Method and apparatus for detecting an operating voltage level in an integrated circuit
AssigneeSGS-Thomson Microelectronics S.A.
InventorsRichard Fournel, Mathieu Lisart
Life of this patent
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Abstract
A Zener diode is used to simplify a circuit for detecting the level of an operating voltage with respect to a specified range of use. The semiconductor junction of this Zener diode is biased alternately by one voltage or another. Under these conditions, the avalanche voltage of this Zener diode changes. The operating voltage to be monitored is connected to the cathode of this Zener diode. If the monitored operating voltage is higher than the avalanche voltage of this Zener diode, the diode alternately conducts. If the operating voltage is outside this range, this diode is either permanently on or permanently off. The variations that result therefrom are detected to report whether the operating voltage is correct.
Claims26
A detection circuit for detecting a voltage level of an operating voltage in an integrated circuit, the detection circuit comprising;
- a diode having
- a semiconductor junction,
- a control terminal, electrically coupled to the semiconductor junction, that receives a bias signal to control an avalanche voltage of the diode,
- a cathode region of a first conductivity type, coupled to the operating voltage of the integrated circuit,
- an anode region of a second conductivity type, adjacent the cathode region such that the semiconductor junction is formed between the anode region and the cathode region, and
- an output, coupled to the anode region, having a voltage level that is a function of the operating voltage level and the avalanche voltage of the diode;
- and
- a biasing circuit, coupled to the control terminal, that provides the diode with the bias signal having a bias voltage with at least one bias value.
A detection circuit for detecting a voltage level of an operating voltage in an integrated circuit, the detection circuit comprising:
- a diode having
- a semiconductor junction,
- a control terminal, electrically coupled to the semiconductor junction, that receives a bias signal to control an avalanche voltage of the diode,
- a cathode region of a first conductivity type, coupled to the operating voltage of the integrated circuit,
- an anode region of a second conductivity type, adjacent the cathode region such that the semiconductor junction is formed between the anode region and the cathode region, and
- an output, coupled to the anode region, having a voltage level that is a function of the operating voltage level and the avalanche voltage of the diode;
- and
- a biasing circuit, coupled to the control terminal, that provides the diode with the bias signal having a bias voltage with at least one bias value wherein the biasing circuit includes a logic circuit, and a number of capacitors cascaded in series and coupled to the logic circuit, coupled to the control terminal of the diode, coupled to a first reference voltage of the integrated circuit, and coupled to a second reference voltage of the integrated circuit.
A detection circuit for detecting a voltage level of an operating voltage in an integrated circuit, the detection circuit comprising:
- a diode having
- a semiconductor junction,
- a control terminal, electrically coupled to the semiconductor junction, that receives a bias signal to control an avalanche voltage of the diode,
- a cathode region of a first conductivity type, coupled to the operating voltage of the integrated circuit,
- an anode region of a second conductivity type, adjacent the cathode region such that the semiconductor junction is formed between the anode region and the cathode region, and
- an output, coupled to the anode region, having a voltage level that is a function of the operating voltage level and the avalanche voltage of the diode;
- a biasing circuit, coupled to the control terminal, that provides the diode with the bias signal having a bias voltage with at least one bias value;
- and
- an output circuit that detects an output level of the detection circuit at a start of each half-wave of an alternating cyclical signal.
A method for detecting a level of an operating voltage in an integrated circuit, the method comprising the steps of:
- providing a detector diode having
- a semiconductor junction,
- a control terminal electrically coupled to the semiconductor junction to control an avalanche voltage of the diode,
- a cathode region of a first conductivity type, and
- an anode region of a second conductivity type, adjacent the cathode region such that the semiconductor junction is formed between the anode region and the cathode region;
- and
- establishing the avalanche voltage of the diode by biasing the semiconductor junction of the detector diode with at least one bias value;
- electrically coupling the cathode region of the diode to the operating voltage of the integrated circuit;
- and
- detecting the voltage level of the operating voltage and providing a signal that is a function of the operating voltage and the avalanche voltage at the anode region of the diode.
The method of claim 14, wherein the biasing step includes a step of providing a cyclical signal to the control terminal to bias the diode at different bias values.
A method for detecting a level of an operating voltage in an integrated circuit, the method comprising the steps of:
- providing a detector diode having
- a semiconductor junction,
- a control terminal electrically coupled to the semiconductor junction to control an avalanche voltage of the diode,
- a cathode region of a first conductivity type, and
- an anode region of a second conductivity type, adjacent the cathode region such that the semiconductor junction is formed between the anode region and the cathode region;
- establishing the avalanche voltage of the diode by biasing the semiconductor junction of the detector diode with at least one bias value;
- electrically coupling the cathode region of the diode to the operating voltage of the integrated circuit;
- and
- detecting the voltage level of the operating voltage and providing a signal that is a function of the operating voltage and the avalanche voltage at the anode region of the diode;
- wherein the biasing step comprises the steps of:
- providing a circuit including a logic circuit;
- coupling a number of capacitors to the logic circuit, to the control terminal to bias the diode, to a first reference voltage terminal of the integrated circuit, and to a second reference voltage terminal of the integrated circuit.
A circuit for detecting a level of an operating voltage of an integrated circuit, the circuit comprising:
- a detecting circuit having a device that exhibits an avalanche breakdown when a voltage across the device exceeds a reference voltage level of the device, having a first terminal coupled to the operating voltage of the integrated circuit and an output terminal for providing an output signal of the detecting circuit, the output signal having a voltage level that is a function of the reference voltage level and the operating voltage of the integrated circuit;
- and
- a biasing circuit, electrically coupled to the device, that provides an alternating cyclical voltage level to adjust the reference voltage level of the device such that the reference voltage level is alternating and cyclical.
A circuit for detecting a level of an operating voltage of an integrated circuit, the circuit comprising:
- a detecting circuit having a device that exhibits an avalanche breakdown when a voltage across the device exceeds a reference voltage level of the device, the detecting circuit having a first terminal coupled to the operating voltage of the integrated circuit and an output terminal for providing an output signal of the detecting circuit, the output signal having a voltage level that is a function of the reference voltage level and the operating voltage of the integrated circuit;
- a biasing circuit, electrically coupled to the device, that provides an alternating cyclical voltage level to adjust the reference voltage level of the device such that the reference voltage level is alternating and cyclical;
- an output circuit coupled to the output terminal;
- and
- means, coupled to the output circuit, for providing a synchronization signal synchronized with the alternating cyclical signal.
Dependencies are inferred from the claim text.