EP0103455A2
Expired / Lapsed
EP
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Power supply circuit
Assignee: Fujitsu Ltd
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Filing: 1983-09-06
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Granted: —
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Expires: 2003-09-06
Abstract
Abstract A power supply having a voltage stabilising circuit includes voltage changing means responsive to an external control signal. In one embodiment, the external control signal (V ext ) is used to control a switching element (TR 14) connected across a part of a voltage device (R13, R14) connected across the stabilised voltage supply, to vary the division ratio at a point in the voltage divider from which the stabilisation control voltage is derived. In another embodiment, the stabilised control voltage is cut off and restored by a switching circuit (SCR, TR21, Figure 5) in response to a control voltage rising above a first threshold and subsequently falling below a second threshold.
Inventors
- 👤 Masayuki Takagi
- 👤 Shigeru Komaju
- 👤 Hiroshi Mugiya
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 05:30
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G05F1/468
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
101 words
A power supply circuit comprising: an output transistor (TRll) providing a stabilized output voltage; a control transistor (TR12) controlling a base potential of the output transistor; an impedance means (R13, R14) connected to a base of the control transistor such that the impedance means divides the stabilized voltage into parts, one of the said parts of the divided voltage being applied to the base of the control transistor; and characterized by a switching means TR14) which is turned on or off in response to an external control signal (Vext) so as to vary the division ratio provided by the impedance means.
Claim 2
Dependent Claim
101 words
A power supply circuit comprising: an output transistor (TRll) providing a stabilized output voltage; a control transistor (TR12) controlling a base potential of the output transistor; an impedance means (R13, R14) connected to a base of the control transistor such that the impedance means divides the stabilized voltage into parts, one of the said parts of the divided voltage being applied to the base of the control transistor; and characterized by a switching means TR14) which is turned on or off in response to an external control signal (Vext) so as to vary the division ratio provided by the impedance means.
Claim 3
Dependent Claim
30 words
A power supply circuit according to claim 1, in which the impedance means includes a variable resistor (R14), a variable resistance terminal thereof being connected to the switching means (TR14).
Claim 4
Dependent Claim
37 words
A power supply circuit according to claim 1 or 2, in which the switching means comprises a switching transistor (TR14) which can be turned on or off in response to the external control signal (V ext ).
Claim 5
Dependent Claim
76 words
A power supply circuit according to claim 1 or 2, in which the switching means comprises: a first switching transistor (TR13) which can be turned on or off in response to the external control signal and a second switching transistor (TR14) provided at an output point of the first switching transistor, the second switching transistor (TR14) changing the division ratio of the impedance means (R13, R14) in response to the operation of the first switching transistor.
Claim 6
Dependent Claim
136 words
A power supply circuit comprising: a stabilized voltage generating circuit (SPS) including an output transistor (TRll) stabilizing the voltage level; and characterized by a thyristor means (SCR) which is connected to a base of the output transistor (TRll) and which is triggered and becomes conductive when a first external control signal (from TH2) reaches a first predetermined value; and a switching means (TR21) which is connected to the thyristor means in series and which is turned on when a second external control signal (from THl) of a lower trigger level than the first external control signal reaches a second predetermined value; wherein the stabilized voltage is cut when the first external control signal reaches the first predetermined value and the stabilized voltage is restored when the second external control signal drops to the second predetermined value.
Claim 7
Dependent Claim
136 words
A power supply circuit comprising: a stabilized voltage generating circuit (SPS) including an output transistor (TRll) stabilizing the voltage level; and characterized by a thyristor means (SCR) which is connected to a base of the output transistor (TRll) and which is triggered and becomes conductive when a first external control signal (from TH2) reaches a first predetermined value; and a switching means (TR21) which is connected to the thyristor means in series and which is turned on when a second external control signal (from THl) of a lower trigger level than the first external control signal reaches a second predetermined value; wherein the stabilized voltage is cut when the first external control signal reaches the first predetermined value and the stabilized voltage is restored when the second external control signal drops to the second predetermined value.
Claim 8
Dependent Claim
16 words
A power supply circuit according to claim 5, in which said thyristor means is a thyristor.
Claim 9
Dependent Claim
16 words
A power supply circuit according to claim 5, in which said thyristor means is a triac.
Claim 10
Dependent Claim
19 words
A power supply circuit according to claim 6 or 7, in which said switching means is a switching transistor.
Claim 11
Dependent Claim
54 words
A power supply circuit according to any one of claims5 to 8, in which the first external control signal is provided by a temperature detecting device (TH2) and in which the first predetermined value is provided by means of a zener diode (D22) to which a signal from the temperature detecting device is applied.
Claim 12
Dependent Claim
50 words
A power supply circuit according to claim 7, in which said second external control signal is provided by a temperature detecting device (THl) and in which the second predetermined value is provided by means of a zener diode (D21) to which a signal from the temperature detecting device is applied.
Claim 13
Dependent Claim
32 words
A power supply circuit according to claim 5, in which the circuit provides two stabilized voltage potentials stepwisely changeable depending on a deadband characteristic which is defined by two external control signals.
References Cited (Backward Citations)
No citation records indexed.
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