Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals

A voltage handling method comprising:

• providing a plurality of 2N stacked switches, the stacked switches proceeding from a first switch closest to a first terminal and farthest from a second terminal to a 2N-th switch farthest from the first terminal and closest to the second terminal, the first terminal being a terminal through which a voltage source is coupled to the unit cell;
• providing a compensation capacitor stack comprising (2N−1) stacked compensation capacitors, the (2N−1) stacked compensation capacitors being referred to as a first stacked compensation capacitor, a second stacked compensation capacitor, . . . , an i-th stacked compensation capacitor, . . . , to a (2N−1)-th stacked compensation capacitor, proceeding in a direction from the first RF terminal to the second RF terminal;
• coupling the stacked switches in series with M capacitors in a manner such that the M capacitors are between the N-th switch and the (N+1)-th switch;
• and
• configuring the compensation capacitor stack to reduce the effect of parasitic capacitances of the plurality of 2N switches on the voltage across each stacked switch when the plurality of 2N switches is off,
• wherein
• N and M represent integers greater than or equal to one,
• a first stack of N switches from among the plurality of 2N switches is connected in series between the first RF terminal and the M capacitors, the M capacitors are connected in series between the first stack of N switches and a second stack of N switches from among the plurality of 2N switches, and the second stack of N switches is connected in series between the M capacitors and the second RF terminal, and
• the i-th stacked compensation capacitor is connected in parallel with the first switch and an i-th switch and all switches in between, i being 1, 2, . . . , (2N−1).

A unit cell for a sub-circuit of a digitally tunable capacitor (DTC), the sub-circuit being adapted to be coupled between a first RF terminal and a second RF terminal, the unit cell comprising:

• a plurality of 2N switches coupled in series with M capacitors, the switches proceeding from a first switch closest the first RF terminal and farthest from the second RF terminal to a 2N-th switch farthest from the first RF terminal and closest to the second RF terminal;
• and
• a compensation capacitor stack, comprising (2N−1) stacked compensation capacitors, the (2N−1) stacked compensation capacitors being referred to as a first stacked compensation capacitor, a second stacked compensation capacitor, . . . , an i-th stacked compensation capacitor, . . . , to a (2N−1)-th stacked compensation capacitor, in a direction proceeding from the first RF terminal to the second RF terminal,
• wherein
• N and M represent integers greater than or equal to one,
• the M capacitors are placed between the N-th switch and the (N+1)-th switch in a manner such that a first stack of N switches from among the plurality of 2N switches is connected in series between the first RF terminal and the M capacitors, the M capacitors are connected in series between the first stack of N switches and a second stack of N switches from among the plurality of 2N switches, and the second stack of N switches is connected in series between the M capacitors and the second RF terminal,
• the i-th stacked compensation capacitor is connected in parallel with the i-th stacked switch, i being 1, 2, . . . , (2N−1),
• the first and the (2N−1)-th stacked compensation capacitors are equal in capacitance value and have the greatest capacitance value among stacked compensation capacitors in the compensation capacitor stack,
• the j-th and the (2N−j)-th stacked compensation capacitors are equal in capacitance values, with capacitance values decreasing as j increases, j being 2, 3, . . . N, and
• capacitance values of the stacked compensation capacitors are configured to reduce the effect of parasitic capacitances of the switch stack on the voltage across each stacked switch when the plurality of 2N switches is off.