Capacitive load driving device
AssigneesHitachi, Ltd., Hitachi Engineering Co., Ltd.
InventorsMitsuhiko Okutsu, Tatsuo Shimura, Tadaaki Kariya
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Abstract
A device for driving a capacitive load, comprising a first switching element responsive to an external control signal for selectively conducting a charge current therethrough to the load, a second switching element responsive to the external control signal for conducting a discharge current from the load and a generator for generating from the discharge current a cutoff signal to be applied to the first switching element to ensure turn-off of the latter.
Claims13
A device for driving a capacitive load in response to an external control signal, comprising:
- charging circuit means being connectable with the capacitive load for charging the latter and including a switching element, said switching element being arranged to be rendered electrically conductive to supply a charge current to the capacitive load when the device receives said control signal;
- and
- discharging circuit means connectable with the capacitive load for discharging the latter with a discharge current passing therethrough when said control signal ceases, said discharging circuit means including means for generating a cutoff signal from said discharge current and applying the cutoff signal to said switching element to ensure turn-off of said switching element, in which said switching element is constituted by a unidirectional tetrode thyristor having an anode connectable with a power source, a cathode connectable with the capacitive load, a first gate for receiving said control signal and a second gate, and said cutoff signal generating means is constituted by a diode having its anode connected with the cathode of said thyristor and its cathode connected with said second gate.
A switching circuit for a capacitive load, comprising:
- a thyristor having a gate, and a cathode, responsive to an external control signal to selectively conduct a charge current to the capacitive load;
- a switch responsive to said external control signal to conduct a discharge current from the capacitive load;
- and
- means connected with said thyristor and passing therethrough said condcuted discharge current to generate therefrom a cutoff signal to be applied to said thyristor to ensure turn-off of the latter.
A device for driving a capacitive load in response to an external control signal, comprising:
- charging circuit means being connectable with the capacitive load for charging the latter and including a switching element, said switching element being arranged to be rendered electrically conductive to supply a charge current to the capacitive load when the device receives said control signal;
- and
- discharging circuit means connectable with the capacitive load for discharging the latter with a discharge current passing therethrough when said control signal ceases, said discharging circuit means including means for generating a cutoff signal from said discharge current and applying the cutoff signal to said switching element to ensure turn-off of said switching element, in which said switching element is constituted by a unidirectional tetrode thyristor having a cathode connectable with a power source, an anode connectable with the capacitive load, a first gate and a second gate for receiving said control signal, and said cutoff signal generating means is constituted by a diode having its anode connected with the first gate of said thyristor and its cathode connected with the anode of said thyristor.
Dependencies are inferred from the claim text.