Special integrated switching power supply design scheme and characteristics
Compared with traditional switching power supplies, special integrated switching power supplies have the characteristics of novel circuits, unique functions, advanced performance, and wide application fields. Common special integrated switching power supplies are usually designed with single-chip switching power supply integrated circuits and corresponding peripheral circuits (including control loops). They have different output characteristics and application fields, and can meet the needs of different users.
Classification of special integrated switching power supplies
Special integrated switching power supply mainly includes the following 5 types:
1) Composite switching power supply;
2) Constant voltage/constant current (CV/CC) switching power supply;
3) Cut-off output switching power supply;
4) Constant power output switching power supply;
5) Other special switching power supplies, such as high-speed modem (HighSpeedModem) power supply, DVD power supply, etc.
Design scheme and characteristics of special integrated switching power supply
There are two design options for special single-chip switching power supplies: the first is to use general-purpose single-chip switching power supply integrated circuits (such as TOpSwitch-Ⅱ, TOpSwitch-FX, TOpSwitch-GX, etc. series), coupled with a voltage control loop and a current control loop. It is designed with other peripheral circuits, which is characterized by large output power, but complex peripheral circuits; the second is to use the recently launched LinkSwitch series of high-efficiency constant voltage/constant current three-terminal monolithic switching power supply chips, or use LinkSwitch -TN series, DpA-Switch series single-chip switching power supply dedicated IC, which can greatly simplify the circuit and reduce costs, and is suitable for forming special switching power supplies of medium and small power.
Performance characteristics of special integrated switching power supply
1) Using high-efficiency constant voltage/constant current monolithic switching power supply LNK500, the AC input voltage range is 85~265V. When the AC input voltage is 265V, the leakage current is <5μA, the rated output voltage is 5.5V, and the maximum output current is 0.45A, output power is 2.5W.
2) Low power consumption, high efficiency, no-load power consumption <0.3W, typical value of power efficiency η≈68%.
3) At the peak power point, the output voltage is allowed to have a ±10% error when the primary.
5) It has overheating protection, output short-circuit protection and open-loop protection functions.
6) Comply with the international electromagnetic compatibility standard CISpR22B/EN55022B.
