Texas Instruments Incorporated Deutschland, Gmbh

Texas Instruments Corporation

Hans Schmeller

Erich Bayer

Christophe Vaucourt

Erich-Johann Bayer

Harald Sandner

Martin Rommel

Helmut Kiml

Christian Meindl

Helmut Kimi

In a switched mode inductive DCDC converter having a first mode that conducts a first current path through an inductor and through a first switch, and a second mode that conducts a second current path through the inductor and through a second switch, a detecting component detects a parameter. The detecting component outputs a biasing signal extend the turn OFF time of one of the switches in order to decrease a voltage build up on the other switch.

Switched mode DCDC converter efficiency improvement by adaptive driver stage

The invention relates to an electronic device, comprising a DC-DC converter for converting a primary supply voltage into an output voltage at an output node to be coupled to a super capacitor and a control stage for operating the regulated DC-DC converter in a forward direction in a boost mode providing a boost voltage level at the output node and for operating the regulated DC-DC converter in a reverse direction in a buck mode providing a buck voltage level at an auxiliary node arranged between a primary voltage supply providing the primary supply voltage and the output node, wherein the control stage is adapted to control the DC-DC converter when operating in reverse direction to provide a current to the auxiliary node using the super capacitor as a power source.

DC-DC converter and method for minimizing battery peak pulse loading

The invention relates to a DC-DC converter, which includes a power stage driven by a pulse width modulator, a first error amplifier with a first input coupled to a first reference voltage source and a second input coupled to a current sink through which a current is fed from an output of the power stage to receive a first feedback voltage (FB), a second error amplifier with a first input coupled to a second reference voltage source and a second input coupled to the output of the power stage to receive a second reference voltage (FB), and switching means (SW) for connecting a control input of the pulse width modulator with the output of the first error amplifier in a current regulation mode and with the output of the second error amplifier in a voltage regulation control mode.

Dual mode regulation loop for switch mode power converter

A method is provided for driving a plurality of light emitters in a plurality of output paths with each output path including at least one light emitter. The method includes the steps of applying a supply voltage level to a plurality of output paths; generating a current for each path during a period of a predetermined length for the output path; sensing a current level for each output path during the period; comparing each sensed current level with a reference level; increasing the supply voltage level if the sensed current level is lower than the reference level; determining a lowest supply voltage level for the worst case output path; and using the lower supply voltage level as a common supply voltage level for all output paths.

LED driver with adaptive algorithm for storage capacitor pre-charge

A method for driving a light-emitting semiconductor is provided. A supply voltage is converted into a secondary output voltage for supplying the light-emitting semiconductor with an output voltage. A level for the supply voltage at the beginning of a high current phase of the light-emitting semiconductor is sensed. A threshold voltage level for the supply voltage level is determined based on the sensed level. The high current phase with the light-emitting semiconductor is stated. The sensed level is continuously compared with the threshold voltage level, and an output current through the light-emitting semiconductor is controlled such that the sensed level does not drop below the threshold voltage level.

Adaptive algorithm for camera flash LED power control vs. battery impedance, state of discharge (SOD), aging, temperature effects

A power switching circuit includes a power MOS transistor that has a maximum source-drain voltage substantially higher than a permissible gate-source voltage, and that has a current path connected in series with a load between first and second supply terminals, and comprising a gate driver circuit that drives the gate of the power MOS transistor directly from the supply voltage. A gate driver circuit has a pair of series-connected switching transistors connected between the first and second supply terminals. An interconnection node between the switching transistors is connected to the gate of the power MOS transistor. The gate driver circuit further includes a reference voltage source and a voltage comparator comparing the gate voltage of the power MOS transistor with the reference voltage to provide a disabling output that disables one of the switching transistors when the gate voltage of the power MOS transistor reaches the reference voltage. By selecting a reference voltage level not higher than the maximum permissible gate-to-source voltage of the power MOS transistor, its gate is effectively protected from excessive gate-to-source voltage. Yet, the switching transistor in the gate driver circuit other than that connected to the ground supply terminal (usually referred to as Vcc terminal), may have its current path connected directly, or through just a feedback resistor, to the high supply terminal (usually referred to as Vcc terminal).

Integrated power switching circuit

The invention relates to a DC/DC converter circuit including a voltage conversion circuit and a regulator circuit comprising a reference voltage generator circuit and a comparator which outputs a control signal for activating/deactivating the voltage conversion circuit as a function of the output load of the converter circuit. The converter circuit additionally comprises a circuit for signaling the regulator circuit ON/OFF comprising a comparator, at the first input of which a further voltage characterizing the output voltage and, at the second input of which a voltage at a capacitor is applied, and a control circuit comprising switches which during the ON time of the regulator circuit control the capacitor so that it is charged to a voltage which differs by a predetermined amount from the voltage characterizing the output voltage, and when it has attained the design value it signaling the regulator circuit OFF and separating the capacitor from the charging voltage, the comparator outputting a signal to the control circuit when the further voltage characterizing the output voltage and the voltage across the capacitor agree, resulting in the regulator circuit being returned ON.

DC/DC converter circuit

An unregulated inductorless direct current to direct current converter comprising a first voltage-to-current converter configured to convert a first voltage to a first current and a second voltage-to-current converter configured to convert a second voltage to a second current. A regulation circuit is coupled to the first and second voltage-to-current converters and configured to generate an output current proportional to the difference between the first and second currents. Also a variable frequency oscillator is coupled to the regulation circuit, the oscillator receiving as a control current the output current therefrom and outputting a clock signal having a frequency proportionate to the control current. The converter further comprises an output stage coupled to receive the clock signal and receiving an input voltage and outputting an output voltage, the output voltage and the input voltage having a ratio that is determined by the clock signal.

Frequency control circuit for unregulated inductorless DC/DC converters

The invention relates to a DC/DC converter including a charge pump circuit comprising one or more capacitors and a plurality of controllable switches connected thereto, the controllable switches being controllable by a control circuit so that the capacitors is/are alternatingly switched in a charging and discharge phase; a first current source set to a predetermined base current located either in the discharge or charging path of the charge pump circuit and a second current source connected in parallel thereto; and a regulator circuit for generating a first control signal representing the difference between a voltage characterizing the output voltage and a first reference voltage and controlling the second current source when the charge pump circuit is active so that the controllable current is reduced or increased with an increase and reduction respectively in the difference to track the voltage characterizing the output voltage in accordance with the first reference voltage; and for generating a second control signal guided to the control circuit, this signal assuming a first status when the voltage characterizing the output voltage exceeds a second reference voltage at a predetermined level above the first reference voltage, upon which the control circuit deactivates the charge pump circuit, and assumes a second status when the voltage characterizing the output voltage drops below the second reference voltage, upon which the control circuit activates the charge pump circuit. The invention relates further to a method of operating a DC/DC converter.

DC/DC converter and method of operating a DC/DC converter

The invention relates to a DC/DC converter operating on the principle of a charge pump, comprising at least one charge pump capacitor and several controllable switches connected thereto. The switches are actuated by a control circuit with an oscillator. A skip mode comparator signals the charge pump alternatingly ON and OFF depending on the condition of the output voltage of the converter. Prior art converters featured high output current spikes and a heavy output voltage ripple. The converter in accordance with the invention reduces these problems by a regulator circuit which receives the control signal of the comparator and converts it into a signal characterizing the momentary ON/OFF duration ratio of the charge pump with which it controls the ON resistance of at least one of the switches so that the ON/OFF duration ratio of the charge pump can be set to a predetermined design value, at which the output current spikes of the charge pump are reduced. Provided parallel to this switch is a further small switch whose ON resistance is not controlled to thus ensure a small idle current of the charge pump at a low load.

DC/DC converter incorporating a skip mode regulator

The invention relates to a DC/DC converter operating on the charge pump principle, regulated to a fixed, predetermined output voltage and comprising two charge pump capacitors switched in a switch matrix consisting of nine switches. A control circuit is provided capable of controlling the switches so that the charge pump is changed over between a charging phase and a discharge phase and which is capable of operating the charge pump in two modes having different voltage gain factors (1.5; 2). The regulator comprises furthermore a regulator circuit capable of setting when the charge pump is active in the charging phase in the first mode the ON resistance of a switch present in the charge path of the charge pump capacitors or in the second mode the ON resistances of two switches present each in one of the charging paths of the first or second charge pump capacitor so that the charging voltage presented to the charge pump capacitors in the charging phase assumes the minimum value possible for a specific input voltage of the converter, a measuring circuit capable of defining the voltage occurring at one of the charge pump capacitors at a defined point in time of the charging phase; and a comparator capable of comparing the measured voltage to a predetermined voltage and then when the former attains the latter, changing over the charge pump into the corresponding other mode, wherein the predetermined voltage is selected so that the efficiency of the converter is optimized and the charging condition of the charge pump capacitors is not altered on changeover.

DC/DC converter

The invention relates to a DC/DC converter operating on the principle of a charge pump and comprising a first capacitor C,alternatingly charged via four MOSFETs M,-M,to the input voltage and then discharged in series with the input voltage via a second capacitor C,connected to the output of the circuit. To set the starting current for charging the as yet empty capacitors to a precisely defined small value a switchable current mirror M,, M,is used comprising one of the four MOSFETs (M,) and a further small MOSFET (M,) which is connected to a current source,. A comparator,handles selection between the starting phase and the normal charge pump mode by comparing the output voltage V,of the converter to a reference voltage V,, it switching the current mirror and&mdash;via two small switches S,and S,connected to the gates of two of the four MOSFETs&mdash;also two of the four MOSFETs so that the capacitors may be charged in an energy-saving way. As compared to existing more complicated achievements this novel DC/DC converter is producable integrated on a smaller circuit area, it in addition to this taking into account the short-circuit case of the converter. In one special embodiment a foldback effect is achievable via a further MOSFET connected in parallel to the current source, the gate of this MOSFET being connected to the output of the converter.

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Woerth, Germany

Hans Schmeller