High-voltage circuit for insulated gate field-effect transistor
First Claim
1. A high-voltage MOSFET (insulated gate field-effect transistor) circuit wherein n MOSFETs are connected in series by electrically connecting a drain of the m-th (1≦
- m≦
n-1) MOSFET and a source of the (m+1)-th MOSFET, a source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the MOSFET circuit, a drain of the n-th MOSFET being used as a drain terminal of the MOSFET circuit, and wherein divided voltages obtained by dividing a voltage applied across the source and drain terminals, by means of a first voltage divider circuit in which a plurality of resistors are connected in series are applied to gates of the second to n-th MOSFETs;
the high-voltage MOSFET circuit being characterized by comprising means for holding the second to n-th MOSFETs in an "on" state by applying bias voltages from a bias voltage supply to the respective gates of said second to n-th MOSFETs.
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Abstract
A high-voltage circuit for insulated gate field-effect transistors (MOSFETs) is provided wherein two MOSFETs are connected in series, the source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the high-voltage circuit, the drain of the second MOSFET being used as a drain terminal of the circuit. First and second resistors are connected in series between the source terminal and the drain terminal, and a biasing voltage supply is connected between the juncture of both the resistors and the gate of the second MOSFET. By virtue of these connections the "on" resistance of the high-voltage circuit is improved due to the effect of the biasing voltage effect in bringing the second MOSFET into an "on" condition.
124 Citations
12 Claims
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1. A high-voltage MOSFET (insulated gate field-effect transistor) circuit wherein n MOSFETs are connected in series by electrically connecting a drain of the m-th (1≦
- m≦
n-1) MOSFET and a source of the (m+1)-th MOSFET, a source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the MOSFET circuit, a drain of the n-th MOSFET being used as a drain terminal of the MOSFET circuit, and wherein divided voltages obtained by dividing a voltage applied across the source and drain terminals, by means of a first voltage divider circuit in which a plurality of resistors are connected in series are applied to gates of the second to n-th MOSFETs;
the high-voltage MOSFET circuit being characterized by comprising means for holding the second to n-th MOSFETs in an "on" state by applying bias voltages from a bias voltage supply to the respective gates of said second to n-th MOSFETs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- m≦
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10. A high-voltage MOSFET (insulated gate field-effect transistor) circuit wherein n MOSFETs are connected in series by electrically connecting a drain of the m-th (1≦
- m≦
n-1) MOSFET and a source of the (m+1)-th MOSFET, a source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the MOSFET circuit, a drain of the n-th MOSFET being used as a drain terminal of the MOSFET circuit, and wherein divided voltages obtained by dividing a voltage applied across the source and drain terminals, by means of a first voltage divider circuit in which a plurality of resistors are connected in series are applied to gates of the second to n-th MOSFETs;
the high-voltage MOSFET circuit being characterized by comprising means for applying bias voltages from a bias voltage supply to the respective gates of said second to n-th MOSFETs, wherein said bias voltage supply means is connected to said gates through rectifiers.
- m≦
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11. A high-voltage MOSFET (insulated gate field-effect transistor) circuit wherein n MOSFETs are connected in series by electrically connecting a drain of the m-th (1≦
- m≦
n-1) MOSFET and a source of the (m+1)-th MOSFET, a source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the MOSFET circuit, a drain of the n-th MOSFET being used as a drain terminal of the MOSFET circuit, and wherein divided voltages obtained by dividing a voltage applied across the source and drain terminals, by means of a first voltage divider circuit in which a plurality of resistors are connected in series are applied to gates of the second to n-th MOSFETs;
the high-voltage MOSFET circuit being characterized by comprising means for applying bias voltages from a bias voltage supply to the respective gates of said second to n-th MOSFETs, wherein said means for applying bias voltages is a circuit which divides a voltage fed from a bias voltage supply terminal, by means of a second voltage divider circuit with a plurality of resistors connected in series and which applies the divided voltages to said respective gates as said bias voltages.
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12. A high-voltage MOSFET (insulated gate fieldeffect transistor) circuit wherein n MOSFETs are connected in series by electrically connecting a drain of the m-th (1≦
- M≦
n-1) MOSFET and a source of the (m+1)-th MOSFET, a source and gate of the first MOSFET being respectively used as a source terminal and gate terminal of the MOSFET circuit, a drain of the n-th MOSFET being used as a drain terminal of the MOSFET circuit, and wherein divided voltages obtained by dividing a voltage applied across the source and drain terminals, by means of a first voltage divider circuit in which a plurality of resistors are connected in series are applied to gates of the second to n-th MOSFETs;
the high-voltage MOSFET circuit being characterized by comprising means for applying bias voltages from a bias voltage supply to the respective gates of said second to n-th MOSFETs, wherein an impedance element having a threshold value is inserted between the adjacent resistors of said first voltage divider circuit, whereby said bias voltages are applied to said respective gates of said second to n-th MOSFETS.
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Specification