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US 2020/0089268 A1Published application
Power source circuit
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorYuji YAMANAKA
Life of this patent
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Abstract
According to an embodiment, a power source circuit has first, second, and third one-conductivity-type transistors with commonly connected emitters, wherein the first transistor has an emitter area that is N times those of the second and third transistors. The power source circuit outputs a reference voltage that is set by a voltage drop that is caused at a resistance between bases of the first and second transistors and a forward voltage of a PN-junction diode, and outputs a BG_OK signal in response to a potential at a collector of the third transistor.
Claims20
A power source circuit, comprising:
- a first conductivity-type first bipolar transistor that has an emitter, a base, and a collector;
- a first conductivity-type second bipolar transistor that has an emitter that has an emitter area that is different from an emitter area of the first bipolar transistor and is commonly connected to the emitter of the first bipolar transistor;
- a first conductivity-type third bipolar transistor that has an emitter that has an emitter area that is different from the emitter area of the first bipolar transistor and is commonly connected to the emitter of the first bipolar transistor;
- an output voltage setting circuit that has a first resistor that is connected between the base of the first bipolar transistor and a base of the second bipolar transistor and a second resistor that is connected between the base of the second bipolar transistor and a base of the third bipolar transistor;
- a PN-junction diode that is connected in a forward direction between the base of the first bipolar transistor and a power source terminal;
- a reference voltage output terminal that is connected to the output voltage setting circuit and outputs a reference voltage that is set by a voltage that is a sum of a forward voltage of the PN-junction diode and a voltage that is a predetermined times a voltage drop that is caused at the first resistor;
- and
- a detection signal output circuit that outputs a detection signal that indicates that the reference voltage reaches a predetermined threshold voltage in response to a potential at a collector of the third bipolar transistor.
5 more elements
A power source circuit, comprising:
- an input terminal where a power source voltage is applied thereto;
- a ground terminal where a ground potential is applied thereto;
- a first NPN bipolar transistor that has an emitter, a base, and a collector;
- a second NPN bipolar transistor that has an emitter that has an emitter area that is different from an emitter area of the first NPN bipolar transistor and is commonly connected to the emitter of the first NPN bipolar transistor;
- a third NPN bipolar transistor that has an emitter that has an emitter area that is different from the emitter area of the first NPN bipolar transistor and is commonly connected to the emitter of the first NPN bipolar transistor;
- an output voltage setting circuit that has a first resistor that is connected between the base of the first NPN bipolar transistor and a base of the second NPN bipolar transistor and a second resistor that is connected between the base of the second NPN bipolar transistor and a base of the third NPN bipolar transistor;
- a PN-junction diode that is connected in a forward direction between the base of the first NPN bipolar transistor and the ground terminal;
- a reference voltage output terminal that is connected to the output voltage setting circuit and outputs a reference voltage that is set by a voltage that is a sum of a forward voltage of the PN-junction diode and a voltage that is a predetermined times a voltage drop that is caused at the first resistor;
- and
- a detection signal output circuit that outputs a detection signal that indicates that the reference voltage reaches a predetermined threshold voltage in response to a potential at a collector of the third NPN bipolar transistor.
7 more elements
A power source circuit, comprising:
- an input terminal where a power source voltage is applied thereto;
- a ground terminal where a ground potential is applied thereto;
- a first PNP bipolar transistor that has an emitter, a base, and a collector;
- a second PNP bipolar transistor that has an emitter that has an emitter area that is different from an emitter area of the first PNP bipolar transistor and is commonly connected to the emitter of the first PNP bipolar transistor;
- a third PNP bipolar transistor that has an emitter that has an emitter area that is different from the emitter area of the first PNP bipolar transistor and is commonly connected to the emitter of the first PNP bipolar transistor;
- an output voltage setting circuit that has a first resistor that is connected between the base of the first PNP bipolar transistor and a base of the second PNP bipolar transistor and a second resistor that is connected between the base of the second PNP bipolar transistor and a base of the third PNP bipolar transistor;
- a PN-junction diode that is connected in a forward direction between the base of the first PNP bipolar transistor and the ground terminal;
- a reference voltage output terminal that is connected to the output voltage setting circuit and outputs a reference voltage that is set by a voltage that is a sum of a forward voltage of the PN-junction diode and a voltage that is a predetermined times a voltage drop that is caused at the first resistor;
- and
- a detection signal output circuit that outputs a detection signal that indicates that the reference voltage reaches a predetermined threshold voltage in response to a potential at a collector of the third PNP bipolar transistor.
7 more elements
Dependencies are inferred from the claim text.