Voltage stabilizer to chip К174УН7

Very popular all any 12... 15 years ago chip К174УН7 (import analog - TBA810S), representing the integrated amplifier of capacity of sound frequency, now at creation of UMZCh is not used almost as to modern measures provides low quality of sounding. But radio fans continue to maintain "ruthlessly" this chip, creating on its basis various interesting devices [1,2].

B [3] was published by p article about an original voltage stabilizer on К174УН4А. In the detailed analysis of the circuit of the device it became clear that the similar stabilizer can be constructed and on more powerful chip К174УН7. However attempt of mirror transfer of the found circuit decision with К174УН4А on К174УН7 did not lead to expected result - stability of target tension appeared low therefore the circuit was processed, and that you see in drawing 1 as a result turned out.

the Compensatory voltage stabilizer works as p at chip К174УН7 in a range of entrance tension 8... 16 In (at U _vy = 5 In) also provides the loading current to 0,5 A.Pri increase in entrance tension with 8 to 16 In target tension changes no more than on 10 мВ (at a current to loading 0,3 And). Disseminated by the chip established on a heat-conducting path the capacity can reach 5 W.

Target tension of the device is defined by working tension of the connected stabilitron (VD1, VD2) plus 1... 1,5 V.Kondensator S4 are prevented by chip self-excitation, the R3 resistor provides stabilizer self-start at the connected low-impedance loading.

This stabilizer has no electronic system of protection against an overload or short circuit on an exit. The inexpensive being self-restored safety lock of FU1 of BOURNS firm is applied to protection of a chip against damages on 0,65 And the MF-R065 [4] type. At desire it is possible to enter and electronic protection as it is described in [3].

In a design can use MLT resistors, C1-4, C2-23 and others. The C4 condenser - K73-17, K10-17, KM-5. Other condensers - oksidny, K50-35, K50-16. Stabilitrons of VD1, VD2 steal up so that to receive the necessary target tension. On a place of VD1 it is possible to try stabilitron КС126К, КС126Л, КС175А, КС182А, КС482А. For obtaining target tension 5 In, VD2 gets out from КС126В, КС126Г, КС139А, КС407А, КС407Б. If in addition to tension 5 In and 9 In one more target tension is required, for example, 12 In, it is necessary to pick up a stabilitron copy from the types D814V, Д814Г, КС210Ж, КС211Ж and to establish the SA1 switch on bigger number of provisions. The chain of the most high-voltage stabilitron should not be disconnected, differently at the moment of SA1 switching on an exit there can be a surge in the tension close on amplitude to entrance tension.

the Light-emitting diode of HL1 intended for indication of normal work, it is possible to take p of any type from АЛ102, АЛ307, КИПД35, КИПД40 and others. the Chip is surely established to p by

on a ridge dural heat-conducting path. A standard ridge or shtyrevy heat-conducting path with which chips К174УН7 are usually equipped, К174УН9 in UMZCh of TVs and tape recorders, will be insufficiently for providing normal working temperature of IMS at maximum entrance tension and a current to loading. It is possible to use two such radiators if each of them to attach to one of heatby-pass flanges of IMS. For long-term reliable operation of the stabilizer it is necessary to aspire to that the temperature of the case of a chip did not exceed 50°С at the most rigid operating mode.

the Length of conclusions of a safety lock of FU1 from a soldering place to the case should be not less than 10 mm. That at connection of loading there was no chip self-excitation, alarm and power chains of the general wire need to be executed separate and to connect among themselves in one point. Chains of connection of condensers C1, С5 to a chip should be as it is possible more shortly. The target current of the stabilizer can be increased to 1 And provided that the capacity disseminated by a chip will not exceed 5 W.

Sources

1. I.Aleksandrov. Inverter of polarity of tension. - Radio, 1993, N11, Page 38.
2. I.Nechayev. The generator 34 on chip К174УН7. - Radio, 2002, N4, Page 52.
3. I.Nechayev. Chip К174УН4А - a voltage stabilizer of a direct current. - Radio, 1993, N9, Page 40.
4. Being self-restored safety locks of MULTIFUSE of BOURNS firm. - Radio, 2000, N11, Page 49... 51.

Author: And. БУТОВ, village Kurba, Yaroslavl Region