Analog Devices Global

Analog Devices,inc.

Analog Devices Technology

Song Qin

Bin Shao

Olli Haila

Apparatus and methods for current sensing in switching regulators include a current sensing circuit to sense current of a power stage of a power converter. The power converter can include first and second transistors. The current sensing circuit comprises a transistor that is a scaled version of one of the transistors of the power converter. A circuit of the current sensing circuit matches a drain-to-source voltage of the transistor of the current sensing circuit to the corresponding transistor of the power converter. A current mirror generates a current that mirrors the current flowing through the transistor of the current sensing circuit. A first resistor converts the mirrored current to a current sensed signal.

Current sensing of switching power regulators

Apparatus and methods for current sensing in switching regulators are provided. In certain implementations, a switching regulator includes a switch transistor, a replica transistor, a current source, a sense resistor, and a current sensing circuit. The drain and gate of the switch transistor can be electrically connected to the drain and gate of the replica transistor, respectively. Additionally, the current sensing circuit can control the voltage of the source of the replica transistor based on the polarity of a current through the switch transistor to generate an output current that changes in response to the switch transistor's current. The sense resistor can receive an offset current from the first current source and the output current from the current sensing circuit such that the voltage across the sense resistor changes in relation to the current through the switch transistor.

Apparatus and methods for bidirectional current sensing in a switching regulator

A negative current protection system for a low side switching converter FET, for use with a switching converter arranged to operate high and low side FETs connected to an output inductor to produce an output voltage. The negative current protection system includes a current sensing circuit which produces an output Vcs that varies with the current in the high side FET, a negative current threshold generator which produces a threshold signal &#x2212;Ith which represents the maximum negative current to which the low side FET is to be subjected, and a comparison circuit arranged to compare the valley portion of Vcs and -Ith and to set a flag if Vcs&#x3c;&#x2212;Ith at a predetermined time in the switching cycle&#x2014;typically after the converter's blanking time. When the flag is set, the system preferably responds by adjusting the operation of the switching FETs to reduce the negative current.

Negative current protection system for low side switching converter FET

Apparatus and methods for current sensing in switching regulators are provided. In certain implementations, a switching regulator includes a switch transistor, a replica transistor, a sense resistor, and a current sensing circuit. The drain and gate of the switch transistor can be electrically connected to the drain and gate of the replica transistor, respectively. The current sensing circuit can generate an output current that varies in response to a sense current from a source of the replica transistor. Additionally, the current sensing circuit can sink the sense current when the sense current flows from the drain to the source of the replica transistor and source the sense current when the sense current flows from the source to the drain of the replica transistor. The sense resistor can receive the output current such that the voltage across the sense resistor changes in relation to the current through the switch transistor.

Apparatus and methods for switching regulator current sensing

An output stage, comprising a first transistor operable to pull a voltage at an output node towards a first voltage, and a rechargeable energy store having a potential difference between first and second terminals wherein the rechargeable energy store is arranged to be controllably connected between the output node and a second voltage supply such that the voltage at the output node can be driven to a voltage outside of a range defined between the first and second voltages.

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Shanghai, China

Song Qin