摘要:
An error amplifier generates an error signal VERR that corresponds to the difference between a feedback signal VFB and a predetermined reference voltage VREF. A first oscillator generates a first cyclic signal VOSC1 having a sloping segment and a first frequency. A second oscillator generates a second cyclic signal VOSC2 having a sloping segment and a second frequency that is lower than the first frequency. A first pulse modulator generates a first pulse signal having a pulse width that corresponds to the error signal VERR, and clamps its pulse width such that it does not become smaller than a first minimum pulse width. A second pulse modulator generates a second pulse signal having a pulse width that corresponds to the error signal VERR. A synthesizing unit combines the first pulse signal and the second pulse signal so as to generate a driving pulse signal.
摘要:
An excess current protection circuit which can change a limited current corresponding to an output voltage by simple constitution. A power supply device (100) is provided with a regulator (10), which regulates the output voltage to be constant based on a reference voltage, and an excess current protection circuit (20). The regulator (10) is a general three-terminal regulator which includes an output transistor (14), an error amplifier (12) and resistors (R1, R2). The excess current protection circuit (20) detects an output current (lout) by a first transistor (M1), and converts it into a voltage by a variable resistor (Rvar). A voltage comparator (24) compares the voltage with a threshold voltage (Vth) corresponding to a limited current and detects an excess current status. A current adjusting circuit (26) drops driving performance of the regulator (10) when the excess current status is detected, and protects the circuit. The resistance value of the variable resistor (Rvar) is set based on an output voltage (Vout), and a value of the limited current is changed corresponding to the output voltage.
摘要:
A power supply unit comprises a series regulator and a switching DC-DC converter controlled by a PWM signal and connected in parallel with the series regulator, which are switchably enabled by a mode instruction signal depending on the magnitude of a load current. In switching the series regulator and the DC-DC converter, they are simultaneously enabled for a predetermined overlapping time. Further, in changing the operating condition of the DC-DC converter, the width of the PWM signal is shortened to extend the dead time of the DC-DC converter by a predetermined period, thereby suppressing free oscillations and accompanying overshoots that could take place in the power supply unit during switching.
摘要:
A control system in which a judgment is made such that (i) a vehicle is in a forward drive control state, on condition that the forward/reverse drive lever is placed in the forward drive position and the actual speed ratio exceeds a specified small value in a forward drive direction, (ii) the vehicle is in a reverse drive control state on condition that the lever is placed in the reverse drive position and the actual speed ratio exceeds a specified small value in a reverse drive direction, (iii) the vehicle is in an engine brake control state, on condition that the lever is placed in the neutral position and the actual speed ratio exceeds the specified small value in the forward or reverse drive direction, (iv) the vehicle is in an FR shift control state, on condition that the lever is placed in the forward or reverse drive position and the actual speed ratio exceeds the specified small value in the reverse or forward drive direction, and (v) the vehicle is in a neutral control state, on condition that the lever is placed in the neutral position and the actual speed ratio does not exceed the specified small values in the forward and reverse drive directions.
摘要:
A driving control device in a crawler type tractor comprises a lever capable of being operated in the forward or reverse (backward) direction and capable of being operated in the right or left direction when the lever is operated so as to move to the end of the forward or reverse direction, and a speed-stage command device capable of generating and transmitting commands for speed stages for the forward and the reverse directions. When a first sensor detects the lever operation in the forward or reverse direction; the transmission speed stages can be selected in accordance with the first sensor output and the output of the speedstage command device, and the operation amount of the lever in the right or left direction is detected by a second sensor so that steering clutches of the tractor can be controlled in accordance with the output of the second sensor.
摘要:
The present invention improves the efficiency of a switching power supply in a light load. A control circuit is configured to repeat a driving duration enabling the switching element to be switched and a stop duration stopping the switching in a light load state. A pulse signal generating portion generates a driving pulse signal, in which the driving pulse signal at least includes a pulse in the driving duration, and the lighter a load is, the less the number of pulses in the driving duration is. A first driver drives a first switching transistor according to the at least one pulse in the driving pulse signal other than predetermined K pulses (K is a natural number). The K pulses are in the driving pulse signal when the number of the pulses is reduced to K.
摘要:
A charging circuit receives electric power from a solar battery, and charges a secondary battery. A charging current detection unit generates a detection signal that corresponds to a charging current supplied from a DC/DC converter to the secondary battery. A control circuit generates a reference voltage that corresponds to the detection signal. A driving unit generates a pulse signal having a duty ratio that is adjusted such that the voltage output from the solar battery matches the reference voltage, and performs switching of a switching transistor according to the pulse signal. A control circuit adjusts the reference voltage such that the reference voltage becomes greater.
摘要:
A semiconductor device capable of suppressing diffusion of noise signals is provided. The semiconductor device has a BGA (Ball Grid Array) structure in which a plurality of electrode terminals to do input and/or output of signals from and to the outside is arranged in a matrix form. The semiconductor device includes a noise source electrode terminal to do input and/or output of signals, and low-impedance electrode terminals. The noise source electrode terminal does input and/or output of signals acting as a source of noises. The low-impedance electrode terminal are arranged so as to be adjacent to the noise source electrode terminal in a vertical or horizontal direction. The low-impedance electrode terminal is arranged so as to be adjacent to the noise source electrode terminal in a slanting direction. In order to make the low-impedance electrode terminals and be of a low impedance, these terminals and are connected to a grounding potential and connected through a capacitor having a large capacitance to the grounding potential. If necessary, the low-impedance electrode terminals are arranged in a place surrounding the electrode terminal that is susceptible to noises.
摘要:
A steering system for use in a track-laying vehicle comprising: a steering motor that is forwardly and reversely rotatable and designed to drive crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a forward/reverse drive state detector for detecting whether the vehicle is in its forward drive state or reverse drive state; a lateral turn instructing device for instructing right turn or left turn of the vehicle; and a steering motor forward/reverse rotation control unit for determining the forward or reverse rotation of the steering motor in accordance with the forward or reverse drive state of the vehicle detected by the forward/reverse drive state detector, such that the vehicle turns to the right or left in response to a right turn instruction or left turn instruction released from the lateral turn instructing device.
摘要:
Upon detection of execution of operation for stopping a vehicle during its running state and of a drop in an actual speed ratio below a predetermined value, the actual speed ratio being the actual ratio of the revolution speed of an output shaft to the revolution speed of a power source, a feedback amount is determined, setting the integral component of the difference between a target motor speed ratio and an actual motor speed ratio to zero. Based on the feedback amount thus determined, an operation amount for controlling the angle of a swash plate is computed. With this amount, the angle of the swash plate is controlled.