Abstract: Coil current loading the induction coils of an induction heating apparatus is directly sensed at the input from the tank circuit and the derived feedback current signal is used to control the power supply to the tank circuit be reference to a signal provided manually or automatically under process control. A voltage feedback signal is derived with a transformer from the input to the tank circuit for providing an input to a voltage limiter operative on the current controller when the voltage to the tank circuit exceeds an acceptable limit. A current limiter overrides the current controller to limit the load current by control of the current controller when the load becomes excessive.

Abstract: A reference voltage generating circuit in a DC power supply includes a differential amplifier for detecting a difference voltage between a reference voltage and the output voltage, and a voltage control circuit which is responsive to an output signal from the differential amplifier so as to control the DC power supply output voltage to limit the difference between the output voltage and the reference voltage to zero. More specifically, the reference voltage generating circuit includes a reference voltage source, a first variable resistor connected in parallel with the reference voltage source, a second variable resistor connected to the negative side of the reference voltage source, a third variable resistor connected to the positive side of the reference voltage source, and a switching circuit for connecting a movable contact piece of the first variable resistor to either the second or third variable resistors, or to neither of them.

Abstract: The voltage regulator circuit includes a Darlington pass device, a feedback circuit and an error amplifier connected between the feedback circuit and the Darlington pass device. The error amplifier is arranged to conduct a current which is proportional to the control current of the pass device so that under standby conditions when the control current of the pass device has a low magnitude the power dissipation of the voltage regulator is minimized. A high voltage sustaining transistor, which is connected between the pass device and the error amplifier, is arranged to have a high voltage sustaining capability.

Abstract: A solid state voltage regulator circuit having an output with absolute voltage change per degree centigrade temperature dependence comprises a voltage regulator having a forward control loop for sensing changes in regulated output voltage, and a temperature transducer having an output voltage connected to the forward loop and adapted to change the sensed regulated voltage input to the regulator in direct proportion to the absolute ambient temperature. The transducer output is connected to the forward loop by an amplifier and the circuit is readily adapted to any desired linear temperature dependence by adjustment of the gain of the amplifier.

Abstract: A temperature-independent reference voltage is developed as the difference between the offset potentials across first and second diode means, the second nested within the first to conduct the same forward bias current.

Abstract: A voltage detection integrated circuit including a voltage regulation circuit for controlling the operation thereof is provided. The voltage detection integrated circuit includes a reference voltage circuit for producing a predetermined reference voltage, a voltage converter for converting a detected voltage for measurement and a comparator circuit for comparing the level of the reference voltage to the level of the converted voltage and for producing a comparison signal representative of the difference in voltage levels compared thereby. The voltage regulation circuit is coupled to the comparator circuit and the reference voltage circuit and/or voltage conversion circuit for selectively adjusting the level of the reference voltage produced by the reference voltage circuit and/or the converted voltage produced by the voltage converter, to thereby control the comparison signal produced by the comparator circuit.