Input interface section:
There are 3 signals in the input part, including 12V DC input VIN, working enable voltage ENB and Panel current control signal DIM. The VIN is provided by the Adapter, the ENB voltage is provided by the MCU on the motherboard, and its value is 0 or 3V, when ENB=0, the Inverter does not work, and when ENB=3V, the Inverter is in normal working condition; The DIM voltage is provided by the main board, the change range is between 0 ~ 5V, the different DIM values are fed back to the PWM controller feedback end, the current provided to the Inverter load will be different, the smaller the DIM value, the greater the Inverter output current.
Voltage start loop:
ENB is high voltage, output high voltage to light the backlight tube of the Panel.
PWM Controller:
It consists of the following functions: internal reference voltage, error amplifier, oscillator and PWM, overvoltage protection, undervoltage protection, short circuit protection, output transistor.
Dc conversion:
The voltage conversion circuit is composed of the MOS switching tube and the energy storage inductor. After the input pulse is amplified by the push-pull amplifier, the MOS tube is driven to perform the switching action, so that the DC voltage charges and discharges the inductor, so that the other end of the inductor can get the AC voltage.
LC Oscillation and output loop:
Make sure the lamp starts at 1600V voltage, and drop the voltage to 800V after the lamp starts.
Output voltage feedback:
When the load is working, the sampling voltage is fed back to stabilize the Inventer voltage output.
You can actually imagine it. What electronic components need positive and negative electrodes, resistors, inductors generally do not need. The diode is generally bad may be broken down as long as the voltage is normal is generally no problem, the transistor will not be switched on. If the voltage regulator is reversed, it will be damaged, but some circuits are generally protected by the single guide of the diode. In is the capacitor, the capacitor has positive and negative points is the electrolytic capacitor, if the positive and negative connection is serious then its shell burst.
Main component diode. Switching tube oscillation transformer. Take a sample. Adjustable width tube. There are oscillating circuit resistance capacitance isoparametric switching circuit principle.
The choice of the main power component of the inverter is very important, the current use of more power components are Darlington power transistor (BJT), power field effect tube (MOSFET), insulated gate transistor (IGBT) and turn-off thyristor (GTO), etc., in the small capacity low-voltage system used more devices for MOSFET, Because MOSFET has a lower on-state voltage drop and a higher switching frequency, IGBT modules are generally used in high-voltage large-capacity systems, because MOSFET's on-state resistance increases with the increase in voltage, and IGBT has a greater advantage in medium capacity systems, and in large capacity (100KVA above) systems. Generally, GTO is used as a power component.
Bulky: FETS or IGBTs, transformers, capacitors, diodes, comparators, and masters such as 3525. Ac DC inverter and rectifier filter.
The power and precision are related to the complexity of the circuit.
IGBT (insulated gate bipolar transistor) as a new type of power semiconductor field control self-turn-off device, set the high-speed performance of power MOSFET and the low resistance of bipolar devices in one, with high input impedance, low voltage control power consumption, simple control circuit, high voltage resistance, withstand current and other characteristics, in a variety of power conversion to obtain a very wide range of applications. At the same time, major semiconductor manufacturers continue to develop IGBT high voltage, high current, high speed, low saturation voltage drop, high reliability, low cost technology, mainly using 1um production process, research and development has made some new progress.
The working principle of the inverter is to control the operation of the entire system through the control circuit, the inverter circuit completes the function of converting direct current to alternating current, and the filter circuit is used to filter out unwanted signals.
The work of the inverter circuit can also be refined into: first, the oscillation circuit converts direct current into alternating current; Secondly, the coil boost turns irregular AC into square-wave AC; Finally, the rectification causes the alternating current to pass through the square wave to the sine wave alternating current.