Switch Power Supply Several Important Components

Switching power adapters are widely used in computer equipment, electronic instruments, communication equipment and household appliances because of their low power consumption, high power and small size. The primary technical objectives of Switching Power Supply are described below.

1. Input voltage scale: when the input voltage of switching Power Supply changes, the input voltage change scale with the same output characteristic shall be adhered to. The wider the scale, the stronger the ability to change the power supply habit of the outside power supply, the wider the operation scale of the switching power supply. It is related to the error amplifier in the switching power supply, the gain of the sampling reaction conditioning circuit and the duty cycle conditioning scale. Now the input voltage of switching power supply has been changed to 90v-270v, which can save a lot of 110V/220V conversion switch on the electrical appliances.

2. Voltage adjustment rate: voltage adjustment rate, also known as voltage stability, is the relative change of output voltage when the output current is unchanged (that is, the load does not change) and the input communication operation voltage changes. The objective of this technique is to verify whether the stability of the output voltage of switching power supply meets the required standard in the most severe power supply voltage environment.

3. Current adjustment rate: current adjustment rate, also known as load adjustment rate, is the relative change of output voltage when the input ac voltage is rated (such as 220VAC) and the output current changes from the minimum value of 0 to the maximum value. This objective is to verify whether the output voltage stability of the switching power adapter meets the required standard under the worst load conditions.

4. Output internal resistance: the ratio of the change of output voltage to the change of output current. The smaller this ratio is, the smaller the change of the output voltage of the power supply with the load size, and the better the voltage stabilizing performance.

5. Transformation power: the ratio of output power and input power of the power supply. The higher this ratio, the higher the change power, the smaller the volume of switching power supply, the higher the reliability. Now the power of switching power supply can reach more than 90%.

6. Ripple of output voltage: because the voltage stabilizing process of switching power supply is a process of continuous sampling and reaction conditioning, there will be a superposition of waver ripple voltage on the output dc voltage, namely the output ripple voltage. The smaller the value, the better the output feature. There are two ways to show ripple: one is the output ripple voltage effective value; The second is the peak and peak value of output ripple voltage. In general, the standard of switching power supply is less than 1% of the output dc voltage, and its bandwidth is 20hz-20mhz or higher frequency, such as 100MHz. Switching power supply in harsh environments, the output after noise ripple dc voltage and the output of the instantaneous voltage, output high and low voltage lines should not exceed (Min and Max values), otherwise will may cause the power supply voltage beyond may be lower than logic circuit, such as TTL circuit operation voltage and misoperation, further formation of crash.

Best regards,

Mandy Huang