48results about How to "Avoid output voltage" patented technology

In a photosensor system formed of a photosensor array including a plurality of photosensors arranged in a two dimensional direction, the intervals of the reset pulse, read pulse and pre-charge pulse applied to each row of the photosensor array are respectively set equal to the sum of the reset period, the read period, and the pre-charge period. It follows that even where the read processing time of a single screen is shortened by allowing the processing cycles for the rows to partially overlap with each other, the reset period, the pre-charge period and the read period are prevented from being overlapped in time with each other, making it possible to perform the read operation accurately.

A vehicle power generation control apparatus has a power supply circuit, a rotation detecting circuit, an exciting current detecting circuit, a torque detecting / maximum exciting current determining circuit, and an exciting current control circuit. The rotation detecting circuit detects a rotation speed of a generator (or vehicle alternator) and the exciting current detecting circuit detects an exciting current flowing through an exciting winding of the generator. The torque detecting / maximum exciting current determining circuit calculates a power generation torque of the generator based on the output voltage, the exciting current, the rotation speed, and calculates an inertia torque of the generator based on a change rate of the rotation speed. The exciting current control circuit suppresses the exciting current flowing through the exciting winding so that a change rate of a total sum of the generation torque and the inertia torque does not exceed a predetermined value, for example, during the idling condition.

A fuel cell system is equipped with a fuel cell, a DC / DC converter that is electrically connected to the fuel cell, and a control unit that controls the supply of a fuel gas and an oxidizing gas to the fuel cell and issues a voltage command to and drives the DC / DC converter to perform high potential avoidance control of restraining an output voltage of the fuel cell from exceeding a high potential avoidance voltage lower than an open circuit voltage. The control unit continues to drive the DC / DC converter so as to perform the high potential avoidance control for a predetermined time after stopping supplying the fuel cell with hydrogen and air in response to the inputting of a system operation stop command.

A multi-output type DC / DC converter including: a reactor connected to a direct-current power supply; a first switching circuit to apply a current to the reactor; a second switching to switch an output from the reactor to any one of output terminals; output voltage detection units to detect voltages of the output terminals; comparison circuits to compare outputs of the output voltage detection units with a waveform signal of a predetermined frequency; and an output selection unit to receive outputs of the comparison circuits as inputs, the output selection unit selecting an output of a comparison circuit, the output having an earlier rise or an earlier fall, to generate a plurality of control signals pertaining to on and off of the first switching circuit and / or the second switching circuit, the output selection unit treating the plurality of control signals in accordance with a predetermined priority order when the outputs of the plurality of comparison circuits change almost at the same time, wherein a current generated by a discharge of energy accumulated in the reactor is output to any one of the output terminals in accordance with the control signals generated by the output selection unit.

Provided is a voltage regulator capable of controlling an output voltage to a predetermined voltage quickly after an undershoot occurs in the output voltage. The voltage regulator includes: an undershoot detection circuit configured to detect a voltage that is based on an output voltage of the voltage regulator, and output a current corresponding to an undershoot amount of the output voltage; and an I-V converter circuit configured to control a current flowing through an output transistor based on a current controlled by an output of an error amplifier and a current flowing from the undershoot detection circuit.

A power generating system for a vehicle is configured to include a power generator, a voltage control device which controls an output voltage of the power generator, a battery which is charged by output power of the power generator, and an ECU which transmits a power generation suppression signal for suppressing power generation by the power generator when a predetermined condition is satisfied toward the voltage control device. The ECU detects a state of the battery, and inhibits transmission of the power generation suppression signal when quantity of this state is below a predetermined value.

A switching power supply, which operates intermittently under a light load for suppressing electric power consumption, reduces output voltage variations caused when a load current increases rapidly from a light load state, and reduces output voltage ringing. The switching power supply includes a comparator that compares a feedback signal obtained by isolating the output from an error amplifier with a burst threshold value and a comparator that compares the feedback signal with a power-supply-interruption threshold value preset to be lower than the burst threshold value. The switching power supply stops output of a driving pulse from a driver circuit when the feedback signal is lower than the burst threshold value. The switching power supply also stops the output of operation power from first power supply circuit when the feedback signal is lower than the power-supply-interruption threshold value.

A vehicle power generation control apparatus has a power supply circuit, a rotation detecting circuit, an exciting current detecting circuit, a torque detecting / maximum exciting current determining circuit, and an exciting current control circuit. The rotation detecting circuit detects a rotation speed of a generator (or vehicle alternator) and the exciting current detecting circuit detects an exciting current flowing through an exciting winding of the generator. The torque detecting / maximum exciting current determining circuit calculates a power generation torque of the generator based on the output voltage, the exciting current, the rotation speed, and calculates an inertia torque of the generator based on a change rate of the rotation speed. The exciting current control circuit suppresses the exciting current flowing through the exciting winding so that a change rate of a total sum of the generation torque and the inertia torque does not exceed a predetermined value, for example, during the idling condition.

A power supply device is connected to an external power supply and supplies electric power to a load. The power supply device includes a battery terminal that is used to connect a secondary battery, a superposition unit that superposes second electric power output from the secondary battery on first electric power supplied from the external power supply, and that outputs resultant electric power to the load; a power consumption amount retrieve unit that retrieves a power consumption amount of the load; and a controller that controls an amount of the second electric power to be output from the secondary battery, based on the power consumption amount.

Disclosed are a switching regulator and a control circuit and a control method therefor. In one embodiment, the control circuit generates a supplementary signal varying with a state parameter of the power stage in a first mode and keeps the supplementary signal substantially unchanged in a second mode with respect to the value thereof at the moment of switching from the first mode to the second mode so that the supplementary signal at the moment of mode switching is maintained substantially constant, therefore, a steady state can be achieved quickly, and ripples in the output voltage are restrained.

Provided is a band gap constant-voltage circuit capable of achieving a quick startup time to thereby preventing an output voltage from being stabilized at 0 V due to noise or the like even under the normal condition. The band gap constant-voltage circuit according to the present invention includes: an output voltage detecting circuit for monitoring a voltage at an output terminal; and a current source which has a current value controlled through an output of the output voltage detecting circuit, in which the current source supplies a bipolar transistor constituting a level shifter circuit with a current when the voltage at the output terminal is lower than a predetermined voltage.

Provided is a voltage regulator including a leakage current correction circuit capable of keeping the accuracy of an output voltage of the voltage regulator even when an output voltage of a reference voltage circuit is decreased due to the influence of a leakage current. The voltage regulator includes: a reference voltage circuit configured to output a reference voltage; an output transistor configured to output an output voltage; a voltage divider circuit configured to divide the output voltage to output a feedback voltage; an error amplifier circuit configured to amplify a difference between the reference voltage and the feedback voltage, and output the amplified difference to control a gate of the output transistor; and a leakage current correction circuit connected to an output terminal of the voltage divider circuit. The leakage current correction circuit is configured to decrease the feedback voltage to prevent the output voltage from dropping at high temperature.

To solve the problem of the conventional reference voltage generation circuit in that an output voltage exceeds a predetermined voltage value, there is provided a reference voltage generation circuit including: a voltage generation circuit provided between a first power supply and a second power supply, to output an output voltage to an output terminal; an auxiliary start-up circuit provided between the output terminal and the first power supply, to supply a voltage of the first power supply to the output terminal; and a control circuit that switches the auxiliary start-up circuit between an operating state and a non-operating state according to a value of a voltage at the output terminal.

Provided is a DC-DC converter comprising: a drive switching element so that a current flows to an inductor, the drive switching element being driven by a PWM control pulse or a PFM control pulse, wherein a direct-current input voltage supplied from a direct-current power source is converted so as to output the converted direct-current voltage having a different potential, and wherein a PWM control is performed when a load is larger than a predetermined value and a PFM control is performed when the load is smaller than the predetermined value, the DC-DC converter further comprising: a pulse width regulation section to regulate the PWM control pulse so as not to have a pulse width smaller than a predetermined pulse width, at least when the PFM control is switched to the PWM control.

A method of hybrid power management is provided in the present invention, comprising steps of: providing a hybrid power output device being coupled to a load and comprising a fuel cell module and a secondary cell module; determining a plurality of threshold values, each representing one of output power modes of the hybrid power output device respectively; and monitoring a characteristic value output from the fuel cell module and comparing the characteristic value with the threshold values to determine one of the output power modes to supply power to the load. Moreover, the present invention further provides a system of hybrid power management using the foregoing method to control switches to select from the output power modes such as supplying power from the fuel cell module only, from both the fuel cell module and the secondary battery, or cutting off power supply to the load according to the power state of the fuel cell module.

To provide a COT-controlled switching regulator capable of preventing an output voltage from excessively exceeding a desired voltage even though a light load is connected to an output terminal. A switching regulator of the present invention is configured to be equipped with a 100% DUTY detection circuit which detects a 100% DUTY at which a high-side switching element continues an on state for a prescribed time or more and outputs a detected signal to an output control circuit and to cause the output control circuit to turn off the high-side switching element when the output control circuit receives the detected signal therein.

A current source for quickly adjusting an output current includes a constant current generation module, coupled to a control node, for generating a predefined current flowing through the control node in order to determine a voltage of the control node; a capacitor, coupled to an output terminal of the current source; a current variation detection module, coupled between the control node and the capacitor, for generating a variation on the voltage of the control node via the capacitor when the output terminal of the current source receives an instant current variation; and a trans-conductance amplifier, coupled between the control node and the output terminal, for changing a magnitude of the output current of the output terminal when the variation on the voltage of the control node is generated.

Provided is a voltage regulator capable of controlling an output voltage to a predetermined voltage quickly after an overshoot occurs in the output voltage. The voltage regulator includes: an overshoot detection circuit configured to detect a voltage that is based on an output voltage of the voltage regulator, and output a current corresponding to an overshoot amount of the output voltage; and an I-V converter circuit configured to control a current flowing through an output transistor based on a current controlled by an output of an error amplifier and a current flowing from the overshoot detection circuit.

An alternator has rectifying module groups. The rectifying module groups form a bridge circuit. The rectifying module groups have a load dump protection judgment section for monitoring an output voltage of rectifying module groups. When the monitored output voltage exceeds a first threshold voltage, the load dump protection judgment section provides to a control section an instruction to turn on MOS transistors in a lower arm of the bridge circuit at a time when a predetermined delay time has elapsed. When a second threshold voltage is lower than the first threshold voltage and the monitored output voltage becomes less than the second threshold voltage after the monitored output voltage exceeds the first threshold voltage, the load dump protection judgment section provides to the control circuit an instruction to turn on the MOS transistors in the lower arm after the MOS transistors are turned off during a predetermined time length.

Disclosed are a switching regulator and a control circuit and a control method therefor. In one embodiment, the control circuit generates a supplementary signal varying with a state parameter of the power stage in a first mode and keeps the supplementary signal substantially unchanged in a second mode with respect to the value thereof at the moment of switching from the first mode to the second mode so that the supplementary signal at the moment of mode switching is maintained substantially constant, therefore, a steady state can be achieved quickly, and ripples in the output voltage are restrained.

A multi-output type DC / DC converter including: a reactor connected to a direct-current power supply; a first switching circuit to apply a current to the reactor; a second switching to switch an output from the reactor to any one of output terminals; output voltage detection units to detect voltages of the output terminals; comparison circuits to compare outputs of the output voltage detection units with a waveform signal of a predetermined frequency; and an output selection unit to receive outputs of the comparison circuits as inputs, the output selection unit selecting an output of a comparison circuit, the output having an earlier rise or an earlier fall, to generate a plurality of control signals pertaining to on and off of the first switching circuit and / or the second switching circuit, the output selection unit treating the plurality of control signals in accordance with a predetermined priority order when the outputs of the plurality of comparison circuits change almost at the same time, wherein a current generated by a discharge of energy accumulated in the reactor is output to any one of the output terminals in accordance with the control signals generated by the output selection unit.

A target electric power operating part (2) operates a target electric power of a fuel cell. A running target point operating part (3) operates targets of both pressure of gas and mass flow rate of gas. A running point controlling part (4) controls a running point of the fuel cell. A running state detecting part (5) detects a running state of the fuel cell. An output power limit operating part (6) operates a limit of the output power produced by the fuel cell, based on the running state e.g., pressure of the gas detected in the running state detecting part (5). A commanded output power operating part (7) operates a commanded output power, the commanded output power being defined as a minimum value between an output from the output power limit operating part (6) and an output from the target electric power operating part (2).

Each driving circuit in a shift register includes an output unit, a precharge unit, a boosting unit, a gate voltage discharge unit, a gate line discharge unit, and an internal line netA. The output unit includes a TFT(F) that outputs a selection voltage to a gate line. The precharge unit includes a TFT(B) that outputs a control voltage for causing the TFT in the output unit to operate. The boosting unit boosts up a gate voltage of the TFT in the output unit through a capacitor (Cbst). The gate voltage discharge unit includes a TFT(K) that pulls down this gate voltage during a non-selection period while the gate line is not selected. The gate line discharge unit includes a TFT(L) that outputs a non-selection voltage to the gate line during the non-selection period while the gate line is not selected. The internal line is connected to a gate terminal of the TFT in the output unit, the precharge unit, the gate voltage discharge unit, and the boosting unit. A gate terminal of at least one of the TFTs in the precharge unit, the gate voltage discharge unit, and the gate line discharge unit is connected to an internal line in another driving circuit.

A lighting device includes: a power converting unit; a voltage measuring unit for measuring an output voltage from the power converting unit or a value equivalent to the output voltage; a current measuring unit for measuring an output current from the power converting unit or a value equivalent to the output current; and a control unit for controlling the power converting unit. When one of the output voltage and the output current of the power converting unit is changed by a specific magnitude per unit hour, the control unit determines that a change in a load status has occurred and controls the power converting unit by switching constant current control in which a measurement value of the current measuring unit is kept at a specific current designated value to constant voltage control in which a measurement value of the voltage measuring unit is kept at a specific voltage designated value.

A control method is disclosed that involves controlling zero-crossing operation of bridge arms in a UPS, wherein the UPS has a rectifying bridge with first and second switching transistors, a midline bridge arm with third and fourth switching transitors, and an inverter bridge arm with fifth and sixth switching transitors. The midline and rectifying bridge arms are controlled to cross zero synchronously. The inverter bridge arm is controlled to be disconnected during a period before a zero-crossing point of the rectifying bridge arm to a period after the zero-crossing point of the rectifying bridge arm. The periods before and after the zero-crossing point of the rectifying bridge arm are time differences between the zero-crossing points of the inverter bridge arm and the rectifying bridge arm. The influence of asynchronous zero-crossing between the PFC circuit and the inverter circuit on the UPS performance indices may be reduced by using the present control method.

A frequency detection device comprises a frequency halving circuit used for conducting frequency halving processing on a periodical signal to be detected to generate a frequency halving signal, a delaying circuit used for conducting delaying on the frequency halving signal to generate a delaying signal, a charging and discharging circuit used for conducting charging or discharging on the output end of the charging and discharging circuit when the delaying signal is first level and resetting the output end of the charging and discharging circuit when the delaying signal is second level and the frequency halving signal is the first level, a comparison circuit used for comparing first reference voltage and the output voltage of the charging and discharging circuit to generate a first comparison signal and comparing second reference voltage and the output voltage of the charging and discharging circuit to generate a second comparison signal when the delaying signal is the second level and an RS latch used for conducting latch processing on the first comparison signal and the second comparison signal. The frequency detection device saves detection time.