Showing papers on "Voltage drop published in 1990"

Method and apparatus for the electronic detection of air inside a thermal inkjet printhead

Abstract: A detection circuit for detecting the existence of non-collapsing bubbles in the ink cells of a thermal inkjet printhead is connected to a heater element of an ink containing cell. The detection circuit has a sensing element of low resistance when compared to the resistance of the heater element so that printing and detecting operations can proceed simultaneously. Current in the heater element is proportional to the potential drop across the sensing element. An amplifier is used to measure the potential drop and is connected to a blocking capacitor. Non-collapsing bubbles are detected if the voltage drop across the sensing element varies from a reference level.

Power conversion system

Abstract: A power conversion system is disclosed in which a direct current is taken out of an AC power supply of variable frequency and variable voltage through a PWM converter in such a manner that in a region of low source voltage, the converter input current is limited to a predetermined value to maximize the DC power taking the voltage drop of the power supply into consideration with the power factor of "1" of the power supply, and when the current reaches an allowable maximum, it is limited to that value. In a region of high source voltage, on the other hand, the quadrature component of the input voltage applied to the source voltage is controlled preferentially in a manner to control the converter input voltage below a predetermined value, thus making it possible to secure the maximum power available from the converter over the entire range of operation. If a battery is connected to the DC side, a cooperative operation is made possible while the battery is charged properly.

Infrared touch input device and light emitted activation circuit

Abstract: A touch input device, suitable for use in detecting the presence of an opaque element within a display area bounded by light emitting elements and light detecting elements includes light emitter activating circuitry in which the light emitting elements are individually selectable. Each light emitting element is contained within a matrix and source drivers and sink drivers are effective to select a specific row and column address for each individual light emitter. Current for the light emitters is provided by a voltage source which is chosen for compatibility with the logic used in the touch input system. A charge pump operating sequentially with the selection light emitting elements is used to establish a voltage greater than the normal supply voltage to overcome the voltage drops of the source and sink driver and the activated light emitter to insure light emission greater than a minimum threshold.

MOS output buffer with reduced supply line disturbance

Abstract: An output buffer with reduced supply line disturbance is provided for use in high performance microprocessor circuits. The output buffer uses a resistor and transistor as a sensing circuit, in parallel with an output driver transistor, thereby providing a negative feedback path into the control circuitry for the output driver. The sensing circuit detects the strength of the output driver transistor, by monitoring the amount of capacitance on the output node when the output buffer is driving the output signal to a logic high or logic low state, and rapidly produces a control voltage. The current flowing through the driver transistor and the sensor transistor causes a voltage drop across the resistor, which is fedback into the control circuitry. The control voltage is fed back into the output buffer control circuitry, thereby facilitating the reduction of the current drive capabilities of the driver and sensor transistors. Thus, the control circuitry reduces the change in current flow (di/dt) attributable to the operation of the driver and sensor transistors during the output buffer logic state transition.

Transistor provided with a current detecting function

Abstract: A transistor provided with a current detecting function does not need any external resistance to detect current but uses a part of the electrode wiring through which main current flows as a resistance to prevent power loss. It detects the magnitude of main current on the basis of voltage drop caused by the resistance. Further, a stable sense voltage can be obtained without being affected by temperature change and sense voltages caused at the both ends of a sense resistance can be maintained constant with temperature change. Sense voltages can accurately correspond to the magnitude of main current flowing through a main transistor to enable excess current to be detected accurately.

Open loop motor control with both voltage and current regulation

Abstract: An open-loop pulse width modulation (PWM) motor control for an induction motor includes a voltage regulator loop which is wrapped around a current regulator. When a load is suddenly encountered by the motor, voltage drops at the output of the current regulator. This is sensed and fed back to a voltage regulator and to a current limiter which then adjust the input signal to the current regulator to prevent an overcurrent that will trip a circuit protection device. The voltage regulator and current limiter may be implemented in either analog or digital circuitry.

Substrate potential generating circuit

Abstract: A substrate potential generating circuit of the present invention includes a first charge-pump circuit which produces a higher-potential voltage whose polarity is the same as that of and whose potential is higher than that of the power supply voltage and a second charge-pump circuit to which is supplied as a power source voltage the higher-potential voltage produced by the first charge-pump circuit and which generates a predetermined substrate potential to be supplied to a substrate of a semiconductor integrated circuit. The polarity of the substrate potential is opposite to that of the higher-potential voltage. The circuit of the present invention has enough capability of stably supplying the necessary substrate potential to the substrate without increasing the size of any transistors or capacitor constituting the second charge-pump circuit. In order to enhance the reliability of the circuit, the generating circuit may further comprise a high-potential control circuit which controls a maximum potential of the higher-potential voltage produced by the first charge-pump circuit and then supplied to the second charge-pump circuit as a power source voltage therefor.

Circuit for internal current limiting in a fast high side power switch

Abstract: A current limiting circuit (200, 300, 400) for instantaneously limiting the peak current of a fast high side power switch (212) or power FET has a reference switch (213) or FET, a first comparator (218), a current source ICL, control circuitry (209), and a clamping circuit (238). The reference FET (213) is smaller than the power FET (212). The first comparator compares the voltage drop across the power FET (212) and compares it with the voltage drop across the reference FET (213) and produces a signal COMPOUT which initiates the turn-off of the power FET (212) if the voltage drop across the power FET (212), caused by a load current flowing through it, is greater than or equal to the reference FET voltage drop induced by ICL. The clamp circuit (238), having diodes (D₁, D₂) and a tracking current source I'CL, disconnects the FETS (212, 213) from the comparator (218) when they are OFF. The circuit (200, 300, 400) may also have a second comparator (250) which protects the power switch (212) from a short circuit condition in the circuit (200, 300, 400).

Motor driving circuit

Abstract: PURPOSE:To prevent large current from flowing in starting a motor and to prevent malfunction of equipment due to voltage drop by gradually charging a capacitor in a smoothing circuit at the rear stage of a switching transistor prior to the start of the motor. CONSTITUTION:When a system control circuit 4 is commanded to start a motor, a charging command signal becomes H-level and a transistor Q2 is turned ON for a specified period before a motor ON/OFF signal is raised. Then, prior to the start of a motor 2 the current limited by a resistance R1 is caused to flow to a capacitor C2 in a smoothing circuit 8, into which the current is charged. The ON state of a charging circuit 9 is cancelled when the motor ON/OFF signal is raised. Large current flow in starting the motor can thereby be suppressed.

Circuit for ensuring the provision of starting energy in motor vehicles with internal combustion engines

Abstract: In order to ensure the provision of starting energy in motor vehicles with internal combustion engines, the voltage of the starting battery is monitored whenever the generator of the vehicle's electrical system has been stationary. When the voltage drops below an adjustable voltage limit, the starting battery is disconnected from the vehicle's electrical system via a voltage-controlled relay switch K2.

Electrical power distribution

Abstract: The present invention relates to power distribution systems and more particularly, to such systems using power storage devices such as batteries and involving a first electrical load best served by a power source having a low current rate and slow discharge period, and a second electrical load best served by a power source having a high current rate and rapid discharge period. One particular application involving these requirements is in automobile electrical systems. The present invention provides an electrical control circuit that functions in conjunction with such power sources to satisfy such electrical system operating requirements. The system of the present invention maintains the power sources in electrically separate condition when the associated vehicle engine is not running, so as to prevent discharge of the power source serving engine starting systems as a result of inadvertent discharge of the other power source. The control circuit detects presence of external conditions such as vibration or voltage drop created as an operator is about to start the engine. The control circuit electrically connects the power sources for starting, and may retain the connection for charging purposes, but disconnects the power sources from each other after engine operation is concluded. Controls are also provided for connection or disconnection of the power source in response to detected conditions such as undesirable voltages or current flows in the electrical system.

Temperature compensation control circuit for exponential gain function of an agc amplifier

Abstract: A temperature compensation control circuit to maintain a constant control gain in an AGC (automatic gain control) amplifier. The present invention compensates for the inherent temperature dependence without using any special processing or non-standard device structures. The present invention utilizes the voltage drop across n diodes in series to produce the control voltage difference (V C -V C *). These n series diodes are coupled to the collectors of a PNP emitter coupled pair with emitter resistance. This causes the control voltage difference to be dependent on temperature (nkT/q), but this dependency cancels out with the other inherent temperature dependency in the exponential function of the AGC amplifier which is also produced by a diode form. Thus, the present invention provides temperature compensation with minimum component matching problems and without the need for a PTAT (proportional to absolute temperature) current source.

Winner-take-all neural net with memory

Abstract: Optically switchable pnpn semiconductor devices have been connected in parallel with a common load resistance. When illuminated, only that device with maximum input will turn on. The voltage across the other devices drops and inhibits their switching ability. With suitable biasing, the winning device can be recalled at any time. >

High voltage follower and sensing circuit

Abstract: An on-chip circuit for producing signals to enable the operation of a circuit of special mode by sensing an externally applied signal to the chip or for supplying the externally applied voltage directly to the circuit in a special mode. The circuit includes an input terminal for inputting externally applied voltage, a controlling node, an output node, a voltage drop element connected between the input terminal and said controlling node to drop the input voltage, a first voltage supplying a terminal for supplying first bias voltage to the controlling node, a second voltage supplying terminal for receiving a second bias voltage, a switching element responsive to the voltage of the controlling node for providing a conducting path between said controlling node and said output node, a third voltage supplying terminal for receiving a third bias voltage, a constant current supply means connected between said third voltage supplying terminal and said output node for constantly supplying the same current to said output node, an output element connected with said output node for producing a signal of a specified logic level when the voltage of said output node exceeds a certain voltage level, a first output terminal connected with said output node and a second output terminal connected with said output element, whereby said first output terminal delivers a first output voltage following the externally applied voltage and said second output terminal delivers a second output voltage having a logic level according to said first output voltage.

Analog circuit for controlling acoustic transducer arrays

Abstract: A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

Charging control apparatus for vehicle generators

Abstract: A battery charging control apparatus for a vehicle generator comprises switching means for controlling a field current flowing through a field winding of the generator intermittently, voltage control means for controlling the switching means to increase the field current gradually in order to maintain a voltage of a battery to be charged at a first predetermined value when the battery voltage drops below the first predetermined value, generator output voltage detecting means for detecting an output voltage of the generator, charging abnormality warning means, which detects occurrence of charging abnormality, when the detected generator output voltage drops to assume a second predetermined value and below, which value is lower than the first predetermined value, and at the same time the battery voltage remains at the first predetermined value and below for a predetermined time, and which then turns on a charging abnormality warning lamp, and current increasing means which increases the field current to thereby increase the generator output voltage to assume the second predetermined value and above within the predetermined time, when the charging abnormality has occurred, whereby it is made possible to prevent erroneous lighting of the charging abnormality warning lamp.

Integrated comparator circuit

Abstract: There is disclosed a three-state buffer including a comparator circuit which comprises a plurality of bipolar transistors and which generates first and second control voltages which are dependent upon the forward biased base to emitter voltage drops of the transistors. The comparator circuit also includes a threshold circuit establishing a threshold voltage intermediate the first and second control voltages which is also dependent upon the forward biased base to emitter voltage drops of the transistors. As a result, the threshold voltage is always intermediate the first and second control voltages to assure reliable operation of the comparator circuit notwithstanding variations in integrated circuit processing parameters or integrated circuit operating temperatures.

MOS switching circuit having gate enhanced lateral bipolar transistor

Abstract: Circuitry for implementing a gate enhanced lateral transistor to provide a circuit having a bipolar current driving capability and an FET channel voltage drop. The circuits provide switching of the lateral transistor by enabling both gate and base connections. The device is merged into an FET providing essentially no voltage drop across the collector-emitter connections permitting the collector to reach a full power supply voltage.

Device and a process for detecting current flow in a MOS transistor

Abstract: In a device for detecting the flow of a current lower than a given threshold current in a load (L) in series with a power MOS transistor (M1), the free terminal of the MOS transistor is connected to a first terminal (1) of a supply source, the second terminal (2) of which is connected to the free terminal of the load (L), the gate (G1) of the MOS transistor being connected to a control source (3). A means (11) for detecting the voltage drop is connected across the terminals of the MOS transistor and a control loop (12) imposes an appropriate gate voltage to the MOS transistor as soon as the voltage drop across its terminals tends to decrease below a determined level.

Ion concentration setting apparatus for ionic water generator

Abstract: An apparatus for setting the ion concentration in an ionic water generator which separates drink water between alkaline ionic water and an acidic ionic water by applying a DC voltage between electrodes in an electrolytic cell which are partitioned by an ion-exchange membrane apparatus comprises a device for measuring voltage drop at a portion leading to the electrolytic cell which is caused when a reference voltage is applied, and a calculator for calculating voltage Vx which is applied to the electrolytic cell to adjust ion concentration to a desired value from a proportion k of the voltage drop which is calculated by application of the reference voltage to water to be examined relative to the reference voltage drop caused by application of the reference voltage to reference water and a set voltage Vn which corresponds to the desired ion concentration on the basis of the following equation: Vx=k×Vn.

Bridge circuit having polarity inversion protection means entailing a reduced voltage drop

Abstract: The additional voltage drop across a guard diode against supply polarity inversion in an integrated bridge circuit for driving an external load and employing two high-side NPN power switches driven by two PNP transistors, all monolithically integrated using a junction-type isolation technique, is substantially eliminated by connecting the emitters of the two PNP drive transistors directly to the positive rail, ie to the anode of the guard diode Integrated PNP transistors are per se intrinsically protected against polarity inversion and when so connected permit to reduce the overall voltage drop across the driving bridge circuit Using a Zener diode as the guard diode and a second Zener diode connected in opposition to the first Zener between the cathode thereof and the negative supply rail an additional spike protection of the circuit's components is implemented

Medical equipment system with identification of one-time use articles - uses electrical resistors with values specifying types and sizes

Abstract: The medical equipment system contains one-time use medical articles (2,3) of different types and sizes with automatically detectable identifications indicating the type and size and an item of medical equipment (1) in which the articles are used. An electrical detection circuit (9) determines the type and size. The identification can be an electrical resistor (4) with a resistance value specifying the type and size of article. The resistor forms a potential divider with a resistor (8) in the medical equipment with which it is connected via external contacts (6,7). The circuit evaluates the resistor's partial voltage drop. ADVANTAGE - Increased reliabilty of medical equipment article identification at low cost.

Temperature measuring circuit

Abstract: The temperature measuring circuit includes a plurality of temperature sensors, each of which is formed by a temperature-dependent measuring resistance having two current terminals and two voltage tapping terminals arranged in each case between an associated current terminal and the temperature-dependent measuring resistance. The temperature sensors are connected via the current terminals in series and the series circuit is connected via two current conductors to an evaluating circuit which sends a constant current through the measuring resistances connected in series. For measuring the voltage drops caused by the constant current at the individual measuring resistances the voltage tapping terminals of each temperature sensor are connected by voltage conductors to the evaluating circuit. The two voltage tapping terminals of two temperature sensors following each other in the series circuit and assigned to two interconnected current terminals are each connected via a resistance to a common voltage conductor. This results in a considerable saving of connecting conductors compared with a temperature measuring circuit with the same number of temperature sensors each connected by two current conductors and two voltage conductors to the evaluating circuit.

Current supply with inrush current limitation

Abstract: 1. Power supply device with a switch-on current limiting circuit. 2.1. The invention relates to a power supply device having a switch-on current limiting circuit which is connected between a supply voltage on the input side and a storage capacitor on the output side and has a first semiconductor switch, parallel to whose switching path there is arranged a parallel resistor and parallel to whose control path there is arranged the parallel circuit consisting of a first capacitor and a first resistor as well as the switching path of a second semiconductor switch. 2.2. It is proposed that the control electrode of the second semiconductor switch be connected to the tap of a first voltage divider, with a second capacitor connected in parallel therewith, the switching path of a third semiconductor switch being connected in parallel with the control path of the second semiconductor switch and being switched off as a function of a control current supplied by a threshold value circuit if the supply voltage drops below a threshold value. 2.3 Power supply devices.

On the effect of non-degenerate doping of polysilicon gate in thin oxide MOS-devices—Analytical modeling

Abstract: A one-dimensional model of the polysilicon-gate-oxide-bulk structure is presented in order to analyze the implanted gate MOS-devices. The influence of the ionized impurity concentration in the polysilicon-gate near the oxide and the charge at the polysilicon-oxide interface on the flat-band voltage, threshold voltage, inversion layer charge and the quasi-static C – V characteristic is quantitatively studied. The calculations show a considerable degradation of the inversion layer charge due to the voltage drop in the gate, especially in thin oxide devices. The calculated quasi-static C – V curves agree with the recently published data of implanted gate devices.

Hot-carrier reliability of bipolar transistors

Abstract: A study of bipolar degradation over a range of stress and measurement conditions is presented. It is shown that the excess base current, Delta I/sub B/, varies in a power-law manner with J/sub C/, I/sub R/, and t. The I/sub R/ dependence results from a significant nonlocal effect in electron temperature that occurs at the periphery of the emitter due to the narrow depletion width. A quasistatic model of the degradation, suitable for SPICE circuit simulation, is presented and used to simulate the degradation of a BiCMOS inverter and differential pair circuit. The simulation of an advanced BiCMOS process indicates a degradation in the low-to-high propagation delay of 7% and 300 K and 3% at 110 K after 10 years of operation with C/sub L/=2 pf and V/sub CC/=5.5 V. For emitter-coupled pair circuits, the base current degradation can create a voltage drop across the base resistance, resulting in an additional offset voltage component. With the modeling methodology presented, one can predict the effect of varying the emitter-extrinsic-base junction doping profile on circuit reliability. >

Space potential measurements with a continuously emitting probe

Abstract: Space potential measurements with a continuously emitting probe suffer from the difficulty of a potential drop across the probe tip. In this paper we derive a simple method to ensure that the measurements are accurate in spite of this potential drop. Experimental results obtained in a single‐ended Q‐machine confirm the theoretical findings and provide reassuring evidence that the potential drop does not disturb the space potential unduly.

Strobe circuit utilizing optocoupler in DC-to-DC converter

Abstract: A strobe alarm circuit utilizing an optocoupler in the DC-to-DC converter portion of the circuit for repetitively connecting and disconnecting an energy-storing inductor across a DC power source. The light-emitting diode portion of the optocoupler is connected in parallel with a resistor connected in series with the inductor for continuously monitoring the current flowing through the inductor; when the inductor current has attained a particular value at which the voltage drop across the resistor is sufficient to turn on the LED, the switch portion of the optocoupler is turned on and disconnects the inductor from across the source. After a short interval determined by the parameters of the optocoupler and associated circuitry, the cycle is repeated.

Commutation losses of a multigap high voltage thyratron

Abstract: Commutation loss measurements have been made on an EEV CX1171 three gap ceramic thyratron. It was operated in a 15 Omega impedance system, switching square pulses derived from a cable pulse forming network (PFN) directly into a matched load. The flat top current reached 1.6 kA at 80 kV charging voltage with a rise time of about 35 ns. Losses were measured from fu.i.dt, u and i being the tube voltage drop and current, respectively. Variable parameters were PFN voltage and reservoir voltage. Further investigation of voltages appearing on the intermediate gradient grids has allowed a better understanding of the commutation process and a localization of the losses within the tube. Ferrite saturable reactors have been series connected to the thyratron, primarily to reduce the commutation loss, but also to improve the di/dt. Both single-turn an multi-turn devices have been tested. At best a reduction in the commutation loss by almost an order of magnitude has been obtained. A comparison of thyratron losses as a function of PFN voltage is given for both single-turn and multi-turn reactors and also without saturable reactor. >

Device for testing electrical appliances used in a motor vehicle

Abstract: An apparatus and method for testing electrical loads such as appliances connected with a DC source in a motor vehicle. The loads receive their signals causing them to operate from an electronic control unit. The latter is connected with a diagnostic computer in a manner so as to comply with the industrial standard DIN/ISO 9141. The diagnostic program is stored in the computer, for instance on a diskette. During a test, a precision resistor or shunt is connected in the current path between the DC source and the load. When the load to be tested has been turned on by the diagnostic computer the precision resistor leads to produces a voltage drop dependent on the current flow in the load. Such voltage drop is measured and compared in the diagnostic computer with a rated value specific for the load. If there is a difference the size of the difference provides information indicating the nature of the fault or malfunction of the load.