摘要:
Conventional transformers with fractional turns have pre-manufactured cores usually with a complicated structure. According to the present invention, a method is provided of manufacturing a planar transformer where a ferrite polymer compound is laminated to a PCB for forming the core of the transformer. Advantageously, this may allow for the provision of a cheap and robust transformer.
摘要:
Resonant gate driver circuits provide for efficient switching of, for example, a MOSFET. However, often an operation of the resonant gate driver circuit does not allow for an application where high switching frequencies are required. According to the present invention, a pre-charging of the inductor of the resonant gate driver circuit is performed. This allows for a highly efficient and fast operation of the MOSFETs.
摘要:
An MR apparatus has a resonant circuit, which is formed by an MR receiving coil (L1) and a capacitor (C1), and has an electronic control circuit (S) for switching the resonant circuit between two or more operating modes. The invention proposes that the electronic control circuit (S) be connected with a receiving device (L2) for wireless reception of a high-frequency electromagnetic control signal.
摘要:
A power converter comprising an inductor for receiving energy from a power supply, and connected to the inductor an output capacitor for providing an output voltage. In order to ensure a quick compensation of a reduction of load at the voltage output using few output capacitors, an additional current path is arranged in parallel either to the inductor or to the capacitor, which additional current path can be opened and closed. A current flowing through the additional current path reaches basically immediately a desired value, when the additional current path is opened. Feedback means are moreover provided for opening the additional current path, when the output voltage reaches a predetermined maximum value.
摘要:
Power conversion circuits often consist of several MOSFETs operating in parallel. Due to thermal cycling and mechanical operations. MOSFETs or the respective electric connections of the MOSFETs may fail. For certain implementations, a diagnosis circuit for a plurality of parallel MOSFETs predicts or determines a possible failure on the basis of at least one of temperatures of the MOSFETs or gate voltages of the MOSFETs. In some applications, the MOSFETs are monitored to facilitate early determination of failures of the MOSFETs.
摘要:
In known converter circuits switching losses occur, which are caused by reverse-recovery currents of a freewheeling diode. To reduce said switching losses it is proposed by the invention to drive the switching elements such that, upon switching from the second to the first switching element, the timing is controlled in such a manner that the shoot through currents and the conduction of the freewheeling diode are kept at a low value or, better still, are precluded. As regards the control mechanism, it is proposed to turn on the first switching element later if shoot through currents occur, and to turn on the first switching element sooner if conduction of the freewheeling diode occurs. Here, a time of overlap may be provided during which both switching elements are simultaneously conducting. For the control mechanism, the voltage across a switching element can be used as a measured input value.
摘要:
Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to the bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in the supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).
摘要:
Conventional transformers with ractional turns have pre-manufactured cores usually with a complicated structure. According to the present invention, a method is provided of manufacturing a planar transformer where a ferrite polymer compound is laminated to a PCB for forming the core of the transformer. Advantageously, this may allow for the provision of a cheap and robust transformer.
摘要:
The invention describes a method of transmitting information between an information transmitter and an information receiver, the potential difference of which moves in cycles between a minimum value and a maximum value and is situated at the minimum value for regular intervals; having the steps: provision of information over the time interval or determining the time interval in which the potential difference between information transmitter and information receiver assumes its minimum value; closing of a switching means of the information transmitter in relation to an information memory assigned to the information receiver, only within the time interval; and transmission and storage of the information in the information memory.
摘要:
Since parallel MOSFETs are usually driven with one gate signal in power applications, the current sharing between the MOSFETs is automatically established with regard to the characteristics of the individual MOSFETs. This may lead to a large non-uniformity of the current distribution between the MOSFETs. According to the present invention, an individual control of the on-resistances of the MOSFETs is provided, which allows for an improved current sharing between paralleled MOSFETs.