WO2009038924A2 - Cancelling low frequency errors in mems systems - Google Patents
Cancelling low frequency errors in mems systems Download PDFInfo
- Publication number
- WO2009038924A2 WO2009038924A2 PCT/US2008/073727 US2008073727W WO2009038924A2 WO 2009038924 A2 WO2009038924 A2 WO 2009038924A2 US 2008073727 W US2008073727 W US 2008073727W WO 2009038924 A2 WO2009038924 A2 WO 2009038924A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- switch
- coupled
- circuitry
- circuit
- switches
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
- G01D3/028—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure
- G01D3/036—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure on measuring arrangements themselves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/4805—Shape
- H01L2224/4809—Loop shape
- H01L2224/48091—Arched
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/481—Disposition
- H01L2224/48135—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
- H01L2224/48137—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip the bodies being arranged next to each other, e.g. on a common substrate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/49—Structure, shape, material or disposition of the wire connectors after the connecting process of a plurality of wire connectors
- H01L2224/491—Disposition
- H01L2224/4912—Layout
- H01L2224/49175—Parallel arrangements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/10—Details of semiconductor or other solid state devices to be connected
- H01L2924/11—Device type
- H01L2924/13—Discrete devices, e.g. 3 terminal devices
- H01L2924/1304—Transistor
- H01L2924/1306—Field-effect transistor [FET]
- H01L2924/13091—Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
Definitions
- the disclosure herein relates generally to micro-electro-mechanical system (MEMS) products.
- MEMS micro-electro-mechanical system
- this disclosure relates to systems and methods for cancelling low frequency errors in MEMS products
- MEMS micro-electro-mechanical system
- This two-chip packaging approach includes, for example, one chip that includes the MEMS device or structure (mechanics) and one chip that includes the associated electronics, and the two chips are included in one single package.
- the two dies that include each of the MEMS and the electronics are connected via wire bonds.
- the reasons for the two-chip approach include difficulties in monolithically integrating the two components (MEMS and electronics), and the ability to separately optimize the MEMS device and the electronics in order to get the optimum overall yield.
- FIG. 1 shows a block circuit diagram of a conventional MEMS device 100, under the prior art.
- This conventional MEMS device 100 includes a MEMS 110 (e g., MEMS die) connected to associated electronics 120 (e.g , electronics die).
- the MEMS 110 is a capacitive accelerometer in which acceleration results in deflection of a movable mass.
- the deflection to which the package is subjected also results in capacitive changes in the MEMS 110, and the capacitive changes can be sensed by the electronics 120
- the sensing capacitors C_S1 and C_S2 of the MEMS 110 change according to the acceleration experienced thereby introducing changes in the signal measured by the electronics
- the bond wires 130 that connect the MEMS 110 to the electronics 120 form parasitic capacitances C PBl and C_PB2 that are modeled in parallel to the sensing capacitors C_S1 and C_S2. If the bond wires 130 do not change their position and the dielectricum between the bond wires 130 stays constant, the bond wires 130 only add constant capacitances to the sense capacitors. This leads to an offset in the system 100, and conventional systems calibrate for this offset by subtracting a constant value from the output signal of the system.
- Figure 1 shows a block circuit diagram of a typical MEMS system, under the prior art.
- Figure 2 is a block diagram of an electronic system including the chopping system, under an embodiment.
- Figure 3 is a top view of a switch of the chopping system, under an embodiment.
- the systems and methods include a first circuit coupled to one or more switches
- One or more bond wires are coupled to the switches and a second circuit.
- Control signals are coupled to the switches, and the control signals are configured to control coupling of the first circuit to the second circuit via the switch to cancel errors introduced by the bond wire in an output of the first circuit.
- the chopping systems include a sensor including a sensing capacitor, and sensing circuitry configured to receive signals from the sensor.
- One or more switches are coupled to the sensor.
- One or more bond wires are coupled to the sensing circuitry and respective ones of the switches.
- Control signals are coupled to the switch(es), and the control signals are configured to control the switch(es) to eliminate errors in the sensor output resulting from the bond between the sensor and the sensing circuitry
- the errors include for example parasitic bond capacitance and offset voltage but are not so limited
- the chopping system described herein allows for accurate calibration of MEMS
- the chopping system removes effects of variable offsets and parasitic bond capacitance, thereby allowing for adequate compensation or calibration for the offset drift in the parasitic bond capacitances resulting from temperature variances and aging. Elimination of the effects due to the change of the dielectric between the bond wires effectively removes this as an obstacle for new applications of MEMS.
- FIG. 2 is a block diagram of an electronic system 200 including the chopping system, under an embodiment
- the electronic system 200 referred to herein as "MEMS,” includes a MEMS sensor 210 or component and sensor electronics 220.
- the MEMS sensor 210 of an embodiment is on a separate die from that of the sensor electronics 220; in alternative embodiments the MEMS sensor can be integrated on the same die as the sensor electronics.
- the MEMS sensor 210 is a capacitive accelerometer that includes sensing capacitors C_S1 and C_S2 coupled or connected in series. The sensing capacitors C_S1 and C_S2 change according to the acceleration experienced (e g., acceleration leads to a deflection of a movable mass) thereby introducing changes in the signal measured by the electronics.
- the MEMS sensor 210 therefore functions to sense deflection to which the package is subjected via capacitive changes, and the capacitive changes are sensed by the sensor electronics.
- Bond wires 230 (include bond wires 232, 234, 236) couple or connect the MEMS sensor 210 to the sensor electronics 220
- the bond wires 230 that connect the MEMS sensor 210 to the sensor electronics 220 form parasitic capacitances CJPBl and C_PB2.
- the parasitic capacitances C_PB1 and C_PB2 are modeled in parallel to the sensing capacitors C_S1 and C_S2.
- the bond wires 230 couple the MEMS sensor 210 to the sensor electronics 220 along with one or more switches
- the switches of an embodiment include a first set of switches and a second set of switches.
- the first set of switches includes a first switch 2511 and a second switch 2512
- the first switch 2511 of the first set is coupled to a first bond wire 231 and a first conductor or plate of the first capacitor C_S1 of the MEMS sensor 210.
- the second switch 2512 of the first set of switches is coupled to a second bond wire 232 and a second conductor of the second capacitor C_S2 of the MEMS sensor 210.
- the second set of switches also includes a first switch 2521 and a second switch 2522
- the first switch 2521 of the second set is coupled to the second bond wire 232 and the first conductor of the first capacitor C_S1 of the MEMS sensor
- the second switch 2522 of the second set of switches is coupled to the first bond wire and the second conductor of the second capacitor C_S2 of the MEMS sensor
- the sensor electronics 220 of an embodiment include first circuitry 221 or electronics and second circuitry 222
- the MEMS sensor outputs are coupled to the inputs of the first circuitry 221 using the bond wires 230 and the switches 2511-2512 and 2521-2522. Outputs of the first circuitry 221 are coupled to inputs of the second circuitry 222.
- the switches of an embodiment also include switches in the coupling or connections between the first circuitry 221 and second circuitry 222
- the first set of switches therefore can include a third switch 2513 and a fourth switch 2514.
- the third switch 2513 of the first set is coupled to a first output of the first circuitry 221 and a first input of the second circuitry 222.
- the fourth switch 2514 of the first set is coupled to a second output of the first circuitry 221 and a second input of the second circuitry 222.
- the second set of switches also includes a third switch 2523 and a fourth switch 2524.
- the third switch 2523 of the second set is coupled to the first output of the first circuitry 221 and the second input of the second circuitry 222.
- the fourth switch 2524 of the second set is coupled to the second output of the first circuitry 221 and the first input of the second circuitry 222
- control signals are coupled to each of the switches
- the control signals are configured to control coupling of the MEMS sensor 210 to the sensor electronics 220 via the switches.
- the controlled coupling resulting from the switches and control signals results in elimination or cancellation of errors introduced in the sensed output of the MEMS sensor by the bond wire.
- the control signals are also configured to control coupling of the first circuitry 221 and second circuitry 222 of the sensor electronics 220.
- the control signals of an embodiment include a first control signal and a second control signal.
- the first control signal is coupled to the first set of switches (collectively include either switches 2511-2512 or switches 2511-2514), and is configured to control the first set of switches to a switch state.
- the second control signal is coupled to the second set of switches (collectively include either switches 2521-2522 or switches 2521-2524) and is configured to control the second set of switches to the switch state.
- the switch state includes a closed or conductive state and an open or non-conductive state but is not so limited.
- the first control signal is configured to control the first set of switches to a state that is opposite a state of the second set of switches.
- the first control signal places the first set of switches in an open state while the second control signal places the second set of switches in a closed state.
- the first control signal places the first set of switches in a closed state while the second control signal places the second set of switches in an open state.
- a phase is associated with each of the first and second control signals.
- the control signals include signals having one of two phases ⁇ l and ⁇ 2.
- the phase relationship between a phase ⁇ l of the first control signal and a phase ⁇ 2 of the second control signal of an embodiment eliminates errors (e g., offset voltage, parasitic capacitance, etc.) introduced in the sensed output of the MEMS sensor by the bond wire.
- errors e g., offset voltage, parasitic capacitance, etc.
- Phases ⁇ l and ⁇ 2 as used herein each represent a time period which repeats with a pre-specified frequency
- the system can be clocked with a clocking signal having a frequency of 1 kilohertz (kHz) and a period of 1 millisecond (ms).
- the period can be divided into two phases ( ⁇ l and ⁇ 2) with each phase being approximately 0.5ms long.
- a switch described herein with reference to phase ⁇ l is closed (conductive) during phase ⁇ l .
- the control signal that is applied to the switch corresponding to phase ⁇ l can be a digital signal, for example, a high logic state (e.g., value "1") of the control signal corresponds to the system being in phase ⁇ l
- a switch described herein with reference to phase ⁇ 2 is closed (conductive) during phase ⁇ 2.
- the control signal that is applied to the switch corresponding to phase ⁇ 2 can also be a digital signal, for example, a high logic state of the control signal corresponds to the system being in phase ⁇ 2. While the example described herein associates a particular phase with a particular set of switches this only represents an instant in time, and at other instances of time during operations of the MEMS system the phase associated with a set of switches is opposite the phase shown and described in this example.
- the MEMS system of an embodiment includes switches clocked by the control signals having phases ⁇ l and ⁇ 2 as described above.
- the control signal phases introduce chopping that results in separation from the MEMS sensor output of any offsets introduced by the connection of the MEMS sensor to the sensor electronics. This separation is done in the frequency domain but is not so limited.
- the offsets or errors including, for example, low frequency changes of parasitic capacitances C_PB1 and C_PB2 and the electronic offset voltage V_offset, are separated or canceled.
- phase ⁇ l For purposes of the following example relationship between control signal phases, described with reference to Figure 2, it is assumed that a switch labeled with phase ⁇ l is closed (conductive) during phase ⁇ l. During phase ⁇ l the voltage potential between the outputs of the first circuitry of the sensor electronics is
- F 1 ⁇ ACS ⁇ gain c + ACP ⁇ gain c ) AV 1n .
- the variable ⁇ V m represents a voltage step applied by the sensor electronics.
- the variable ⁇ CS represents the changes in the sensing capacitance of sensing capacitors C_S1 and C_S2.
- the variable ⁇ CP represents the changes in the parasitic capacitance of parasitic capacitors C_PB1 and C PB2.
- the quantity gainc is a constant set by the ratio of two sensing capacitors C_S1 and C_S2. Therefore, during phase ⁇ l the voltage potential between the inputs of the second circuitry of the sensor electronics is
- phase ⁇ 2 the voltage potential between the outputs of the first circuitry of the sensor electronics is
- V x (- ACS ⁇ gain c + ACP ⁇ gain c )- AV m .
- V 2 [ACS - gain, - ACP ⁇ gain c )- AV 1n .
- the switches on the MEMS die described herein have a resistance when closed.
- the resistance of the closed switches is referred to as on-resistance
- the value of the on- resistance only affects the time constant of the interface between the MEMS die and the electronics die , For example, in time discrete systems the on-resistance would affect the settling time of switched-capacitor amplifiers. Even if the on-resistance was on the order of 1 ,000 Ohms this would not affect the function of the system configurations described herein. Therefore switches with high on-resistance can be used with relatively little or no impact on the configurations described herein.
- the switches of an embodiment include a relay structure, but are not so limited.
- Figure 3 is a top view of a switch 300 of the chopping system, under an embodiment.
- the MEMS sensor or MEMS die of an embodiment includes the switch 300 but the embodiments are not so limited.
- the switches 300 can be implemented for example using a MEMS process that uses Poly-Silicon as a structural material.
- the switch 300 includes a movable beam MB having a first end that is fixed and a second end that is free and therefore moveable.
- a central portion or region of the movable beam MB is positioned between two fixed electrodes or terminals Fl and F2.
- Each of the fixed electrodes Fl and F2 is coupled to an energy source (not shown) described herein as the control signals.
- the second end of the movable beam MB is positioned between two output terminals OUTl and OUT2.
- the output terminals OUTl and OUT2 include mechanically fixed structures.
- the second end of the movable beam MB is configured to contact one or the other of the output terminals OUTl and OUT2 in response to a voltage applied to the fixed electrodes.
- the movable beam MB can be switched between the output terminals OUTl and OUT2 by applying a voltage between MB and either the first fixed electrode Fl or the second fixed electrode F2.
- the control signals configure the movable beam MB to connect to output terminal OUTl
- the voltage between the movable beam MB and fixed electrode Fl is higher than the voltage between the movable beam MB and fixed electrode F2. This generates a net electrostatic force which pulls the movable beam MB towards output terminal OUTl until the movable beam MB and output terminal OUTl make physical contact and the switch 300 is closed.
- the control signals configure the movable beam MB to connect to output terminal OUT2
- the voltage between the movable beam MB and fixed electrode F2 is higher than the voltage between the movable beam MB and fixed electrode Fl
- This generates a net electrostatic force which pulls the movable beam MB towards output terminal OUT2 until the movable beam MB and output terminal OUT2 make physical contact and the switch 300 is closed
- the switches of an alternative embodiment include active electronic devices, but are not so limited As one example, the active electronic devices include but are not limited to transistors
- the active electronic devices can be integrated on the MEMS die but are not limited to integration on the MEMS die.
- the active electronic devices can be integrated in the sensor electronics or on another substrate or device of the system.
- the chopping systems of an embodiment include a system comprising a sensor including a sensing capacitor.
- the system of an embodiment includes sensing circuitry configured to receive signals from the sensor.
- the system of an embodiment includes at least one bond wire and at least one switch coupled to the sensor and the sensing circuitry.
- the system of an embodiment includes at least one control signal coupled to the at least one switch and configured to control the at least one switch to separate parasitic bond capacitance of the at least one bond wire from sensing capacitance of the sensor.
- the capacitive sensor of the system of an embodiment includes a first capacitor and a second capacitor coupled in series.
- the at least one switch of the system of an embodiment includes a first set of switches and a second set of switches.
- the first set of switches of the system of an embodiment includes a first switch coupled to a first bond wire and a first conductor of the first capacitor and a second switch coupled to a second bond wire and a second conductor of the second capacitor.
- the second set of switches of the system of an embodiment includes a third switch coupled to the second bond wire and the first conductor of the first capacitor and a fourth switch coupled to the first bond wire and the second conductor of the second capacitor.
- the sensing circuitry of the system of an embodiment comprises first circuitry and second circuitry.
- the first circuitry of an embodiment is coupled to the at least one bond wire and the second circuitry
- the first set of switches of the system of an embodiment includes a fifth switch and a sixth switch.
- the fifth switch of an embodiment is coupled to a first output of the first circuitry and a first input of the second circuitry.
- the sixth switch of an embodiment is coupled to a second output of the first circuitry and a second input of the second circuitry.
- the second set of switches of the system of an embodiment includes a seventh switch and an eighth switch.
- the seventh switch of an embodiment is coupled to the first output of the first circuitry and the second input of the second circuitry.
- the eighth switch of an embodiment is coupled to the second output of the first circuitry and the first input of the second circuitry.
- the at least one control signal of the system of an embodiment includes a first control signal coupled to the first set of switches and a second control signal coupled to the second set of switches.
- the first control signal of the system of an embodiment is configured to control the first set of switches to a first state and the second control signal is configured to control the second set of switches to a second state.
- the first state of an embodiment is opposite the second state.
- the at least one switch of the system of an embodiment comprises at least one transistor.
- the system of an embodiment includes a first die including the sensor.
- the system of an embodiment includes a second die including the sensing circuitry Separating the parasitic bond capacitance from the sensing capacitance of an embodiment is a frequency domain separation.
- the chopping systems of an embodiment include a system comprising a first circuit coupled to at least one switch.
- the system of an embodiment includes a bond wire coupled to the at least one switch.
- the system of an embodiment includes a second circuit coupled to the bond wire.
- the system of an embodiment includes at least one control signal coupled to the at least one switch The at least one control signal of an embodiment is configured to control coupling of the first circuit to the second circuit via the switch to cancel a variable offset introduced by the bond wire in an output of the first circuit.
- variable offset of the system of an embodiment includes one or more of parasitic capacitance and offset voltage.
- the system of an embodiment includes a third circuit coupled to second circuit via the at least one switch.
- the chopping systems of an embodiment include a system comprising a first die including a first circuit.
- the system of an embodiment includes at least one switch coupled to the first circuit.
- the system of an embodiment includes a second die including a second circuit.
- the system of an embodiment includes a bond wire coupled to the at least one switch and the second circuit.
- the system of an embodiment includes control signals coupled to the at least one switch The control signals of an embodiment are configured to control a connection of the first circuit to the second circuit via the switch to eliminate offsets introduced in an output of the first circuit by the coupling.
- aspects of the chopping systems described herein may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs), programmable array logic (PAL) devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific integiated circuits (ASICs)
- PLDs programmable logic devices
- FPGAs field programmable gate arrays
- PAL programmable array logic
- ASICs application specific integiated circuits
- microcontrollers with memory such as electronically erasable programmable read only memory (EEPROM)
- EEPROM electronically erasable programmable read only memory
- embedded microprocessors firmware, software, etc.
- aspects of the multi-analog receiver front end system may be embodied in microprocessors having software -based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types.
- the underlying device technologies may be provided in a variety of component types, e.g , metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter -coupled logic (ECL), polymer technologies (e g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, etc.
- MOSFET metal-oxide semiconductor field-effect transistor
- CMOS complementary metal-oxide semiconductor
- ECL emitter -coupled logic
- polymer technologies e g., silicon-conjugated polymer and metal-conjugated polymer-metal structures
- mixed analog and digital etc.
- the functions described herein can be performed by programs or sets of program codes, including software, firmware, executable code or instructions running on or otherwise being executed by one or more general-purpose computers or processor-based systems.
- the computers or other processor-based systems may include one or more central processing units for executing program code, volatile memory, such as RAM for temporarily storing data and data structures during program execution, non- volatile memory, such as a hard disc drive or optical drive, for storing programs and data, including databases and other data stores, and a network interface for accessing an intranet and/or the Internet.
- volatile memory such as RAM for temporarily storing data and data structures during program execution
- non- volatile memory such as a hard disc drive or optical drive
- programs and data including databases and other data stores
- a network interface for accessing an intranet and/or the Internet.
- the functions described herein may also be implemented using special purpose computers, wireless computers, state machines, and/or hardwired electronic circuits.
- components of the various systems and methods disclosed herein may be described using computer aided design tools and expressed (or represented), as data and/or instructions embodied in various computer-readable media, in terms of their behavioral, register transfer, logic component, transistor, layout geometries, and/or other characteristics.
- Formats of files and other objects in which such circuit expressions may be implemented include, but are not limited to, formats supporting behavioral languages such as C, Verilog, and HLDL, formats supporting register level description languages like RTL, and formats supporting geometry description languages such as GDSII, GDSIII, GDSIV, CIF, MEBES and any other suitable formats and languages.
- Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof.
- non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof.
- Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the Internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, etc.)
- data transfer protocols e.g., HTTP, FTP, SMTP, etc.
- a processing entity e.g., one or more processors
- execution of one or more other computer programs including, without limitation, net-list generation programs, place and route programs and the like.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Micromachines (AREA)
- Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Systems and methods are described below for cancelling low frequency errors in electronic systems including MEMS systems. The systems include a first circuit coupled to one or more switches. One or more bond wires are coupled to the switches and a second circuit. Control signals are coupled to the switches, and the control signals are configured to control coupling of the first circuit to the second circuit via the switch to cancel variable offsets introduced by the bond wire in an output of the first circuit.
Description
CANCELLING LOW FREQUENCY ERRORS IN MEMS SYSTEMS
Inventors:
Christoph Lang
Vladimir Petkov
Udo Gomez
TECHNICAL FIELD
The disclosure herein relates generally to micro-electro-mechanical system (MEMS) products. In particular, this disclosure relates to systems and methods for cancelling low frequency errors in MEMS products
BACKGROUND
Conventional micro-electro-mechanical system (MEMS) products combine two chips into a single integrated package. This two-chip packaging approach includes, for example, one chip that includes the MEMS device or structure (mechanics) and one chip that includes the associated electronics, and the two chips are included in one single package. The two dies that include each of the MEMS and the electronics are connected via wire bonds. The reasons for the two-chip approach include difficulties in monolithically integrating the two components (MEMS and electronics), and the ability to separately optimize the MEMS device and the electronics in order to get the optimum overall yield.
Figure 1 shows a block circuit diagram of a conventional MEMS device 100, under the prior art. This conventional MEMS device 100 includes a MEMS 110 (e g., MEMS die) connected to associated electronics 120 (e.g , electronics die). The MEMS 110 is a capacitive accelerometer in which acceleration results in deflection of a movable mass. The deflection to which the package is subjected also results in capacitive changes in the MEMS 110, and the capacitive changes can be sensed by the electronics 120 The sensing capacitors C_S1 and C_S2 of the MEMS 110 change according to the acceleration experienced thereby introducing changes in the signal measured by the electronics The bond wires 130 that connect the MEMS 110 to the electronics 120 form parasitic capacitances C PBl and C_PB2 that are modeled in parallel to the sensing capacitors C_S1 and C_S2. If the bond wires 130 do not change their position and the dielectricum between the bond wires 130 stays constant,
the bond wires 130 only add constant capacitances to the sense capacitors. This leads to an offset in the system 100, and conventional systems calibrate for this offset by subtracting a constant value from the output signal of the system.
However, changes in the distance of the bond wires or the dielectric between the bond wires as a result of temperature changes and system age can make accurate system calibration difficult. The parasitic capacitances C_PB1 and C_PB2 being connected in parallel to the sensing capacitors C_S1 and C_S2 make it difficult in conventional systems to adequately compensate or calibrate for the offset drift in the parasitic bond capacitances C_PB1 and C PB2 resulting from temperature variances and aging. For example, the distance of the bond wires in molded packages changes because of the thermal expansion coefficient of the molded mass of the system, and these changes in distance introduce changes in the parasitic capacitances C_PB 1 and C PB2.
Conventional MEMS systems are unable to compensate for the change of these parasitic capacitances because it is impossible to predict in which direction the bond wires will be deflected. Furthermore, a change of the dielectric between the bond wires (e.g. because of humidity) also introduces changes in the parasitic capacitances C_PB 1 and C_PB2 The uncompensated variable offset due to the change of the dielectric between the bond wires can be a major obstacle for new applications of the MEMS (e.g., automobile hill hold control, automobile alarm, etc ) Consequently, there is a need for systems and methods that control the coupling or connection of the MEMS die to the electronics die to eliminate or cancel errors introduced by the bond wire in an output of the MEMS die.
INCORPORATION BY REFERENCE
Each patent, patent application, and/or publication mentioned in this specification is herein incorporated by reference in its entirety to the same extent as if each individual patent, patent application, and/or publication was specifically and individually indicated to be incorporated by reference
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a block circuit diagram of a typical MEMS system, under the prior art.
Figure 2 is a block diagram of an electronic system including the chopping system, under an embodiment.
Figure 3 is a top view of a switch of the chopping system, under an embodiment.
DETAILED DESCRIPTION
Systems and methods are described below for cancelling low frequency errors in electronic systems. The systems and methods, collectively referred to herein as chopping systems, include a first circuit coupled to one or more switches One or more bond wires are coupled to the switches and a second circuit. Control signals are coupled to the switches, and the control signals are configured to control coupling of the first circuit to the second circuit via the switch to cancel errors introduced by the bond wire in an output of the first circuit.
More particularly, the chopping systems described below cancel low frequency errors in electronic systems including MEMS. The chopping systems include a sensor including a sensing capacitor, and sensing circuitry configured to receive signals from the sensor. One or more switches are coupled to the sensor. One or more bond wires are coupled to the sensing circuitry and respective ones of the switches. Control signals are coupled to the switch(es), and the control signals are configured to control the switch(es) to eliminate errors in the sensor output resulting from the bond between the sensor and the sensing circuitry The errors include for example parasitic bond capacitance and offset voltage but are not so limited
The chopping system described herein allows for accurate calibration of MEMS The chopping system removes effects of variable offsets and parasitic bond capacitance, thereby allowing for adequate compensation or calibration for the offset drift in the parasitic bond capacitances resulting from temperature variances and aging. Elimination of the effects due to the change of the dielectric between the bond wires effectively removes this as an obstacle for new applications of MEMS.
In the following description, numerous specific details are introduced to provide a thorough understanding of, and enabling description for, embodiments of the chopping systems One skilled in the relevant art, however, will recognize that these embodiments can be practiced without one or more of the specific details, or with other components, systems, etc. In other instances, well-known structures or
operations aie not shown, or are not described in detail, to avoid obscuring aspects of the disclosed embodiments of the chopping systems.
Figure 2 is a block diagram of an electronic system 200 including the chopping system, under an embodiment The electronic system 200, referred to herein as "MEMS," includes a MEMS sensor 210 or component and sensor electronics 220. The MEMS sensor 210 of an embodiment is on a separate die from that of the sensor electronics 220; in alternative embodiments the MEMS sensor can be integrated on the same die as the sensor electronics. The MEMS sensor 210 is a capacitive accelerometer that includes sensing capacitors C_S1 and C_S2 coupled or connected in series. The sensing capacitors C_S1 and C_S2 change according to the acceleration experienced (e g., acceleration leads to a deflection of a movable mass) thereby introducing changes in the signal measured by the electronics. The MEMS sensor 210 therefore functions to sense deflection to which the package is subjected via capacitive changes, and the capacitive changes are sensed by the sensor electronics.
Bond wires 230 (include bond wires 232, 234, 236) couple or connect the MEMS sensor 210 to the sensor electronics 220 The bond wires 230 that connect the MEMS sensor 210 to the sensor electronics 220 form parasitic capacitances CJPBl and C_PB2. The parasitic capacitances C_PB1 and C_PB2 are modeled in parallel to the sensing capacitors C_S1 and C_S2.
The bond wires 230 couple the MEMS sensor 210 to the sensor electronics 220 along with one or more switches The switches of an embodiment include a first set of switches and a second set of switches. The first set of switches includes a first switch 2511 and a second switch 2512 The first switch 2511 of the first set is coupled to a first bond wire 231 and a first conductor or plate of the first capacitor C_S1 of the MEMS sensor 210. The second switch 2512 of the first set of switches is coupled to a second bond wire 232 and a second conductor of the second capacitor C_S2 of the MEMS sensor 210.
The second set of switches also includes a first switch 2521 and a second switch 2522 The first switch 2521 of the second set is coupled to the second bond wire 232 and the first conductor of the first capacitor C_S1 of the MEMS sensor The second switch 2522 of the second set of switches is coupled to the first bond wire and the second conductor of the second capacitor C_S2 of the MEMS sensor
The sensor electronics 220 of an embodiment include first circuitry 221 or electronics and second circuitry 222 The MEMS sensor outputs are coupled to the inputs of the first circuitry 221 using the bond wires 230 and the switches 2511-2512 and 2521-2522. Outputs of the first circuitry 221 are coupled to inputs of the second circuitry 222.
The switches of an embodiment also include switches in the coupling or connections between the first circuitry 221 and second circuitry 222 The first set of switches therefore can include a third switch 2513 and a fourth switch 2514. The third switch 2513 of the first set is coupled to a first output of the first circuitry 221 and a first input of the second circuitry 222. The fourth switch 2514 of the first set is coupled to a second output of the first circuitry 221 and a second input of the second circuitry 222.
Similarly, the second set of switches also includes a third switch 2523 and a fourth switch 2524. The third switch 2523 of the second set is coupled to the first output of the first circuitry 221 and the second input of the second circuitry 222. The fourth switch 2524 of the second set is coupled to the second output of the first circuitry 221 and the first input of the second circuitry 222
As described above, control signals (not shown) are coupled to each of the switches The control signals are configured to control coupling of the MEMS sensor 210 to the sensor electronics 220 via the switches. The controlled coupling resulting from the switches and control signals results in elimination or cancellation of errors introduced in the sensed output of the MEMS sensor by the bond wire. The control signals are also configured to control coupling of the first circuitry 221 and second circuitry 222 of the sensor electronics 220.
The control signals of an embodiment include a first control signal and a second control signal. The first control signal is coupled to the first set of switches (collectively include either switches 2511-2512 or switches 2511-2514), and is configured to control the first set of switches to a switch state. The second control signal is coupled to the second set of switches (collectively include either switches 2521-2522 or switches 2521-2524) and is configured to control the second set of switches to the switch state. The switch state includes a closed or conductive state and an open or non-conductive state but is not so limited. In an embodiment, the first control signal is configured to control the first set of switches to a state that is opposite a state of the second set of switches. For example, the first control signal
places the first set of switches in an open state while the second control signal places the second set of switches in a closed state. As another example, the first control signal places the first set of switches in a closed state while the second control signal places the second set of switches in an open state.
A phase is associated with each of the first and second control signals. As used herein, the control signals include signals having one of two phases Φl and Φ2. The phase relationship between a phase Φl of the first control signal and a phase Φ2 of the second control signal of an embodiment eliminates errors (e g., offset voltage, parasitic capacitance, etc.) introduced in the sensed output of the MEMS sensor by the bond wire The relationship between the control signals is described in detail below
Phases Φl and Φ2 as used herein each represent a time period which repeats with a pre-specified frequency For example, the system can be clocked with a clocking signal having a frequency of 1 kilohertz (kHz) and a period of 1 millisecond (ms). The period can be divided into two phases (Φl and Φ2) with each phase being approximately 0.5ms long.
A switch described herein with reference to phase Φl is closed (conductive) during phase Φl . The control signal that is applied to the switch corresponding to phase Φl can be a digital signal, for example, a high logic state (e.g., value "1") of the control signal corresponds to the system being in phase Φl
A switch described herein with reference to phase Φ2 is closed (conductive) during phase Φ2. The control signal that is applied to the switch corresponding to phase Φ2 can also be a digital signal, for example, a high logic state of the control signal corresponds to the system being in phase Φ2. While the example described herein associates a particular phase with a particular set of switches this only represents an instant in time, and at other instances of time during operations of the MEMS system the phase associated with a set of switches is opposite the phase shown and described in this example.
The MEMS system of an embodiment includes switches clocked by the control signals having phases Φl and Φ2 as described above. The control signal phases introduce chopping that results in separation from the MEMS sensor output of any offsets introduced by the connection of the MEMS sensor to the sensor electronics. This separation is done in the frequency domain but is not so limited. As a result of this switching scheme, the offsets or errors including, for example, low
frequency changes of parasitic capacitances C_PB1 and C_PB2 and the electronic offset voltage V_offset, are separated or canceled.
For purposes of the following example relationship between control signal phases, described with reference to Figure 2, it is assumed that a switch labeled with phase Φl is closed (conductive) during phase Φl. During phase Φl the voltage potential between the outputs of the first circuitry of the sensor electronics is
F1 = {ACS ■ gainc + ACP ■ gainc ) AV1n .
The variable ΔVm represents a voltage step applied by the sensor electronics. The variable ΔCS represents the changes in the sensing capacitance of sensing capacitors C_S1 and C_S2. The variable ΔCP represents the changes in the parasitic capacitance of parasitic capacitors C_PB1 and C PB2. The quantity gainc is a constant set by the ratio of two sensing capacitors C_S1 and C_S2. Therefore, during phase Φl the voltage potential between the inputs of the second circuitry of the sensor electronics is
V = V
During phase Φ2 the voltage potential between the outputs of the first circuitry of the sensor electronics is
Vx = (- ACS ■ gainc + ACP ■ gainc )- AVm .
Therefore, during phase Φ2 the voltage potential between the inputs of the second circuitry of the sensor electronics is
Substituting produces a result as follows
V2 = [ACS - gain, - ACP ■ gainc )- AV1n .
Generating an average of V2 over the phases Φl and Φ2 provides a result as follows
V2,avc)age = (V2M + V2 φ2)/2 = ACS ■ gain, - AV1n .
The result of the average of V2 over the phases Φl and Φ2 shows that any contribution of parasitic capacitance ΔCP has been eliminated. Similarly, any contribution of the offset voltage V_Offset that models the input referred offset of the first circuitry of the sensor electronics has been eliminated.
The switches on the MEMS die described herein have a resistance when closed. The resistance of the closed switches is referred to as on-resistance In a capacitive sensor like the MEMS sensor described above the value of the on- resistance only affects the time constant of the interface between the MEMS die and the electronics die , For example, in time discrete systems the on-resistance would affect the settling time of switched-capacitor amplifiers. Even if the on-resistance was on the order of 1 ,000 Ohms this would not affect the function of the system configurations described herein. Therefore switches with high on-resistance can be used with relatively little or no impact on the configurations described herein.
The switches of an embodiment include a relay structure, but are not so limited. Figure 3 is a top view of a switch 300 of the chopping system, under an embodiment. The MEMS sensor or MEMS die of an embodiment includes the switch 300 but the embodiments are not so limited. The switches 300 can be implemented for example using a MEMS process that uses Poly-Silicon as a structural material.
The switch 300 includes a movable beam MB having a first end that is fixed and a second end that is free and therefore moveable. A central portion or region of the movable beam MB is positioned between two fixed electrodes or terminals Fl and F2. Each of the fixed electrodes Fl and F2 is coupled to an energy source (not shown) described herein as the control signals. The second end of the movable beam MB is positioned between two output terminals OUTl and OUT2. The output terminals OUTl and OUT2 include mechanically fixed structures. The second end of the movable beam MB is configured to contact one or the other of the output terminals OUTl and OUT2 in response to a voltage applied to the fixed electrodes.
In operation, the movable beam MB can be switched between the output terminals OUTl and OUT2 by applying a voltage between MB and either the first
fixed electrode Fl or the second fixed electrode F2. For example if the control signals configure the movable beam MB to connect to output terminal OUTl, the voltage between the movable beam MB and fixed electrode Fl is higher than the voltage between the movable beam MB and fixed electrode F2. This generates a net electrostatic force which pulls the movable beam MB towards output terminal OUTl until the movable beam MB and output terminal OUTl make physical contact and the switch 300 is closed. Furthermore, if the control signals configure the movable beam MB to connect to output terminal OUT2, the voltage between the movable beam MB and fixed electrode F2 is higher than the voltage between the movable beam MB and fixed electrode Fl This generates a net electrostatic force which pulls the movable beam MB towards output terminal OUT2 until the movable beam MB and output terminal OUT2 make physical contact and the switch 300 is closed
The switches of an alternative embodiment include active electronic devices, but are not so limited As one example, the active electronic devices include but are not limited to transistors The active electronic devices can be integrated on the MEMS die but are not limited to integration on the MEMS die. For example, the active electronic devices can be integrated in the sensor electronics or on another substrate or device of the system.
The chopping systems of an embodiment include a system comprising a sensor including a sensing capacitor. The system of an embodiment includes sensing circuitry configured to receive signals from the sensor. The system of an embodiment includes at least one bond wire and at least one switch coupled to the sensor and the sensing circuitry. The system of an embodiment includes at least one control signal coupled to the at least one switch and configured to control the at least one switch to separate parasitic bond capacitance of the at least one bond wire from sensing capacitance of the sensor.
The capacitive sensor of the system of an embodiment includes a first capacitor and a second capacitor coupled in series.
The at least one switch of the system of an embodiment includes a first set of switches and a second set of switches.
The first set of switches of the system of an embodiment includes a first switch coupled to a first bond wire and a first conductor of the first capacitor and a second switch coupled to a second bond wire and a second conductor of the second capacitor. The second set of switches of the system of an embodiment includes a
third switch coupled to the second bond wire and the first conductor of the first capacitor and a fourth switch coupled to the first bond wire and the second conductor of the second capacitor.
The sensing circuitry of the system of an embodiment comprises first circuitry and second circuitry. The first circuitry of an embodiment is coupled to the at least one bond wire and the second circuitry
The first set of switches of the system of an embodiment includes a fifth switch and a sixth switch. The fifth switch of an embodiment is coupled to a first output of the first circuitry and a first input of the second circuitry. The sixth switch of an embodiment is coupled to a second output of the first circuitry and a second input of the second circuitry.
The second set of switches of the system of an embodiment includes a seventh switch and an eighth switch. The seventh switch of an embodiment is coupled to the first output of the first circuitry and the second input of the second circuitry. The eighth switch of an embodiment is coupled to the second output of the first circuitry and the first input of the second circuitry.
The at least one control signal of the system of an embodiment includes a first control signal coupled to the first set of switches and a second control signal coupled to the second set of switches.
The first control signal of the system of an embodiment is configured to control the first set of switches to a first state and the second control signal is configured to control the second set of switches to a second state. The first state of an embodiment is opposite the second state.
A phase relationship between the first control signal and the second control signal of the system of an embodiment eliminates one or more of an offset voltage between the sensor and the sensing circuitry and the parasitic bond capacitance
The at least one switch of the system of an embodiment comprises at least one transistor.
The at least one switch of the system of an embodiment comprises a relay including a movable beam positioned between a plurality of fixed electrodes
The system of an embodiment includes a first die including the sensor.
The system of an embodiment includes a second die including the sensing circuitry
Separating the parasitic bond capacitance from the sensing capacitance of an embodiment is a frequency domain separation.
The chopping systems of an embodiment include a system comprising a first circuit coupled to at least one switch. The system of an embodiment includes a bond wire coupled to the at least one switch The system of an embodiment includes a second circuit coupled to the bond wire. The system of an embodiment includes at least one control signal coupled to the at least one switch The at least one control signal of an embodiment is configured to control coupling of the first circuit to the second circuit via the switch to cancel a variable offset introduced by the bond wire in an output of the first circuit.
The variable offset of the system of an embodiment includes one or more of parasitic capacitance and offset voltage.
Canceling the variable offset of the system of an embodiment includes separating parasitic bond capacitance of the bond wire from capacitance of the first circuit
The system of an embodiment includes a third circuit coupled to second circuit via the at least one switch.
The chopping systems of an embodiment include a system comprising a first die including a first circuit. The system of an embodiment includes at least one switch coupled to the first circuit. The system of an embodiment includes a second die including a second circuit The system of an embodiment includes a bond wire coupled to the at least one switch and the second circuit. The system of an embodiment includes control signals coupled to the at least one switch The control signals of an embodiment are configured to control a connection of the first circuit to the second circuit via the switch to eliminate offsets introduced in an output of the first circuit by the coupling.
A phase relationship between different ones of the control signals of the system of an embodiment eliminates the offsets including one or more of a parasitic capacitance and an offset voltage
Aspects of the chopping systems described herein may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs), programmable array logic (PAL) devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific
integiated circuits (ASICs) Some other possibilities for implementing aspects of the chopping systems include: microcontrollers with memory (such as electronically erasable programmable read only memory (EEPROM)), embedded microprocessors, firmware, software, etc. Furthermore, aspects of the multi-analog receiver front end system may be embodied in microprocessors having software -based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. Of course the underlying device technologies may be provided in a variety of component types, e.g , metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter -coupled logic (ECL), polymer technologies (e g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, etc
The functions described herein can be performed by programs or sets of program codes, including software, firmware, executable code or instructions running on or otherwise being executed by one or more general-purpose computers or processor-based systems. The computers or other processor-based systems may include one or more central processing units for executing program code, volatile memory, such as RAM for temporarily storing data and data structures during program execution, non- volatile memory, such as a hard disc drive or optical drive, for storing programs and data, including databases and other data stores, and a network interface for accessing an intranet and/or the Internet. However, the functions described herein may also be implemented using special purpose computers, wireless computers, state machines, and/or hardwired electronic circuits.
It should be noted that components of the various systems and methods disclosed herein may be described using computer aided design tools and expressed (or represented), as data and/or instructions embodied in various computer-readable media, in terms of their behavioral, register transfer, logic component, transistor, layout geometries, and/or other characteristics. Formats of files and other objects in which such circuit expressions may be implemented include, but are not limited to, formats supporting behavioral languages such as C, Verilog, and HLDL, formats supporting register level description languages like RTL, and formats supporting geometry description languages such as GDSII, GDSIII, GDSIV, CIF, MEBES and any other suitable formats and languages.
Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof. Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the Internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, etc.) When received within a computer system via one or more computer -readable media, such data and/or instruction-based expressions of the above described systems and methods may be processed by a processing entity (e.g., one or more processors) within the computer system in conjunction with execution of one or more other computer programs including, without limitation, net-list generation programs, place and route programs and the like.
Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise," "comprising," and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of "including, but not limited to." Words using the singular or plural number also include the plural or singular number respectively, Additionally, the words "herein," "hereunder," "above," "below," and words of similar import refer to this application as a whole and not to any particular portions of this application. When the word "or" is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.
The above description of illustrated embodiments of the chopping systems is not intended to be exhaustive or to limit the chopping systems to the precise form disclosed. While specific embodiments of, and examples for, the chopping systems are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the chopping systems, as those skilled in the relevant art will recognize. The teachings of the chopping systems provided herein can be applied to other systems and methods, not only for the chopping systems described above
The elements and acts of the various embodiments described above can be combined to provide further1 embodiments. These and other changes can be made to the chopping systems in light of the above detailed description.
In general, in the following claims, the terms used should not be construed to limit the chopping systems to the specific embodiments disclosed in the specification and the claims, but should be construed to include all systems and methods that operate under the claims. Accordingly, the chopping systems are not limited by the disclosure, but instead the scope of the chopping systems is to be determined entirely by the claims
While certain aspects of the chopping systems are presented below in certain claim forms, the inventors contemplate the various aspects of the chopping systems in any number of claim forms. Accordingly, the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the chopping systems.
Claims
1. A system comprising: a sensor including a sensing capacitor; sensing circuitry configured to receive signals from the sensor; at least one bond wire and at least one switch coupled to the sensor and the sensing circuitry, and at least one control signal coupled to the at least one switch and configured to control the at least one switch to separate parasitic bond capacitance of the at least one bond wire from sensing capacitance of the sensor.
2. The system of claim 1, wherein the capacitive sensor includes a first capacitor and a second capacitor coupled in series.
3. The system of claim 2, wherein the at least one switch includes a first set of switches and a second set of switches.
4. The system of claim 3, wherein the first set of switches includes a first switch coupled to a first bond wire and a first conductor of the first capacitor and a second switch coupled to a second bond wire and a second conductor of the second capacitor
5 The system of claim 4, wherein the second set of switches includes a third switch coupled to the second bond wire and the first conductor of the first capacitor and a fourth switch coupled to the first bond wire and the second conductor of the second capacitor
6. The system of claim 1, wherein the sensing circuitry comprises first circuitry and second circuitry, wherein the first circuitry is coupled to the at least one bond wire and the second circuitry.
7 The system of claim 6, wherein the first set of switches includes a fifth switch and a sixth switch, wherein the fifth switch is coupled to a first output of the first circuitry and a first input of the second circuitry, wherein the sixth switch is coupled to a second output of the first circuitry and a second input of the second circuitry.
8. The system of claim 7, wherein the second set of switches includes a seventh switch and an eighth switch, wherein the seventh switch is coupled to the first output of the first circuitry and the second input of the second circuitry, wherein the eighth switch is coupled to the second output of the first circuitry and the first input of the second circuitry.
9. The system of claim 1, wherein the at least one control signal includes a first control signal coupled to the first set of switches and a second control signal coupled to the second set of switches.
10. The system of claim 9, wherein the first control signal is configured to control the first set of switches to a first state and the second control signal is configured to control the second set of switches to a second state, wherein the first state is opposite the second state
11. The system of claim 9, wherein a phase relationship between the first control signal and the second control signal eliminates one or more of an offset voltage between the sensor and the sensing circuitry and the parasitic bond capacitance
12. The system of claim 1, wherein the at least one switch comprises at least one transistor.
13 The system of claim 1 , wherein the at least one switch comprises a relay including a movable beam positioned between a plurality of fixed electrodes.
14. The system of claim 1, comprising a first die including the sensor.
15 The system of claim 14, comprising a second die including the sensing ciicuitry.
16 The system of claim 1, wherein separating the parasitic bond capacitance from the sensing capacitance is a frequency domain separation.
17 A system comprising' a first circuit coupled to at least one switch; a bond wire coupled to the at least one switch; a second circuit coupled to the bond wire; and at least one control signal coupled to the at least one switch, the at least one control signal configured to control coupling of the first circuit to the second circuit via the switch to cancel a variable offset introduced by the bond wire in an output of the fust circuit
18 The system of claim 17, wherein the variable offset includes one or more of parasitic capacitance and offset voltage.
19. The system of claim 17, wherein canceling the variable offset includes separating parasitic bond capacitance of the bond wire from capacitance of the first circuit.
20. The system of claim 17, comprising a third circuit coupled to second circuit via the at least one switch.
21. A system comprising: a first die including a first circuit; at least one switch coupled to the first circuit; a second die including a second circuit; a bond wire coupled to the at least one switch and the second circuit, and control signals coupled to the at least one switch, the control signals configured to control a connection of the first circuit to the second circuit via the switch to eliminate offsets introduced in an output of the first circuit by the coupling.
22 The system of claim 21, wherein a phase relationship between different ones of the control signals eliminates the offsets including one or more of a parasitic capacitance and an offset voltage.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP08832653.3A EP2193340B1 (en) | 2007-09-19 | 2008-08-20 | Cancelling low frequency errors in mems systems |
JP2010525869A JP5730017B2 (en) | 2007-09-19 | 2008-08-20 | Method and system for removing low frequency errors in MEMS systems |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/857,796 | 2007-09-19 | ||
US11/857,796 US7786738B2 (en) | 2007-09-19 | 2007-09-19 | Cancelling low frequency errors in MEMS systems |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2009038924A2 true WO2009038924A2 (en) | 2009-03-26 |
WO2009038924A3 WO2009038924A3 (en) | 2009-06-04 |
Family
ID=40453786
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2008/073727 WO2009038924A2 (en) | 2007-09-19 | 2008-08-20 | Cancelling low frequency errors in mems systems |
Country Status (4)
Country | Link |
---|---|
US (1) | US7786738B2 (en) |
EP (1) | EP2193340B1 (en) |
JP (1) | JP5730017B2 (en) |
WO (1) | WO2009038924A2 (en) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013033113A1 (en) * | 2011-08-29 | 2013-03-07 | Robert Bosch Gmbh | Surface charge reduction technique for capacitive sensors |
WO2013040084A1 (en) * | 2011-09-13 | 2013-03-21 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
WO2014016689A3 (en) * | 2012-07-25 | 2014-03-13 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
EP2775308A1 (en) * | 2013-03-07 | 2014-09-10 | Robert Bosch Gmbh | Pseudo-differential accelerometer with high electromagnetic interference rejection |
EP2647954A3 (en) * | 2012-04-05 | 2015-11-04 | Fairchild Semiconductor Corporation | Self test of mems gyroscope with asics integrated capacitors |
US9278846B2 (en) | 2010-09-18 | 2016-03-08 | Fairchild Semiconductor Corporation | Micromachined monolithic 6-axis inertial sensor |
US9444404B2 (en) | 2012-04-05 | 2016-09-13 | Fairchild Semiconductor Corporation | MEMS device front-end charge amplifier |
US9488693B2 (en) | 2012-04-04 | 2016-11-08 | Fairchild Semiconductor Corporation | Self test of MEMS accelerometer with ASICS integrated capacitors |
US9599472B2 (en) | 2012-02-01 | 2017-03-21 | Fairchild Semiconductor Corporation | MEMS proof mass with split Z-axis portions |
US9618361B2 (en) | 2012-04-05 | 2017-04-11 | Fairchild Semiconductor Corporation | MEMS device automatic-gain control loop for mechanical amplitude drive |
US9625272B2 (en) | 2012-04-12 | 2017-04-18 | Fairchild Semiconductor Corporation | MEMS quadrature cancellation and signal demodulation |
US9802814B2 (en) | 2012-09-12 | 2017-10-31 | Fairchild Semiconductor Corporation | Through silicon via including multi-material fill |
US9856132B2 (en) | 2010-09-18 | 2018-01-02 | Fairchild Semiconductor Corporation | Sealed packaging for microelectromechanical systems |
US10050155B2 (en) | 2010-09-18 | 2018-08-14 | Fairchild Semiconductor Corporation | Micromachined monolithic 3-axis gyroscope with single drive |
US10060757B2 (en) | 2012-04-05 | 2018-08-28 | Fairchild Semiconductor Corporation | MEMS device quadrature shift cancellation |
US10065851B2 (en) | 2010-09-20 | 2018-09-04 | Fairchild Semiconductor Corporation | Microelectromechanical pressure sensor including reference capacitor |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2466785B (en) | 2008-12-30 | 2011-06-08 | Wolfson Microelectronics Plc | Apparatus and method for testing a capacitive transducer and/or associated electronic circuitry |
DE102009026496B4 (en) | 2009-05-27 | 2022-04-28 | Robert Bosch Gmbh | Compensation capacitance for a capacitive sensor |
US8417867B2 (en) * | 2010-11-17 | 2013-04-09 | Xilinx, Inc. | Multichip module for communications |
DE102017102614A1 (en) * | 2017-02-09 | 2018-08-09 | Efaflex Tor- Und Sicherheitssysteme Gmbh & Co. Kg | Door panel crash detection system, door panel crash detection system, and door panel crash detection method |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6781468B1 (en) * | 2003-04-30 | 2004-08-24 | Agilent Technologies, Inc | Photo-amplifier circuit with improved power supply rejection |
US20060049506A1 (en) * | 2004-09-08 | 2006-03-09 | Denso Corporation | Capacitance type semiconductor sensor |
WO2008042015A2 (en) * | 2006-09-28 | 2008-04-10 | Medtronic, Inc. | Capacitive interface circuit for low power sensor system |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4167714A (en) * | 1978-03-20 | 1979-09-11 | Burroughs Corporation | Constant impedance transmission line routing network |
JP3216955B2 (en) * | 1994-05-31 | 2001-10-09 | 株式会社日立製作所 | Capacitive sensor device |
DE19650681C2 (en) * | 1996-12-06 | 2001-08-16 | Zentr Mikroelekt Dresden Gmbh | Capacitive sensor arrangement |
JP3732919B2 (en) * | 1996-12-19 | 2006-01-11 | トヨタ自動車株式会社 | Capacitive angle detector |
US5770802A (en) * | 1997-04-16 | 1998-06-23 | Texas Instruments Incorporated | Sensor with improved capacitive to voltage converter integrated circuit |
JP2000074939A (en) * | 1998-08-28 | 2000-03-14 | Denso Corp | Capacitive acceleration sensor |
JP2003028607A (en) * | 2001-07-12 | 2003-01-29 | Sony Corp | Capacitance detector and fingerprint collation apparatus using the same |
ITTO20010705A1 (en) * | 2001-07-18 | 2003-01-18 | St Microelectronics Srl | SELF-CALIBRATING OVER-SAMPLING ELECTROMECHANICAL MODULATOR AND RELATED SELF-CALIBRATION METHOD. |
US6744264B2 (en) * | 2002-04-25 | 2004-06-01 | Motorola, Inc. | Testing circuit and method for MEMS sensor packaged with an integrated circuit |
JP2004294071A (en) * | 2003-03-25 | 2004-10-21 | Denso Corp | Capacity type semiconductor sensor device |
DE10342472B4 (en) * | 2003-09-15 | 2008-01-31 | Infineon Technologies Ag | Circuit arrangement and method for testing a capacitance field in an integrated circuit |
JP4364609B2 (en) * | 2003-11-25 | 2009-11-18 | アルプス電気株式会社 | Capacitance detection circuit and fingerprint sensor using the same |
JP2006329778A (en) * | 2005-05-25 | 2006-12-07 | Mitsubishi Electric Corp | Capacity detection circuit |
US7288946B2 (en) * | 2005-06-03 | 2007-10-30 | Synaptics Incorporated | Methods and systems for detecting a capacitance using sigma-delta measurement techniques |
EP1918725B1 (en) * | 2005-08-25 | 2015-03-11 | Panasonic Corporation | Voltage monitor and electrical storage device using the same |
EP1793497B1 (en) * | 2005-12-02 | 2011-04-27 | STMicroelectronics Srl | Device and method for reading a capacitive sensor, in particular of a micro-electromechanical type |
US20090045822A1 (en) * | 2007-08-13 | 2009-02-19 | Windbond Electronics Corporation | Capacitive detection systems, modules and methods |
-
2007
- 2007-09-19 US US11/857,796 patent/US7786738B2/en active Active
-
2008
- 2008-08-20 EP EP08832653.3A patent/EP2193340B1/en active Active
- 2008-08-20 WO PCT/US2008/073727 patent/WO2009038924A2/en active Application Filing
- 2008-08-20 JP JP2010525869A patent/JP5730017B2/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6781468B1 (en) * | 2003-04-30 | 2004-08-24 | Agilent Technologies, Inc | Photo-amplifier circuit with improved power supply rejection |
US20060049506A1 (en) * | 2004-09-08 | 2006-03-09 | Denso Corporation | Capacitance type semiconductor sensor |
WO2008042015A2 (en) * | 2006-09-28 | 2008-04-10 | Medtronic, Inc. | Capacitive interface circuit for low power sensor system |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10050155B2 (en) | 2010-09-18 | 2018-08-14 | Fairchild Semiconductor Corporation | Micromachined monolithic 3-axis gyroscope with single drive |
US9856132B2 (en) | 2010-09-18 | 2018-01-02 | Fairchild Semiconductor Corporation | Sealed packaging for microelectromechanical systems |
US9278846B2 (en) | 2010-09-18 | 2016-03-08 | Fairchild Semiconductor Corporation | Micromachined monolithic 6-axis inertial sensor |
US10065851B2 (en) | 2010-09-20 | 2018-09-04 | Fairchild Semiconductor Corporation | Microelectromechanical pressure sensor including reference capacitor |
US8866498B2 (en) | 2011-08-29 | 2014-10-21 | Robert Bosch Gmbh | Surface charge reduction technique for capacitive sensors |
WO2013033113A1 (en) * | 2011-08-29 | 2013-03-07 | Robert Bosch Gmbh | Surface charge reduction technique for capacitive sensors |
US8860440B2 (en) | 2011-09-13 | 2014-10-14 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
US8854057B2 (en) | 2011-09-13 | 2014-10-07 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
WO2013040084A1 (en) * | 2011-09-13 | 2013-03-21 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
US9599472B2 (en) | 2012-02-01 | 2017-03-21 | Fairchild Semiconductor Corporation | MEMS proof mass with split Z-axis portions |
US9488693B2 (en) | 2012-04-04 | 2016-11-08 | Fairchild Semiconductor Corporation | Self test of MEMS accelerometer with ASICS integrated capacitors |
EP3315908A1 (en) * | 2012-04-05 | 2018-05-02 | Fairchild Semiconductor Corporation | Self test of mems gyroscope with asics integrated capacitors |
US9618361B2 (en) | 2012-04-05 | 2017-04-11 | Fairchild Semiconductor Corporation | MEMS device automatic-gain control loop for mechanical amplitude drive |
EP2647954A3 (en) * | 2012-04-05 | 2015-11-04 | Fairchild Semiconductor Corporation | Self test of mems gyroscope with asics integrated capacitors |
US10060757B2 (en) | 2012-04-05 | 2018-08-28 | Fairchild Semiconductor Corporation | MEMS device quadrature shift cancellation |
US9444404B2 (en) | 2012-04-05 | 2016-09-13 | Fairchild Semiconductor Corporation | MEMS device front-end charge amplifier |
US9625272B2 (en) | 2012-04-12 | 2017-04-18 | Fairchild Semiconductor Corporation | MEMS quadrature cancellation and signal demodulation |
WO2014016689A3 (en) * | 2012-07-25 | 2014-03-13 | Robert Bosch Gmbh | Scheme to achieve robustness to electromagnetic interference in inertial sensors |
US9802814B2 (en) | 2012-09-12 | 2017-10-31 | Fairchild Semiconductor Corporation | Through silicon via including multi-material fill |
EP2775308A1 (en) * | 2013-03-07 | 2014-09-10 | Robert Bosch Gmbh | Pseudo-differential accelerometer with high electromagnetic interference rejection |
Also Published As
Publication number | Publication date |
---|---|
US7786738B2 (en) | 2010-08-31 |
US20090072840A1 (en) | 2009-03-19 |
EP2193340B1 (en) | 2017-10-11 |
EP2193340A2 (en) | 2010-06-09 |
JP2010539514A (en) | 2010-12-16 |
JP5730017B2 (en) | 2015-06-03 |
WO2009038924A3 (en) | 2009-06-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2193340B1 (en) | Cancelling low frequency errors in mems systems | |
JP3498318B2 (en) | Capacitance detection system and method | |
US7109727B2 (en) | Capacitive physical quantity sensor | |
US5751154A (en) | capacitive sensor interface circuit | |
US5661240A (en) | Sampled-data interface circuit for capacitive sensors | |
US10338022B2 (en) | Sensor circuit and method for measuring a physical or chemical quantity | |
EP2508874B1 (en) | Capacitive sensor, integrated circuit, electronic device and method | |
US8310248B2 (en) | Capacitive sensor device | |
US5986497A (en) | Interface circuit for capacitive sensor | |
US10948444B2 (en) | Conductivity sensor | |
CN102318193A (en) | Wide region charge balance electric capacity digital quantizer | |
JP3265942B2 (en) | Micro capacitance detection circuit | |
CN111198217A (en) | Detection device, control method for detection device, and charge-voltage conversion circuit | |
CN111198215A (en) | Detection device | |
JP2582160B2 (en) | Sensor device | |
JP6362915B2 (en) | Sensor circuit configuration | |
US20090051656A1 (en) | Capacitance/voltage converting circuit, input apparatus using the same, electronic device, and capacitance/voltage converting method | |
JP6538929B2 (en) | Interface circuit for capacitive acceleration sensor | |
US10845329B2 (en) | Ion concentration distribution measuring device | |
CN111164774B (en) | Input device | |
US6323660B1 (en) | Integrated device for capacitive measuring of nanometer distances | |
JPH07243863A (en) | Capacity-type sensor | |
CN1421703A (en) | Capacitance measuring circuit structure and measurement method adopting the structure | |
CN112166313B (en) | Sensor device and method for operating a sensor device | |
Aezinia et al. | A low power CMOS integrated circuit for differential capacitive measurement |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 08832653 Country of ref document: EP Kind code of ref document: A2 |
|
REEP | Request for entry into the european phase |
Ref document number: 2008832653 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2008832653 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2010525869 Country of ref document: JP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |