44 results about "Modulation transformer" patented technology

A simplified electronic ballast for a discharge lamp which provides dimming by control of inverter frequency through modulation of magnetizing current in a transformer such that the switching frequency is made substantially independent of the load presented. The principle of frequency control in a manner independent of the load is extendable to other types of loads and power supplies and converters to regulate power coupled to the load. Clamping capacitors are used to replace other clamping circuits in order to allow current injection to be controlled by a simple variable voltage while frequency control by current injection provides enhanced circuit performance.

A history-independent and noise-immune modulated transformer-coupled gate control signaling method and apparatus provides robust design characteristics in switching power circuits having a transformer-coupled gate drive. A modulated control signal at a rate substantially higher than the switching circuit gate control rate is provided from the controller circuit to a demodulator via transformer coupling. Codes specified by relative timing of transitions in multiple periods of the modulated control are assigned to gate-on and gate-off timing events that control the switching transistor gate(s) and unassigned patterns are decoded as gate-off events, reducing the possibility that a switching transistor will be erroneously activated due to noise. The modulated signal is constructed so that signal history is not required for decoding, eliminating any requirement of a reference clock. Blanking may be employed to conserve power between codes and to avoid mis-triggering due to noise events during power switching.

An amplitude modulated pulse transmitter designed to operate across a multi MHz range of modulation frequencies. A wire wound rare earth magnet is to be utilized instead of the typical modulation transformer. Additionally, a plurality of electrolytic capacitors are also employed in the transmitter.

A digital image process for a digital camera contains a preprocessor and a postprocessor. The preprocessor can include, for example, a uniformity corrector, a sampling filter, a modulation transformer, and a ditherer. The postprocessor can include a color interpolator, an RGB reconstruction block, a digital compressor, and a color pattern data buffer. The digital image process is programmable to operate one or more of the processing blocks of one or both the preprocessor and the postprocessor for flexible programming that can adapt to the requirements of various digital camera designs or users.

The invention relates to an emission device for transmission through space, using electromagnetic waves in the infrared range and / or visible range and / or ultraviolet range that are produced by one or more light-emitting diodes. The device is connected via its input terminals (1) to an energy distribution network. A mains filter (2) reduces the electromagnetic interference produced by the power circuits, which comprise a rectifier (3), a power-factor correction circuit (4), an auxiliary power supply (5) and a DC / DC converter (8). The DC / DC converter (8) has its output connected to several series-connected light-emitting diodes (9). An assembly for receiving the transmissions via energy distribution network lines (6) delivers demodulated signals applied to the control circuit (7), which delivers the current setpoint of the DC / DC converter (8) and the modulated current applied to the light-emitting diodes (9) through the modulation transformer (10), according to the demodulated signals and the temperature measured by a temperature sensor (11). The light produced is modulated according to the demodulated signals.

A modulated transformer-coupled gate control signaling method and apparatus provides reduction of circuit complexity and robust design characteristics in switching power circuits having a transformer-coupled gate drive. A modulated control signal at a rate substantially higher than the switching circuit gate control rate is provided from the controller circuit to a demodulator via transformer coupling. Power for the demodulator can be obtained by rectifying the modulated control signal at the demodulator, or from another transformer winding. The modulation scheme is chosen to have a DC average value of zero, eliminating any magnetization current management requirements. The modulated control signal may carry redundant control information and / or may encode additional information to provide a more sophisticated gate drive control, such as oversampled gate control information.

A direct current metering device belongs to current metering equipment in the electrotechnology, solves the problems of insufficient precision and stability of the existing current sensing device used for industrial gauging, and is used for the standard gauging in the strong direct current industrial field with the reliable and stably operated structure. The direct current metering device comprises a sensing head, an exciting transformer, a modulation transformer, a low pass filter, a phase sensitive demodulator, a synthesis modulator and a power amplifier; the sensing head is annular and comprises a first annular detection iron core, a second annular detection iron core and an annular magnetic shield iron core; the first and second annular detection iron cores, respectively wound by two sets of detection windings, are overlapped to be wholly placed in the annular hollow cavity of the annular magnetic shield iron core; and a feedback winding surrounds the annular magnetic shield iron core. The direct current metering device can realize the accurate gauging of the industrial strong direct current with ten thousands of amperes, realizes full automation traction in the whole process without unbalance, and is high in stability and reliability and suitable for industrial application, and the proportion precision achieves more than 0.02%.