Abstract: A tap sensitive alarm clock has a housing (20), a vibration sensor (22) mechanically coupled to the housing for receiving a shock due to a user tapping the housing, and a control circuit (24) coupled to the vibration sensor for controlling a function of the alarm clock. An audio unit (26) is coupled to an audio circuit (25) for generating sound, e.g. a loudspeaker in an alarm clock or a wake up light. To avoid interference of the sound and the vibration sensor, the alarm clock is provided with a filter (23) coupled to the vibration sensor and the control circuit. The filter has a filter curve matched to block frequencies occurring in the sound. Advantageously it is avoided that the sound frequencies trigger the function, while the sensor is sensitive to other frequencies up to the frequency range of the sound for reliably detecting the tapping.

Abstract: A tap sensitive alarm clock has a housing (20), a vibration sensor (22) mechanically coupled to the housing for receiving a shock due to a user tapping the housing, and a control circuit (24) coupled to the vibration sensor for controlling a function of the alarm clock. An audio unit (26) is coupled to an audio circuit (25) for generating sound, e.g. a loudspeaker in an alarm clock or a wake up light. To avoid interference of the sound and the vibration sensor, the alarm clock is provided with a filter (23) coupled to the vibration sensor and the control circuit. The filter has a filter curve matched to block frequencies occurring in the sound. Advantageously it is avoided that the sound frequencies trigger the function, while the sensor is sensitive to other frequencies up to the frequency range of the sound for reliably detecting the tapping.

Abstract: A LED driver system (1) comprises a current source (4) which supplies a power supply current (i) to a parallel arrangement of a parallel switch (20) and a LED (10). The parallel switch (20) short-circuits the LED (10) when it is closed. A controller (15) generates during use: (i) a first control signal (E) to control the current source (4) to change from a regulating mode wherein the power supply (i) current is regulated to have a non-zero average level into a decaying mode wherein the power supply current (i) decays during a decay period (Td), and (ii) a second control signal (CSO) to control the parallel switch (20) to open during an open period (To) comprising a sub-period of the decay period (Td).

Abstract: A tap sensitive alarm clock has a housing (20), a vibration sensor (22) mechanically coupled to the housing for receiving a shock due to a user tapping the housing, and a control circuit (24) coupled to the vibration sensor for controlling a function of the alarm clock. An audio unit (26) is coupled to an audio circuit (25) for generating sound, e.g. a loudspeaker in an alarm clock or a wake up light. To avoid interference of the sound and the vibration sensor, the alarm clock is provided with a filter (23) coupled to the vibration sensor and the control circuit. The filter has a filter curve matched to block frequencies occurring in the sound. Advantageously it is avoided that the sound frequencies trigger the function, while the sensor is sensitive to other frequencies up to the frequency range of the sound for reliably detecting the tapping.

Abstract: A LED driver system (1) comprises a current source (4) which supplies a power supply current (i) to a parallel arrangement of a parallel switch (20) and a LED (10). The parallel switch (20) short-circuits the LED (10) when it is closed. A controller (15) generates during use: (i) a first control signal (E) to control the current source (4) to change from a regulating mode wherein the power supply (i) current is regulated to have a non-zero average level into a decaying mode wherein the power supply current (i) decays during a decay period (Td), and (ii) a second control signal (CSO) to control the parallel switch (20) to open during an open period (To) comprising a sub-period of the decay period (Td).

Abstract: A wake-up lighting device is described, comprising a gas discharge lamp (10) and a lamp driver (1; 2) comprising a power source (100) capable of generating spaced-apart current bursts (51) of alternating lamp current (I). The wake-up lighting device is capable of operating in an off-mode in which no lamp current is generated, and is adapted to switch from its off-mode to a wake-up mode in which the power source (100) operates to:—initially generate an alternating lamp current (I) with a minimum duty cycle value (?T) and a reduced current amplitude (IR) close to zero;—subsequently gradually increase the current amplitude while keeping the duty cycle (?) constant at the minimum duty cycle value (?T), until the current amplitude reaches a nominal current amplitude (IM);—subsequently gradually increase the duty cycle (?) while keeping the current amplitude constant at the nominal current amplitude (IM).

Abstract: A tap sensitive alarm clock has a housing (20), a vibration sensor (22) mechanically coupled to the housing for receiving a shock due to a user tapping the housing, and a control circuit (24) coupled to the vibration sensor for controlling a function of the alarm clock. An audio unit (26) is coupled to an audio circuit (25) for generating sound, e.g. a loudspeaker in an alarm clock or a wake up light. To avoid interference of the sound and the vibration sensor, the alarm clock is provided with a filter (23) coupled to the vibration sensor and the control circuit. The filter has a filter curve matched to block frequencies occurring in the sound. Advantageously it is avoided that the sound frequencies trigger the function, while the sensor is sensitive to other frequencies up to the frequency range of the sound for reliably detecting the tapping.

Abstract: A battery voltage monitoring system monitors voltage of an arrangement of more than two batteries (U1, U2, U3, U4, U5) in series. The system comprises a voltage divider comprises a first (R1, R2, R3, R4) and second resistive element (R5, R6, R7, R8) arranged parallel to at least a part of the battery arrangement and connected to a reference voltage line and to a node (N1, N2, N3, N4) in the battery arrangement. In between the first (R1, R2, R3, R4) and second resistive element (R5, R6, R7, R8) a transistor (Q11, Q12, Q13, Q14) is arranged. The base of the transistor is, via a diode (D1, D2, D3, D4), connected to a further node (N2, N3, N4, N5) in the series arrangement of batteries, and a switching element (Q1, Q2, Q3, Q4) is provided to address the transistor (Q11, Q12, Q13,Q14).

Abstract: A fraction of the battery energy is kept in reserve during operational use of a battery-powered apparatus. The motor of the apparatus is switched off when the battery has discharged to the level of this reserve fraction. The reserve is made available again for operational use when the user has recharged the apparatus for a little while. This approach 5 simulates a super fast charging operation.

Abstract: A wake-up lighting device is described, comprising a gas discharge lamp (10) and a lamp driver (1; 2) comprising a power source (100) capable of generating spaced-apart current bursts (51) of alternating lamp current (I). The wake-up lighting device is capable of operating in an off-mode in which no lamp current is generated, and is adapted to switch from its off-mode to a wake-up mode in which the power source (100) operates to:—initially generate an alternating lamp current (I) with a minimum duty cycle value (?T) and a reduced current amplitude (IR) close to zero;—subsequently gradually increase the current amplitude while keeping the duty cycle (?) constant at the minimum duty cycle value (?T), until the current amplitude reaches a nominal current amplitude (IM);—subsequently gradually increase the duty cycle (?) while keeping the current amplitude constant at the nominal current amplitude (IM).

Abstract: A fraction of the battery energy is kept in reserve during operational use of a battery-powered apparatus. The motor of the apparatus is switched off when the battery has discharged to the level of this reserve fraction. The reserve is made available again for operational use when the user has recharged the apparatus for a little while. This approach 5 simulates a super fast charging operation.

Abstract: A battery voltage monitoring system monitors voltage of an arrangement of more than two batteries (U1, U2, U3, U4, U5) in series. The system comprises a voltage divider comprises a first (R1, R2, R3, R4) and second resistive element (R5, R6, R7, R8) arranged parallel to at least a part of the battery arrangement and connected to a reference voltage line and to a node (N1, N2, N3, N4) in the battery arrangement. In between the first (R1, R2, R3, R4) and second resistive element (R5, R6, R7, R8) a transistor (Q11, Q12, Q13, Q14) is arranged. The base of the transistor is, via a diode (D1, D2, D3, D4), connected to a further node (N2, N3, N4, N5) in the series arrangement of batteries, and a switching element (Q1, Q2, Q3, Q4) is provided to address the transistor (Q11, Q12, Q13,Q14).

Abstract: The system comprises, for example, an electric shaver (1) and a cartridge (2) mounted in a chamber (12) of the shaver (1). The shaver (1) comprises a shaving head (3) having drivable cutters (31) and an electric motor (11) for driving the cutters (31) via a coupling pin (14). The cartridge (2) comprises a reservoir (25) for holding an auxiliary fluid. This auxiliary fluid may, for example, serve to reduce the friction between the shaving head (3) and the skin of a user. The cartridge (2) has an outlet channel (22) and a diaphragm pump (23) for feeding the auxiliary fluid from the reservoir (21) to the outlet channel (22). For the actuation of the diaphragm pump (23) the shaver (1) comprises a button (15) and a lever (17) which is pivotable about a pivot (18). When the button (15) is pressed the diaphragm pump (23) is actuated and a small amount of the auxiliary fluid is applied to the skin of a user via an outlet opening (32).

Abstract: A switched-mode power supply uses duty cycle control for the switching transistor. The primary current through the primary winding is sensed by means of a sensing resistor in series with the switching transistor. The voltage across the sensing resistor is differentiated, compared with a reference and integrated. The integrated signal lengthens the off period of the switching transistor, thereby limiting the peak value of the primary current at the beginning of the on period of the switching transistor. The peak value of the primary current at the end of the on period is limited by sensing the voltage across the sensing resistor. The combined limitations of the primary current ensure that the output current of the switched-mode power supply is limited in a well-defined manner.

Abstract: In a self-oscillating power-supply circuit for charging a battery, a switching transistor (T2) is turned off if the voltage across a sensing resistor (R3) exceeds the threshold voltage of a zener diode (D5). The zener diode is arranged in parallel with the series arrangement of the base-emitter junction of the switching transistor and the sensing resistor, so that the voltage of the battery does not influence the peak current at which the switching transistor is turned off. A diode (D6) is arranged in series with the zener diode and can be short-circuited by means of a switch (T3) in order to switch the power-supply circuit from slow charging to rapid charging. A voltage sensor (R8, R9, T4) monitors the battery voltage and eliminates the short-circuit of the diode (D6) when a given battery voltage is reached so that the power-supply circuit changes over to slow charging.

Abstract: In a self-oscillating power-supply circuit for charging a battery (B) the switching transistor (T2) is turned off if the voltage across the sensing resistor (R3) exceeds the threshold voltage of a zener diode (D5). Instead of the zener diode (D5) it is possible to use a switching transistor which is actuated when the current through the switching transistor exceeds a given value. A diode (D6) is arranged in series with the zener diode (D5) and can be short-circuited by means of a switch (T3) in order to switch the power-supply circuit from slow charging to rapid charging. A voltage sensor may be added to monitor the battery voltage and to eliminate the short-circuit of the diode (D6) when a given battery voltage is reached, as a result of which the power-supply circuit changes over to slow charging.

Abstract: In a self-oscillating power-supply circuit for charging a battery, the main switching transistor is turned off by a second switching transistor (T2) of an opposite conductivity type, which is arranged in series with the main switching transistor (T1) via a sensing resistor (R8). This configuration allows rapid switching of the main switching transistor (T1). The power-supply circuit can be turned on and off in a simple manner (R7, T4). Moreover, it is simple to provide a compensation (R4) for varying mains voltages, an auxiliary voltage (D6, C4) for powering additional circuits (R9, R10), which auxiliary voltage also remains available when the power-supply circuit is turned off.

Abstract: In a switched-mode power supply a coil is periodically connected across an input voltage by means of a switching element. The switching element is turned off when the voltage across a sensing resistor in series with the switching element exceeds a given threshold. The threshold is reached sooner when the input voltage increases. This effect is compensated by an inductive element in series with the sensing resistor, through which inductive element the same current flows as through the sensing resistor.

Abstract: A buck converter comprises a load or a rechargeable battery (B), a self-inductance (L2), a diode (D2) and a switching transistor (T1). The current through the switching transistor (T1) is measured by means of a current sensor (Rs) which triggers a monostable multivibrator (MMV) when a given peak current is reached. The monostable multivibrator (MMV) turns off the switching transistor (T1) for a fixed time within which the current through the self-inductance (L2) is supplied to the load (B) via the diode (D2).

Abstract: The system comprises, for example, an electric shaver (1) and a cartridge (2) mounted in a chamber (12) of the shaver (1). The shaver (1) comprises a shaving head (3) having drivable cutters (31) and an electric motor (11) for driving the cutters (31) via a coupling pin (14). The cartridge (2) comprises a reservoir (25) for holding an auxiliary fluid. This auxiliary fluid may, for example, serve to reduce the friction between the shaving head (3) and the skin of a user. The cartridge (2) has an outlet channel (22) and a diaphragm pump (23) for feeding the auxiliary fluid from the reservoir (21) to the outlet channel (22). For the actuation of the diaphragm pump (23) the shaver (1) comprises a button (15) and a lever (17) which is pivotable about a pivot (18). When the button (15) is pressed the diaphragm pump (23) is actuated and a small amount of the auxiliary fluid is applied to the skin of a user via an outlet opening (32).