Determining Voltage Accuracy of Switch-Mode Power Supplies (Download)
Switch-mode power supplies (SMPS) have a feedback pin that can be used to set an output voltage. This voltage is regulated by the power-supply circuit. However, the question arises as to how precisely the voltage is regulated.
Figure 1 shows an SMPS according to the step-down principle. An existing, usually unregulated, supply voltage (input voltage) is used to generate an output voltage, which is regulated as accurately as possible.