Abstract: A method of synchesizing a system which effectively forces finite value of an impedance to zero comprising a most inner positive voltage feedback loop and an inner negative voltage feedback loop and an outer negative voltage feedback loop, whereby a voltage difference between the most inner positive feedback loop and the inner negative feedback loop is fed back to compensate for the voltage drop across the impedance of interest in both steady state and transient and whereby no current through the impedance is sensed and no parameters of the impedance including parameters of the plant under the control are required to be known implying minimization of measurement noise and adaptive/self-tuning operation, respectively, in applications in which the method is used to synthesize load independent switch mode power converters and electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero order dynamics.

Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising positive current feedback of exactly specified nature and value of its transfer function. The stability and dynamics of the system are controlled by additional voltage loop. The zero-impedance converter is used to synthesize load-independent systems including switch-mode power converters and pulse width modulated electric motor drive systems incorporating any kind of motor.

Abstract: A circuit for the conversion of an unregulated input voltage (UE) into a regulated DC output voltage (UA) is specified, with which the input voltage (UE) can assume both a higher and a lower value than the desired output voltage (UA). In addition to a set/actual value comparator (SIV), a current simulation (SNB) is provided, which simulates the current (JL) in the storage choke (L2) during charging as capacitor voltage, a common driver circuit (TRS), designed as switched constant current source, for both semiconductor switches (V1, V2), an input voltage monitoring (ESU), which switches off the switched-mode regulator when there is too low an input voltage (UE) and an output monitoring circuit (ASU), which reduces the set value of the regulating circuit on crossing in the downward direction of a selectable threshold.

Abstract: A current mode switching regulator power supply with an improved regulator system achieves a constant operating period by predetermining the off time of the switching transistor. The off time is programmed by the input and output voltages acting on a resistor-capacitor timing circuit enabled by a current mode controller.

Abstract: An hysteretic current-mode controlled DC to DC converter has an input voltage, an output voltage and a control switch. The switch alternately coupled the input voltage into an energy storage inductor. It is controlled by an hysteretic conparater sensing the current of the inductor and having turn-on and turn-off limits. The limits are symmetrical about an average inductor current. The limits are adjusted by simple non-closed-loop methods to maintain an approximately constant frequency of oscillation. The average inductor current is controlled by an error amplifier to maintain a constant output voltage. The two controls are independent.

Abstract: Circuitry is provided to eliminate high frequency noise spikes in the output of a pulse width modulator and inverters employing pulse width modulators. This circuitry provides a precision noise spike elimination circuit based on a discovery that the switching of a MOSFET has two distinct regions: one in which only the drain current changes, and the other in which only the drain to source voltage changes. The precision noise spike elimination circuit includes a pair of back-to-back Zener diodes connected in parallel with the first current generator and direct feedback of the rate of change of voltage across the catch diode, thereby eliminating the effect of non-linear capacitance of the MOSFET in the feedback path. The back-to-back Zener diodes provide very precise control of the rate of change of the MOSFET current and catch-diode voltage. The more linear switching of the MOSFET due to the improved feedback results in a reduction in losses in the MOSFET for the same degree of noise reduction.

Abstract: A method of synthesizing load invariant switch-mode power converters comprising positive current feedback of exactly specified nature and value of its transfer function. The system transfer function independent of load is realized while stability and dynamics of the system are controlled by an additional voltage loop.

Abstract: A DC voltage converter comprising: a switching transistor for establishing a load current circuit which connects a DC power source to a load to supply a load current to the load; a differentiating circuit connected in series to the load current circuit for producing a voltage drop corresponding to a differentiated value of the load current; an integrating capacitor connected in parallel with the load via an output terminal for outputting as an output voltage to be supplied to the load a voltage corresponding to an integrated value of a current flowing through the capacitor; a control width setting circuit for setting a width defined by upper and lower limits for controlling the output voltage in accordance with the voltage drop derived from the differentiating circuit; a ripple detection circuit receiving the output voltage from the capacitor and for detecting a ripple caused by an "ON-OFF" operation of the switching transistor; an output-reference-level setting circuit for setting a reference voltage of the

Abstract: An electronic control for a motor drives the motor with pulses of current, and protects the motor from extreme values of line voltage and motor current. A current sensor, connected in series with a conductor which supplies current to the motor windings, develops a monitoring signal that is sensed for the purpose of shutting down the motor when the monitoring signal indicates that the motor current is excessive. A power supply in the control isolates the control from the AC line voltage, provides regulated DC voltages to power various portions of the control, and provides an unregulated DC sense voltage which indicates when the AC line voltage is too high or too low so that the motor can be shut down.

Abstract: A bias generating circuit for reducing an external DC power supply voltage to a predetermined, lower, stable DC voltage used as a power source for internal logic circuits in a semiconductor IC chip includes an oscillator for converting the external DC voltage into a pulse signal, a smoothing circuit for converting a pulse signal into the lower DC voltage, and a control circuit interposed between the oscillator and the smoothing circuit for varying the pulse duration of the pulse signal from the oscillator to a changed pulse signal, and for regulating the lower DC voltage to a predetermined amplitude in response to the voltage variation in the lower DC voltage. The control circuit comprises a CMOS inverter, a CMOS buffer circuit for varying the pulse duration of the output signal of the CMOS inverter, and a voltage compensating circuit for controlling the transconductance of the CMOS inverter in response to the variation of the lower DC voltage.

Abstract: The voltage present at an input is chopped by a switch which is actuated by a pulse-width modulator controlled by the output voltage and is smoothed at least by a low-pass filter, consisting of an inductance and a capacitance, at the output. In order to reduce to a minimum the delay between the time an input voltage is applied and the time a rated value is at least approximately reached by the output voltage, the inductance is bypassed by a bypassing circuit which has a low inductance and which conducts if the output voltage is below a minimum voltage and in other cases is turned off. It contains, for example, a switch which is constructed as a switchable current source and which is actuated by a comparator comparing the output voltage with a reference voltage. In transformer-coupled embodiments, isolation between the output and the input is possible. The supply unit is suited, for example for supplying auxiliary devices of an instrument transformer from the current of the power-line to be monitored.

Abstract: A controller for providing PWM drive to an inductive load incorporating an input rectifier bridge (24) the output of which is filtered by capacitors (106, 108) and which includes input impedance (116, 118) for limiting start-up current surges. A by-pass network (124) controlled from a high voltage sensor circuit (32) controls the by-pass network. The sensor circuit also provides an enablement signal (40) to a pulse width modulation circuit (42). A low voltage power supply (36) is coupled with the output (26) of the rectifier and filter function (24) to supply isolated power to the discrete driver networks of a driver circuit (48). The driver networks are controlled from the pulse width modulation circuit which, in turn, is controlled from a microprocessor (68). The drivers provide drive to three, phase designated transistor pairs of an inverter switching bridge (50) which is supplied power from the rectifier and filter circuit (24).

Abstract: A link regulator is disclosed for providing a regulated voltage over a wide range of input frequencies and load currents. The frequency of an internal VCO and the input frequency are phase compared to provide a reference error signal. The unregulated DC voltage is integrated for a duration proportional to the error signal. This duration controls a series switching element to provide a constant volts/seconds. The output of the series switching element is filtered to a DC voltage that controls the frequency of the VCO. The DC voltage is proportional to the error signal, thus providing a feed forward system to regulate the DC voltage. During the period when the series switching element is not conducting, a shunt switch presents a low impedance to the input of the filter to clamp the input to ground. This allows for operation over a wide range of load currents without losing regulation.

Abstract: In a current controlled two-state modulation system having a power switch and a low pass filter, a current sensor provides a current feedback signal representative of the current delivered by the power switch to the low pass filter. The low pass filter also provides a voltage feedback signal that is combined with a reference signal to provide a combined signal. A limiting amplifier amplifies the combined signal for further combination with the current feedback signal to provide a switching signal that is delivered to a circuit characterized by hysteresis. This circuit determines the instant when the power switch is switched so as to maintain the output voltage provided by the low pass filter substantially constant so long as the load current is less than a predetermined limiting value determined by the limiting amplifier and thereafter limits the output current to substantially the predetermined limiting value.

Abstract: A pulse-width modulated current regulator (FIG. 4) includes a current flare out control (406,407,409,412) to limit current output at low output voltages. Current variation in an output filter inductor (408) is monitored and compared with a reference standard (407). A conduction interval is controlled in response to the comparison in order to limit current flare out.

Abstract: A free-running switching regulator of the type including a transistor switch serially-connected between a voltage source and a load is disclosed. The duty cycle of the switch is varied in response to changes in the load voltage to maintain it at a predetermined regulated magnitude. Feedback means is provided for controlling the switching frequency and the duty cycle of the switch substantially independently of the load impedance such that feedback loop stability is maintained irrespective of the load reactance and an essentially constant switching period of duration T is maintained despite changes in the load resistance.

Abstract: A current monitoring scheme operates in an indirect fashion to estimate the current output of a circuit from a measured voltage output. Voltage data is processed in accord with state variable theory to derive a current estimate without direct sensing of the current.

Abstract: A switching regulator for a television display apparatus includes a controllable switch coupled to a source of unregulated direct voltage. The switch is operated at the deflection rate to produce a pulsating direct voltage. A filter including a series choke and a shunt capacitor has its input coupled to the switch for filtering the pulsating direct voltage to form a direct voltage for operating the television display apparatus. An integrator has its input coupled to the input of the filter for averaging the pulsating direct voltage.A feedback voltage control circuit has an input coupled to the integrator and an output coupled to a control electrode of the controllable switch for maintaining the average of the pulsating direct voltage constant over a wide range of unregulated direct voltage and load current variations.

Abstract: To equalize current flow through a pair of chokes supplying a d-c load from a d-c source, and, if desired, to limit current flow through either a single choke or both to a predetermined maximum value, without using measuring shunts, the voltage drop through the choke itself is being measured by summing circuits, which may form the algebraic sum or difference, respectively, of the voltages across the chokes, the sum or difference signals then being passed through low-pass filters to form signals representative of inductive voltage difference of two chokes, or of the voltage drop through one or both of them, which signals are then applied to respective regulators which, in turn, control the duty cycle of one or two semiconductor switches, respectively connected in series with the respective chokes.

Abstract: A bleeder circuit is utilized to insure proper operation of a filter inductor in a pulsed power system. A control arrangement couples a bleeder resistor to the filter inductor in response to actual current discontinuities in the inductor. The control arrangement responds to actual current discontinuities by responding to a voltage collapse in the inductor and activates a switch to couple the bleeder resistor to the inductor.