Showing papers on "Precision rectifier published in 1985"

Pulsed light detection circuit

Abstract: Improved circuitry for detecting pulsed infrared light which is particularly suitable for use with laser therapeutic devices. Laser therapeutic devices generally utilize pulsed laser energy of infrared wavelengths. Because such light is invisible the operator of the therapeutic device cannot determine if it is actually working. The invention provides pulsed infrared light detection circuitry which is very compact so that it may be made part of the therapeutic device. The circuitry includes an infrared sensitive transducer coupled to the input of an inverting operational amplifier, a peak detector coupled to the output of the inverting amplifier, and a non-inverting amplifier coupled to the output of the peak detector for driving a display to indicate the detection of pulsed infrared energy.

Constant duty cycle peak detector

Abstract: A signal detector whose output voltage approximates the true average to peak value of an applied signal of a generally arbitrary waveform employs current sources to regulate the charge-discharge duty cycle of an integrating storage device. The integrating storage device, such as an integrating capacitor, is employed in a high gain circuit with negative feedback to develop a signal representative of the peak level of the applied signal. The device approaches true peak detection over a wide dynamic and frequency operating range relative to known prior art at peak detection devices.

Circuit for detecting and suppressing pulse-shaped interferences

Abstract: The circuit arrangement for detecting pulse-shaped interferences in an electrical signal comprises an input (7), a high-pass filter (8) having a cut-off frequency lying between 40 Hz and 1000 Hz, one or two signal paths (25, 25') and an output (5). A signal path (25) comprises a peak detector (10), a device (11) for determining a running average value, of its input signal, a delay unit (12) and a comparator (15). The output of the peak detector (10) is coupled via the device (11) for determining a running average value to a first input (13) of the comparator and via the delay unit (12) to a second input (14) of the comparator. The comparator compares the delayed output signal of the peak detector with the output signal of the device for determining the running average value and supplies an output signal to its output (16) if the output signal of the peak detector is larger than a times the output signal of the device for determining the running average value, where it holds that a>1. With this circuit arrangement, a more satisfactory detection of pulse-shaped interferences is attained (FIG. 3). The circuit arrangement may be used, for example, as a detector circuit in an arrangement for detecting and suppressing pulse-shaped interferences. (FIG. 1).

Power transfer circuit

Abstract: A power transfer circuit includes a power transformer (2) having a center tap (12) provided in its secondary winding, a full-wave rectifier circuit (13), a level discriminator circuit (15) and a switching circuit (14). In response to a level discrimination made by the level discriminator circuit that a DC voltage outputted from one output terminal of the full-wave rectifier circuit is less than a predetermined voltage level, a transistor (Q1) and a thyristor (SCR) of the switching circuit are made conductive so as to ground the other output terminal of the full-wave rectifier circuit. In response to a level discrimination made by the level discriminator circuit that the DC voltage outputted from the said one output terminal of the full-wave rectifier circuit exceeds the predetermined voltage level, a diode (D9) connected to the center tap of the power transformer is made conductive to ground the center tap. Thus, the full-wave rectifier circuit outputs a constant DC voltage even if AC voltages at different levels are inputted in the primary winding of the power transformer.

Synchronous power rectifier and applications thereof

Abstract: @ A synchronous power rectifier of high efficiency incorporates a bipolar power transistor (Q33) operable by a control circuit (80) in a switching mode to rectify the energy from a secondary winding (N32) of a power transformer (T31). The synchronous rectifier reduces or eliminates the need of rectifier diodes, which provides power rectification without the power loss associated with the rectifier diode voltage drops. Moreover, the rectifier switching time is adjustable to accommodate delayed turn-off times of bipolar power devices, as well as the switching signal duration to provide regulation of the output voltage (Vo) independent of the excitation of the primary of the transformer (T31).

Fast acquisition circuit for synchronous digital receiver operating in wideband noise

Abstract: A signal acquisition circuit for a synchronous receiver that requires frequency sweep to acquire a digitally modulated signal but tends to false lock onto data sidebands or for a receiver that cannot use a frequency discriminator because of wideband noise. The receiver must provide a phase error output signal and also a signal-acquired indication that does not assert during false locks. The circuit comprises an integrator selectively coupled either to the phase error signal or to a square wave sweep waveform used for signal acquisition. The integrator is controlled by a detector output analysis circuit that compares the envelope of the signal received during frequency sweeps with the peak of the envelope determined from successive sweeps by a peak detector with a long time constant. The circuit avoids false locks and continues to sweep through successive false locks until the signal-acquired indication asserts to indicate true lock.

Automatic switchover circuit

Abstract: A circuit for automatically operating a switching power supply is capable of operating from first and second input voltage ranges. The circuit changes the switching power supply from a full-wave rectifier circuit to a voltage doubler rectifier circuit by electrically connecting first and second nodes. The circuit includes a rectifier circuit and a voltage level sensing device for generating an output voltage to trigger a triac, which connects the first and second nodes.

Multiphase rectifier circuit with dynamic AC input to DC output voltage range compression utilizing half and full wave rectification modes

Abstract: A rectifier circuit connected with a variable voltage AC source for providing a range of DC output voltages narrower than the range of AC voltage input by controllably switching between half-wave and full wave rectification.

Shunt arrangement with power overload protection by a voltage responsive bidirectional switch

Abstract: A shunt arrangement for processing the output current of an inductive current transformer having a wide dynamic range in which, in order to provide high-precision conversion with smaller currents, a power shunt is connected in series with a precision shunt which is connected in parallel with an overvoltage protection circuit containing a switchable semiconductor rectifier and a control circuit. The rectifier changes to a conductive state if the voltage at the precision shunt reaches a limit value. The control circuit contains a symmetric voltage limiting element which is constructed as a pair of limiting diodes or as a fullwave rectifier, the output of which is connected to a reference diode. In order to check the switching state of the overvoltage protection circuit, the series circuit including the power shunt and the precision shunt is connected in parallel with a series circuit consisting of a first bridge resistor and a second bridge resistor which, together with the shunts, form a balanced bridge circuit whereby, when the overvoltage protection circuit is inhibited, bridge circuit is monitored by a window discriminator.

Switched capacitor rectifier circuit

Abstract: A rectifier circuit is disclosed in which the levels of an input signal and a reference signal are compared, and the polarity of the equivalent resistor is set at positive or negative depending on the result of the comparison. The equivalent resistor is connected, as an input resistor, to a differential amplifier. A feedback resistor is connected between the input and output of the differential amplifier. This arrangement enables the rectifier circuit, with only a single differential amplifier, to perform the rectifying operation with a gain.

Analog-to-digital interface circuit for electronic musical equipment

Abstract: An interface circuit for converting analog signals from a musical instrument and/or a microphone to digital pulse signals for use with electronic music synthesizers and the like includes an input amplifier for receiving analog signals from a musical instrument and/or a microphone. A precision rectifier is coupled to the input amplifier for generating full-wave rectified analog signals. A strictly digital output circuit is connected to the rectifier for generating a strictly digital pulse signal. A quasi-digital output circuit is connected to the rectifier for generating a quasi-digital pulse signal in synchronism with the strictly digital pulse signal. The digital pulse signal from the digital output circuit and the quasi-digital pulse signal from the quasi-digital output circuit are adapted to drive a music synthesizer.

Programmable automatic cable equalizer

Abstract: The circuit (10) has a gain section which includes a first AGC circuit (12). The output of the gain section goes to a signal shaping section which includes a biquadratic filter (24), a summer (45), and a second AGC circuit (40). The two AGC circuits (12,40) are controlled by respective separate peak detectors (20, 50) and are noninteracting. For "short" cables, only the first AGC circuit (12) is active. For "long" cables, the first AGC circuit (12) is set at its gain breakpoint and the second AGC circuit (40) alone has active control. The shaping section includes a biquadratic filter (24) which is a tandem arrangement of a low-pass filter (26), an inverter (28), and an integrator (32). The low pass output (35) of the integrator (32) is connected to the noninverting (+) input of the a summing amplifier (45). The input (42) of the second AGC circuit (40) is connected to the band pass output (33) of the inverter (28), while its output (44) is connected to the inverting input (-) of the summing amplifier (45). The input of the second peak detector (50) is connected to the output (48) of the summing amplifier (45) and its output is connected to the control node (52) of the second AGC circuit (40). Operational amplifiers (G1,G2,G3,G4) of the first peak detector (20), the low-pass filter (26), the integrator (32), and the summing amplifier (45) are designed to be programmable by means of decoders (22, 36, 38, 46) to permit the equalizer (10) to accommodate different data rates.

A protonic rectifier diode

Abstract: A rectifier diode based on the protonicp -n junction has been constructed. The breakdown voltage of a single diode is 7 V and the turn-on voltage is close to 0 V.

Regulator with rectifier IR drop compensation

Abstract: A regulator for compensating for the IR drop of a rectifier coupled between the secondary winding of a transformer and a load circuit includes a pass transistor connected between the load circuit and the rectifier. A DC reference voltage is developed by a circuit connected across the secondary winding that is not subject to current fluctuations. A differential amplifier is supplied with the reference voltage as one input and the load voltage as another input. The output of the differential amplifier controls the conductivity of the pass transistor. A current limiting transistor is included in the base circuit of the pass transistor and, in turn, is controlled by another differential amplifier supplied with potentials representative of the IR drop across the rectifier. A shut down transistor is provided for cutting of the pass transistor in the event the load circuit voltage drops below a predetermined level.

A Diode Rectifier Series Tap On An HVDC Line

Abstract: Electrical energy of a rather small isolated source in vicinity of an HVDC line may be transmitted via the same line by application of a series tapping station. For such purposes, a diode rectifier series tap, which offers considerable savings as well as a high degree of reliability, is proposed and discussed in this paper.

Design, performance, and application of new bipolar synchronous rectifier

Abstract: A bipolar transistor has been developed which is aimed at synchronous rectifier applications. Because of its low on-resistance of approximately 7 milliohms, this device achieves improved efficiency over a conventional Schottky rectifier at currents up to approximately 40A. The emitter-base junction is purposely designed to have a breakdown voltage in excess of 50V rather than the usual 6 to 12V of a conventional transistor. Thus both first and third quadrant blocking capability is achieved. This behavior is not available with a power MOSFET and enables this transistor to be used in a PWM mode where both regulation and rectification can be achieved in the power supply secondary. Circuit problems attributable to the storage time of the bipolar are alleviated by using a novel base drive circuit which gives only a minor increase in circuit complexity and allows operation at switching frequencies up to 250 kHz.

dv/dt Protection circuit device for an AC-DC converter apparatus

Abstract: A dv/dt protection circuit device for an AC-DC converter apparatus including control board switching arrangement having a current cut-off function which conducts an interrupts current from a power source to a load and refluxes the load current while the current is uninterrupted by a full-wave bridge rectifier circuit having a plurality of arms. Each arm of the bridge rectifier circuit connects a reactor for suppressing a rate of change of a power source line voltage of the bridge rectifier circuit at the switching time of the switching arrangement and a condenser is provided for absorbing an overvoltage generated at an inductance on the side of the power source, the condenser being connected on the side of the power source connected to the bridge rectifier circuit.

Amplifier with automatic inhibition of acoustic feedback

Abstract: An amplifier for acoustic signals provided with means for suppressing undesired acoustic feedback signals in a rapid manner. The amplifier includes a high-pass filter which separates a part of the signal to be amplified to obtain a control signal for reducing the gain of the amplifier when an acoustic feedback signal is detected. The output of the high-pass filter is connected to a periodicity detector, e.g. a single peak detector, which discriminates between an acoustic feedback signal having a regular periodicity and a signal having an irregular character, such as noise or speech. The control signal is derived from the output of the periodicity detector.

Low voltage AC ohmeter

Abstract: An AC ohmeter is adapted for testing insulated pipe flanges where flammable substances are involved. It employs a low frequency, low voltage oscillator and includes a precision rectifier. The output of the rectifier is smoothed and applied to a dual comparator circuit such that high, low and intermediate resistance readings are obtained.

A novel switched-capacitor rectifier

Abstract: A novel switched-capacitor full-wave rectifier which obviates the need for a voltage comparator is described. This circuit can also work as a half-wave rectifier and can be used to determine the absolute difference between inputs.

DC power supply generator e.g. for gas discharge lamp - obtains regulated DC voltage from mains supply giving sinusoidal input to filter and rectifier

Abstract: The rectifier (4) output is controlled by a switching transistor (11) in parallel with a load (14). Switching is controlled by an impulse generator (6) which gives a maximum frequency when the rectified voltage is minimum, and a minimum frequency when the rectified voltage is maximum. The variation in frequency between these limits is arranged such that the second derivative of frequency with respect to time is zero or negative. The impulse generator input is from a voltage to frequency converter (25). The impulse generator contains an integrator (28) responsive to the rectifier output current as measured by a resistor (16). The integrator time constant is less than the reciprocal of the maximum frequency. The integrator output (U9) is applied to the inverting input of a differential amplifier (29) whose non-inverting input is a measure of the rectifier voltage. The amplifier is connected to a comparator (27) whose other input is a measure of the rectifier current (U4). If the integrated quantity exceeds the voltage proportional signal the amplifier output changes sign, the comparator switches state and the output is used to end the impulse. ADVANTAGE - Reduces interference voltages which can occur at lower frequencies.

Electronic proximity switch with a rectifier following the oscillator

Abstract: The invention relates to an electronic proximity switch with an oscillator and a rectifier following the oscillator, the rectified voltage of which actuates a threshold switch which controls a load switch. To be able to evaluate very small output signals and very small amplitude changes of the oscillator and to keep the current consumption, particularly of the rectifier, very small, an averaging rectifier with two transistors T1 and T2 is used, the base of T2 of which is connected to the emitter of T1 and the base of T1 of which is connected to the collector of T2. Between the emitter of T1 and the collector of T2, a diode D1 is connected with the anode to the emitter of T1. The rectified voltage is dropped across the collector resistor of T1. The diode causes the transistor T1 to be conductive during the entire negative halfwave of the input current. A temperature-dependent influencing of the rectified voltage is avoided.

Multiple output multiple step-up rectifier circuit

Abstract: In a multiple output multiple step-up rectifier circuit of the invention, an output voltage of a power source circuit is supplied to a plurality of Crockroft-Walton multiple step-up rectifier circuits connected in parallel with each other. The capacitor capacitance ratio of the rectifier circuits is proportional to the ratio of the numbers of multiplication stages of respective rectifier circuits. Particularly, when the squares of the number of multiplication stages is comparatively large, the capacitor capacitance ratio is set to be proportional to n1 2 /n2 2 where n1 and n2 are the numbers of multiplication stages of two rectifier circuits of the plurality of rectifier circuits. When the number of multiplication stages is small, the capacitor capacitance ratio is set to be proportional to: (2n1.sup.2 /3+n1/2-1/6)/(2n2.sup.2 /3+n2/2-1/6). The power source circuit can change its output voltage such that the output of any of the plurality of rectifier circuits is the same in the non-load and load states.

Open-Loop Instability of the Bridge Rectifier with Input Filter

Abstract: The instability characteristics of the bridge rectifier with input filter are described. A stability criterion based on the perturbational analysis is proposed. According to this criterion, the steady-stale circuit variables during stable operation are employed to examine the stability of the rectifier. Thereby, a simple and flexible stability method is developed. The method is applied to six-pulse and two-pulse bridge circuits with LC type input filter. The accuracy of the results is verified by experiment. The effects of converter output ripple, input voltage distortion, and type of gating circuit on the stability of the converter are examined experimentally and justified theoretically. Finally, the stability condition is determined explicitly in terms of the circuit parameters.

Non-linear integration circuit

Abstract: In a non-linear integration circuit, an audio sine wave signal is processed by a rectifier circuit and a smoothing circuit so that a DC output is obtained according to the amplitude of the signal. A hybrid diode which is similar in voltage-current characteristic to a silicon diode and is referred to as an "analogous diode" is connected to the smoothing circuit, so that a DC output is obtained by means of the analogous diode in response to an abrupt change in amplitude of the input signal. The signal can be processed on a low supply voltage, and employment of the analogous diode provides an output which is similar to that which is provided by the use of a silicon diode.

Signal evaluation method for a fiber-optic rotation sensor

Abstract: A fiber-optic rotation sensor (fiber gyro) includes an optical transmission system into which a light signal is fed by means of a laser diode. The modulation is effected by means of a piezomodulator. The coupled-out signal is fed to a receiver diode and the amplified output signal of the latter is fed to a phase sensitive rectifier and to a peak-to-peak value measuring device. The measured peak-to-peak value represents the proportionality factor K through which the output signal of rectifier is divided. Therefore it is possible with this method to constantly measure the proportionality factor K, which changes under various influences and to thus eliminate errors in the determination of the Sagnac phase.

Automatic focus adjusting device

Abstract: PURPOSE:To drive a focusing element in corresponding directions at speeds in a specific sequence from a high speed to a low speed every time an output is inverted and to perform speedy and secure automatic focus adjusting operation by comparing the level of a focusing information signal with specific corresponding levels. CONSTITUTION:Reflected luminous flux from an object 1 is image-formed on the photoelectric conversion surface of an image pickup element 6 through lenses 2 and 5 and the photoelectric conversion output signal is inputted to a video process circuit 8 and converted into a video signal output 9. A vertical synchronizing signal used by the circuit 8 is frequency-divided by a frequency divider 16 and inputted to a vibrating means 3 to vibrate the lens 5 in optical-axis directions. The output of a high frequency signal extracting means 9 which is passed through differentiation circuits 17 and 18 is inputted to a peak detector 20 and the level of the generated focusing information signal is compared by a comparator circuit 23 with a specific level. A ring counter 29 generates a signal for selecting a high-speed, intermediate- speed, or low-speed level every time the output of the circuit 23 is inverted to driving the lens 2 in charge of the focusing adjustment of a photographic optical system. Thus, the automatic focus adjusting operation is performed speedily and securely.

Power supply system and a starting method thereof

Abstract: A power supply system for supplying a load current to a load including a serially connected circuit of a controlled rectifier, a switch and a capacitor. A diode is connected in parallel with the capacitor or with a serially connected circuit of the switch and the capacitor and a control circuit. Which controls the controlled rectifier such that when a first voltage between the capacitor is larger than or equal to a specified voltage the controlled rectifier is operated as bypass pair mode and when the first voltage is below the specified voltage the controlled rectifier is operated as current control mode. A method for starting a power supply system is also disclosed.

Chrominance signal processor

Abstract: PURPOSE:To obtain an ACC detector free from less and over density with respect to noises by utilizing a peak detector and a synchronous detector for an ACC detector and by controlling and ACC amplifier by means of added outputs. CONSTITUTION:A burst input 8 from an ACC amplifier 1 and an oscillation output 75 from a subcarrier oscillator are added to a frequency detecting-type ACC detector 70 for synchronization-detecting a burst, and an output 78 whose burst period is sample-held is outputted. A burst signal 8 is envelope-detected and added to an envelope detecting-type ACC detector 71 for holding a peak value, and a peak hold value 77 is outputted. Outputs of said detector 70 and 71 are added in resistances 72 and 73, and their outputs are added to a DC voltage amplifier 74, where a level is shifted and amplified. Then a gain control of the ACC amplifier 1 is executed.