Back to results
US 2003/0227306 A1Published application
Low voltage Vcc detector
OwnerErcole Rosario Di Iorioinventor
Life of this patent
Estimating the term…
Abstract
A low voltage supply voltage detector uses a current comparator and transistors with mirrored currents to deassert a reset signal when the supply voltage reaches a programmable threshold voltage.
Claims35
A method for operating a reset signal on a supply voltage, comprising:
- providing the supply voltage to first and second transistors to generate first and second currents therein;
- mirroring the first and the second currents with third and fourth transistors;
- comparing the mirrored currents with a current comparator;
- and
- switching the current comparator output to deassert a reset signal when the supply voltage reaches a predetermined threshold.
2 more elements
A method for deasserting a reset signal, comprising:
- maintaining a node voltage for an inverter input below the inverter voltage threshold until a supply voltage reaches a predetermined level;
- and
- deasserting the reset signal at the inverter output when the supply voltage reaches the predetermined level.
A method for indicating a predetermined threshold voltage condition for a supply voltage has been reached, comprising:
- providing the supply voltage to a detection circuit;
- drawing first and second currents through first and second distinct current paths in the circuit, the current paths having characteristics to cause the currents therein to move from a first current situation in which the first current is greater than the second current to a second situation in which the second current equals and exceeds the first current;
- mirroring the first and the second currents in third and fourth current paths in the circuit;
- and
- deasserting a reset signal when the second current exceeds the first current.
2 more elements
A method of detecting sufficiency of a ramped supply voltage, comprising:
- providing the supply voltage to a detection circuit;
- and
- deasserting a detection circuit reset signal when the ramped supply voltage reaches a minimum voltage.
A circuit, comprising:
- first, second, third, and fourth current paths between a supply voltage and ground, the third and fourth current paths mirroring current in the first and second current paths, respectively;
- a current comparator to compare the currents in the third and the fourth current paths;
- an inverter having an input connected between the current converter and the fourth current path;
- wherein the current comparator raises a voltage in the fourth current path above a threshold value of the inverter when the supply voltage reaches a predetermined level.
1 more element
A low voltage detector, comprising:
- first and second transistors each diode connected between a supply voltage and ground;
- first and second resistors connected in series with each other and in series with the first transistor;
- a third resistor connected in series with the second transistor;
- third and fourth transistors mirroring current in the first and second transistors, respectively;
- a current comparator connected between the supply voltage and the third and fourth transistors, the current comparator to compare the currents in the third and the fourth transistors;
- and
- an inverter having an input connected between the current comparator and the fourth transistor, the inverter to generate a logic high signal until the voltage at its input exceeds a threshold voltage of the inverter.
4 more elements
Dependencies are inferred from the claim text.