## 1 Introduction  
The trend for the last years is the widespread introduction of LED lighting, which replaces thermal and gas-discharge light sources [1; 2]. All LED lamps can be divided into LED lamps for indoor use, which replace incandescent lamps, and lamps for outdoor use lighting. The last one should work in a wide range of temperatures [3; 4]. Most structures of LED lighting devices are built on the basis of electronic control circuits (drivers), which can be conventionally divided into the following types [5; 6; 7; 8]:  
1. Drivers that do not compensate for changes in electrical and lighting parameters when the network voltage changes, this also includes simple linear ballast circuits without current stabilization (linear drivers);
2. Linear drivers with LED current stabilization, where resistors are usually used as current feedback (linear driver circuits). Such drivers are most often built according to the high-voltage compensating scheme current stabilizers, where the compensating one's were gradually connected with the LEDs element (field effect transistor);
3. impulse drivers built, for example, with generators with wide pulse modulation (PWM), where the load current is determined by the density output pulses at a constant value of their frequency (IS drivers). They are mainly used in power chains of more powerful lighting devices, for example, in street lights or floodlights. They have a relatively high efficiency (up to 95%).  
As the analysis of the circuits shows, in most of the drivers listed above, there is no compensation for changing the light parameters of LEDs or LED matrices (light flux) when the temperature regime of their operation changes, although this effect is very significant [9; 10]. The temperature dependence of the intensity of LED radiation is most significant in cases where LEDs are operated in outdoor conditions environment. For example, in summer, the temperature of the environment is quite high, and the level of outdoor lighting is also high. In these conditions, the light source should be brighter, but the luminous flux of LEDs decreases with increasing temperature. Therefore, to compensate for this decrease, it is necessary not to stabilize the LED current, but conversely, to increase it.  
Goals of this article:  
* definitioning the effect of ambient temperature on the parameters of LED lighting devices built on different types of drivers;
* estimate of the ability of various driver schemes used to power LEDs to stabilize the operating current not only when the supply voltage changes, but also when the ambient temperature changes;
* definitioning the adequacy of the influence of temperature on the parameters of LED devices only according to those characteristics that are given in the technical documentation on one or another type of LEDs (datasheet), based on the obtained experimental temperature characteristics;
* development of constructive proposals for the structure of drivers of LED light sources, which could partially or completely compensate for temperature efficiency radiation intensity of LEDs when the temperature regime of their operation changes.  
To achieve these goals, we will provide a study of the characteristics of LEDs that can be used to assess the effect of temperature environment on the light and electrical parameters of the LED device, namely: the dependence of the forward voltage of the LED Ud on the temperature Tc at a constant (nominal) value of the current and the dependence of the relative value of the luminous flux of the LED F/F0 from the temperature \(T_{c}\)[11].