Method and apparatus for band-gap based power-on-reset including fast, low power and accurate brownout detection
First Claim
Patent Images
1. A power-on reset (POR) circuit, compromising:
- a power-up detector circuit for detecting power supply ramp-up, wherein the power-up detector circuit comprises a pull-down network and a first RC delay;
a brownout detector circuit for sensing power supply falling down;
a set-reset (SR) latch to generate a power-on-reset (POR) signal, wherein the SR latch comprises a first output and a second output serving as a control for multiple switches to connect or disconnect blocks for power savings;
a start-up network having an output coupled to a first input of the pull-down network, a second input of the first RC delay, and a third input of the SR latch, wherein the third input of the SR latch is configured as an alternative reset signal at beginning of the power supply ramp-up; and
an internal band-gap voltage reference circuit having an output coupled to a first input of a first resistor ladder and a first input of a first comparator in the power-up detector circuit, wherein a first input of the internal band-gap voltage reference circuit couples with the first input of the start-up network, wherein the internal band-gap voltage reference circuit is configured to be started by the start-up network to serve as a reference for the power-up detector circuit.
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Abstract
A power-on reset (POR) circuit with an auxiliary control circuit and an enhanced resistor ladder for brownouts circuit detectors in low power applications includes a power-up detector circuit for detecting power supply ramp-up while charging; a brownout detector circuit for sensing power supply falling down; a set-reset (SR) latch to generate a power-on-reset (POR) signal; a start-up network; and an internal band-gap voltage reference circuit, wherein the internal band-gap voltage reference circuit is configured to be started by the start-up network to serve as a reference for the power-up detector circuit.
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Citations
11 Claims
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1. A power-on reset (POR) circuit, compromising:
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a power-up detector circuit for detecting power supply ramp-up, wherein the power-up detector circuit comprises a pull-down network and a first RC delay; a brownout detector circuit for sensing power supply falling down; a set-reset (SR) latch to generate a power-on-reset (POR) signal, wherein the SR latch comprises a first output and a second output serving as a control for multiple switches to connect or disconnect blocks for power savings; a start-up network having an output coupled to a first input of the pull-down network, a second input of the first RC delay, and a third input of the SR latch, wherein the third input of the SR latch is configured as an alternative reset signal at beginning of the power supply ramp-up; and an internal band-gap voltage reference circuit having an output coupled to a first input of a first resistor ladder and a first input of a first comparator in the power-up detector circuit, wherein a first input of the internal band-gap voltage reference circuit couples with the first input of the start-up network, wherein the internal band-gap voltage reference circuit is configured to be started by the start-up network to serve as a reference for the power-up detector circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification