摘要:
A string of LED loads is supplied by means of a rectified mains voltage. A cathode of each LED load is coupled to ground by means of a string. The strings are made conductive and non-conductive one by one in dependency of the instantaneous value of the rectified mains using both voltage and current sensing.
摘要:
A string of LED loads is supplied by means of a rectified mains voltage. A cathode of each LED load is coupled to ground by means of a string. The strings are made conductive and non-conductive one by one in dependency of the instantaneous value of the rectified mains using both voltage and current sensing.
摘要:
Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1,1′, 2, 2′) is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and/or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40) coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.
摘要:
Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1,1′, 2, 2′) is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and/or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40) coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.
摘要:
An electronic circuit for supplying a common mode voltage to a differential output of an amplifier stage (AMPSTG). The common mode voltage at the terminals (1) and (2) is approximately equal to the reference voltage (VCM). Transistors (T1-T4) are biased in their linear region whereas transistors (T5-T8) are biased in their saturation region. In order to choose the lowest possible reference voltage (VCM), the dimensioning of the transistors (T1-T4) is such that the currents through the transistors (T1-T3) have equal current densities, and the current through the transistor (T4) has a current density which is a factor N smaller than the former current densities. The factor N is determined by the ratio of the nominal value of the current through the transistor (T1) and the minimum value of the current through the transistor (T1).
摘要:
A method and a control system (20) are provided for determining a relation between stimulation settings for a brain stimulation probe (10) and a corresponding V-field. The brain stimulation probe (10) comprises multiple stimulation electrodes (11). The V-field is an electrical field in brain tissue surrounding the stimulation electrodes (11). The method comprises sequentially applying a test current to n stimulation electrodes (11), n being a number between 2 and the number of stimulation electrodes (11) of the brain stimulation probe (10), for each test current at one of the n stimulation electrodes (11), measuring a resulting excitation voltage at m stimulation electrodes, m being a number between 2 and the number of stimulation electrodes (11) of the brain stimulation probe (10), from the stimulation settings and the measured excitation voltages, deriving an (m*{acute over (η)}) coupling matrix, an element (q, p) in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes (11), and using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field.
摘要:
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.
摘要:
The present invention relates to a bidirectional semiconductor switch (M1, M2) with extremely low control power consumption and a bootstrap circuit which allows reliable start of operation of the switch and the hosting device after unlimited duration of mains interruptions. Intelligent control options are provided by operating from a small energy storage and no extra means are required to recover from a depleted energy storage condition. The absence of audible noise and mechanical wear also enables more frequent recharging cycles and allows smaller and thus cheaper energy storage components.
摘要:
A method and a control system (20) are provided for determining a relation between stimulation settings for a brain stimulation probe (10) and a corresponding V-field. The brain stimulation probe (10) comprises multiple stimulation electrodes (11). The V-field is an electrical field in brain tissue surrounding the stimulation electrodes (11). The method comprises sequentially applying a test current to n stimulation electrodes (11), n being a number between 2 and the number of stimulation electrodes (11) of the brain stimulation probe (10), for each test current at one of the n stimulation electrodes (11), measuring a resulting excitation voltage at m stimulation electrodes, m being a number between 2 and the number of stimulation electrodes (11) of the brain stimulation probe (10), from the stimulation settings and the measured excitation voltages, deriving an (m*{acute over (η)}) coupling matrix, an element (q, p) in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes (11), and using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field.
摘要:
A common mode voltage generating circuit has a first and a second output terminal (O1, O2) to supply a common mode voltage (Vcm) to a differential output of an amplifier stage (AMP). A first FET (T1) and a second FET (T2) have interconnected drains, and both have a source coupled to a supply terminal (Vss). A third FET (T3) has a source coupled to the drain of T1, a drain coupled to O1 and to a gate of T1. A fourth FET (T4) has a source coupled to a drain of T2, a drain coupled to O2 and to a gate of T2. A fifth FET (T5) has a gate for receiving a first reference voltage (VI), and a sixth FET (T6) has a source coupled to the drain of T5, a drain receiving a current (2I) from a current source (CS4), wherein the drain and the gate of T6 are interconnected. T3, T4 and T6 have interconnected gates and are biased to operate in their saturation region. T1, T2 and T5 are biased to operate in their linear regions. The common mode voltage generating circuit further comprises a seventh FET (T7) with a source coupled to Vss, a drain coupled to the drain of T5, and with a gate which receives a second reference voltage (Vh). T7 is biased to operate in its linear region. Bipolar transistors may be used instead of FET's.