Abstract: The present invention relates to a resistive touchscreen for recognizing touch coordinates through a capacitor charging time constant, and more specifically, the invention comprises: an equal resistance line operating means for obtaining the same resistance line according to an (Rv+Ry+) value and the same resistance line according to an (Rv+Ry?) value by using the charge time constant after a charge time constant measuring means measures charge time constants of capacitors CconL and CconR; and a coordinate calculating means for obtaining intersecting points of the resistance lines, thereby perceiving the intersecting points as touch positions. According to the present invention, a conventional ADC (analog to digital converter) is not used because the touch positions can be perceived through the capacitor charging time constants, whereby the invention is advantageous for IC integration.

Abstract: The present invention relates to a resistive touchscreen for recognizing touch coordinates through a capacitor charging time constant, and more specifically, the invention comprises: an equal resistance line operating means for obtaining the same resistance line according to an (Rv+Ry+) value and the same resistance line according to an (Rv+Ry?) value by using the charge time constant after a charge time constant measuring means measures charge time constants of capacitors CconL and CconR; and a coordinate calculating means for obtaining intersecting points of the resistance lines, thereby perceiving the intersecting points as touch positions. According to the present invention, a conventional ADC (analog to digital converter) is not used because the touch positions can be perceived through the capacitor charging time constants, whereby the invention is advantageous for IC integration.

Abstract: The present invention relates to a high-frequency power amplifier having differential inputs, and more specifically to a high-frequency power amplifier having differential inputs, in which a structure of an output port of a communication system for 2.4 GHz ISM frequency band can be simplified by designing and producing the high-frequency power amplifier having differential inputs for 2.4 GHz ISM frequency band using a silicon germanium (SiGe) microwave monolithic integrated circuit (MMIC), thereby decreasing the number of components of a transmission unit and reducing a price of the communication system.

Abstract: A power supply according to the principles of the inventions comprises two stages. The first stage is a power factor corrector stage. This stage provides the required line regulation, including greater than 95% power factor correction, and provides a range of outputs from approximately 5 volts to 200 volts with good load regulation at low voltages. The second stage is a soft switching power supply having good load regulation from approximately 40 to approximately 175 volts. An intermediate high voltage of the first stage supplies the input to the second stage, thereby achieving extremely good line regulation and low regulation.

Abstract: A converter utilizing a multifilar transformer having its primary and auxiliary windings made simultaneously, a technique known as bifilar winding, provides high efficiency and low noise. The multifilar winding technique yields minimum leakage inductance between the windings and reduces the proximity effect to a minimum achievable using most well-known wires. The converter utilizes an improved soft-switcher topology which advantageously reduces the interwinding capacitance between the primary and auxiliary windings of the transformer. The topology includes a resonant LC circuit interposed in series with one leg of the auxiliary winding and the auxiliary switch. The other leg of the auxiliary winding is at ground. A controller is provided to control switch timing such that the converter optimizes switch loss and resonant pulse loss.

Abstract: A dual mode converter is provided that may be operated as a variable-frequency, naturally-commutated controller in a Zero-Voltage-Switching mode and as a fixed-off-time controller in a Fixed-Off-Time mode. The converter includes four functional elements. A reference and biases element generates voltage references and biases utilized to determine various signal states. A Timing element generates a fixed off time signal and a voltage ramp signal utilized to create the dual modes of operation. A Catastrophic-Event element detects events that cause the converter output be inhibited and the controller to be restarted. A Mode Detection and Pulse Width Modulation element determines the mode of operation for the converter based on signal inputs from the other functional elements and modulates the output accordingly. In a primary mode, the controller utilizes variable frequency operation to deliver primary power. In a standby mode, the controller utilizes fixed frequency operation to provide low power (less than 5W).