Abstract: A medical device for use on the human eye is described. The device is placed in an extrocular location in a patient and delivers an electrical current that stimulates the retina of patients who are blind or have vision disorders. It has at least one electrode that makes contact with the scleral surface of the eye, the electrode typically being activated by an electrical stimulator. The device produces electrical pulses which pass through the electrodes on the scleral surface of the eye, to activate the retina of the eye, which causes the patient to experience improved vision, visual sensations or the prevention of deterioration of vision. By this means, sight can be restored or improved where patients have disorders of their retina or other parts of their visual system.

Abstract: A medical device for use on the human eye is described. The device is placed in an extrocular location in a patient and delivers an electrical current that stimulates the retina of patients who are blind or have vision disorders. It has at least one electrode that makes contact with the scleral surface of the eye, the electrode typically being activated by an electrical stimulator. The device produces electrical pulses which pass through the electrodes on the scleral surface of the eye, to activate the retina of the eye, which causes the patient to experience improved vision, visual sensations or the prevention of deterioration of vision. By this means, sight can be restored or improved where patients have disorders of their retina or other parts of their visual system.

Abstract: A circuit for generating an output voltage which is proportional to temperature with a required gradient is disclosed. The circuit relies on the principle that the difference in the base emitter voltage of two bipolar transistors with differing areas, if appropriately connected, can result in a current which has a positive temperature coefficient, that is a current which varies linearly with temperature such that as the temperature increases the current increases. It is important to maintain a stable internal line voltage in the face of significant variations in a supply voltage to the circuit. This is achieved herein by providing control elements appropriately connected to a differential amplifier. The stable internal supply voltage can be used to power a subsequent stage of the circuit for fine control of the gradient of the voltage proportional to temperature.

Abstract: A circuit for generating an output voltage proportional to temperature with a required gradient, the circuit including a first stage arranged to generate a first voltage which is proportional to temperature with a predetermined gradient but has a positive value when the temperature falls below zero and a second stage connected to the first stage and including a differential amplifier having a first input connected to receive the first voltage and a second input connected to receive a feedback voltage which is derived from an output signal of the differential amplifier via an offset circuit which introduces an offset voltage such that the output signal of the differential amplifier provides at an output node the output voltage which has a negative variation with negative temperatures.

Abstract: A circuit for generating an output voltage proportional to temperature with a required gradient, the circuit including a first stage arranged to generate a first voltage which is proportional to temperature with a predetermined gradient, the first stage including first and second bipolar transistors with different emitter areas having their emitters connected together and their bases connected across a bridge resistive element, wherein the collectors of the transistors are connected to an internal supply line via respective matched resistive elements as the voltage across the bridge resistive element is proportional to temperature; a differential amplifier having its input connected respectively to the collectors, and its output connected to stabilisation circuitry connected between first and second power supply rails and an internal supply line which cooperates with the differential amplifier to maintain a stable voltage on the internal supply line despite variations between the first and second power supply

Abstract: A circuit for generating an output voltage which is proportional to temperature with a required gradient is disclosed. The circuit relies on the principle that the difference in the base emitter voltage of two bipolar transistors with differing areas, if appropriately connected, can result in a current which has a positive temperature coefficient, that is a current which varies linearly with temperature such that as the temperature increases the current increases. It is important to maintain a stable internal line voltage in the face of significant variations in a supply voltage to the circuit. This is achieved herein by providing control elements appropriately connected to a differential amplifier. The stable internal supply voltage can be used to power a subsequent stage of the circuit for fine control of the gradient of the voltage proportional to temperature.

Abstract: A circuit for generating an output voltage which is proportional to temperature with a required gradient is disclosed. The circuit relies on the principle that the difference in the base emitter voltage of two bipolar transistors with differing areas, if appropriately connected, can result in a current which has a positive temperature coefficient, that is a current which varies linearly with temperature such that as the temperature increases the current increases. It is important to maintain a stable internal line voltage in the face of significant variations in a supply voltage to the circuit. This is achieved herein by providing control elements appropriately connected to a differential amplifier. The stable internal supply voltage can be used to power a subsequent stage of the circuit for fine control of the gradient of the voltage proportional to temperature.

Abstract: A circuit for generating an output voltage proportional to temperature with a required gradient, the circuit including a first stage arranged to generate a first voltage which is proportional to temperature with a predetermined gradient but has a positive value when the temperature falls below zero and a second stage connected to the first stage and including a differential amplifier having a first input connected to receive the first voltage and a second input connected to receive a feedback voltage which is derived from an output signal of the differential amplifier via an offset circuit which introduces an offset voltage such that the output signal of the differential amplifier provides at an output node the output voltage which has a negative variation with negative temperatures.

Abstract: A driver circuit has an input stage with an input node for receiving a control signal. A capacitor circuit is connected to the input node and a first power supply and is arranged to be charged up by said first power supply under the control of the control signal. The driver circuit also has an output stage connected to a second power supply and is arranged to provide a driver signal in dependence on the charge stored at the capacitor circuit. A buffer circuit is connected between the capacitor circuit and the output stage.