The inverter is a DC to AC transformer. In fact, the converter is a voltage inversion process.
The converter is to convert the AC voltage of the power grid into a stable 12V DC output, and the inverter is to convert the 12V DC voltage output by the Adapter to a high-frequency AC voltage; the same applies to the pulse widths used in both parts. Modulation (PWM) technology. The core part is a PWM integrated controller, Adapter UC3842, inverter uses TL5001 chip. TL5001 operating voltage range 3.6 ~ 40V, its internal error amplifier, a regulator, oscillator, PWM control with dead-zone control, low-voltage protection circuit and short circuit protection circuit.
Input interface part: Input part has 3 signals, 12V DC input VIN, working enable voltage ENB and Panel current control signal DIM. VIN is provided by the Adapter. The ENB voltage is provided by the MCU on the motherboard. The value is 0 or 3V. When ENB=0, the inverter does not work, while at ENB=3V, the inverter is in normal operation; and the DIM voltage Provided by the mainboard, the change range is between 0 and 5V. Different DIM values are fed back to the feedback end of the PWM controller. The current provided by the inverter to the load will also be different. The smaller the DIM value, the lower the output current of the inverter. The bigger it is.
Voltage startup loop: ENB is high
Output high voltage to light the backlight of the Panel.
PWM controller: It has the following functions: internal reference voltage, error amplifier, oscillator and PWM, overvoltage protection, undervoltage protection, short circuit protection, and output transistor.
DC conversion: The MOS switch and energy storage inductors form a voltage conversion circuit. After the input pulse is amplified by the push-pull amplifier, it drives the MOS tube to perform the switching action, so that the DC voltage charges and discharges the inductor, so that the other end of the inductor can be exchanged. Voltage.
LC Oscillation and Output Circuit: The 1600V voltage required for starting the lamp is controlled, and the voltage is reduced to 800V after the lamp is started.
Output voltage feedback: When the load is working, the sampled voltage is fed back to stabilize the I-inverter voltage output.