How The Inverter Works

- Apr 15, 2019-

The inverter is a DC to AC transformer, which is actually a voltage inverter process with the converter. The converter converts the AC voltage of the power grid into a stable 12V DC output, and the inverter converts the 12V DC voltage of the Adapter output into a high-frequency alternating current, and the two parts also adopt a more used pulse width modulation (PWM) technique. Its core part is a PWM integrated controller, Adapter uses the UC3842, the inverter uses the TL5001 chip.


The operating voltage range of the TL5001 is 3.6~40V, and its interior is equipped with an error amplifier, a regulator, an oscillator, a dead zone controlled PWM generator, a low-voltage protection loop and a short-circuit protection loop. Input interface part: The input part has 3 signals, 12V dc input VIN, working enabling voltage ENB and Panel current control signal DIM. VIN is provided by Adapter, the ENB voltage is provided by the MCU on the motherboard, its value is 0 or 3V, when ENB=0, the inverter does not work, and ENB=3V, the inverter is in a normal working state, while the DIM voltage is provided by the motherboard, the range of change between 0~5V,


The different DIM values are fed back to the PWM controller feedback end, and the current provided by the inverter to the load will be different, and the smaller the DIM value, the greater the current of the inverter output.


Voltage start loop: ENB for high-power normal, output high pressure to light the Panel's backlight lamp lamp.


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PWM controller: There are several functions: Internal reference voltage, error amplifier, oscillator and PWM, overvoltage protection, undervoltage protection, short-circuit protection, output transistor.


DC Transform: The voltage transformation circuit composed of MOS switch tube and energy storage inductance, the input pulse is amplified by the push-pull amplifier to drive the MOS tube to do the switch action, so that the DC voltage to charge and discharge the inductance, so that the other end of the inductance can get AC voltage.


LC Oscillation and output loop: to ensure that the lamp start the required 1600V voltage, and after the lamp start to reduce the voltage to 800V. Output voltage feedback: When the load is working, the feedback sampling voltage plays the role of stabilizing the voltage output of the I inverter.