Murata Manufacturing Co., Ltd.

Fukami Patent Office

Yukio Maeba

Kiyoteru Igashira

Takahito Chinomi

Masashi Nakasaka

Shigeki Kasai

A DC power supply which is adapted to produce a DC main voltage between a main output terminal provided at one end of a first line and a ground terminal provided at one end of a second line; the power supply being characterized in that there is disposed a constant-voltage-drop means between the second line and the ground terminal; a third line extends from the second line side of the constant voltage drop means; and also an inverse polarity side output terminal is disposed at one end thereof so that an inverse polarity DC side voltage is adapted to be outputted between the inverse polarity side output terminal and the ground terminal, whereby main and side output voltage having opposite polarities can be produced through a simple construction.

DC power supply having bipolar outputs

A high-voltage power supply apparatus includes a transformer, and an input winding is turned on and off repeatedly by a switching element, and thereby an alternating current (AC) is generated in the input winding. By varying the duration of a turned-on state or a turned-off state of the switching element, an output voltage from the output winding of the transformer is regulated. A series connection of a first resistor and a transistor is connected between one end of the output winding and a reference potential. A second resistor is connected in parallel with the series connection. A medium voltage circuit is connected through a diode between the other end of the output winding and the reference potential, and a high voltage circuit is connected between a connection point of the medium voltage circuit and the diode and the reference potential. When the high voltage circuit is to be operated, the transistor is turned on, and a state of the switching element, and thereby, an input voltage of the transformer, is controlled based on a current flowing through the first and second resistors. When the high voltage circuit is not to be operated, the transistor is turned off, and the input voltage is controlled based on a current flowing through the second resistor.

High-voltage power supply apparatus

In a direct current power unit, a-c (alternating current) voltages outputted to secondary windings (28, 47) of transformers (26, 45) are rectified by rectifier diodes (30a, 30b), respectively, to output a positive d-c (direct current) voltage and a negative d-c voltage. The level of the positive d-c voltage is regulated by a first voltage regulator crcuit (34a) while the level of the negative d-c voltage is regulated by a second voltage regulator circuit (34b). A first switch (36a) and a first variable resistance (38a) as well as a second variable resistance (38b) and a second switch (36b) are connected in series to outputs of the first voltage regulator circuit and the second voltage regulator circuit, respectively. When the first switch is closed and the second switch is opened, the positive d-c voltage is outputted to an output terminal (44) from the first variable resistance through a backflow preventing diode (42a). On the other hand, when the first switch is opened and the second switch is closed, the negative d-c voltage is outputted to the output terminal from the second variable resistance through a backflow preventing diode (42b).

Direct current power unit

A high voltage power source for supplying a DC high voltage to a discharge tube, can detect an abnormality when created at the discharge tube side and stop its output. The high voltage power source is provided with a detector circuit which detects when the DC high voltage is larger than a predetermined reference value and a control circuit which cuts off the output of the DC high voltage in response to the above detection. When an abnormality occurs at the discharge tube, for example, non-operation or unstable operation occurs, since a load becomes lighter than normal, and the DC high voltage to be supplied to the discharge tube becomes higher than normal and is detected by the detector circuit so that the control circuit responds to the detected high voltage and cuts off the output of the DC high voltage.

High voltage power source for a discharge tube

An inventive regulated high-voltage power supply circuit comprises a push-pull oscillation circuit (30) including two transistors (TR4, TR5), a control circuit (20) for controlling voltage to be supplied to the oscillation circuit, a short detecting circuit (50) for detecting shorting in the secondary side of a high-voltage transformer thereby to attenuate output voltage from the control circuit and a time-constant circuit (60) for maintaining an attenuated state of the output voltage of the control circuit caused by the short detecting circuit after releasing of the shorting for a prescribed period of time. Since the osccillation circuit is of the push-pull type, the same can oscillate over the entire periods of positive and negative halfwaves of the AC waveform, thereby to increase outputted power. When shorting of the secondary side is detected, the output voltage of the control circuit is attenuated, and the attenuated state of the output voltage of the control circuit is maintained by the time-constant circuit even if the shorting detection is released, thereby to reduce the overcurrent per unit time.

Regulated high-voltage power supply

A high-voltage power supply apparatus comprises a transformer, and an input winding is turned on and off repeatedly by a switching element, and thereby an alternating current (AC) is generated in the input winding. By varying a turned-on state or a turned-off state of the switching element, a voltage outputted from an output winding of the transformer is regulated. An output voltage of a dividing circuit which is constituted with two series resistors and divides an output voltage is compared with a reference voltage by a comparator, and a control signal in accordance with an output of the comparator is given to the switching element. A switching circuit is connected to one of the resistors of the voltage dividing circuit in parallel. When a switching circuit is turned on, the output voltage of the voltage dividing circuit becomes relatively small and a voltage of the AC generated in the input winding becomes high, and therefore a voltage of a magnitude required for both the high voltage circuit and the medium voltage circuit is obtained from the output winding. When the switching circuit is turned off, the voltage of the AC becomes low, and therefore a voltage required only for the medium voltage circuit is obtained from the output winding.

Apparatus for supplying high and medium output voltages with a single

A regulated high-voltage power supply comprising a tuned-collector type oscillation circuit (3) having an oscillation transistor (TR4), a control circuit (2) for controlling the base current of the oscillation transistor (TR4), a resistance circuit (4) for supplying the base current to the oscillation transistor (TR4) in response to the output from the control circuit (2) and a protection circuit (5) having a protective transistor (TR3) for partially receiving the output from the resistance circuit (4) to attenuate the output from the control circuit (2) when short-circuiting is caused in the area of a load (RL). The protective transistor (TR3) is made conductive upon short-circuiting in the area of the load (RL). In order to delay the oscillation starting time of the oscillation circuit (3) immediately after releasing of the short-circuiting, provided is a time-constant circuit (51) formed by a delay capacitor (C51) and discharge resistors (R51, R52) for discharging the storage charge of the delay capacitor.

Regulated high-voltage power supply with output shorting prevention

A stabilizing power-supply circuit adapted to apply the output signals of a comparison amplifier directly upon the base circuit of the oscillation transistor of an oscillating circuit through a zener diode. The oscillation is reduced to a given output voltage during the no-load thereby to protect the power-supply apparatus.

Growing community of inventors

Nagaokakyo, Japan

Yukio Maeba