Direct-current stabilization power supply device

A direct-current stabilization power supply device comprising:

• a power transistor for acting as a power element between an input and output terminals, and
• a control section which compares an output voltage of said power transistor with a predetermined reference voltage and controls a base current of said power transistor in accordance with a difference between said output voltage and said predetermined reference voltage,
• said control section having a short-circuit protective circuit for including:
• an error amplifier for comparing an output voltage of said power transistor with said reference voltage,
• a base resistance Rs for detecting a base current Id of said power transistor,
• a base current generating section which is disposed between said base resistance Rs and a base of said power transistor and which amplifies a control current corresponding to a difference between said output voltage and said reference voltage so as to generate said base current Id,
• a referenced resistance Rr,
• a current drawing section which connects said referenced resistance Rr between power source lines and which draws a larger current from an input power source line into said referenced resistance Rr as said output voltage becomes lower,
• a partial pressure resistance section for dividing a terminal voltage of said referenced resistance Rr, and
• a current mirror circuit CM1 for adjusting said control current so as to balance a partial pressure value of said partial pressure resistance section with a voltage between terminals of said base resistance Rs.

A direct-current stabilization power supply device comprising:

• a power element which is disposed between an input and output terminals,
• an output partial pressure resistance for dividing an output voltage of said power element so as to obtain a feedback voltage,
• a constant voltage circuit, which compares said feedback voltage with a predetermined reference voltage and controls a control current of said power element in accordance with a difference between said feedback voltage and said predetermined reference voltage so as to realize a constant voltage operation, including an error amplifier for comparing said feedback voltage and said reference voltage so as to find the difference, and
• a short-circuit protective circuit for detecting said feedback voltage so as to realize a short-circuit protective operation, which reduces an output current as an output voltage becomes lower, and for applying a current, which is equal to a base current of an input transistor of said error amplifier upon outputting a rated voltage, to a partial pressure point of said output partial pressure resistance.

The direct-current stabilization power supply device comprising:

• a power transistor connected between input and output terminals;
• a resistor which is in series with said power transistor between said input terminal and said power transistor;
• an output partial pressure resistor which divides an output voltage of said power transistor so as to obtain a feedback voltage;
• an amplifier which compares said feedback voltage with a first predetermined reference voltage and produces a control current in accordance with a difference between said feedback voltage and said first predetermined reference voltage;
• a base current generating section which amplifies said control current so as to generate a base current of said power transistor, and thereby minimize the difference between said feedback voltage and said first predetermined reference voltage;
• an overcurrent protective circuit which compares a second predetermined reference voltage and a voltage between both terminals of said resistor, and reduces said control current when said voltage between both terminals of said resistor exceeds said second predetermined reference voltage;
• and
• a short-circuit protective circuit which monitors said feedback voltage, and adjusts said control current so as to suppress said base current of said power transistor when said feedback voltage is minimized.