Research On Drive Control Technology Of High Accuracy Semiconductor Illuminant Based On ARM

Semiconductor illuminant is a semiconductor device which takes PN knot as working material and it takes inject current as excitation.It is a kind of device with high and efficiency power.Its ability to withstand the impact of current is very weak. Semiconductor illuminant is a current drive device. Weak drive current and will lead to its changing of optical power or device parameters. Even current mutations can lead to damage of semiconductor devices. So the stability of the drive current has thedirect influence on the light power. The operationmaterial of semiconductor illuminant is PN knot,which is very sensitive to temperature.Temperature change will directly affect the semiconductor illuminant threshold current and the stability of optical power. Even seriously damage the working characteristic of semiconductor illuminant. In order to work well,the working temperature of semiconductor illuminant must be under the control.In this paper, the study mainly on constant-current source,optical power control and temperature control.First of all,this paper introduces the principle and characters of semiconductor illuminant,analyses the necessity of designing a special driver power with high quality and analysis the theory of optical power control and temperature control by referring a lot of domestic and foreign references.Designed the semiconductor illuminant driver based on ARM. It includes Digital constant-current source driver circuit,Photoelectric detection circuit and temperature control circuit. Optical power control circuits are constituted of constant-current source circuit and photoelectric detection circuit. The constant-current circuit is constituted of ADuC7026 micro controller and its DA converters,slow start-up circuit and V/I convert circuit.The whole design idea is to use Super chopper-stabilized amplifier and principle of negative feedback to stabilize output current which obtains the lowest current error and the highest current stability. TEC was controlled automatically using closed-loop PID by ADN8830.The thermistor internal of Semiconductor illuminant components is used as temperature sensor. Designed the software of the digital control system,which includes system initialization, DA conversion,AD conversion,optical power control and temperature,optical power and drive current acquisition and display.In the last part of the paper,the stability of the drive current,operating temperature and optical power under the control of temperature and optical power or no are validated by experiments.It proves that the semiconductor illuminant driver designed in this paper can work well. Under the control of the semiconductor illuminant driver, we can obtain very stable optical power.