Potential sources of damage inside switching power supplies
1. Pulsation and noise
An ideal DC power supply should provide pure DC, but there are always some interferences present, such as pulsating currents and high-frequency oscillations superimposed at the output port of the switching power supply. These two types of interference, combined with the spike noise generated by the power supply itself, result in intermittent and random drift of the power supply.
2. Stability
When the line voltage or load current changes, the output voltage of the DC power supply will also fluctuate. The degree of voltage stabilization is determined by the parameters of the voltage stabilization circuit, which refer to the capacity of the filtering capacitor and the rate of energy release.
If a relatively constant power source is used to supply power, only basic load stabilization is required. The magnitude of stability is generally defined as the percentage of output voltage or the change in voltage when unloaded or fully loaded.
3. Internal impedance
A relatively large internal resistance of the power supply has two disadvantages for the load. Firstly, it is not conducive to the operation of the load voltage regulator circuit. Even more disadvantageous is that any change in the load current will cause fluctuations in the output of the DC power supply. The impact of these fluctuations on the test results is exactly the same as the impact of pulses and noise on the test results.
4. Transient response or recovery of switching power supply
The magnitude of the transient response and recovery time of the power supply indicates the ability of the power regulator circuit to restore normal voltage when the output load suddenly changes. There are two parameters to calibrate the transient response and recovery of the power supply: one is the deviation value output when the load suddenly changes; The second is the time it takes for the output to return to its original value. For the sake of uniformity, when the load changes by 10%, the deviation of the output from the peak voltage is calibrated in millivolts, and the recovery time is calibrated in millivolts when the output returns to normal. Some manufacturers also use larger changes in load current to measure recovery time. For example, the time required to restore normal values when the output current changes by 50% to 100%.
