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EP0535797A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Insulated gate enhancement mode field effect transistor with slew-rate control on drain output

Assignee: STMicroelectronics lnc USA
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Filing: 1992-08-25
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Granted: —
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Expires: 2012-08-25
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Abstract

Abstract Voltage slew-rate control for inductive load connected to the drain of an insulated gate enhancement mode field effect transistor is disclosed. The voltage slew-rate control is accomplished by incorporating a current integrator between the gate and drain of the field effect transistor, thereby effectively annihilating the capacitance of the field effect transistor which has heretofore proven to be generally responsible for instability and oscillations when slew-rate control is attempted in such a circuit. The current integrator includes a capacitor and a current source in circuit with a high speed unity gain buffer amplifier. The buffer amplifier preferably has a low impedance through the frequencies of interest to prevent the natural resonances of stray capacitances with the inductive load. <IMAGE>

Inventors

  • 👤 Francesco Carobolante

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 03:23
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/16; H03K17/161; H03K17/165; H03K17/166

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 104 words
In combination with circuit means including an insulated gate enhancement mode field effect transistor means, said field effect transistor means including a gate, a source and a drain, an inductive load means connected in circuit with said drain of said field effect transistor, the improvement which comprises: load voltage slew rate control means comprising constant current integrator means, said constant current integrator means connected in circuit between said gate and said drain of said field effect transistor means, whereby, the local feedback at said gate of said field effect transistor means due to gate-drain capacitance is effectively annihilated by said constant current integrator means.
Claim 2
Dependent Claim 76 words
The combination of claim 1, wherein said current integrator means comprises capacitor means having one end connected in circuit between said load and said drain of said field effect transistor means, a current source connected in circuit with the other end of said capacitor means, a buffer amplifier means having a predetermined operating frequency range is connected in circuit between said other end of said capacitor means and said gate of said field effect transistor means.
Claim 3
Dependent Claim 14 words
The combination of claim 2, wherein said current source is a constant current source.
Claim 4
Dependent Claim 17 words
The combination of claim 2, wherein the buffer stage of said buffer amplifier means comprises NPN-type transistors.
Claim 5
Dependent Claim 31 words
The combination of claim 2, wherein said buffer amplifier means has a predetermined output impedance of less than about 500 ohms over the operating frequency range of said buffer amplifier means.
Claim 6
Dependent Claim 43 words
The combination of claim 5, wherein said buffer amplifier means has an operating frequency range such that the bandwidth of said buffer amplifier means is at least ten times the resonant frequency of said load means together with said field effect transistor means.
Claim 7
Dependent Claim 20 words
The combination of claim 2, wherein the buffer stage of said buffer amplifier means comprises a class AB-type amplification stage.

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