Firecomms Limited

Colm Donovan

Ciaran Cahill

Patrick Murphy

A supply circuit for providing pulses of current has a current source, a reference voltage source for controlling magnitude of the current, and a current switch for controlling whether or not the current passes through a load. Also, there is a switch control signal terminal for controlling the current switch, and glitch compensation elements including at least one capacitance circuit and associated capacitor drive circuit for feeding a variable correcting voltage back to the reference voltage, and a controller to control said variable voltage.

Glitch compensation in electronic circuits

A voltage comparator () has a high switching speed and simplicity of design. It minimizes pulse-width distortion of input digital signals when functioning as a digital input buffer in high speed communications applications. In addition it provides a simple hysteresis circuit () that is easily tuneable with a reference current. The hysteresis circuit () is dependent on a reference current. This current may be chosen to have a proportionality to temperature, supply, or another selectable parameter, and may be programmable, in order to create the desired hysteresis performance.

Voltage comparator

A receiver has a differential transimpedance amplifier () with two inputs and two outputs. The differential transimpedance amplifier () provides a differential output and this is peak-detected () to provide amplitude reference signals. The differential transimpedance amplifier output and the amplitude reference signals are fed to a differential summing amplifier (), which provides a fully differential signal to a comparator, or to an automatic gain control circuit () to regulate the differential transimpedance amplifier gain. The differential summing amplifier () output is a fully differential signal, thereby having lower distortion for DC and burst mode receiver applications.

Optical receiver

A transconductance circuit has an input terminal (V) and an output terminal (Out), a first current source () having a gate connected to said input terminal (V); and a second current source (), in parallel with said first current source, and having a higher transconductance and a wider dynamic range than the first current source. The current sources are configured so that at a low input voltage only the first current source () is on. A voltage drop circuit provides a lower bias voltage for the second current source than for the first current source.

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Colm Donovan