Abstract: A power supply system comprises a parallel arrangement of a first switched mode power supply (1) which has a first system bandwidth (LB 1) and a second switched mode power supply (2) which has a second system bandwidth (LB2) covering higher frequencies than the first system bandwidth (LB 1). The first switched mode power supply (1) is dimensioned to supply a first maximal output power (P1m), the second switched mode power supply (2) is dimensioned to supply a second maximal output power (P2m) being smaller than the first maximal output power (P1m). A control circuit (3) varies a reference voltage (Vr) of both the first switched mode power supply (1) and the second switched mode power supply (2) to obtain a corresponding variation of an output voltage (Vout) of the parallel arrangement.

Abstract: The present invention relates to an all n-type transistor current mirror for mirroring an input current to an output current. The current mirror comprises an input n-type transistor (T4, QO, T1) interposed between a positive supply plane (VCC) and an input node (104, 202, 310) with its collector being connected to the positive supply plane (VCC) and its emitter being connected to the input node (104, 202, 310). An output n-type transistor (T3, Q1, T2) is interposed between the positive supply plane (VCC) and an output node (106, 204, 314) with its collector being connected to the positive supply plane (VCC) and its emitter being connected to the output node (106, 204, 314). A feedback circuit equals base-emitter voltages of the input (T4, QO, T1) and the output transistor (T3, Q1, T2) in order to mirror the emitter current of the input transistor (T4, QO, T1) to the emitter current of the output transistor (T3, Q1, T2).

Abstract: A transmitter comprises a power amplifier which has an amplifier power-supply input and an output to supply a transmission signal with an output power. A power supply has power supply outputs to supply a first power supply voltage and a second power supply voltage. A switching circuit is arranged between the power supply outputs and the amplifier power-supply input. A controller has an input to receive a power change command to control: first the switching circuit to supply the first power supply voltage to the amplifier power-supply input, and the power supply to vary a level of the second power supply voltage, the level of the second power supply voltage being lower or higher than a level of the first power supply voltage if the power change command indicates that the output power has to decrease or increase, respectively, and secondly the switching circuit to supply the second power supply voltage to the amplifier power-supply input.

Abstract: A transmitter comprises a power amplifier (PA) with a power supply input (PI) and an output (PAO) to supply a transmission signal (Vo) with an output power (Po). A power supply (PS) has power supply outputs (PSO1, PSO2) to supply a first power supply voltage (PV1) with a first level and a second power supply voltage (PV2) with a second level, higher than the first level. A switching circuit (SC) is arranged between the power supply outputs (PSOI, PSQ2) and the power supply input (PI) to supply a selected one of the first power supply voltage (PV1) or the second power supply voltage (PV2) to the power amplifier (PA). A controller (CO) supplies a control signal to the switching circuit (SC) in response to a first power change command (PC) indicating a first desired level of the output power (Po), to supply the first power supply voltage (PV1) to the power supply input (PI).

Abstract: A power supply system comprises a parallel arrangement of a first switched mode power supply (1) which has a first system bandwidth (LB1) and a second switched mode power supply (2) which has a second system bandwidth (LB2) covering higher frequencies than the first system bandwidth (LB1). The first switched mode power supply (1) is dimensioned to supply a first maximal output power (P1m), the second switched mode power supply (2) is dimensioned to supply a second maximal output power (P2m) being smaller than the first maximal output power (P1m). A control circuit (3) varies a reference voltage (Vr) of both the first switched mode power supply (1) and the second switched mode power supply (2) to obtain a corresponding variation of an output voltage (Vout) of the parallel arrangement.

Abstract: A transmitter comprises a power amplifier (PA) which has an amplifier powersupply input (PI) and an output (PAO) to supply a transmission signal (Vo) with an output power (Po). A power supply (PS) has power supply outputs (PSO1, PSO2) to supply a first power supply voltage (PV1) and a second power supply voltage (PV2). A switching circuit(SC) is arranged between the power supply outputs (PSO 1, PSO2) and the amplifier powersupply input (PI).

Abstract: A transmitter comprises a power amplifier which has an amplifier power-supply input and an output to supply a transmission signal with an output power. A power supply has power supply outputs to supply a first power supply voltage and a second power supply voltage. A switching circuit is arranged between the power supply outputs and the amplifier power-supply input. A controller has an input to receive a power change command to control: first the switching circuit to supply the first power supply voltage to the amplifier power-supply input, and the power supply to vary a level of the second power supply voltage, the level of the second power supply voltage being lower or higher than a level of the first power supply voltage if the power change command indicates that the output power has to decrease or increase, respectively, and secondly the switching circuit to supply the second power supply voltage to the amplifier power-supply input.

Abstract: The present invention relates to an amplifier intended to deliver to a load impedance RL connected between two output terminals of the amplifier an output current Iout which is representative of an input signal (Vin, ?Vin) applied to two input terminals of the amplifier, which amplifier includes a first and a second transistor T1 and T2 connected as a differential pair around the load impedance RL. The amplifier according to the invention further includes a third and a fourth transistor T3 and T4 which form a differential pair; degenerated by means of a degenerating impedance Req which has a nominal value equal to that of the load impedance RL of the amplifier, which differential pair (T3, T4) is intended to be controlled by means of a control signal (?Vin/2, Vin/2), in anti-phase with the input signal (Vin, ?Vin). The invention permits to double the output current Iout of the amplifier without, however, increasing its power consumption.

Abstract: A transmitter comprises a power amplifier (PA) with a power supply input (PI) and an output (PAO) to supply a transmission signal (Vo) with an output power (Po). A power supply (PS) has power supply outputs (PSO1, PSO2) to supply a first power supply voltage (PV1) with a first level and a second power supply voltage (PV2) with a second level, higher than the first level. A switching circuit (SC) is arranged between the power supply outputs (PSOI, PSQ2) and the power supply input (PI) to supply a selected one of the first power supply voltage (PV 1) or the second power supply voltage (PV2) to the power amplifier (PA). A controller (CO) supplies a control signal to the switching circuit (SC) in response to a first power change command (PC) indicating a first desired level of the output power (Po), to supply the first power supply voltage (PV1) to the power supply input (PI).

Abstract: The invention provides a method for reducing power dissipation in a power amplifier used in wireless communication systems, said power amplifier having transistors showing a quiescent current, wherein the quiescent current of the power amplifier is adaptively changed according to the average output power of the power amplifier. A power amplifier for use in wireless communication systems is provided, said power amplifier having transistors showing a quiescent current, comprises adaptive biasing means changing the quiescent current of the power amplifier in accordance with the average output power of the power amplifier for reducing power dissipation in the power amplifier. A UMTS hand set comprises a power amplifier as specified above.

Abstract: A transmitter comprises a power amplifier (PA) which has an amplifier powersupply input (PI) and an output (PAO) to supply a transmission signal (Vo) with an output power (Po). A power supply (PS) has power supply outputs (PSO1, PSO2) to supply a first power supply voltage (PV1) and a second power supply voltage (PV2). A switching circuit(SC) is arranged between the power supply outputs (PSO1, PSO2) and the amplifier powersupply input (PI).

Abstract: The invention provides a method for reducing power dissipation in a power amplifier used in wireless communication systems, said power amplifier having transistors showing a quiescent current, wherein the quiescent current of the power amplifier is adaptively changed according to the average output power of the power amplifier. A power amplifier for use in wireless communication systems is provided, said power amplifier having transistors showing a quiescent current, comprises adaptive biasing means changing the quiescent current of the power amplifier in accordance with the average output power of the power amplifier for reducing power dissipation in the power amplifier. A UMTS hand set comprises a power amplifier as specified above.

Abstract: The present invention relates to a power amplifier being preferably applied in mobile communication devices andusing an envelope tracking technique. It is the object of the invention to improve a power amplifier with respect to its efficiency by simultaneously enabling an adaptation of the supply voltage for the unit 110 to fast variations of an envelope signal. This object is achieved by providing a second DC/DC converter 140 for generating a variety of n+1 voltage levels and n threshold values both in response to a received power control signal representing a required output power of the RF output signal and by a first DC/DC converter 130 to select one of said n+1 voltage levels as the supply voltage for said unit 110 in response to the result of a comparison between the envelope signaland said n threshold values.

Abstract: The invention relates to a method of reading of magnetic information. In an example embodiment, a read head includes a magneto-resistive rod polarized with an electrical signal. The magneto-resistive rod supplies a data signal whose variations are representative of magnetic-field variations to which the read head is exposed. Included in the embodiment, there is a compression of the data signal triggered when a thermal asperity is detected.

Abstract: The present invention relates to a power amplifier being preferably applied in mobile communication devices andusing an envelope tracking technique. It is the object of the invention to improve a power amplifier with respect to its efficiency by simultaneously enabling an adaptation of the supply voltage for the unit 110 to fast variations of an envelope signal. This object is achieved by providing a second DC/DC converter 140 for generating a variety of n+1 voltage levels and n threshold values both in response to a received power control signal representing a required output power of the RF output signal and by a first DC/DC converter 130 to select one of said n+1 voltage levels as the supply voltage for said unit 110 in response to the result of a comparison between the envelope signaland said n threshold values.

Abstract: The present invention relates to an amplifier intended to deliver to a load impedance RL connected between two output terminals of the amplifier an output current Iout which is representative of an input signal (Vin, −Vin) applied to two input terminals of the amplifier, which amplifier includes a first and a second transistor T1 and T2 connected as a differential pair around the load impedance RL.

Abstract: The invention relates to a method of reading magnetic information by means of a read head including a magneto-resistive rod RMR, which is to be polarized by means of an electrical signal Imr and serves to supply a data signal Vmr whose variations are representative of the magnetic-field variations to which the read head is exposed.