US 6,969,981 B1Granted

Voltage regulator power management apparatus

AssigneeNational Semiconductor Corporation

InventorsJohn Patrick Fairbanks, Hidehiko Suzuki

Life of this patent

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Abstract

Quiescent currents in a circuit that includes a regulator are reduced by disabling selected portions of the circuit. A window comparator is selected activated to evaluate the input voltage such that a first operating mode is activated when the input voltage is within a predetermined voltage range and a second operating mode is activated when the input voltage is outside of the predetermined voltage range. The battery voltage is used a reference signal when the first mode is selected such that a voltage reference circuit can be disabled to reduce power, while the voltage reference circuit is enabled when the second mode is selected. Another comparator circuit is periodically activated to compare the reference signal to the output voltage. The regulator is disabled after the output voltage exceeds a first level. The output voltage collapses below a second level associated, the evaluation and regulation process is repeated.

Claims24

Dependent claims

An apparatus that is arranged to conserve power in a circuit that includes a regulator that provides an output voltage from an input voltage, the apparatus comprising:

a window comparator that is selectively enabled in response to a first control signal, wherein the window comparator is arranged to select a reference mode when enabled, wherein the reference mode corresponds to a first mode when the input voltage is within a predetermined range and a second mode when the input voltage is outside of the predetermined range;
a reference circuit that is selectively enabled in response to a second control signal, wherein the reference circuit is arranged to provide a reference voltage when enabled;
an output comparator that is selectively enabled in response to a third control signal, wherein the output comparator is arranged to selectively activate the regulator by evaluating a reference signal and the output voltage when enabled;
a switching circuit that is arranged to select the reference signal based on the reference mode such that the reference signal is associated with the input voltage in the first mode and the reference signal is associated with the reference voltage in the second mode;
and
a power management unit that is arranged to provide the first control signal, the second control signal, and the third control signal such that the reference circuit and the window comparator are enabled to evaluate the input voltage, the reference circuit is disabled when the first mode is selected, and the output comparator is enabled between switching cycles of the regulator.

3 more elements

A method of conserving power in a circuit that includes a regulator, wherein the regulator provides an output voltage from an input voltage, the method comprising:

initiating a quiescent current reduction cycle by:
activating a window comparator and a reference voltage circuit to evaluate the input voltage, wherein the reference voltage circuit is arranged to provide a reference voltage when activated;
selecting a first mode when the input voltage is within a voltage range that is associated with the reference voltage;
selecting a second mode when the input voltage is outside of the voltage range that is associated with the reference voltage;
processing the first mode by:
deactivating the voltage reference;
activating an output comparator;
sensing the output voltage;
enabling the regulator while the sensed output voltage is below a positive threshold that is associated with the output comparator, wherein the positive threshold is related to the input voltage;
disabling the regulator after the desired sensed output voltage is achieved;
and
processing the second mode by:
activating the output comparator;
sensing the output voltage;
enabling the regulator while the sensed output voltage is below a positive threshold that is associated with the output comparator, wherein the positive threshold is related to the reference voltage;
and
disabling the regulator after the desired sensed output voltage is achieved.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/658,678Filed 9 Sep 2003
Granted: 29 Nov 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H02M 3/28
By static converters: using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
H02J 7/02
Circuit arrangements for charging or discharging batteries or for supplying loads from batteries: for charging batteries from AC mains by converters
G05F 1/562
Using semiconductor devices in series with the load as final control devices: with a threshold detection shunting the control path of the final…
H02J 2207/20
Details of circuit arrangements for charging or discharging batteries or supplying loads from batteries: charging or discharging characterised by…