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US 4,366,470 AGranted
Converter
AssigneesHitachi, Ltd., Hitachi Microcomputer Engineering Ltd.
InventorsAkira Takanashi, Yasuhiko Ishigami
Life of this patent
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Abstract
A converter includes a voltage selector which employs IGFETs as voltage switching elements, and a controller which controls the IGFETs. Each of the IGFETs in the voltage selector is made either the P-channel type or the N-channel type, depending upon a voltage level to be thereby switched and a level of a binary signal supplied from the controller. As a result, a voltage of comparatively great level can be switched by a binary signal of small level amplitude.
Claims15
An electronic sound generator comprising:
- first and second converters, each comprising:
- a plurality of input points supplied with voltages of levels different from one another, a single common output point, and a plurality of insulated-gate field effect transistors with their source--drain paths connected between said plurality of input points and said common output point;
- and
- a driving circuit which provides binary signals of a plurality of bits for controlling "on" and "off" states of said plurality of insulated-gate field effect transistors,
- wherein each of said plurality of insulated-gate field effect transistors has its conductivity type determined to permit switching each said transistor into the "on" state by a level of a binary signal affording a greater level difference relative to the voltage to be switched by said each transistor;
- a reference signal generator having an output terminal for providing a plurality of digital reference signals representative of different sounds;
- means for coupling said digital reference signals from said output of said reference signal generator directly to the driving circuit of said first converter;
- an inverter coupled between the output terminal of said reference signal generator and the driving circuit of said second converter to provide inverted digital reference signals from the reference signal generator to said driving circuit of the second converter;
- an oscillator for producing an audio frequency signal at an output terminal;
- mixing means coupled to receive the outputs of said first and second converters and said oscillator to produce a single mixed output signal V.sub.0 by mixing the respective outputs of said first and second converters and said oscillator;
- and
- transducer means coupled to receive the output signal V.sub.0 from said mixing means to produce a sound from said output signal V.sub.0.
9 more elements
An electronic sound generator comprising:
- a first insulated gate field effect transistor of p-channel type having a drain coupled to an output point, a gate, and a source;
- a second insulated gate field effect transistor of n-channel type having a drain coupled to the output point, a gate coupled to the gate of the first insulated gate field effect transistor, and a source;
- a first variable resistance circuit having a first output terminal connected to a first power supply terminal, a second output terminal connected to a source of the first insulated gate field effect transistor, and a control terminal;
- a second variable resistance circuit havving a first output terminal connected to a second power supply terminal, a second output terminal connected to a source of the second insulated gate field effect transistor, and a control terminal;
- a first feedback element connected between the output point and the gates of the first and second insulated field effect transistors;
- and
- a second feedback element connected between the gates of the first and second insulated gate field effect transistors and an input point to which an input signal is applied,
- wherin a level ratio of an output signal derived from the output point and the input signal is varied by the resistances of the first and second variable resistance circuits.
5 more elements
Dependencies are inferred from the claim text.