The foreword LED manufacturer suggested that causes light emitter diode through the control forward current maintains the fixed luminous flux and the specific color temperature. In view to the fact that the LED brightness with is being proportional to your magnitude of current, this control method is really best LED power source software. In addition, the LED direct voltage and also the output receives the junction temperature the strict limit, specially high efficiency LED is so;
The junction temperature could be the well known influence quality and the service life key parameter. Accurately speaking, elevates along with the junction temperature, the direct voltage and the output will reduce gradually, the drifting can cause the critical current to pick up. For through reduces the direct voltage to solve the hot drifting problem, enhances the system overall energy efficiency, adjusts the lighting technical control brightness through PWM or the simulation, obtains against expiration management and the overheat control function, the lighting system to has the specific control function LED driver's demand to enhance unceasingly. If for applications and so on construction illumination and street lighting increases the value, likewise needs to increase the remote control function from the LED driver. Because costly efficiency factor exchange - transformer can transform the electrical network alternating voltage Cheng Genggao the input DC voltage, therefore illuminates the LED driver usually to use the standard voltage dropping analysis situs ordinary, this kind of driver based on integrates a power switch's simulation monolithic solution, the maximum output electric current achieves 350mA. If the voltage is higher than 50/60V, because of the chip technology limit, the monolithic solution will be in order to be competent.
Many illumination platforms need these to use many driver's multi-channel output systems, but this will increase system construction and the domain design complexity, finally will cause the designed cost to increase. Basic solution mainly with concerns using the limit depending on parallel resistor and the internal comparator's electric current examination method. The comparator stays from the keen resistor back coupling's electric current and the materials for internal reference magnitude of current the comparison, then produces one to inside the signal grid driving circuit's output signal.
This commonly used analogue control method has realized to the peak class control, because the LED light color drifting doesn't allow in many request strict illumination application domain, therefore this method is not the high quality illumination answer.
Innovation LED driver An italian man , law semiconductor proposed which satisfy the illumination request the high cost benefit street lighting platform response. This plan has the outstanding performance, the superelevation energy efficiency (when capacity load overall energy efficiency is bigger than 91%), the complete against expiration management (overflow protection, overvoltage protection and short circuit protection) the function.
This platform by two major part is composed: Power unit and electric current controller. And, the ac current controller is a digital electric current controller. Power circuit's peak power output achieves 130W (48V,2.7A), this electric circuit is derived from two levels of electric circuits: Based on L6562AT front end power factor adjuster (PFC) and dependent upon L6599AT LLC resonance switch. This design's characteristic is as follows: Expansion Europe inputs the alternating voltage scope (177/277 VAC - frequency 45/55 Hz) The superelevation energy efficiency (full load was ninety three.85%) has avoided to radiator's demand Non-electrolytic capacitor, long-time reliable Conforms to EN61000-3-2 Class-C (exchange overtone), EN55022-Class-B(EMI) and EN60950 double insulates the (SELV) standard