Dialog Semiconductor Gmbh

John Stuart Malcolm

Eric Marschalkowski

David Dearn

Axel Pannwitz

A circuit and a related method to sense the inductor current of CD/DC buck converters have been achieved. The inductor current is sensed by generation of a voltage drop across a fully integrated sense resistor. The voltage drop is proportional to the inductor current in the pass device by supplying a fraction of the inductor current out of a source-follower, which matches to the pass device. The source of said source-follower is connected to a sense-resistor that is connected to the same supply as the pass device. The current, which is needed to generate the voltage drop, is fed back into the inductor current minimizing therefore the efficiency loss. Mirroring, amplification and offset correction of the voltage drop across the sense-resistor is performed by using a single matching pair of source-follower, which is supplied by a current tracking the internal reference voltage and the process variations of the resistors.

Current sensing circuit for DC/DC buck converters

A method and a circuit to achieve a low drop-out voltage regulator with a wide output load range has been achieved. A fast loop is introduced in the circuit. The circuit is internally compensated and uses a capacitor to ensure that the internal pole is more dominant than the output pole as in standard Miller compensation. The quiescent current is set being proportional to the output load current. No explicit low power drive stage is required. The whole output range is covered by one output drive stage. By that means the total consumption of quiescent or wasted current is reduced. An excellent PSRR is achieved due to load dependent bias current.

LDO regulator with wide output load range and fast internal loop

A method and a circuit to monitor exactly the charge status of a battery of a battery powered device is achieved. The charge and discharge currents are continuously measured and integrated over time to get the exact charge of the battery. Inaccuracies caused by the offset of the integrators are precisely compensated by a bridge-like design of said circuit and by a feedback of said offset to the input of the integrators. The system is clocked in a way to enable a continuous operation. Another advantage is the low current consumption of the circuit by sharing some of the components for the integration of the currents and handling of the offset. The improved accuracy is optimizing the operation of said battery driven device and is avoiding any potential damage of the battery.

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Headley, United Kingdom

John Stuart Malcolm