Diode by conduction through the variable cut-off recovery period, resulting in a DC power supply transient short-circuit, resulting in a tremendous impact on current and all this often leads to both ends of the switching device voltage spikes, the device is easy to be breakdown. When the power supply at high frequencies, the parasitic capacitance and stray inductance in the circuit easy to form the oscillation, and thus produce losses, the peripheral circuit 6 Environmental electromagnetic interference. In short, the use of phase-shift PWM control is to regulate the output voltage by changing the size of the circuit two bridge arm angle FET drive signal phase shift angle, making the entire circuit switching state in a zero voltage switching, the switch is in the state of the soft work switching loss, switching nine frequency increased. The wireless presenter green laser pointer has many functions.
Modulated pulse output of the circuit and overcurrent protection for solid pulse laser pumping process a big impact, changes in the frequency of the inverter circuit, volatility also makes the charging voltage to produce instability, especially the peak compared with the current pulse in the discharge circuit high, if not its limit is often very easy to cause the IGBT damage. To ensure that the system is stable and reliable operation of the PIC16F877 MCU as the master chip laser power system (shown in Figure 2-4) can be used the MAX813L as the voltage monitoring by the Hall element, the current sensor detects the load at both ends of the xenon lamp voltage and current values, the test results sent to the microcontroller PIC16F877 2, 3-side (RA 0 / AN 0 RA 1 / AN 1) design software delivery more sampled values were compared. The wireless presenter green laser pointer includes page up function.
When the sampled value is higher than the reference voltage current system settings, by the PIC16F877 6,7-ended (RA 4 RA) output flow through the pressure control signal, and the logical OR gate 74LS32 and IGBT driver tube blockade of the IR2110. side SD connected to hair when the students flow through the pressure control signal to the driver IR2110 blockade, effectively cut off the PWM output, the real closure of the drive signal to ensure the safety of the IGBT. Figure 2-4 capacitance charging the normal operation of the pump light, the main control circuit diagram 2.3 pulse pumping light to trigger the xenon lamp pre-combustion system design 2.3.1 pulse triggers a pulse xenon lamp operating voltage should be less than pressure since the lightning. Therefore, when the above-mentioned power supply system to the storage capacitor charged to the operating voltage, the xenon lamp is not self-discharge and flash, which is basically in the open state. The wireless presenter green laser pointer has page down function.
Make xenon lamp controlled discharge and flash must be equipped with a 10 set a dedicated trigger system. The storage capacitor discharge pulse xenon lamp is usually triggered by a high-pressure pulse caused by the role of the trigger pulse is established between the poles of the ionization of the spark channel leading to the occurrence of the main discharge. Pulsed xenon lamp trigger, external trigger, the trigger [2]. Within the trigger pulse will be directly added to the lamp electrodes, leaving the ionized gas within the lamp. The trigger circuit shown in Figure 2-5, which uses a pulse transformer B generated by pulsed high voltage trigger xenon lamp. The trigger circuit used in power supply V1 is generally a few hundred volts, capacitor C1 is 1 ~ 10uF. When the capacitor C1 is charged to V1 after given control signal turns on SCR. The wireless presenter green laser pointer owns black screen function.
C1 through the primary coil of the transformer B's discharge, the secondary coil will induce a high voltage pulse of tens of thousands of volts, so that the light within the gas ionization channel formed, the energy storage capacitor C discharge discharge a large current transformer saturation, which is equivalent series in the discharge circuit inductance. Figure 2-5 trigger and external trigger circuit schematic diagram is the high-voltage pulse is not directly added to the lamp electrodes to trigger. Shown in Figure 2-6, this high-voltage pulse trigger mode can be added on a nickel-chrome wire wrapped around the tube outer wall or other potential reference surface. The trigger voltage between 5kV - 10kV. Is generally believed that the negative trigger pulse is good, it enables the laser to obtain a stable output. Figure 2-6 outside the trigger circuit schematic diagram of these two to trigger a common drawback whenever the xenon lamp lit, need to be a high-voltage trigger pulse. The wireless presenter green laser is equipped with hyperlink function and so on.
No comments:
Post a Comment