This post explains for the Switching Power Supply.
The Part Number is HT203C.
The function of this semiconductor is High Performance Current Mode PWM Switching Power Supply.
The package is DIP 8 Pin type
Preview images :
The HT203C is a high-performance current mode PWM switching power supply designed for cost-effective AC/DC converter systems. It provides up to 12W of continuous output power in a wide voltage range of AC85V-265V, and the peak output power can be as high as 18W. The optimized and reasonable circuit design combined with the Bipolar integrated circuit technology with high performance and price ratio saves the overall cost of the product to the greatest extent.
The HT203C can work in a typical flyback topology power supply to form a compact AC/DC converter. The start-up circuit inside the HT203C 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; when the output power is small, the HT203C will automatically reduce the operating frequency , resulting in 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, which greatly improves the withstand voltage capability of the power tube to a high voltage of 700V, ensuring the safety of the power tube .
. Built-in 700V high-voltage power switch tube, very few peripheral components
. 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
. Built-in thermal protection circuit
. Low startup and operating current
. VCC overvoltage automatic limit
. VCC low voltage protection and low voltage restart function