摘要:
A motor drive method and apparatus for reducing noise of a motor. The motor drive apparatus includes first, second and third half bridge circuits. Each of the first, second and third half bridge circuits includes a first transistor which is adapted to form a current path between a first operational potential and an output terminal thereof and a second transistor which is adapted to form a current path between a second operational potential and the output terminal thereof. Each of the output terminals are connected to the corresponding drive coil of a motor. Each of the first and second transistors includes a control terminal to which a control signal is supplied. The motor drive apparatus detects a counter-induced voltage of the drive coil corresponding to the second half bridge circuit by supplying control signals to the first and second transistors thereof for making each current path therein a non-conducting state, and for forming current paths in the first transistor of the first half bridge circuit and in the second transistor of the third half bridge circuit respectively. Further the motor drive apparatus cuts off the current path of the first transistor in the first half bridge circuit, forms it and cuts it off again by supplying a control signal thereto after start of supplying a control signal for forming the current path of the first transistor in the second half bridge circuit. A control signal for forming the current path is supplied to the control terminal of the second transistor in the third half bridge circuit.
摘要:
A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.
摘要:
A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.
摘要:
A pulse current having such a short duration as the rotor does not react is passed through field coils of respective phases of a brushless motor in first and second, mutually opposite, directions sequentially, voltages induced, by the pulse currents in two directions at each of the field coils of the non-conducting phase are combined, the polarity of a combined voltage is detected, and a field coil pair where a current is to be passed to start the motor is determined based on the result of detection for each of field coil of the non-conducting phase.
摘要:
Two output transistors constituting a push-pull output amplifier circuit are connected in series between a power supply and a grounded point, and an output terminal is disposed at a point where the two output transistors are commonly connected. An operation detector circuit detects the operation of one output transistor. A level detector circuit detects a d-c voltage level at the output terminal. The two output transistors are driven by a drive circuit in a push-pull manner. The output of the operation detector circuit and the output of the level detector circuit control the drive circuit via a control circuit. When the operation detector circuit detected the fact that the operation of one output transistor has deviated beyond a predetermined detection level, the control circuit works to confine the operation of the abovementioned output transistor within a predetermined restriction level via the drive circuit. The power loss in the restriction level is smaller than the power loss in the detection level. During a period in which the output terminal is short-circuited to the grounded point in a d-c manner, the level detector circuit so controls the control circuit that the operation of the abovementioned one output transistor is confined within the restriction level.
摘要:
A first resistor and a second resistor are connected in series across the collector and emitter of a transistor that is to be protected thereby to detect a voltage across the collector and emitter thereof, as well as to detect a collector current or an emitter current thereof, and a third resistor is connected to be collector or the emitter of the transistor that is to be protected. A detector transistor is driven by a voltage produced across the second and third transistors. A fourth resistor is connected between the collector and the base of the detector transistor, one end of the fourth resistor connected to the base of the detector transistor being connected to a constant-current circuit, and the other end of the fourth resistor connected to the collector of the detector transistor being connected to the base of a control transistor. The emitter of the control transistor is connected to the collector or the emitter of the transistor that is to be protected via the third resistor. The collector of the control transistor directly or indirectly controls the base current of the transistor that is to be protected.
摘要:
In a transistor circuit comprising a monolithic semiconductor integrated circuit including at least one first conductivity type transistor having a base connected to a signal input terminal, a collector connected to an output terminal and also connected to a source voltage supply terminal through a collector load resistance, and an emitter connected to a reference potential through an emitter resistance, and a voltage dividing resistance circuit connected externally to the integrated circuit to establish a base-emitter biasing voltage of the first conductivity type transistor, another resistance element is provided between the source voltage supply terminal and the load resistance and a second conductivity type transistor is provided with the emitter and the collector connected to the interconnection point of the two resistances and the reference potential, respectively, and the base connected to the emitter of the first conductivity type transistor, integrating a source voltage ripple removing circuit in the integrated circuit. This transistor circuit is adapted for a high output power integrated circuit and provides a wide range of operable source voltage as well as the removal of the ac ripple voltage component of the voltage source and the reduction in the number of external connecting pins.
摘要:
When a current that flows into a power output element is greater than a predetermined value, pulse width-modulated signals are formed which vary in inverse proportion to the current value in order to drive the power output element. When an excess current flows into the power output element, therefore, the power output element is allowed to intermittently operate for only short periods of time, and the current can be decreased during the current-limiting operation.
摘要:
An acoustic monolithic IC, which is enabled by a simple modification of the external circuit thereof to realize either the amplification of the left and right channels of stereophonic signals or the application to a balanced transformer-less (BTL) amplifier circuit, is composed of first and second differential amplifier circuits each having non-inverting and inverting inputs and of first and second amplifier output circuits each having non-inverting and inverting inputs.The first differential amplifier circuit has its non-inverting and inverting inputs led as the first and second input terminals of the acoustic monolithic IC to the outside thereof whereas the second differential amplifier circuit has its non-inverting and inverting inputs led as the third and fourth input terminals of the acoustic monolithic IC to the outside thereof.The output signals of the first and second differential amplifier circuits are impressed upon the non-inverting inputs of the first and second amplifier output circuits, respectively. The inverting inputs of the first and second amplifier output circuits are led as first and second feedback terminals to the outside of the acoustic monolithic IC so as to determine the gains and output DC levels of those amplifier output circuits.The output terminals of the first and second amplifier output circuits are led as the first and second output terminals of the acoustic monolithic IC to the outside thereof.
摘要:
A signal composing circuit suitable for a decoder device of a 4-channel matrix stereophonic system comprises two types of circuit units, one being a differential type circuit in which the common emitters are connected to ground through constant current means, the other having a like circuit arrangement as the differential type circuit but having constant current means shunted with a capacitor so as to ground the common emitters for A.C. signals. The signal composing circuit is suited for monolithic integrated circuits.