Dialog Semiconductor Gmbh

Axel Pannwitz

Achim Stellberger

David Dearn

Hans Martin Von Staudt

John Stuart Malcolm

A method and circuits to improve the stability of low dropout voltage regulators having an adaptive biased driving stage. Said improvement of stabilization is valid through the total range of output current possible. A serial impedance is added to the gate capacitance of the PMOS pass device of said LDO. Said serial impedance could be a resistor or a transistor. In case of low load currents said impedance is not dominating, for high load currents said impedance keeps the gate pole close to the resonance frequency of the output tank. In case of medium load currents, wherein the inner resistance of the driving stage is about equal to said serial impedance, the gate pole could get too low. This problem is solved by reducing said serial impedance by shunting. Said shunting can be performed stepwise depending on the size of the load current. A special circuitry detects the condition of medium load currents and can initialize the shunting of said serial impedance accordingly in order to keep the gate pole on the optimum frequency.

Frequency compensation scheme for low drop out voltage regulators using adaptive bias

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

The invention refers to a charge/discharge protection circuit for a rechargeable battery being able to differentiate between a temporary overvoltage on the charge/discharge terminals and a permanent overvoltage and in the last case for security reasons to permanently disconnect the battery from the charge/discharge terminals. Hereby said protection circuit comprises a number of partial switches ( &lsqb;1:&rsqb;), being either parallel to a load switch (LS) or parallel to the charge terminals, and an overvoltage detector ( ) which closes in case of an overvoltage all partial switches via a control logic ( ) and which afterwards opens one partial switch after the other. A voltage detector ( ), monitoring the remaining voltage over the partial switches, inhibits, however, the opening of at that time next partial switch if the remaining voltage over the still closed partial switches is higher than a predefined limit of said remaining voltage. In case the cycle is not completed within a predefined time interval, that means that after the time interval at least the last partial switch is still closed, the control circuit activates a permanent disconnection of the battery from charge terminals.

Charge/discharge protection circuit for a rechargeable battery

A charge/discharge protection circuit with n parallel load current switches and a control logic for the latter, which in an over-voltage event disconnects the battery from the charge/discharge terminals through sequentially controlled melting of integrated fusible links, where the control logic in an over-voltage event, simultaneously closes all load current switches, then following sequentially opens a first number of the load current switches, and at the same time closes the switch segments of a short-circuit switch array associated with the respective load current switch, so that the associated fusible links melt sequentially. After the opening of this first number of load current switches the latter closes again and at the same time the remaining number of still closed load current switches opens, as well as continues to sequentially close the remaining switch segments.

Charge/discharge protection circuit

The invention refers to a charge/discharge protection circuit for a rechargeable battery which is protected by a fusible link, where the rechargeable battery comprises a control logic which opens or closes a load switch depending on the magnitude of the battery voltage, the voltage on the charge/discharge terminals of the protection circuit and the charge/discharge current. The protection circuit is designed so that the electric strength needs to match only the actual maximum battery voltage, thus requiring little real estate on an IC chip and also allowing most components to be integrated.

The invention refers to a charge/discharge protection circuit for a rechargeable battery, where the protection circuit is integrated on a single chip, including the fusible link, the load current switch and the short-circuit switch. This is achieved by dividing the functions of the fusible link, the load current switch, and the short-circuit switch into in parallel arranged T-sections, each of which is designed for only a fraction of the nominal load so that each of the easily integrated fuse segments carry only the respective fraction of the nominal current. It is important that the entire protection circuit or its control logic will not be destroyed before through an unduly high over-voltage, in which case the sequential melting of the fuse segments would no longer be guaranteed. This is handled by a semiconductor switch which short-circuits the over-voltage immediately.

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Lenningen, Germany

Axel Pannwitz