This post explains for the controller IC.
The Part Number is THX208.
The function of this semiconductor is Switching power supply controller IC.
Manufacturer: TongHuaXin
Preview images :
Description
The THX208 is High performance current mode PWM controller. Designed for cost-effective AC/DC converters. exist It provides nearly 4W continuous output power in a wide voltage range of 85V-265V. The optimized and highly rational circuit design combined with the high-performance and cost-effective bipolar manufacturing process saves the overall cost of the product to the greatest extent.
The power controller can work in a typical flyback circuit topology to form a compact AC/DC converter. The start-up circuit inside the IC is designed as a unique current sink method, which can use the amplification of the power switch tube itself to complete the start-up, which significantly reduces the power consumption of the start-up resistor; and when the output power is small, the IC will automatically reduce the operating frequency , resulting in an extremely low Standby power consumption. When the power tube is cut off, the internal circuit reverse-biases the power tube, directly using the CB high withstand voltage characteristic of the bipolar transistor, and greatly improving the withstand voltage capability of the power tube to a high voltage of 700V, which ensures the safety of the power tube .
[…]
Features:
. Built-in 700V high-voltage power switch tube, very few periphera. devices
. Latch pulse width modulation, pulse-by-pulse current limit detection
. Low output frequency reduction function, no output power consumption can be lower than 0.25W
. Built-in slope and feedback compensation function
. Independent upper limit current detection controller, real-time processing of overcurrent and overload of the controller
. Off-period emitter bias output, which improves the withstand voltage of the power tube
. Built-in current limiting resistor with temperature compensation, precise current limiting
. Built-in therma. protection circuit
. Using the amplification effect of the switching power tube to complete the startup, the power consumption of the startup resistor is reduced by more than 10 times
. Very few externa. components
. Low starting and working current
. VCC overvoltage automatic limit