Abstract: Traditional temperature-control products have the problem that the temperature of the working surface reaches the setting temperature too slowly when heating up or recovering from a temperature drop. A traditional temperature control circuit and temperature-settings selector components are modified to solve this problem. When heating begins, the modified circuit increases the initial setting temperature to be above the target setting temperature. The modified circuit then adjusts the setting temperature by measuring the heating power consumption. Once the working surface of the temperature control product reaches the initial setting temperature, the heating power consumption drops and the modified circuit reduces the temperature setting to the target setting temperature. The temperature control product can rapidly achieve the target temperature. A positive-temperature-coefficient heating component is used in the temperature control product.

Abstract: A semiconductor integrated circuit (IC) acts as a controller of a heating-controlled device or appliance. A heating body has a positive temperature coefficient and acts as both a heating element and a temperature sensor. A Silicon-Controlled Rectifier (SCR) switches AC current to the heating body to increase its temperature. When the SCR switches off, temperature sensing is performed using a sampling resistor, isolation diode, voltage comparator, and switch for a low-voltage DC supply are formed on an integrated circuit that has a first circuit branch and a second circuit branch. A compensation diode and a compensation resistor can be added in parallel to reference resistors. The compensation diode compensates for the forward voltage drop of the isolation diode that would otherwise create an inaccurate temperature measurement. The diodes have the same temperature response, allowing for a more accurate temperature measurement over a full temperature range of the sensorless appliance.

Abstract: An electromechanical/solid-state AC relay has an electromechanical winding coil that moves an armature to force mechanical contacts to open or close. Electrical arcing across the mechanical contacts that occur as the contacts are opening or closing can damage and severely reduce the lifetime of the relay. Contact arcing is prevented by pulsing a triac on for a short period of time just before and after the mechanical contacts make or break contact. The triac limits the voltage difference across the mechanical contacts to less than one volt to prevent arcing. The triac is turned off after the mechanical contacts finish moving, reducing the heating and average power through the triac. A zero-sampling circuit that detects when the AC input voltage switches across 0 volts and activates a control integrated circuit to switch on the triac during zero-crossings to minimize power surges.

Abstract: A charge pump for a phase-locked loop (PLL) has accurate matching of charge and discharge currents applied to the PLL's loop filter. A variable current-sink transistor has its gate-to-source voltage adjusted to match a source current from a fixed current source. An intermediate node in-between series transistors between the current source and sink is sampled by a sampling transistor that connects the intermediate node to a sampling capacitor. The sampling capacitor's voltage is the gate-to-source voltage of the variable current-sink transistor. The variable current-sink transistor has its gate and drain coupled together through the sampling transistor during calibration periods when the charge pump is otherwise idle. When the source current exactly matches the sink current, the gate-to-source voltage stored on the sampling capacitor reaches steady state. Up and down currents are balanced in driver transistors that match the series transistors.

Abstract: A fully duplex cordless telephone has a transmitter and a receiver connected to a common antenna. A broad-band antenna coupler such as a ferrite-core hybrid transformer may replace a more costly duplexer with filters. Since all characteristics of the transmit signal are known, the transmit signal removes itself from the receiver by signal cancellation. The canceling signal is extracted from the composite signal from within the receiver front end, after the antenna coupler and low noise amplifier. This composite signal is coupled to the first input of a difference amplifier, and the output of this amplifier is coupled to the remainder of the receiver. The composite signal is coupled to the second input, after its smaller receive component has been further suppressed, and its remaining transmit signal has been adjusted by two feedback control systems to restore its phase and amplitude to be equal to the transmit component of the composite signal.