The main reason for the instability of the output voltage of the regulated power supply (only about thirty words is briefly summarized)
1, the grid input voltage instability 2, the load changes formed
3, the regulator itself to promote the conditions
4, components due to temperature, humidity and other environmental impact
And change its performance
The main reasons are the following:
1. As the input voltage is unstable (usually AC power grid allows ± 10% of the fluctuations), resulting in rectifier filter circuit output DC voltage instability
2. As the rectifier filter circuit internal resistance, when the load changes, causing the load current changes, so that the output DC voltage changes
3. Since the parameters of the electronic components (especially the conductor devices) are related to the temperature, when the ambient temperature changes, the circuit component parameters are changed, resulting in a change in the output voltage
4. Rectifier filter obtained after the DC voltage will still have a small amount of ripple components, can not be directly supplied to those who require a higher power quality of the circuit.
Therefore, the rectified filtered DC voltage must take some voltage regulator measures to meet the needs of electronic equipment. Commonly used DC voltage regulator circuit with parallel and series voltage regulator circuit two types.
Above is the DC voltage regulator output voltage stability of the reasons for the simple analysis, we can combine the actual use of the situation to conduct in-depth analysis.
The reason why the output voltage stability of the DC regulated power supply is poor.
(1) Maximum input voltage
Is to ensure that the DC power supply safe operation of the maximum input voltage.
(2) the maximum output current
Is to ensure that the safe operation of the regulator to allow the maximum output current.
Rectified filter output after the DC voltage, although the degree of smoothness is good, but its stability is still relatively poor.
