Claims
- 1. A power line connection circuit for controlling a connection of a power supply line to a load circuit, comprising:
- a MOS transistor connecting said power supply line to said load circuit, the conductance of said MOS transistor being changeable by applying a signal to a gate of said MOS transistor;
- voltage conversion means for converting a voltage of said power supply line and applying the converted voltage to said gate of said MOS transistor; and
- clamp means for limiting, and simultaneously, for allowing said converted voltage output from said voltage conversion means to be less than or equal to a sum of a predetermined voltage plus the voltage of said power supply line;
- wherein said voltage conversion means is a charge-pump circuit and
- said clamp means includes a constant voltage drop circuit, connected to said charge pump and said gate of said MOS transistor at a first end;
- a first transistor, connected to a second end of said constant voltage drop circuit and ground, conductance of said first transistor controlled by a connection to the power supply; and
- a second transistor connected to said second end of said constant voltage drop circuit and ground, conductance of said second transistor controlled by a connection to said MOS transistor.
- 2. The power line connection circuit of claim 1, wherein
- said voltage drop circuit includes one or more diodes connected in series.
- 3. The power line connection circuit of claim 2, wherein said first and second transistors are bipolar junction transistors, each having a collector connected to ground, each having an emitter connected to said second end of said constant voltage drop circuit, said first transistor having a base connected to the power supply line and said second transistor having a base connected to said MOS transistor.
- 4. A switch IC for controlling a connection of a power supply line to a load circuit, comprising:
- a MOS transistor connecting said power supply line to said load circuit, the conductance of said MOS transistor being changed by applying a signal to a gate of said MOS transistor;
- voltage conversion means for convening a voltage of said power supply line and applying said converted voltage to said gate of said MOS transistor; and
- clamp means for limiting, and simultaneously, for allowing said convened voltage output from said voltage conversion means to be less than or equal to a sum of a predetermined voltage plus the voltage of said power supply line;
- wherein said voltage conversion means is a charge-pump circuit and
- said clamp means includes a constant voltage drop circuit, connected to said charge pump and said gate of said MOS transistor at a first end;
- a first transistor, connected to a second end of said constant voltage drop circuit and ground, conductance of said first transistor controlled by a connection to the power supply; and
- a second transistor connected to said second end of said constant voltage drop circuit and ground, conductance of said second transistor controlled by a connection to said MOS transistor.
- 5. The IC switch of claim 4, wherein
- said voltage drop circuit includes one or more diodes connected in series.
- 6. The switch IC of claim 5, wherein said first and second transistors are bipolar junction transistors, each having a collector connected to ground, each having an emitter connected to said second end of said constant voltage drop circuit, said first transistor having a base connected to the power supply line and said second transistor having a base connected to said MOS transistor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-126271 |
May 1993 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 08/249,022 filed May 25, 1994, now abandoned.
US Referenced Citations (21)
Foreign Referenced Citations (5)
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EPX |
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Non-Patent Literature Citations (1)
Entry |
Low-Cost Circuits Maintain Quality of Multiplexed Video Signals by Greg Schaffer, 2119 E.D.N. Electrical Design News 32 (1987) May 14, No. 10, pp. 193-200. |
Continuations (1)
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Number |
Date |
Country |
Parent |
249022 |
May 1994 |
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