Zero power start-up circuit
AssigneeMicron Technology, Inc.
InventorHagop Nazarian
Life of this patent
Estimating the term…
Abstract
An improved start-up circuit and method for self-bias circuits is described that applies a start-up voltage and current to a self-bias circuit to initialize its operation in its desired stable state. Once the self-bias circuit converges to its desired state of operation a start-up voltage reference/voltage clamping circuit shuts off current flow to the self-bias circuit and the start-up circuit enters a low power mode of operation to reduce its overall current and power draw. This allows for embodiments of the present invention to be utilized in portable and/or low power devices where low power consumption is of increased importance. In one embodiment of the present invention, a band-gap voltage reference circuit is initiated utilizing a start-up circuit.
Claims38
A start-up circuit, comprising:
- a current mirror;
- a start-up voltage reference coupled to a first output of the current mirror;
- and
- an output transistor coupled between a second output of the current mirror and an output of the start-up circuit, wherein the output transistor is controlled by the voltage difference between a voltage output of the start-up voltage reference and a voltage of the output of the start-up circuit.
A self-bias circuit, comprising:
- a feedback-controlled circuit having two or more stable states of operation, wherein the feedback controlled circuit contains a central circuit where current can be injected to bootstrap the feedback-controlled circuit into a desired state of operation;
- and
- a start-up circuit having an output, wherein the output is coupled to the central circuit, the start-up circuit comprising,
- a current mirror,
- a start-up voltage reference coupled to a first output of the current mirror, and
- an output transistor coupled between a second output of the current mirror and the output of the start-up circuit, wherein the output transistor is controlled by the voltage difference between a voltage of the start-up voltage reference and a voltage of the central circuit.
A band-gap voltage reference circuit, comprising:
- a current mirror coupled to an upper power rail;
- a first current path having a first bipolar junction transistor with a collector coupled to the current mirror through a first resistor, and an emitter coupled to a lower power rail, wherein the collector is coupled to a base of the first bipolar transistor;
- a second current path having second bipolar junction transistor and a second resistor, wherein a collector of the second bipolar junction transistor is coupled to the current mirror, a base of the second bipolar junction transistor coupled to the base of the first bipolar transistor, and where the second resistor is coupled between an emitter of the second bipolar junction transistor and the lower power rail;
- and
- a start-up circuit having an output, wherein the output is coupled to the first current path, the start-up circuit comprising,
- a start-up circuit current mirror,
- a start-up voltage reference coupled to a first output of the start-up circuit current mirror, and
- an output transistor coupled between a second output of the start-up circuit current mirror and the output of the start-up circuit, wherein the output transistor is controlled by the voltage difference between a voltage of the start-up voltage reference and a voltage of the first current path.
A memory device, comprising:
- an array of memory cells;
- and
- a band-gap voltage reference circuit, comprising:
- a current mirror coupled to an upper power rail;
- a first current path having a first bipolar junction transistor with a collector coupled to the current mirror through a first resistor, and an emitter coupled to a lower power rail, wherein the collector is coupled to a base of the first bipolar transistor;
- a second current path having second bipolar junction transistor and a second resistor, wherein a collector of the second bipolar junction transistor is coupled to the current mirror, a base of the second bipolar junction transistor coupled to the base of the first bipolar transistor, and where the second resistor is coupled between an emitter of the second bipolar junction transistor and the lower power rail;
- and
- a start-up circuit having an output, wherein the output is coupled to the first current path, the start-up circuit comprising,
- a start-up circuit current mirror,
- a start-up voltage reference coupled to a first output of the start-up circuit current mirror, and
- an output transistor coupled between a second output of the start-up circuit current mirror and the output of the start-up circuit, wherein the output transistor is controlled by the voltage difference between a voltage of the start-up voltage reference and a voltage of the first current path.
A system, comprising:
- a processor coupled to a memory device, wherein the memory device comprises,
- an array of memory cells;
- and
- a band-gap voltage reference circuit, comprising:
- a current mirror coupled to an upper power rail;
- a first current path having a first bipolar junction transistor with a collector coupled to the current mirror through a first resistor, and an emitter coupled to a lower power rail, wherein the collector is coupled to a base of the first bipolar transistor;
- a second current path having second bipolar junction transistor and a second resistor, wherein a collector of the second bipolar junction transistor is coupled to the current mirror, a base of the second bipolar junction transistor coupled to the base of the first bipolar transistor, and where the second resistor is coupled between an emitter of the second bipolar junction transistor and the lower power rail;
- and
- a start-up circuit having an output, wherein the output is coupled to the first current path, the start-up circuit comprising,
- a start-up circuit current mirror,
- a start-up voltage reference coupled to a first output of the start-up circuit current mirror, and
- an output transistor coupled between a second output of the start-up circuit current mirror and the output of the start-up circuit, wherein the output transistor is controlled by the voltage difference between a voltage of the start-up voltage reference and a voltage of the first current path.
A start-up circuit, comprising:
- a means for providing a mirrored current having a first and second outputs, wherein the current flowing from the second output controls the current flowing from the first output;
- a means for providing a start-up voltage reference coupled to a first output of the current mirror means;
- and
- means for selectively coupling the second output of the current means to an output of the start-up circuit, wherein the means for selectively coupling the second output of the current means is controlled by difference between a voltage of the start-up voltage reference means and a voltage of the output.
A method of operating a start-up circuit, comprising:
- outputting a start-up current from an output for a self-bias circuit from a current mirror source of a start-up circuit upon power-up;
- halting output of the start-up current when the output of the start-up circuit is greater than a start-up voltage reference;
- and
- halting operation of the current mirror upon halting output of the start-up current.
A method of starting a self-bias circuit, comprising:
- injecting a start-up current from a start-up current mirror upon power-up into a central circuit of a self-bias circuit with two or more stable states of operation, wherein the injected start-up current operates to bootstrap the self-bias circuit into a desired state of operation;
- halting injection of the start-up current when a voltage of the central circuit is greater than a start-up voltage reference;
- and
- halting operation of the start-up current mirror upon halting injection of the start-up current.
A method of starting a self-bias circuit, comprising:
- injecting a start-up current from a start-up current mirror upon power-up into a self-bias circuit that utilizes feedback and has two or more stable states of operation wherein the injected start-up current operates to bootstrap the feedback of the self-bias circuit into a desired state of operation;
- halting injection of the start-up current when a voltage of the self-bias circuit is greater than a voltage of a start-up voltage reference;
- and
- halting operation of the start-up current mirror upon halting injection of the start-up current.
A method of operating a band-gap voltage reference that comprises a current mirror coupled to an upper power rail, a first current path having a first bipolar junction transistor with a collector coupled to the current mirror through a first resistor, and an emitter coupled to a lower power rail, wherein the collector is coupled to a base of the first bipolar transistor, a second current path having second bipolar junction transistor and a second resistor, wherein a collector of the second bipolar junction transistor is coupled to the current mirror, a base of the second bipolar junction transistor coupled to the base of the first bipolar transistor, and where the second resistor is coupled between an emitter of the second bipolar junction transistor and the lower power rail, and a start-up circuit having an output, wherein the output is coupled to the first current path, the start-up circuit comprising, a start-up circuit current mirror, a start-up voltage reference coupled to a first output of the start-up circuit current mirror, and an output transistor coupled between a second output of the start-up circuit current mirror and the output of the start-up circuit, comprising:
- operating the start-up circuit to provide a start-up current from the output of the start-up circuit to the first current path until a voltage of the first current path is greater than a voltage of the start-up voltage reference.
Dependencies are inferred from the claim text.