Low power beta multiplier start-up circuit and method
AssigneeCypress Semiconductor Corporation
InventorsT.V. Chanakya Rao, Badrinarayanan Kothandaraman
Life of this patent
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Abstract
A circuit (200) can include a reference circuit (202) and a start-up circuit (204). A start-up circuit (204) can include a low threshold voltage reference current device (N3) that can pull a start node (210) low in a start-up operation. This can enable activation device (P3), which can place reference circuit (202) in a stable operating mode. Operation of transistor (N3) can be essentially independent of a high power supply voltage and start-up circuit (204) can include no resistors.
Claims20
An integrated circuit device, comprising:
- a self-biased reference circuit that provides a reference value to the integrated circuit, the reference circuit being disposed between a first power supply node and a second power supply node and including transistors of a first conductivity type and transistors of a second conductivity type;
- and
- a start-up circuit comprising
- a start-up current path coupled between the first power supply node and the second power supply node that includes a reference current transistor having a threshold voltage that is closer in magnitude to a second power supply voltage than the transistors of the first conductivity type and second conductivity type, and
- an activation device coupled between the second power supply node and the self-biased reference circuit that is enabled in response to a potential established by the current supply transistor.
A reference circuit, comprising:
- a reference section that provides a reference value for other circuits of an integrated circuit according to a bias voltage at a reference bias node;
- and
- a start-up circuit comprising
- a biasing device having a controllable impedance path between the reference bias node and a first power supply node, and
- a reference current transistor having a drain coupled to the biasing device and a source and gate commonly coupled to a second power supply node.
A method of starting up a self-biased reference circuit, comprising the steps of:
- in a start-up operation,
- applying a first supply voltage to a first supply node and applying a reference voltage to a reference node of the self-biased reference circuit;
- and
- coupling a bias node of a self-biased reference circuit to the first supply voltage by operation of a reference current transistor having a threshold voltage that does not vary from the reference voltage by more than about 150 mV.
Dependencies are inferred from the claim text.