Substrate biasing circuit that utilizes a gated diode to set the bias on the substrate
First Claim
1. A substrate biasing circuit formed in a semiconductor material of a first conductivity type, the circuit comprising:
- a first well of a second conductivity type formed in the semiconductor material;
a second well of the first conductivity type formed in the first well;
a gated diode formed in the second well;
a cell diode connected between the gated diode and ground; and
an oscillator connected to the gated diode.
2 Assignments
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Accused Products
Abstract
A substrate biasing circuit utilizes a gated diode and a detection transistor to set the potential on a substrate to a desired substrate bias level. The potential on the substrate is set to the desired substrate bias level by applying a series of pulses to the gated diode. Each of the pulses applied to the gated diode causes a fixed amount of charge to be injected into the substrate. When the potential on the substrate has reached the desired substrate bias level, the pulses are insufficient to cause any further charge to be injected into the substrate. The detection transistor is used to determine when the potential is at the desired substrate bias level by biasing the transistor to output a current that corresponds to the potential on the substrate.
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Citations
18 Claims
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1. A substrate biasing circuit formed in a semiconductor material of a first conductivity type, the circuit comprising:
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a first well of a second conductivity type formed in the semiconductor material; a second well of the first conductivity type formed in the first well; a gated diode formed in the second well; a cell diode connected between the gated diode and ground; and an oscillator connected to the gated diode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for biasing a semiconductor material to a desired substrate bias level from an initial level with a substrate biasing circuit, the circuit comprising:
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a first well of a second conductivity type which is formed in a semiconductor material of a first conductivity type; a second well of the first conductivity type formed in the first well; a gated diode formed in the second well; a cell diode connected between the gated diode and ground; and an oscillator connected to the gated diode; the method comprising the step of applying pulses to the gated diode, the pulses being insufficient to cause charge to flow through the cell diode when the potential on the second well is equal to the desired substrate bias level. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification