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EP0029681A2
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Bias-voltage generator
Assignee: Fujitsu Ltd
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Filing: 1980-11-11
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Granted: —
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Expires: 2000-11-11
Abstract
Abstract A bias-voltage generator is disclosed. The bias-voltage generator is comprised of an oscillator, a charge pumping circuit which absorbs electric charges, accmulated in the semiconductor substrate, by cooperating with the oscillator, via a coupling capacitor. The oscillator contains therein a means for varying the oscillating frequency thereof in accordance with the variation of the voltage level of the semiconductor substrate. Said means is preferably comprised of a CR circuit fabricated by a variable resistor (R) and a capacitor (C). The variable resistor is made of a MOSFET. The gate electrode of the MOSFET is directly connected to the semiconductor substrate.
Inventors
- 👤 Setsuo Kurafuji
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 21:06
CPC Classifications
H; H10; H10D; H10D89/00; H10D89/211; H10D89/213; H10D89/215; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/205
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
109 words
A bias-voltage generator applying a bias voltage to a semiconductor substrate being provided with a MOS integrated circuit thereon comprising: an oscillator producing an oscillating AC signal; a coupling capacitor connecting, at one end thereof, to the output of said oscillator, and; a charge pumping circuit for absorbing electric charges, accumulated in said semiconductor substrate, connecting, firstly to the other end of said coupling capacitor, secondly to a ground of said MOS integrated circuit and thirdly to said semiconductor substrate, characterized in that the oscillating frequency of said oscillating AC signal, produced from said oscillator, varies in proportion to the variation of the voltage level of said semiconductor substrate.
Claim 2
Dependent Claim
109 words
A bias-voltage generator applying a bias voltage to a semiconductor substrate being provided with a MOS integrated circuit thereon comprising: an oscillator producing an oscillating AC signal; a coupling capacitor connecting, at one end thereof, to the output of said oscillator, and; a charge pumping circuit for absorbing electric charges, accumulated in said semiconductor substrate, connecting, firstly to the other end of said coupling capacitor, secondly to a ground of said MOS integrated circuit and thirdly to said semiconductor substrate, characterized in that the oscillating frequency of said oscillating AC signal, produced from said oscillator, varies in proportion to the variation of the voltage level of said semiconductor substrate.
Claim 3
Dependent Claim
41 words
A generator as set forth in claim 1, wherein said oscillator contains therein and cooperates therewith a means for varying the frequency of said oscillating AC signal, which means responds to the variation of the voltage level of said semiconductor substrate.
Claim 4
Dependent Claim
55 words
A generator as set forth in claim 2, wherein said means for varying the frequency of said oscillating A C signal is a CR circuit, comprised of a capacitor (C) and a variable resistor (R), the resistance value of the resistor varies in accordance with the variation of the voltage level of the semiconductor substrate.
Claim 5
Dependent Claim
29 words
A generator as set forth in claim 3, wherein said variable resistor is made of a MOSFET, the gate electrode of which is directly connected to the semiconductor substrate.
Claim 6
Dependent Claim
24 words
A generator as set forth in claim 3, wherein said CR circuit is mounted on the semiconductor substrate together with said MOS integrated circuit.
Claim 7
Dependent Claim
51 words
A generator as set forth in claim 4, wherein said oscillator is fabricated by odd number inverters, at least one CR circuit is inserted between at least one pair of adjacent inverters, these inverters and at least one CR circuit are connected in series so as to form a ring oscillator.
Claim 8
Dependent Claim
48 words
A generator as set forth in claim 4, wherein said oscillator is formed as a multivibrator, comprised of pair of MOSFETs, pair of load transistors and two said CR circuits, said MOSFETs are interconnected with each other via said CR circuits, at respective drains and gate electrodes thereof.
Claim 9
Dependent Claim
57 words
A generator as set forth in claim 6, wherein each of said inverters is fabricated by both a load MOSFET and a MOSFET, the former load MOSFET is made of a depletion-type MOSFET, the latter MOSFET is made of an enhancement-type MOSFET, the MOSFET for comprising at least one CR circuit is made of a depletion-type MOSFET.
References Cited (Backward Citations)
No citation records indexed.
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