Bandgap Reference Circuits
First Claim
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1. A bandgap reference circuit, comprising:
- a voltage generation circuit comprising;
a current mirror comprising at least one output terminal;
an operational amplifier coupled to the current mirror;
first and second BJT transistors coupled to two input terminals of the operational amplifier respectively, wherein at least one of the first and second BJT transistors is coupled to the output terminal of the current mirror through a conductive path; and
a start-up circuit triggering the current mirror;
wherein when powering on, the start-up circuit triggers the current mirror until at least one of the first and second BJT transistors operates in a forward-active region.
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Abstract
Bandgap reference circuits capable of preventing start failure. A voltage generation circuit generates a temperature-independent fixed voltage and comprises a current mirror, an operational amplifier, and first and second BJT transistors. A start-up circuit triggers the current mirror until at least one of the first and second BJT transistors operates in a forward-active region when powering on.
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Citations
32 Claims
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1. A bandgap reference circuit, comprising:
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a voltage generation circuit comprising; a current mirror comprising at least one output terminal; an operational amplifier coupled to the current mirror; first and second BJT transistors coupled to two input terminals of the operational amplifier respectively, wherein at least one of the first and second BJT transistors is coupled to the output terminal of the current mirror through a conductive path; and a start-up circuit triggering the current mirror; wherein when powering on, the start-up circuit triggers the current mirror until at least one of the first and second BJT transistors operates in a forward-active region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A bandgap reference circuit, comprising:
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a voltage generation circuit generating a fixed voltage and comprising; a current mirror comprising at least one output terminal; an operational amplifier coupled to the current mirror; first and second BJT transistors coupled to two input terminals of the operational amplifier respectively, wherein at least one of the first and second BJT transistors is coupled to the output terminal of the current mirror through a conductive path; and a start-up circuit coupled between the current mirror and a node on the conductive path. - View Dependent Claims (12, 13, 14, 15)
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16. A bandgap reference circuit, comprising:
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a voltage generation circuit generating a temperature-independent fixed voltage and comprising a current mirror, an operational amplifier and first and second BJT transistors; and a start-up circuit triggering the current mirror until at least one of the first and second BJT transistors operates in a forward-active region when powering on. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A start-up method for a bandgap reference circuit, comprising:
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powering on the bandgap reference circuit; and triggering a current mirror in the bandgap reference circuit, such that at least one diode-connected BJT transistor in the bandgap reference circuit operates in a forward active region. - View Dependent Claims (27, 28, 29, 30)
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31. A start-up method for a bandgap reference circuit, comprising:
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powering on the bandgap reference circuit; triggering a current mirror in the bandgap reference circuit to make at least one diode-connected BJT transistor in the bandgap reference circuit reach a forward active region; and stop the triggering.
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32. A start-up method for a bandgap reference circuit, comprising:
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powering on the bandgap reference circuit; and triggering a current mirror in the bandgap reference circuit to make at least one diode-connected BJT transistor in the bandgap reference circuit reach a forward active region; wherein the triggering is done by a start-up circuit and the start-up circuit is not within a feedback loop of the bandgap reference circuit.
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Specification