Shilan Microelectronics Introduces the Primary Side Control Switching Power Supply Sd6853 / 6854 of

Sd6853 / 6854 is an off-line switching power supply integrated circuit with built-in high-voltage MOS tube, high-end switching power supply controller with line loss compensation and peak current compensation, and adopts the patented technology with independent intellectual property rights of Shilan microelectronics. By detecting the peak current of the primary coil of the transformer and the feedback voltage of the auxiliary coil, the output voltage and current of the system are indirectly controlled, so as to achieve the purpose of outputting constant voltage or constant current. In a certain output power range, the output voltage can be set through the feedback resistance; The output current can be set through the peak current sampling resistance. Line loss compensation and peak current compensation can also be set as needed to achieve the best adjustment rate of output voltage and output current.

The normal working cycle is divided into peak current detection and feedback voltage detection: when the MOS tube is turned on, the current of the primary coil is detected through the sampling resistance, the output capacitor supplies power to the load, and the output voltage Vout decreases; When the current of the primary coil reaches the peak value, the MOS tube is turned off to detect the FB terminal voltage. The energy stored in the secondary coil charges the output capacitor, the output voltage Vout rises and supplies power to the load. When the opening conditions of constant voltage and constant current loop control are met at the same time, the MOS transistor is turned on, and the chip enters the peak current detection again.

In addition, the chip integrates temperature protection circuit, loop open circuit protection, current limiting circuit, overvoltage protection, undervoltage locking and other multi-functional circuits to ensure the normal working environment of the chip and prolong its service life.

At present, sd6853 provides 4.0w output power (5V / 800mA), sd6854 provides 5.0w output power (5V / 1a), the average efficiency is greater than 68% (using 1.8m awg28 cable), the standby power consumption is less than 100MW, the load adjustment rate of output voltage is better than ± 4.0%, the input line voltage adjustment rate of output voltage is better than ± 0.6%, and the ESD capacity of the whole machine to air is greater than ± 15kev. The output power range provided by subsequent sd6853 can reach 3W 5W, and the output power range provided by sd6854 can reach 5W 12W.

Sd6853 / 6854 is manufactured based on the 0.8 micron BiCMOS / BCD process independently developed by Shilan microelectronics. It adopts the dip-8a packaging form with built-in high-voltage MOS tube. It has the outstanding characteristics of high integration, small board area and easy debugging of the whole machine. Sd6853 / 6854 is used to design the whole machine system. Without optocoupler and Y capacitor, secondary feedback control and loop compensation can be omitted. Only a few peripheral components are required to form a complete power supply system, which greatly saves the power consumption of the system and reduces the volume of the circuit board, which is conducive to users to simplify the design layout and reduce the development and manufacturing cost.

The future development trend of small charging equipment is lower standby power consumption and higher energy conversion efficiency. Shilan Microelectronics will continue to invest in R & D in this field and launch new products. It is expected that an upgraded version of sd6852 / 6853 / 6854 will be launched in the first half of 2012, which meets the energy star 2.0 standard and level 5 specification. The standby power consumption is less than 30MW and the average efficiency can reach 70%.