Transformerless Power Supply Application Note

Make it on your own risk its extremely dangerous to work with ac mains without proper experience and precaution.

Transformerless power supply application note. Resistive transformerless power supply. It is cost effective lighter and smaller. Resistive type power supply on the other hand dissipates more heat so the power loss is quite high. Typically the need is to convert the line voltage to a small dc value such as 3 3 v or 5 v.

Many times a simple off line power supply is required for low power applications such as e meters battery chargers etc. Transformerless power supplies provide a low cost alternative to transformer based and switcher based power supplies. Thus here excess energy is dissipated as heat across the voltage dropping resistor. Figure 1 capacitive transformerless ac to dc power supply with common hot.

Advantages of this transformerless power supply over transformer based supply are that. This application note will discuss both with a focus on the. If a circuit requires very low current of a few milliamperes transformerless power supply is an ideal solution. Figure 2 capacitive transformerless ac to dc power supply with common neutral.

The formulas and information come from microchip application note an954 written by reston condit. In fact in the case of a half wave rectifier one of the two wires of the ac voltage shall be connected to the ground terminal of the dc voltage available at. Circuit diagram resistive transformer less power supply circuit diagram. The last two are.

Before designing a transformerless power supply some facts about ac dropping through a capacitor or resistor are to be considered. Please i am having this issues with transformerless power supply. The type of rectifier circuit half wave or full wave used in these applications is of fundamental importance. Resistive transformer less power supply is similar to capacitor power supply except that instead of reactance it uses resistance to limit current.

Application note an alternative solution to capacitive power supply using buck converter based on viper12a introduction in this paper three different power supplies with two outputs are introduced. Transformerless power supply calculator this tool calculates output parameters of a transformerless power supply where a capacitor is used to drop the voltage. The two basic types of transformerless power supplies are resistive and capacitive. This can be done with a line frequency power transformer or a complex ac dc off line power supply.

Transformerless power supplies are widely used to control electronic components such as triac and scr in ac applications. The power supply may be significantly less than the cost of the power supply alone.