Auxiliary power supply device

An auxiliary power supply device comprising:

• a main power supply part including a bridge diode for full-wave rectifying an alternating power source inputted from the external, a transformer for smoothing the voltage from the bridge diode and for exciting a secondary winding via a primary winding, a diode and a capacitor for rectifying and smoothing the excited voltage of the transformer and for applying it to a load, a control section for generating a control signal to control the switching operation of a switching transistor according to an output voltage from the capacitor, and a switching transistor for controlling current flowing through the transformer by means of the control signal from the control section;
• a rectifying section for rectifying voltage outputted from the bridge diode;
• a trigger part for outputting a trigger signal by charging or discharging the voltage from the rectifying section;
• an auxiliary power generating section for receiving the trigger signal from the trigger part and for outputting the voltage from the rectifying section as an auxiliary power source;
• a resetting means for receiving the trigger signal from the trigger part, for applying the auxiliary power source to the control section and for initiallizing the trigger part;
• and
• a current sink section for controlling the current in the auxiliary power generating section to output an invariable auxiliary power source regardless of the output voltage of the bridge diode.

An auxiliary power supply device comprising:

• a main power supply part including a bridge diode for full-wave rectifying an alternating power source inputted from the external, a transformer for smoothing the voltage from the bridge diode and for exciting a secondary winding via a primary winding, a diode and a capacitor for rectifying and smoothing the excited voltage of the transformer and for applying it to a load, a control section for generating a control signal to control the switching operation of a switching transistor according to an output voltage from the capacitor, and a switching transistor for controlling current flowing through the transformer by means of the control signal from the control section;
• a rectifying section for rectifying voltage outputted from the bridge diode;
• a trigger part for outputting a trigger signal by charging or discharging the voltage from the rectifying section;
• an auxiliary power generating section for receiving the trigger signal from the trigger part and for outputting the voltage from the rectifying section as an auxiliary power source;
• a resetting means for receiving the trigger signal from the trigger part, for applying the auxiliary power source to the control section and for initiallizing the trigger part;
• and
• a current mirror for controlling the amount of the current of the auxiliary power generating section depending upon the voltage from the rectifying section.