testing IC TL494 and its analogues

(M1114EY4, mPC494C, IR3M02)
The typical circuit ps AT, 39k
schemes ps ATX, 220k

Into structure by this IC enters: the specifying generator of a sawtooth pressure(voltage) А1,
The frequency of the generator is set by the external resistor R1 by the condenser C1 and can
To be approximately determined under the formula f=1 / (C1*R1). R1 is included between
By conclusions 6 and 7, and C1 between conclusions 5 and 7. Amplitude of a saw does not depend from
Face values R1 and C1 also is approximately equal 4В; the amplifier of a circuit of a feedback
DA2; the pulse-width modulator, made'ing on the comparator DA4; the amplifier
Protection PS from overload on current or short circuit on
To loading DA1; a divider of frequency on two, executed on accounting trigger DD2;
Cascades of concurrence on elements DD1, DD5, DD6; the cascade on the comparator DA3,
Allowing to construct:

- Circuit of exception overpower on an output(exit) of the converter in transitive
- Circuit of restriction of a range of change of factor of filling in
Necessary limits;
- Circuit of maintenance of a smooth output(exit) of the converter on a mode.
And also includes:
- Logic elements DD3, DD4 intended for the task of a mode
Managements or single-cycle or push-pull by converters;
- Target transistors Q1 and Q2;
- Built - in continuous stabilizer of a pressure(voltage) DA5 and relay of a pressure(voltage)
( Threshold unit) DA6;
- Untying diodes D1, D2 for maintenance of function "OR" for target(day off)
Signals of microcircuits DA1, DA2.

The microcircuit of management works as follows.
The continuous stabilizer of a voltage provides with a feed(meal) all
Functional units IC also sets optron a pressure(voltage) +5V (conclusion 14)
Concerning a general(common) conclusion 7. The relay of a pressure(voltage) DA6 permits passage
Signals of management on bases of transistors Q1 and Q2 only in the event that
DA5 Has left on a mode.

The sawtooth pressure(voltage) (conclusion 5), developed generator А1, acts
On an input(entrance) of comparators DA3, DA4.
On other input(entrance) of the SIP-COMPARATOR DA4, through the untying diode D2 acts
Signal of a mismatch from the amplifier of a mistake DA2. On one of inputs(entrances) DA2,
Directly or through a divider, the source basic is connected
Pressure(voltage) from a conclusion 14, and on other input(entrance) the voltage of a circuit by opposite acts
connection, i.e. target any of the channel (it is usual from the channel +5В). Between
Conclusions 3 and 3, as a rule, is included adjusting RC-circuit for
Maintenance of steady work of the stabilizing converter. From an output(exit)
THE SIP-COMPARATOR the rectangular pulses act on one input(entrance) of the circuit
Concurrence DD1, with its(her) output(exit) pulses pass on accounting тригер DD2 and on
The circuits of concurrence DD5, DD6.
If on a managing input(entrance) of elements DD3, DD4 (conclusion 13) is sent logic
Unit, a microcircuit provides management push-pull
By converters with pauses on zero, and if on a conclusion 13 is sent logic
Zero (conclusion 13 connect with conclusion 7), DD2 does not affect on
Work of keys DD3, DD4 and in this case microcircuit can be used
For SIM or FIM of management single-cycle transform. For construction
Protection of overloads on a current, as it was marked earlier, can be used
DA1, thus on one of its inputs(entrances) the basic voltage moves,
Determining a level of operation current of protection, and on the second input(entrance) moves
Signal from the gauge of a current.

The units with use of the circuits DA1 and DA3 can be diversified.
Some examples are considered at the description of the below-mentioned circuits of blocks
A feed(meal).

3.2. Basic parameters M1114EY3, M1114EY4 U IC(conclusion 12) - Umin=9V; Umax=40V Allowable voltage on an input(entrance) DA1, DA2 no more Uпит/2 Allowable parameters of target transistors Q1, Q2: Uke less 40V; Ik.max Less 250mA Residual voltage a collector - emmiter of target transistors No more 1.3V. I consumed by a microcircuit - 10-12mA Allowable capacity of dispersion: 0.8W At temperature air +25C; 0.3W At temperature air +70C. Frequency of the built - in basic generator no more 100KHz.
The conclusions M1114EY4 completely correspond(meet) above listed foreign To analogues, and the conformity between conclusions M1114EY3 and M1114EY4 is submitted Below. M1114EY4 - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 M1114EY3 - 4 5 6 7 8 9 15 10 11 12 13 14 16 1 2 3
Algorithm of search of malfunctions M1114EY3, M1114EY4 Check of serviceability of a microcircuit is made at switched - off PS (power supply) and at A feed(meal) IC from external IVEP by a pressure(voltage) +9В... +15В sent on 12 conclusion Rather 7-th. All measurements will be carried out(spent) too rather of 7-th conclusion. Except for that connection to IC is better to carry out connect wires, instead of with By the help of "crocodiles", it will ensure(supply) raised(increased) reliability of contact and Will exclude an opportunity of false contacts. 1. At submission of an external voltage oscillograf a pressure(voltage) on 14 Conclusion, it should be +5V (+ /-5 of %) and to remain stable at change Pressure(voltage) on 12 conclusion from +9V up to +15V. If it does not occur, Means there was out of operation internal stabilizer of a voltage DA5 2. With help oscillograf notice presence of a sawtooth voltage on Conclusion 5 (see fig.1.1a Uin DA4) if it is absent or has deformed The form, is necessary is to checked up by(with) serviceability времязадающих of elements C1 and R1 Connected accordingly to 5 and 6 to conclusions, if these elements Are serviceable, the built - in generator is faulty and the replacement ИС is necessary. 3. We check presence of rectangular pulses on conclusions 8 and 11. They owe To correspond(meet) to the diagram 5 and 5 ' in a fig. 1.1. If the pulses are absent, ИС is faulty, and if are present, we check serviceability others Units IC. 4. Having connected a conductor 4-th conclusion with 7-th, we should see, that width Pulses on 8-м and 11-м conclusions has increased; having connected 4-th conclusion with 14-м The pulses should disappear, if it is not observed, it is necessary to change ИС. Having lowered a voltage of an external source up to 5V, we should see, that pulses Have disappeared (it speaks, that has worked the relay of a pressure(voltage) DA6), and having lifted Pressure(voltage) up to +9V... +15V pulses should again appear, if it not Has taken place also pulses (which can be any) are present on 8 and 11, then in ИС the relay of a pressure(voltage) is faulty and the replacement is necessary Microcircuits. 5. Check of serviceability DA2. We remove the earlier established crosspiece Between 4-м and 7-м by a conclusion, we submit on 12 conclusion a pressure(voltage) of a feed(meal) in limits +9В... +15В and having connected 1-st conclusion with 14-м we should see, that on 8-м and 11-м Conclusions width by a pulse became iqvival to zero, if it does not occur, DA2 Is faulty and it is necessary to change IC. 6. In PS in a fig. 2, the fig. 3, .4, DA1 is used in units current of protection and If the previous tests have shown, that all other units IC function It is normal, the check of serviceability DA1 is carried out as follows: We submit on 12 conclusion +9V... +15V also is observable on 8 and 11 meandr Pulses. From other power supply submit negative pressure(voltage) on 15 conclusions (rather 7-th) thus pulses on 8 and 11 should disappear. If it does not occur, then unit of protection on DA1 does not work.

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