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US 4,380,729 AGranted
Switching regulator
AssigneeHitachi, Ltd.
InventorsMasaro Kaku, Yasumasa Sawaki, Kunio Ando
Life of this patent
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Abstract
A switching regulator which chops an unstabilized D.C. input voltage by a switching transistor and rectifies the chopped voltage to produce a stabilized D.C. output voltage is disclosed. A series circuit of a resistor, a capacitor and a coil is inserted between a stabilized D.C. output terminal and a base electrode of an exciting transistor which excites the switching transistor to suppress the increase of a ripple voltage produced when the unstabilized D.C. input voltage drops.
Claims6
A switching regulator comprising:
- (a) a D.C. input terminal across which and a common terminal an unstabilized D.C. voltage is applied,
- (b) a switching element having a control input terminal, an output terminal and an input terminal connected to said D.C. terminal,
- (c) a D.C. output terminal across which and said common terminal a stabilized D.C. voltage is produced,
- (d) a rectifying filter circuit having an input terminal connected to said output terminal of said switching element and an output terminal connected to said D.C. output terminal for rectifying a voltage chopped by said switching element,
- (e) a control circuit having an input terminal across which and said common terminal a switching pulse is applied, a control input terminal coupled to said D.C. output terminal and an output terminal for providing a control output signal, for varying a pulse width of said switching pulse in accordance with a change in the voltage at said D.C. output terminal to produce said control output signal,
- (f) an exciting transistor having a base electrode coupled to said output terminal of said control circuit, a collector electrode coupled to said control input terminal of said switching element and an emitter electrode coupled to said common terminal, and
- (g) a voltage feedback circuit connected between said D.C. output terminal and said base electrode of said exciting transistor, said voltage feedback circuit comprising a series circuit of a capacitive element, a resistive element and a reactive element connected in series between the D.C. output terminal and the exciting transistor base electrode.
4 more elements
A switching regulator comprising:
- (a) a D.C. input terminal across which and a common terminal an unstabilized D.C. voltage is applied,
- (b) a switching element having a control input terminal, an output terminal and an input terminal connected to said D.C. input terminal,
- (c) a D.C. output terminal across which and said common terminal a stabilized D.C. voltage is produced,
- (d) a rectifying filter circuit having an input terminal connected to said output terminal of said switching element and an output terminal connected to said D.C. output terminal for rectifying a voltage chopped by said switching element,
- (e) a control circuit having an input terminal across which and said common terminal a switching pulse is applied, a control input terminal coupled to said D.C. output terminal and an output terminal for providing a control output signal, for varying a pulse width of said switching pulse in accordance with a change in the voltage at said D.C. output terminal to produce said control output signal,
- (f) an exciting transistor having a base electrode coupled to said output terminal of said control circuit, a collector electrode coupled to said control input terminal of said switching element and an emitter electrode coupled to said common terminal, and
- (g) a voltage feedback circuit connected between said D.C. ouput terminal and said base electrode of said exciting transistor to feed back to said base electrode a ripple voltage which develops in the stabilized D.C. voltage at said output terminal when said unstabilized D.C. voltage at said input terminal falls below a preset voltage in order to suppress an increase in said ripple voltage, wherein said voltage feedback circuit comprises a series circuit of a capacitive element, a resistive element and a reactive element connected in series between the D.C. output terminal and the exciting transistor base electrode.
4 more elements
Dependencies are inferred from the claim text.