Abstract: A charging circuit is provided to decrease the settling time of a reference capacitor storing a reference voltage for data acquisition circuits. The charging circuit includes one or more comparator circuits for comparing the voltage across the reference capacitor to the reference voltage provided by a reference source. If the voltage from the reference source deviates by a predetermined amount, one or more buffer circuits rapidly charge the reference capacitor to a voltage substantially equal to the new reference voltage. The reference source is then coupled directly to the capacitor to complete the charging of the capacitor to the new reference voltage.

Abstract: A voltage reference source for supplying one or more reference voltages to load circuitry. The reference source comprises an ungrounded voltage reference cell (20) floated between two power supply levels (Vcc and Vee), and an operational amplifier (22) whose non-inverting input (terminal 9) may be connected to sense the voltage of the load circuit's ground node. The inverting input of the op amp (terminal 10) may be connected to various nodes (6, 8, 11) in the reference cell; the voltage on the selected node is forced to match the sensed ground voltage and that node thus becomes an internal ground reference point. The high input impedance of the op amp (22) limits the current in the ground sensing path to a very low value, such as about 10 nA. Consequently, very little voltage is developed in the leads from the load circuit's ground node to the op amp input. The floating reference cell (20) has a resistive divider (48, 50) across its output.

Abstract: The invention relates to power supply circuits, and in particular those used for directly supplying, from a telephone line, the bell or other items in a telephone set. In order to avoid unacceptable crosstalk or distortion due to saturation of the power supply circuit when the AC signal on the line drops below the value (Vs) of the regulated output voltage of the power supply, there is provision for detection of this saturation (56) and current shunting (T2, T3) that increases progressively with saturation, such that, seen from the line, the current consumption or impedance of the set remains constant despite the disturbances due to saturation.

Abstract: A control system for regulating a system parameter includes three sensing elements to independently sense a single system parameter and provide respective feedback signals. Three substantially identical controllers are responsive to these feedback signals with the controllers each having a bridge network of three resistors and being connected to a common resistor. In response to the feedback signals and signals representative of the imbalance in the bridge networks, the controllers act to cause bridge balance by collectively supplying current to the common resistor to effect a balance and to thus control the system parameter in accordance with the middle valued of the three feedback signals.

Abstract: In a series voltage regulator having a regulating transistor (T) arranged with its emitter-to-collector path in a series arm of the regulator, the base of this regulating transistor being controlled by a differential amplifier (V) which compares a voltage proportional to the regulator output voltage (U.sub.2) with a reference voltage (U.sub.C), this reference voltage is available from a capacitor (C) to which a voltage limiting circuit (B) limiting the reference voltage to a maximum level (U.sub.R) is assigned, and which is connected to the output of a transconductance circuit (G) whose output current (I.sub.A) depends on the difference (U.sub.D) between the output voltage (U.sub.2) and the input voltage (U.sub.1) of the series voltage regulator.

Abstract: A constant voltage circuit has two rails 10 and 12, with one rail 12 at a variable potential V, possibly supplied by a voltaic cell. In one arm between the rails there is voltage reference means Z1, 14, with a circuit output line 16 connected thereto, and the line 16 is required to be maintained at a potential V.sub.o, corresponding to a maximum value for V. In a second arm there is provided a first resistor R1, connected to the rail 12, and in series with a transistor T2. A second, equal, resistor R2 is connected between the output line 16 and the transistor T2. Means Z2, 30, T3, causes a potential, corresponding to the variable, decreasing, potential V, to be applied between the second resistor R2 and the transistor T2. The current to the transistor T2 is constant over a wide range dV for V, by a compensating current portion dI flowing through the second resistor R2, thereby maintaining V.sub. o constant.

Abstract: A current regulating convertor includes a pulse generator which generates a voltage pulse train having a variable duty cycle. A low pass filter is connected to receive the pulse train and has a cutoff frequency which is well below the frequency of the pulse train. The low pass filter generates a D/C voltage signal which has a voltage level that is proportional to the duty cycle of the pulse train. The D/C signal is used in a circuit that draws a current from a power supply which is proportional to the voltage level of the D/C signal. The power supply is connected to the circuit by a 4-20 mA currrent loop.

Abstract: A control transistor (3) is connected between a power supply terminal (1) and an output terminal (19). The base bias of the control transistor (3) is controlled by bias control transistors (12, 13), thereby the output voltage is maintained at a constant value. An overcurrent state is detected by a current control detecting transistor (22), and the base bias of the control transistor (3) is controlled by the bias control transistors (12, 13), so as to prevent the overcurrent. The current control detecting transistor (22) further detects the time when the potential of the output terminal (19) becomes approximately 0 V by, e.g., short-circuiting of a load, so as to control the base bias of the control transistor (3) through the bias control transistors (12, 13), thereby the current to the load is decreased to a value considerably smaller than a limited value for preventing the overcurrent.

Abstract: A regulated voltage supply (10) for delivering a substantially constant voltage to a load (12) having a regulator (24) for controlling a raw voltage supply (22) to deliver that constant potential, wherein the supply includes sense leads (28 and 30) between the load and the regulator for monitoring load voltage, provided with a sense current cancellation circuit (30) for nulling sense current and preventing it from flowing through the sense leads; in a preferred implementation, including voltage-to-current converters (42 and 44) bridging respectively the output terminals (14 and 16) and the sense terminals (32 and 34), it provides a cancellation current equal in magnitude and opposite in direction to the sense current.

Abstract: A two wire circuit has a total direct current signal, I.sub.t, proportional to a sensor signal which is responsive to a parameter to be sensed. I.sub.t flows through a first terminal which is coupled to an external power source and load and then through a second terminal. A current controller is coupled to the sensor and across the first and second terminals for controlling I.sub.t. A feedback amplifier amplifies a feedback signal which is responsive to I.sub.t to provide an amplified feedback signal. A span adjustment is coupled to the feedback amplifier and the current controller for receiving the amplified feedback signal to adjust the amplified feedback signal such that I.sub.t is controlled by the current controller as a function of the sensor signal and the adjusted, amplified feedback signal.

Abstract: A power supply circuit which comprises a first power source terminal for applying a plus voltage and a second power source terminal for applying a minus voltage. A first transistor is inserted between the first power source terminal and a load. A second transistor is inserted between a base of the first transistor and a ground potential and is controlled by the voltages applied to the first and second power source terminals. A capacitor is connected to the second power source and ground potential. A sequence of applying or cutting-off voltages to be applied to the load is predetermined even when a sequence of applying or cutting-off the voltages from said first and second power source terminals becomes erratic.

Abstract: Disclosed is a regulator circuitry (stabilizer) for controlling the output of an RF generator according to a programmable input signal. A power stage is responsive to the selected value of the programmable input signal to drive the RF generator at the desired power level. A forward power feedback control circuit monitors and controls the power output stage so that the desired RF output level is maintained at a constant level. In this particular mode of operation, RF output power is maintained constant and therefore independent of variations in gain due to temperature changes and other parameters which could effect the overall transfer function of said generator (and including mismatch of the generator into the load).

Abstract: A DC power circuit comprises a first control means which is provided between a DC power source and a pair of output terminals for controlling voltages as well as currents supplied to a load from the DC power source. An output current detector detects the output current from the DC power source, and provides a first control potential proportional to the detected current. On the other hand, an output voltage detector is coupled between the pair of output terminals for detecting the voltage applied to the load, and provides a second control potential proportional to the detected voltage. A second control means selectively assumes one of two stable states in response to external control. A third control means receives the first and second control potentials, and responds to the state of the second control means for controlling the first control means based on the received two control potentials.

Abstract: An induction heating coil and a self-excited inverter are connected to a ripple voltage source. The self-excited inverter comprises a transistor as a switching element and the transistor is rendered conductive responsive to a drive voltage applied for each cycle of the ripple voltage source, whereby the self-excited inverter is started at each cycle of the ripple voltage source. The self-excited inverter stops the oscillation when the voltage of the ripple voltage source becomes lower than a predetermined value. During the non-oscillation period of the intermittent oscillation, the oscillation output of the self-excited inverter is detected. If and when the oscillation output is detected at that time, the oscillation of the inverter is stopped. Furthermore, the pulses of the attenuating oscillation of the self-excited inverter during the oscillation rest period are counted.

Abstract: A regulator circuit which provides voltage regulation for a normal power supply and a battery used in a battery back-up system. A first portion of the circuit detects when the battery is about to go into a deep discharge condition (when operated in the battery back-up mode) and a second portion of the circuit is used to regulate the output voltage to a load. When the first portion of the circuit detects the deep discharge condition, it disconnects the load and the second portion of the circuit from the battery. The first portion of the circuit draws a very small current.

Abstract: An electronic timepiece contains a supply voltage source which provides a supply voltage controlled in accordance with temperature, whereby power consumption is reduced by supplying the timepiece circuit with only the amplitude of supply voltage required at any particular operating temperature. Voltage control is performed in accordance with variations in propagation times of circuit elements with temperature, as determined by variations in the frequency of a ring oscillator circuit.

Abstract: An active power supply ripple filter with low noise and low power dissipation characteristics, which tracks the voltage of the power source with low voltage drop and high current capability. The circuit consists of a control transistor connected between one terminal of a power source and one terminal of a load, a reference circuit which tracks the supply voltage, a low pass filter which filters the reference voltage and an amplifier for driving the control transistor in response to the filtered reference voltage and a feedback voltage from the load. The circuit minimizes the voltage drop across the control transistor as well as minimizing the capacitance values required for the filter capacitors.

Abstract: A DC power supply having an input stage receiving input power at one voltage and an output stage connected to the input stage producing output power at another, output voltage. The output stage receives a control signal reducing the output voltage by a prescribed amount when the output current exceeds a given level. The control unit includes a comparator which compares the output current with a reference level and produces a current foldback signal if the output current exceeds the reference level.

Abstract: A dynamic load for testing regulated power supplies comprises a pass transistor or transistors which are controlled by current or voltage regulating means operates under current regulation for loading a voltage regulated power supply and under voltage regulation for loading a current regulated power supply. Only a small bias voltage is required to keep the pass transistor in conduction when the terminal voltage of the power supply under test is programmed to zero output voltage. Otherwise the power required for the dynamic load power supply comes from the power supply under test. Programming the dynamic load power supply provides a complete range of loads to the power supply under test. Additionally, feedback from the power supply under test to the dynamic load power supply can cause the latter to simulate a fixed resistor load. The dynamic load power supply replaces a wide range of the conventional power resistors used for regulated power supply testing.

Abstract: Circuitry for controlling the power output of an R.F. generator for regulating the forward power transmitted into a load of varying impedance, such as an R.F. sputtering target, and for limiting reflected power to a safe predetermined level. Forward power is controlled by circuitry that compares the voltage across the target with a predetermined reference voltage and the amplified output is applied to the signal generator control circuitry. Reflected power is measured by a sensor that outputs a proportional D.C. signal that is compared with a predetermined threshold voltage. Whenever the reflected power signal exceeds this threshold, it removes the effect of the target voltage input signal so that the amplified control signal to the R.F. generator is a function only of the reflected power.