## 3 Results
### Study of the Characteristics of the Driver with Voltage Stabilization
In Figures 20-22 show the dependence of the relative values of \(U_{d0}/U_{d0\,25}\)C, \(I_{d0}/I_{d0\,25}\)C and \(F_{0}/F_{0\,25}\)C on the temperature \(T_{c}\) for the driver (Figure 19) at different values of the \(U_{AC}\) voltage. Figure 19: Driver scheme based on TL783 for experimental measurements of LED characteristics. Figure 20: Dependencies of voltage on LEDs \(U_{d0}/U_{d0\,25}\)C on temperature \(T_{c}\) for a driver with voltage stabilization on LEDs. As can be seen from Figure 20, the voltage of LEDs with temperature changes remains practically unchanged. For different network voltage values, the voltage drop does not exceed 1%. At the same time, the LED current grows non-linearly (Figure 21), and this growth reaches 17% of its value at \(T_{c}\) = +25 \({}^{\circ}\)C. The increase in LED current with temperature (Figure 10) allows the driver not only to compensate for the drop in their luminous flux (Figure 22). In the temperature range +20=+60 \({}^{\circ}\)C, the luminous flux even increases nonlinearly to almost 7% at a temperature of +60 \({}^{\circ}\)C relative to the value at \(T_{c}\) = +25 \({}^{\circ}\)C.  
Moreover, these characteristics remain unchanged at \(U_{AC}\) voltages of the power supply network \(\pm\)10% of the nominal value (not shown in the graphs of Figures 20-22). There are no current and luminous flux pulsations when powering the LEDs because the driver circuit uses the electrolytic capacitor of the low-frequency filter C2, which is turned on after the VDS diode bridge (Figure 19). The driver scheme shown in Figure 23 allows you to use the TL783 to connect to a 220 V power supply. Additional circuit elements VT1, VD1, and R2 reduce the input voltage of the TL783 to a value not exceeding 125 V. R1 is the discharge resistance of capacitor C1. The last one also serves to partially reduce the input voltage of the TL783 stabilizer. Figure 21: Dependencies of LED current \(I_{d0}\)/\(I_{d0\,25}\)\({}^{\circ}\)C on temperature \(T_{c}\) for a driver with voltage stabilization on LEDs. Figure 22: Dependencies of luminous flux \(F_{0}\)/\(F_{0\,25}\)\({}^{\circ}\)C on temperature \(T_{c}\) for a driver with voltage stabilization on LEDs. In the driver with voltage stabilization on LEDs (Figure 19), the current increases with increasing operating temperature, and this increase at temperature \(T_{c}\) = +60 \({}^{\circ}\)C can reach 15% or more of its nominal value \(I_{d0}\) at \(T_{c}\) = +25 \({}^{\circ}\)C (Figure 21). Therefore, for drivers used to work in lighting devices of a higher power, when their cost can be justified as higher, it is possible to propose additionally, in addition to stabilizing the voltage on the LEDs, limiting the maximum value of the current, for example, at the level of (1.15-1.20):\(I_{d0\,25\,^{\circ}\text{C}}\). For this, in the driver circuit (Figure 24), it is necessary to turn on another microcircuit of the same type in series with the voltage stabilizer, which will perform the function of the current stabilizer [20]. The value of the stabilized current \(I_{st}\) will be determined by the resistance of the resistor R3, \(U_{ref}\)--the voltage between the outputs OUT and ADJ of the stabilizer D1 (Figure 24):  
\[I_{st}=U_{ref}/\text{R3}, \tag{3}\]  
D1 is a current stabilizer that limits the maximum current of the LEDs, and D2 is the voltage regulator on LEDs. It is also possible to propose the implementation of a driver based on a voltage stabilizer according to a scheme that uses a low-power but high-voltage voltage stabilizer LR8N3 with the following parameters [26]:  
* change in the output voltage when the input voltage changes by 1.4%;
* change in output voltage with a temperature of 1%;
* input voltage 15-450 V;
* output voltage 1.2-440 V;
* output current 10 mA. The functional circuit of the LR8N3 voltage stabilizer is shown in Figure 18.0  
Figure 18.1 Electric circuit of the driver based on TL783 for powering LEDs with the possibility of connecting to a 220 V mains voltage.