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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Chip KR1182PM1 - phase power regulator. Reference data
Encyclopedia of radio electronics and electrical engineering / Reference materials Chips KR1182PM1 - another solution to the problem of power regulation of high-voltage powerful loads. Microcircuits can be used to smoothly turn on and off electric incandescent lamps and change the brightness of the glow, to control more powerful semiconductor switching devices, to control the speed of electric motors. The devices are manufactured using epitaxial technology with dielectric insulation. Of the features of the regulator, it should be noted its ability to limit the power in the load when the maximum allowable temperature of the device case is reached. The KR1182PM1 regulator is designed in a plastic case of the all-European design POWEP-DIP (12+4). This is a sixteen-pin case (Fig. 1) with a metric pin pitch, in which pins 4, 5 and 12, 13 are left free. Mechanically and electrically, these pins are combined and designed to remove heat from the crystal. In addition to these, conclusions 1, 2, 7, 8 are also not used. The mass of the device is not more than 1,5 g.
In the early stages of mastering the microcircuit in production, it was produced in a frameless version and in the widespread European DIP16 package. On fig. 2 shows a schematic diagram of the regulator and a typical diagram of its inclusion. The microcircuit consists of two trinistors, each assembled according to the transistor analog circuit of the trinistor (VT1, VT2 and VT3, VT4) and connected in anti-parallel, and a control unit (VT5-VT17). The output of the control unit is connected to the control outputs of the trinistors by separating diodes VD6, VD7.
The control unit is powered by a diode bridge connected by alternating voltage to network pins 14, 15 and 10, 11 of the microcircuit. The bridge configuration is somewhat different from the traditional one (Fig. 3). Resistors R3 and R6 play the role of ballast.
External capacitors C1, C2 provide the necessary turn-on delay of the trinistors at each half-wave of the mains voltage relative to the moment of its transition through "zero". These capacitors also prevent the SCRs from opening when mains voltage is applied. The control unit, in turn, consists of a stabilized power supply on transistors VT7-VT9, a current generator on transistors VT11, VT12, which charges an external time-setting capacitor C3, a voltage-to-current converter on transistors VT13-VT15 and a "current mirror" VT16-VT17 . A thermal protection device for the microcircuit is assembled on the VT10 transistor and resistors R5, R7. On fig. 2 as an example shows an external control circuit diagram - elements C3, R1, SB1 - for using the regulator in the device for smoothly turning on and off the lighting lamp EL1. The power regulator works as follows. When mains voltage is applied, the trinistors VT1, VT2 and VT3, VT4 are closed. A supply voltage of 6,3 V is supplied to the control unit from the power source and it generates some output current Iout (collector current of the transistor VT17). Let's assume that at the current moment the combined outputs 14, 15 have a positive network voltage, and 10, 11 - negative. The output current of the control unit of the microcircuit through the diode VD7 will charge the delay capacitor C2. After some time, the voltage on this capacitor will increase to a level at which the trinistor VT1, VT2 will open. From this moment until the end of the half-cycle, a current will flow through the load - the EL1 lamp - and the rectifier bridge supplying the control unit will be shunted by an open trinistor. Capacitor C1 remains discharged. After changing the polarity of the mains voltage, charging of the capacitor C1 begins and the trinistor VT3, VT4 will open with the same delay. Capacitor C2 during this half-cycle will quickly discharge through resistor R1 and transistor VT5. On fig. 4 shows the timing diagrams of the voltage across capacitors C1 and C2. The solid lines show the processes described above, corresponding to some intermediate value of the output current of the control unit. It can be seen that the opening of the trinistors occurs at a voltage on the capacitors C1, C2, equal to 0,7 V. The shape of the voltage on the load is shown in fig. 4, g.
The turn-on delay of the trinistors in seconds relative to the beginning of the half-cycle is tset=0,7C2/Iout, where 0,7 V is the threshold voltage for opening the trinistors; C2=C1 - capacitance of delay capacitors (in microfarads); Iout - output current (in microamperes) of the control unit. If you change the output current of the control unit, the turn-on delay of the trinistors in each half-cycle of the mains voltage will change, and hence the power released in the load. On fig. 4 this is illustrated by bold dashed lines. At the minimum value of the output current Iout min, the delay must exceed half the period. In the first few half-cycles after the mains voltage is applied to the regulator (Fig. 2), the discharged time-setting capacitor C3 closes pins 3 and 6 of the microcircuit like a wire jumper, so the output current Iout = Iout min. However, since the current generator on transistors VT11, VT12, resistor R8 and diode VD8 provides a stable current flowing through pin 6, capacitor C3 is smoothly charged. This leads to an increase in the voltage at the base of the VT14 transistor, due to which the VT15 transistor begins to open. As a result, the output current of the control unit increases, the turn-on delay of the trinistors in each subsequent half-cycle decreases - the brightness of the EL1 lamp glow smoothly increases from zero to maximum. If we now close the contacts of the switch SB1, the capacitor C3 will be discharged through the resistor R1, and the brightness of the lamp will decrease until it goes out completely. The discharge current of the capacitor must be greater than the current of its charging from the side of pin 6 of the microcircuit. Main technical characteristics at Tacr.av=25°С
The absence of active closing of the trinistors of the microcircuit makes it possible to use it to control the power of an inductive load, since after the mains voltage phase passes through "zero", the corresponding trinistor will remain open until the current through the load is completely stopped. In order to ensure the normal operation of the power regulator, it is necessary to determine the minimum and maximum output current of the control unit of the microcircuit. So, for a delay in the opening of trinistors by 10 ms with a capacitance C1=C2=1 μF and a threshold opening voltage of 0,7 V, the above formula gives a value of the minimum output current of about 70 μA.
On fig. 5-9 shows the main graphical dependences of the operational characteristics of the KR1182PM1 series microcircuits. The dependence of the saturation voltage of the trinistors of the microcircuit on the load current is shown in fig. 5; in this and other figures, the zone of technological dispersion is shaded. On fig. 6 and 7 show the dependences of the consumed current and the control current of the trinistors on the voltage at the control input of the microcircuit (pin 6).
The main switching circuit of the KR1182PM1 regulator is shown in fig. 2. When the contacts of the SB1 switch are open, the EL1 lamp turns on smoothly by applying mains voltage, after opening it goes out smoothly. By changing the capacitance of the time-setting capacitor C3 from 20 to 100 microfarads, you can change the turn-on time from tenths of a second (visually smoothness is not noticeable, but the lamp filament will be protected from an excessively large current surge) to 1 ... 2 s. The turn-off time is set by selecting the resistor R1 in the range from 47 ohms to several kilo-ohms. On fig. 10 shows a diagram of a manual power regulator for an incandescent lamp, an electric soldering iron, or the speed of a domestic fan. Here, it is desirable to combine the power switch SA1 with the power level regulator - resistor R1, and the SA1 contacts should open after setting the slider of the resistor R1 to the minimum resistance position, which corresponds to turning off the load. In this position, the regulator should be connected to the network. Chips KR1182PM1 allow parallel connection of two or more devices. This allows you to increase the output power of the regulator. So, the device, the scheme of which is shown in Fig. 11, can work with a load Rn up to 300 W. The number of hinged elements with parallel connection of microcircuits remains the same. It is easy to see that the trinistors of both regulators DA1 and DA2 are opened by the voltage generated by the DA2 chip. Control conclusions 6 and 3 of all additional regulators close. With a significant load power, it may turn out that the design of the switch SA1, combined with the adjusting resistor R1, is not designed for such a large current. In this case, you will have to slightly modify the circuit by moving the regulator switch to the control circuit, as shown in Fig. 11 dashed lines.
Note that in the new circuit version, the regulator is turned off when the SA1 contacts are closed (and not open, as in the original one). It is necessary to include such a regulator in the network with closed contacts SA1 and in the position of the minimum resistance of the regulating resistor R1. Before turning off the load, it is desirable to reduce the power on it to a minimum by setting the slider of the resistor R1 to the upper position according to the diagram. A decisive increase in load power (up to 1 kW) can be achieved by introducing a powerful discrete triac VS1 into the controller (Fig. 12).
When using the KR1182PM1 regulator to control the brightness of incandescent lamps, it must be remembered that the resistance of a cold lamp spiral is almost 10 times less than a hot one. Because of this, the amplitude value of the current at the moment the 150 W power lamp is turned on can reach 10 A. The design of the microcircuit allows such a current for only a few microseconds, while the heating of the spiral continues for several half-cycles of the mains voltage. With the recommended ratings of the external incandescent control circuit for smoothly turning on and off the incandescent lamp (see Fig. 2), the current through the 150 W lamp for the entire process of turning it on does not exceed 2 ... 2,5 A. Author: A. Nemich, Bryansk
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