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

Disclosed a multi-output type DC / DC converter including: a reactor connected to a direct-current power supply; a first switching circuit composed of switches to apply a current to the reactor; a second switching circuit composed of switches to switch an output from the reactor to any one of output terminals; output voltage detection sections to detect voltages of the output terminals; comparison circuits to compare outputs with a waveform signal of a predetermined frequency; and an output selection circuit to receive inputs form comparison circuits, and to select an output of a comparison circuit, the output having the earliest rise or the earliest fall, so as to generate a control signal pertaining to on and off of the first and / or second switching circuit, wherein a current generated by a discharge of energy accumulated in the reactor is output to any one of the terminals in accordance with the control signal.

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.

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.

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.

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.

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 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 pop-free single-ended output class-D amplifier includes: an input signal generator for generating an input signal; a power supply for supplying input power; a reference voltage generator for generating a reference voltage; a gain-adjustable stage for generating an amplified signal according to the reference voltage and adjusting a gain of the single-ended output class-D amplifier; a pulse width modulation module for outputting a pulse width modulation signal according to the reference voltage, the amplified signal, and the input power; a low-pass filter for low-pass filtering the pulse width modulation signal to generate an output voltage; and a logic controller for generating at least one control signal to control the reference voltage generator, the gain-adjustable stage, and the pulse width modulation module according to the input power, the reference voltage, and the pulse width modulation signal.

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.