic 
case, beneath the it at least a newspaper, not to split the 
diodes, especially germanium! Or collect the protection of the 
installation, my Speccy so is.


   Finally, check all visual, no polenites.Mozhete zvyaknut 
device shemu.Ot positive probe, with +5 V and +12 V to the 
negative probe of stem 40 readings should be much less (for 
resistance) than vice versa (from 40 feet to plus food

com). Turn on PC without VGshki and trying
voltage sockets (minus a leg at 20,
plus on the leg 21 - must be 5V, and plus
on foot 40 - should not be less than 11V).
If the power is there, you can turn off the computer,
insert (PRAVILNO!) VGshku and not be afraid
for its fate. Otherwise, look for the cause of breakup,
from the power supply and fault
ending sverhprozhorlivym device, which
you measured with a voltage. By the way, continuity
scheme readings can vary smoothly due to overcharging of 
capacitors in circuits of power companies, so we have to wait 
when the rate of change in testimony did not reach the junior 
level in the second. 



                 Scheme # 2.

    +12

     | I set it to all the Speccy

     | (Which serve at home)

  ---+--- Since 2003.

    | /

    | / Diodes are the same.

    | /

  ---+--- Conder makes life easier on failure.

     |

     |

     *-----------*----> The 40-th leg

     | | / KR1818VG93

     | |

  ---+--- |

    / | ----- Capacitor at any

   / | ----- 0.1mkF. But it is more convenient

  / | | Date, is maximal
  ---+--- | FIR sizes.

     | |

     | ------
   +5 V (minus common)


   Characterized by the presence of the capacitor, shunting the 
RF interference 12V. Need for it no, because with good 
nutrition constant component is much larger than Level pomeh.V 
normal work it does not affect, except that an insignificant

(Percent) reduction in noise from the very
VGshki. Another matter emergency power supply, t.e.ponizhennoe 
stress. If +12 V simply disappear, and 5V will be normal, 
Conder is not needed. Actually, this is the most likely 
emergency situatsiya.No may feed will be confused - 
interference may further overheating VGshku. Capacitor excludes 
the option of t.k.snizhaet oscillation amplitude to an 
acceptable level when Key performance mikruhi enough to respond 
to changing supply. 

   On the one hand, it is absurd, t.k.pitanie
contains a large electrolytic Conder
containers that do not allow dangerous
interference (but should be more simple nonpolar Conder, 
parallel polar optimalnoe ratio Cnepol = Cpol / (1e3Ў1e4)), 
with On the other hand, this is my konderny caprice

I do not feel sorry for Conder for pure power. A
How is your system? Maybe everyone already
worn, posohlo ...



           The implementation of the scheme # 2.


   All similar to the first circuit, the capacitor
also conveniently placed on the reverse side
board. However, his body can rest
on board and more stable to hold onto
rations. Connect to negative on Pentagon'ah
You can have D52 legs 7, the other systems, see for yourself.

   In one Tower'e fee Pentagon'a hung
on the racks, I soldered Conder and a diode from the 5V with
the reverse side, and a diode with 12V directly to the power 
cord and a wire connected to MGTF with the board (board was 
without connectors), himself a diode placed in kembrik.V 
finally cut a track on the board was not necessary. Of course, 
flopogryz ate a separate wire. 



                 Scheme # 3.

    +12

     | How to serving my Speccy.

     |

  ---+--
    | / Diodes were used and non-polar

    | / Conder - the same (see above).

    | /

  ---+--- Good scheme for a weak +12 V

     |

     | To the 40-kovoy

     *-----------*-------*-----> Leg

     | | / KR1818VG93

     | |

  ---+--- | 10 Ohm

    / | ----- 0.125Vt

   / | ----- +

  / | | 4700mkF

  ---+--- | 16B

     |

     |

   +5 V (minus common)


   Differs from the previous presence RCtsepochki: polar 
capacitor rezistora.Eta scheme really makes sense for lousy 
food. Lousy, in the sense of understated - somewhere in 
derevne.Konechno if you have a switching power supply, can not

worry, but if the transformer, and
voltage on the verge of decline, it is better to put a 
zaschitu.Osobenno if the light is often prigasaet (vibrations 
noticeable to the eye). However, if you have a +12 V is 
obtained from the 18B above, we can not bespokoitsya.A if the 
15V, and by Krenke (integral stabilizer

with three legs), and flopohrust old type
with an electromagnetic lock head ... In
Overall, there may be problems ...

   Popular integral stabilizers
eaten by at least 2 V difference between the input and
napryazheniem.I weekends if you need to 12V
Serve at least 14, or no stability budet.I not aware that under 
load the voltage drop at the entrance, and must supply at least 
1.5V. 

   Drive guzzles energy pulse, and
lack of tension pulls the current, causing further decline in 
the +12 V, with VGshka this may fail. Remember, there were a

writing files with errors? discs do not deteriorate
in the evenings? Evening meal reduced, the people sitting at 
home watching all advertising and pop music ...


   This scheme saves from short-term
voltage drops (literally 1-2 seconds).

   Energy is stored in a capacitor. Resistor is needed to limit 
the charging current (at inclusion). Without the resistor can 
punch diod.Rezistor can be removed if we use average power 
diode (D7), but it's same way. Enhance the capacity of the 
impractical it is dangerous for the upper diode and increase 
the resistance - increasing the loss of emergency power. In the 
diagram, 10 ohms, the loss of all 0.2V, but raise them 
nezhelatelno.Pri emergency power supply voltage has already 
reached 11B instead of 12 will decrease. Reduce the capacity 
impractical due to the reduction of time the emergency power, 
then it is better block normal power supply.




           The implementation of the scheme # 3.


   First, you can put diodes and nonpolar Conder, and then 
dopayat RC-chain. 

   These parts are (at least, Conder)
under the card is not relevant. We'll have to hang
sverhu.Minus Conder to minus some
mikruhi, the hole in the track power. Himself
Conder mikruhi can be put on top, but
if it is old - in an aluminum housing, it is better to wrap his 
tape to see if touched on other Conder, not locked power. Plus 
Conder solder to the resistor with long enough legs to reach 
the sockets VGshki. However, solder conclusion of the assembly 
to the leg sockets almost impossible, so the output resistor

extension wire and slid under the plateau where
and solder. Rezyuk insulating tape, adhesive tape or varnish.

   Fortunately, my Pentagon'e track
Power of VGshki top, and I did not have
pull the wire down. I cut the track and
brought the whole scheme of the sockets, solder postings MGTF 
intersected by the track. True, Conder rests with VGshke, and 
without Desoldering mikruhu it is not replaced. Maybe someday 
throw this RC-chain, yet power supply current.




      Parts used in the schemes.


   If you find these components in the diagram, you can proceed 
to implementation, and If not found, then maybe you can help 
the following information. And also, if you are unsure about 
their knowledge and components ... Do not rely on the off 
chance! 



              Selection of the diodes.


   In general, you can use more than 68%
diodes, the old sample and 96% new.
But because many of the old diodes are inconvenient in size, 
and new ones are not always well common, and I have a little 
background material on the diodes, I selected the most Popular 
diodes last century, checked their identities and indicated on 
the diagram of the series. 

   Except in special cases can be used
Diodes with any letter index (letter,
written after the series). But germanium diodes is relatively 
weak, and so use is permitted only with letters. Generally, 
data on the diodes in the different references may be slightly 
different, and I chose the letters, which according to various 
sources will do. 

   Diodes are selected by two parameters: the maximum (nominal) 
Average (over time) rectified current Ipr = 20mA (better if 
larger, then the loss of the diode is less than) the maximum 
reverse voltage Uobr not less than 7V. I do not remember the 
diodes are not suitable for voltage, but these are -

a rare case (in particular, transitions
transistors, so they better not as diodes
use). More are diodes that are critical
dc.

   You can vlepit two diodes in parallel, but
we must remember that this is not resistors, and 
characteristics of the diodes must be equal, ie need to pick up 
the diodes with the same direct fall at the same temperature 
(to hold together a bit in one hand, and then compete 
separately). 

   You can vlepit two diodes D9 with any letter in parallel 
instead of one, if consistent with each will rezyuk 10 Ohm any 
power and accuracy. To select diodes You do not need.


   The lowest voltage drop is expected
(I have not tested), when used instead of
two germanium diodes, transistors (base
of collectors to join to form the cathode, and
anode emitter will - for the pnp type). But
selection is small, from small fit
a GT115, the remaining few Ueb. However,
I have data for all transistors.

   And the best just to buy diodes taste of
suggested above. Cost no more than two
rubles.



       Features selection of diodes.


   Why you should not use force
and high voltage diodes? Well, power can be
but they are great - uncomfortable and slightly
increases current consumption at 12V (for
leakage at 5 V) is, of course, to anything, but
unlikely to cause crashes - unless the 12V frankly parshivoe.A 
here high voltage diodes can not be used! They have increased 
voltage drop and, consequently, reduced power to VGshku.Krome, 
some diodes actually consist of several (Volt poles, and 
therefore can withstand a large reverse voltage). Placing such 
diodes, can cause a paradoxical situation: to put protection to 
VGshka not burned, and she podohla from a lack of tension. 

   Actually, why I prefer to use germanium diodes? They fall
smaller than silicon, and fewer losses
Power kontrollera.Konechno will work
and with silicon - the difference is only a fraction
volts. But someone has power and has worse
reduced. Can I guarantee bessboynuyu work at an even greater 
decline? After not for nothing that food is 12V with a 
tolerance of 5%, and no 10-11B, it is critical to 
primeru.Osobenno with emergency power (lower LED on 5V)

here is a question not a failure, and subsequent repair VGshki.

   If you have a good, well-regulated power supply,
can not think of the type of diodes. If
run down, it's better to put germanium. But
warn once, germanium (D9) is usually
in a more brittle-metal housing
and require more careful handling than
silicon (KD521). And if you are inexperienced in
this case, place the silicon.

   There are still microcomponents, and diodes, too,
They are inexpensive, and their parameters are probably
should be fine, but I would not use them because of 
inconvenient miniature montazha.Nadezhnost can be reached 
kompaktnosti.No below if you are developing his scheme to the 
disk controller, it is You can use minikomponenty - take place 
on board specifically for nih.Pravda, they are made from 
silicon, germanium pro I have not heard anything. 



          Selection of capacitors.


   All prosto.Rabochee voltage is not less
12B (previously issued such electrolytes)
possible, but growing dimensions.

   It is better to buy a modern - small
yellowish on 0.1mkF, because the old
green pellets typically 63V and above - are inconvenient in 
size, and small flat green tantalum - a long time for all 
posdavali money. Modern cost in a matter of

Dollars. But be careful with the solder away from
housing, some badly assembled, easy
come unsoldered.

   Electrolyte 4700mkF better imported,
t.k.nashi dry. Modern, a voltage
16B - convenient small size and isolated case. At higher voltage
should not be taken due to the increased size
and prices. Will cost RUR 10.



               Well, rezyuk.


   Nominal value of 10 ohms each (up to 20%, old
there were also 30%), precision and power. Better
0.125Vt power - it's small. More
power is inconvenient to install and very expensive rezyuk. 
Little is worth 50 cents. 

   Change denominations rezyuka and electrolyte
I consider it inappropriate, it is better to give
of Option 3, and gathered a good power supply, use Option 1 or 
2. 

   If you decide to put less Conder
capacity (10-100mkF), the resistor must
be at least 4.7 ohms. For larger capacity -
10 ohms, to a lesser can not put a resistor.

(C) KSA-7G -------> Read the rest ...