Abstract: A self-oscillating DC-DC buck converter with zero hysteresis is described. The converter comprises a comparator with a supply input, a non-inverting input to which a reference voltage is applied, an inverting input to which a feedback signal is applied, and an output to which a filter network is connected. The feedback signal is derived from the filter network and the output voltage of the converter is determined by the reference voltage. Connecting a filter network with an inductor and a capacitor to the output of the comparator and deriving the feedback signal from the filter network, results in an output of the comparator which is a DC output with a superimposed ripple. The level of the DC output is controlled by the reference voltage applied to the non-inverting input of the comparator, and the inductor current develops the ripple in the equivalent series resistance of the load circuit connected to the comparator output. The ripple can be regarded as the ramp signal in a conventional DC-DC converter.

Abstract: A buck-boost DC/DC converter includes an inductor and a power stage having a set of switches selectively connecting the inductor between a voltage input, a voltage output and a reference level in accordance with buck or boost mode. The converter has a switch control providing control signals to the set of switches in the power stage. A comparator provides to the switch control a first pulse width modulation signal in buck mode and a second pulse width modulation signal in boost mode. A ramp generator provides to the comparator a first ramp signal for buck mode and a second ramp signal for boost mode. An overlap control provides a ramp shift signal to the ramp generator in response to a detection signal that indicates activity of the switches in the power stage. The ramp shift signal adjusts the first and second ramp signals relative to each other so as to minimize any gap and any overlap between the first and second ramp signals.

Abstract: An otoplastic for production of behind-the-ear hearing aids. The hearing aid includes a preferably flexible signal conductor, such as an acoustic tube positioned in the auditory canal, whereby the otoplastic matches the individual anatomy of the patient and its locating part is in the form of a clip, which, at least partly arched, follows the outer edge of the cavum conchae. A branch following the edge of the cavum conchae transforms, above the antitragus, into a bent crosspiece traversing the cavum conchae and extending in the direction of the porous acusticus externus. The end section of the crosspiece lies in the upper section of the auditory canal and widens to accept the signal conductor (42).

Abstract: An otoplastic for production of behind-the-ear hearing aids. The hearing aid includes a preferably flexible signal conductor, such as e.g. an acoustic tube positioned in the auditory canal, whereby the otoplastic matches the individual anatomy of the patient and its locating part is in the form of a clip, which, at least partly arched, follows the outer edge of the cavum conchae. A branch which following the edge of the cavum conchae transforms, above the antitragus, into a bent crosspiece traversing the cavum conchae and extending in the direction of the porus acusticus externus. The end section of said crosspiece lies in the upper section of the auditory canal and widens to accept the signal conductor.

Abstract: An improved level shifter circuit with AC feed-forward is disclosed. The integrated circuit device includes a first circuit part biased from a lower voltage supply and a second circuit part biased from a higher voltage supply. One of the circuit parts has an RS flip-flop with two complementary signal outputs and the other one has a signal input and a first and a second switching transistor. The first and the second switching transistors each have a current channel DC coupled in series with a respective cascode-connected transistor which is connected to a respective one of the signal outputs. One of these outputs is coupled to the input through a first feed-forward AC series circuit of an inverter and a first coupling capacitor, and the other output is coupled to the input through a second feed-forward AC circuit including a second coupling capacitor.

Abstract: 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.

Abstract: A hysteretic DC/DC converter is proposed that operates at a high switching frequency without producing undesired pulse bursts at the output. The converter has a converter power stage with a supply voltage input, a controlled voltage output and an enable input. A comparator has a reference voltage input, a feedback input and an output, and a gating circuit connected between the output of the comparator and the enabling input of the converter power stage. The gating circuit inhibits as a function of load requirements the propagation of enabling pulses from the output of the comparator to the enabling input of the converter power stage. By gating the output of the comparator in a way to separate the output from the enabling input of the converter power stage immediately after the start of each conversion pulse, the generation of further pulses immediately after each conversion pulse is prevented, thereby keeping the output voltage ripple low.

Abstract: A DC/DC converter has a linear voltage regulator for reducing or eliminating the output ripple of the converter with a minimum loss of efficiency. The converter comprises a converter stage with a supply voltage input, a converted voltage output and a control input, a regulator stage having an input connected to the converted voltage output of the converter stage and an output connected to a load, and a tracking circuit with inputs for a voltage at the converted voltage output of the converter stage, a voltage at the output of the regulator stage and a load sense current, and an output connected to the control input of the converter stage. The tracking circuit controls the converter stage so as to increase the converted voltage with an increasing load sense current and vice versa. The output voltage of the converter is always just sufficient to eliminate the ripple without having to operate the regulator's pass transistor in its linear range.

Abstract: An improved level shifter circuit with AC feed-forward is disclosed. The integrated circuit device includes a first circuit part biased from a lower voltage supply and a second circuit part biased from a higher voltage supply. One of the circuit parts has an RS flip-flop with two complementary signal outputs and the other one has a signal input and a first and a second switching transistor. The first and the second switching transistors each have a current channel DC coupled in series with a respective cascode-connected transistor which is connected to a respective one of the signal outputs. One of these outputs is coupled to the input through a first feed-forward AC series circuit of an inverter and a first coupling capacitor, and the other output is coupled to the input through a second feed-forward AC circuit including a second coupling capacitor.

Abstract: An improved power switching circuit is disclosed. The circuit comprises 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 comprises 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.

Abstract: An otoplasty for behind-the-ear provisions for hearing aids, with which a preferably flexible signal conductor coming from the behind-the-ear device, such as a sound tube, can be positioned in the auditory canal. The otoplasty is individually adapted to the anatomy of the patient. Its fixing part is essentially in the form of a hook that follows the outer edge of the patient's cavum conchae in an arch, at least in some areas. A limb that follows the edge of the cavum conchae becomes a bent transversal section above the patient's antitragus, traversing the cavum conchae, extending in the direction of the patient's porus acusticus externus and expanding at its end section which comes to rest in the upper area of the auditory canal, to receive the signal conductor.

Abstract: A method for producing a self-supporting electron-optical transparent structure that includes multi-layer strips and recesses located between the multi-layer strips. The method includes applying a first layer to a second layer, presetting a pattern by exposing or irradiating the first layer and etching the pattern out of the first layer so that partial areas of the second layer are uncovered. The method further includes galvanically applying layers to the uncovered partial areas of the second layer so that multi-layer strips are formed thereon and an electron-optical transparent structure is formed and removing the electron-optical transparent structure off the second layer.

Abstract: The invention relates to an otoplastic for production of behind-the-ear hearing aids. Said hearing aid comprises a preferably flexible signal conductor, such as e.g. an acoustic tube (28) which can be positioned in the auditory canal, whereby the otoplastic matches the individual anatomy of the patient and its locating part is essentially in the form of a clip, which, at least partly arched, follows the outer edge (36) of the cavum conchae (22). A branch (32) which follows the edge of the cavum conchae transforms, above the antitragus(30), into a bent crosspiece (34) which traverses the cavum conchae and runs in the direction of the porus acusticus externus. The end section (40) of said crosspiece (34) lies in the upper section of the auditory canal (26) and widens to accept the signal conductor (42).

Abstract: A method for producing a self-supporting electron-optical transparent structure that includes multi-layer strips and recesses located between the multi-layer strips. The method includes applying a first layer to a second layer, presetting a pattern by exposing or irradiating the first layer and etching the pattern out of the first layer so that partial areas of the second layer are uncovered. The method further includes galvanically applying layers to the uncovered partial areas of the second layer so that multi-layer strips are formed thereon and an electron-optical transparent structure is formed and removing the electron-optical transparent structure off the second layer.

Abstract: The invention relates to an otoplasty for behind-the ear provisions for hearing aids, with which a preferably flexible signal conductor coming from the behind-the-ear device, such as a sound tube (28) can be positioned in the auditory canal. The otoplasty is individually adapted to the anatomy of the patient. Its fixing part is essentially in the form of a hook which follows the outer edge (36) of the cavum conchae (22) in an arch, at least in some areas. A limb (32) which follows the edge of the cavum conchae becomes a bent transversal section (34) above the antitragus (30), traversing the cavum conchae, extending in the direction of the porus acusticus externus and expanding at its end section (40) which comes to rest in the upper area of the auditory canal (26), in order to receive the signal conductor (42).

Abstract: A charge pump-type DC/DC converter comprises n (n≧2) elementary stages, each consisting of a charge pump capacitor and several controllable switches connected thereto, whereby the input voltage of the DC/DC converter is applied to the input of the first stage, both electrodes of the charge pump capacitor of the kth stage are each connectable to one of the controllable switches with the output of the (k−1)th stage, k=2, . . . , n and the output of the nth stage forms the output of the DC/DC converter. The DC/DC converter in accordance with the invention is characterized in that it in addition enables one or more further controllable switches to be connected, via which the electrode of the charge pump capacitor of the nth stage which in the discharge phase is not connected to the output of the converter, to one or more outputs of the 1th stage (1=(n−2), . . .

Abstract: 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 capacitor(s) 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 co

Abstract: 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 cont

Abstract: 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.

Abstract: A charge pump (10) includes a supply voltage terminal (16) and a ground terminal (18) for generating at an output terminal an output voltage (34) which is higher than the voltage present at the supply voltage terminal. It has two complementary MOS field-effect transistors (12, 14), the source-drain paths of which are connected in series between the supply voltage terminal and the ground terminal. It further has a driving circuit (26) for driving the two MOS field-effect transistors and a charge storage capacitor connected by one terminal to the point connecting the source-drain paths of the two MOS field-effect transistors. This charge storage capacitor is formed by the gate capacitance of a further MOS field-effect transistor (20), the source-drain path of which is connected at one end via a first diode (22) to the supply voltage terminal and at the other end via a second diode (24) to the output terminal.