Atmel Corporation

Gian Marco Bo

Massimo Mazzucco

Fabrizio De Nisi

A method for sensing the supply current of a switched DC-to-DC converter is discussed. The method sensing a first voltage that is proportional to the supply current, wherein the first voltage has first noise; outputting a second voltage that is based on the first voltage, and wherein the second voltage has second noise that is smaller than the first noise; and comparing the second voltage to a reference voltage to provide an indication of the supply current. According to the systems and methods disclosed herein, accurate current sensing is provided.

Method for current sensing in switched DC-to-DC converters

A versatile voltage regulator accommodates either an Alkaline or Lithium-Ion battery main battery and provides low-current power for a real time clock module and for charging a backup battery. Depending upon the battery power source that is used, the present invention provides a best circuit configuration for efficient power conversion. If the power converter according to the present invention provides a regulated output voltage that is greater than the main battery voltage of an Alkaline battery, a low drop-out-voltage (LDO) voltage regulator is used in feedback loop with a charge pump. Otherwise, for a Lithium-Ion battery, only a LDO voltage regulator is used. The voltage regulator includes a series low drop-out-voltage (LDO) voltage regulator that is coupled between the main external battery and the vout load terminal, when the voltage at the vout load terminal is less than the voltage of the main external battery. The voltage regulator also includes a charge pump circuit adapted to be connected in feedback loop with the LDO regulator and the vout load terminal, when the voltage at the vout load terminal exceeds the voltage of the main external battery.

Method and circuit for a voltage supply for real time clock circuitry based on voltage regulated charge pump

A system for sensing the supply current of a switched DC-to-DC converter. The system includes a first circuit that senses a first voltage that is proportional to the supply current, wherein the first voltage has first ripple; a second circuit coupled to the first circuit, wherein the second circuit outputs a second voltage that is based on the first voltage, and wherein the second voltage has a second ripple that is smaller than the first ripple; and a third circuit coupled to the second circuit, wherein the third circuit compares the second voltage to a reference voltage to provide an indication of the supply current.

System for current sensing in switched DC-to-DC converters

A circuit for limiting a power current from a power-controlling pass device, the power-controlling pass device being coupled to a supply voltage, comprises the following. A sense device is coupled to the supply voltage with the sense device being configured to draw a sense current that is proportional to the power current. A current mirror is coupled to the sense device and the supply voltage through a low impedance node, the current mirror being configured to draw a mirror current through the low impedance node that is relative to the sense current. A limiting device is coupled to the supply voltage, the power-controlling pass device, and the low impedance node, the limiting device being configured to limit the power current according to a voltage difference between the low impedance node and the supply voltage.

Method and apparatus for current limitation in voltage regulators

A circuit for limiting a power current from a power-controlling pass device, the power-controlling pass device being coupled to a supply voltage, comprises the following. A sense device is coupled to the supply voltage with the sense device being configured to draw a sense current that is proportional to the power current. A current mirror is coupled to the sense device and the supply voltage through a low impedance node, the current mirror being configured to draw a mirror current through the low impedance node that is relative to the sense current. A limiting device is coupled to the supply voltage, the power-controlling pass device, and the low impedance node, the limiting device being configured to limit the power current according to a voltage difference between the low impedance node and the supply voltage. A resistance device or PMOS transistor that generates the voltage difference and that may be controlled through a proper bias circuit to adjust the voltage difference.

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Savona, Italy

Gian Marco Bo