Analog Devices International Unlimited Company

Ercan Kaymaksut

Celal Avci

Mehmet Arda Akkaya

Yalcin Alper Eken

Shawn S Kuo

Turusan Kolcuoglu

Huseyin Kayahan

Atilim Ergul

Murat Davulcu

Radio frequency switches with improved switching speed are provided. In certain embodiments, an RF switching circuit includes a FET switch including a gate, a digital buffer configured to provide a first output voltage to the gate of the FET during a steady-state, and a fast switching circuit in parallel with the digital buffer and configured to provide a second output voltage to the gate of the FET during a switching state. The fast switching circuit includes at least one charge pump configured to boost at least one supply voltage to a multiple of the at least one supply voltage. The fast switching circuit is configured to generate the second output voltage based on the boosted at least one supply voltage.

Radio frequency switches with fast switching speed

Passive gate bias network topologies are implemented for stacked FET switch structures, which improve the settling time and low cut-off frequency for both DC and non-DC operation. DC capable stacked switch bias structures provide gate and bulk bias voltages, using input DC voltages, which are coupled to the gate terminals and the bulk terminals of the stacked switches. The DC coupling can be achieved using resistors, or a combination of resistors and diodes. An exemplary SPST switch includes a series stacked switch in combination with a shunt stacked switch, which can be controlled between alternating states. For low cut-off frequency improvement structures, an input signal is coupled to the gate terminals and bulk terminals of the switches in the stacked switches, using a DC block capacitor and resistors. The low cut-off of the bulk can be improved by connecting the bulk terminal of one switch to the opposite polarity switch.

Bias networks for DC or extended low frequency capable fast stacked switches

Laser driver designs that aim to reduce or eliminate the problem of fault laser firing are disclosed. Various laser driver designs presented herein are based on providing a current dissipation path that is configured to start providing a resistance for dissipating at least a portion, but preferably substantially all, of the negative current from the laser diode. Dissipating at least a portion of the negative current may decrease the unintentional increase of the voltage at the input to the laser diode and, therefore, reduce the likelihood that fault laser firing will occur. A control logic may be used to control the timing of when the current dissipation path is activated (i.e., provides the resistance to dissipate the negative current from the laser diode) and when it is deactivated.

Laser driver designs to reduce or eliminate fault laser firing

A resonant H-bridge laser driver circuit topology is described that can achieve high current levels at narrow pulse widths while using smaller transistor sizes. The resonant H-bridge topology can utilize parasitic inductors in conjunction with an external capacitor to create a resonant circuit in parallel with the load.

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Istanbul, Turkey

Ercan Kaymaksut