High Q linear controlled variable capacitor using translinear amplifier
First Claim
1. A circuit to control the capacitance of a variable capacitor in a strictly linear mode through a steady tuning voltage and to achieve a high Q-factor at the same time;
- comprising;
means for a set of individual small capacitors;
means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel;
means to linearly control the switching function for each of said set of continuous switching devices;
means for a set of translinear amplifier stages to produce said linear controls for said switching functions;
means to individually provide the threshold points for each individual capacitor switching stage; and
means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages.
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Accused Products
Abstract
A voltage controlled variable capacitor, formed of a larger number of fixed capacitor segments and a corresponding number of switching elements, uses translinear amplifiers to control each switching element. Each translinear amplifier linearly switches from the fully off to the fully on state; a minimum number of switching stages (ideally only one) is in the mode-of-change at any one time with a minimum overlap. The arrangement achieves a nearly linear change of capacitance at linear tuning voltage change, while resulting in high Q-factor due to the low RDSon and high RDSoff of the fully switched stages. The invention eliminates temperature and voltage dependencies of other solutions like varactor diodes.
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Citations
52 Claims
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1. A circuit to control the capacitance of a variable capacitor in a strictly linear mode through a steady tuning voltage and to achieve a high Q-factor at the same time;
- comprising;
means for a set of individual small capacitors;
means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel;
means to linearly control the switching function for each of said set of continuous switching devices;
means for a set of translinear amplifier stages to produce said linear controls for said switching functions;
means to individually provide the threshold points for each individual capacitor switching stage; and
means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- comprising;
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17. A circuit to control the capacitance of a variable capacitor in a strictly linear mode through a steady tuning voltage and to achieve a high Q-factor at the same time by sharply cutting off the control signal, when said switching device is outside its dedicated active working area;
- comprising;
means for a set of individual small capacitors;
means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel;
means to linearly control the switching function for each of said set of continuous switching devices, when said switching device is in its dedicated active working area;
means to drive said switching device to a fully on status, when said switching device is outside its dedicated active working area on the lower resistance side. means to drive said switching device to a fully off status, when said switching device is beyond its dedicated active working area on the higher resistance side. means for a set of translinear amplifier stages to produce said linear controls for said switching functions;
means to individually provide the threshold points for each individual capacitor switching stage; and
means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
- comprising;
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26. A circuit to control the capacitance of a variable capacitor in a strictly linear mode through a steady tuning voltage and to achieve a high Q-factor at the same time and to compensate the temperature deviation of the capacitor switching device;
- comprising;
means for a set of individual small capacitors;
means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel;
means to linearly control the switching function for each of said set of continuous switching devices;
means for a set of translinear amplifier stages to produce said linear controls for said switching functions;
means to compensate the temperature deviation of said switching device;
means to individually provide the threshold points for each individual capacitor switching stage; and
means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (27, 28)
- comprising;
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29. A circuit to control the capacitance of a variable capacitor in a steady mode, but with predefined non-linear relation to the tuning voltage, through a steady tuning voltage and to achieve a high Q-factor at the same time;
- comprising;
means for a set of individual small capacitors;
means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel;
means to linearly control the switching function for each of said set of continuous switching devices;
means for a set of translinear amplifier stages to produce said linear controls for each of said set of continuous switching devices;
means to individually provide the threshold points for each individual capacitor switching stage;
means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages and;
means to provide a non-linear relation between said tuning voltage and said threshold points. - View Dependent Claims (30, 31, 32)
- comprising;
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33. A method to control the capacitance of a variable capacitor in a strictly linear mode through a tuning voltage and to achieve a high Q-factor at the same time;
- comprising;
providing means for a set of individual small capacitors, means for a set of switching devices to continually switch on each capacitor of said set of capacitors in parallel, means to linearly control the switching function for each of said continuous switching devices, means for a set of translinear amplifier stages to produce said linear controls for said switching functions, means to linearly control said switching function for each of said set of continuous switching devices, means to individually provide the threshold points for each individual capacitor switching stage, means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages;
continually switching on one of said continuous switching devices in order to switch one of said small capacitors in parallel to the already switched on capacitors, one after the other;
linearly controlling the switching function for each of said continuous switching devices;
amplifying, by the means of a translinear amplifier, the difference of the capacitance tuning voltage and the threshold points of each amplifier stage to produce the linear control signal for said continually switching operation;
providing said threshold points for each individual capacitor switching stage; and
supplying a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42)
- comprising;
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43. A method to control the capacitance of a variable capacitor in a strictly linear mode through a tuning voltage and to achieve a high Q-factor at the same time by sharply cutting off the control signal, when said switching device is outside its dedicated active working area;
- comprising;
providing means for a set of individual small capacitors, means for a set of switching devices to continually switch on said capacitors in parallel, one for each of said small capacitors, means to linearly control the switching function for each of said continuous switching devices, when said switching device is in its dedicated active working area, means to drive said switching device to a fully-on status, when said switching device is outside its dedicated active working area on the lower resistance side, means to drive said switching device to a fully-off status, when said switching device is beyond its dedicated active working area on the higher resistance side, means for a set of translinear amplifier stages to produce said linear controls for said switching functions, means to individually provide the threshold points for each individual capacitor switching stage, means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages;
continually switching on one of said continuous switching devices in order to switch one of said small capacitors in parallel to the already switched on capacitors, one after the other;
linearly controlling the switching function for each of said continuous switching devices, when said switching device is in its dedicated active working area;
driving said switching device to a fully on status, when said switching device is outside its dedicated active working area on the lower resistance side;
driving said switching device to a fully off status, when said switching device is beyond its dedicated active working area on the higher resistance side;
amplifying, by the means of a translinear amplifier, the difference of the capacitance tuning voltage and the threshold points of each amplifier stage to produce the linear control signal for said continually switching operation;
providing said threshold points for each individual capacitor switching stage; and
supplying a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (44, 45, 46)
- comprising;
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47. A method to control the capacitance of a variable capacitor in a strictly linear mode through a tuning voltage and to achieve a high Q-factor at the same time and to compensate the temperature deviation of the capacitor switching device;
- comprising;
providing means for a set of individual small capacitors, means for a set of switching devices to continually switch on said capacitors in parallel, means for a set of translinear amplifier stages to produce said linear controls for said switching functions, means to linearly control the switching function for each of said continuous switching devices, means to compensate the temperature deviation of said switching device, means to individually provide the threshold points for each individual capacitor switching stage, means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages;
continually switching on one of said continuous switching devices in order to switch one of said small capacitors in parallel to the already switched on capacitors, one after the other;
linearly controlling the switching function for each of said continuous switching devices;
compensating the temperature deviation of said switching;
amplifying, by the means of a translinear amplifier, the difference of the capacitance tuning voltage and the threshold points of each amplifier stage to produce the linear control signal for said continually switching operation;
providing said threshold points for each individual capacitor switching stage; and
supplying a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages. - View Dependent Claims (48, 49)
- comprising;
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50. A method to control the capacitance of a variable capacitor in a steady mode, but with predefined non-linear relation to the tuning voltage, through a tuning voltage and to achieve a high Q-factor at the same time;
- comprising;
providing means for a set of individual small capacitors, means for a set of switching devices to continually switch on said capacitors in parallel, means to linearly control the switching function for each of said continuous switching devices, means for a set of translinear amplifier stages to produce said linear controls for said switching functions, means to individually provide the threshold points for each individual capacitor switching stage, means to provide a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages;
continually switching on one of said continuous switching devices in order to switch one of said small capacitors in parallel to the already switched on capacitors, one after the other;
linearly controlling the switching function for each of said continuous switching devices;
amplifying, by the means of a translinear amplifier, the difference of the capacitance tuning voltage and the threshold points of each amplifier stage to produce the linear control signal for said continually switching operation;
providing said threshold points for each individual capacitor switching stage, producing non-linear instead of linear steps;
supplying a signal, dependent on the tuning voltage, dedicated for the voltage controlled capacitance change, to all of said translinear amplifier stages; and
providing a non-linear relation between said tuning voltage and said threshold points. - View Dependent Claims (51, 52)
- comprising;
Specification